WorldWideScience

Sample records for ccr5-restricted hiv-1 envelope

  1. Asn 362 in gp120 contributes to enhanced fusogenicity by CCR5-restricted HIV-1 envelope glycoprotein variants from patients with AIDS

    Directory of Open Access Journals (Sweden)

    Wang Bin

    2007-12-01

    Full Text Available Abstract Background CCR5-restricted (R5 human immunodeficiency virus type 1 (HIV-1 variants cause CD4+ T-cell loss in the majority of individuals who progress to AIDS, but mechanisms underlying the pathogenicity of R5 strains are poorly understood. To better understand envelope glycoprotein (Env determinants contributing to pathogenicity of R5 viruses, we characterized 37 full-length R5 Envs from cross-sectional and longitudinal R5 viruses isolated from blood of patients with asymptomatic infection or AIDS, referred to as pre-AIDS (PA and AIDS (A R5 Envs, respectively. Results Compared to PA-R5 Envs, A-R5 Envs had enhanced fusogenicity in quantitative cell-cell fusion assays, and reduced sensitivity to inhibition by the fusion inhibitor T-20. Sequence analysis identified the presence of Asn 362 (N362, a potential N-linked glycosylation site immediately N-terminal to CD4-binding site (CD4bs residues in the C3 region of gp120, more frequently in A-R5 Envs than PA-R5 Envs. N362 was associated with enhanced fusogenicity, faster entry kinetics, and increased sensitivity of Env-pseudotyped reporter viruses to neutralization by the CD4bs-directed Env mAb IgG1b12. Mutagenesis studies showed N362 contributes to enhanced fusogenicity of most A-R5 Envs. Molecular models indicate N362 is located adjacent to the CD4 binding loop of gp120, and suggest N362 may enhance fusogenicity by promoting greater exposure of the CD4bs and/or stabilizing the CD4-bound Env structure. Conclusion Enhanced fusogenicity is a phenotype of the A-R5 Envs studied, which was associated with the presence of N362, enhanced HIV-1 entry kinetics and increased CD4bs exposure in gp120. N362 contributes to fusogenicity of R5 Envs in a strain dependent manner. Our studies suggest enhanced fusogenicity of A-R5 Envs may contribute to CD4+ T-cell loss in subjects who progress to AIDS whilst harbouring R5 HIV-1 variants. N362 may contribute to this effect in some individuals.

  2. Enhanced CD4+ cellular apoptosis by CCR5-restricted HIV-1 envelope glycoprotein variants from patients with progressive HIV-1 infection

    International Nuclear Information System (INIS)

    CCR5-using (R5) human immunodeficiency virus type 1 (HIV-1) strains cause CD4+ T-cell loss in most infected individuals, but mechanisms underlying cytopathicity of R5 viruses are poorly understood. We investigated mechanisms contributing to R5 envelope glycoprotein (Env)-mediated cellular apoptosis by constructing a panel of retroviral vectors engineered to co-express GFP and R5 Envs derived from two HIV-1-infected subjects spanning asymptomatic (Early, E-R5 Envs) to late stages of infection (Late, L-R5 Envs). The L-R5 Envs induced significantly more cellular apoptosis than E-R5 Envs, but only in Env-expressing (GFP-positive) cells, and only in cells where CD4 and CCR5 levels were limiting. Studies with fusion-defective Env mutants showed induction of apoptosis required membrane-fusing events. Our results provide evidence for an intracellular mechanism of R5 Env-induced apoptosis of CD4+ cells that requires membrane fusion. Furthermore, they contribute to a better understanding of mechanisms involved in CD4+ T-cell loss in subjects experiencing progressive R5 HIV-1 infection.

  3. Structural basis for membrane anchoring of HIV-1 envelope spike.

    Science.gov (United States)

    Dev, Jyoti; Park, Donghyun; Fu, Qingshan; Chen, Jia; Ha, Heather Jiwon; Ghantous, Fadi; Herrmann, Tobias; Chang, Weiting; Liu, Zhijun; Frey, Gary; Seaman, Michael S; Chen, Bing; Chou, James J

    2016-07-01

    HIV-1 envelope spike (Env) is a type I membrane protein that mediates viral entry. We used nuclear magnetic resonance to determine an atomic structure of the transmembrane (TM) domain of HIV-1 Env reconstituted in bicelles that mimic a lipid bilayer. The TM forms a well-ordered trimer that protects a conserved membrane-embedded arginine. An amino-terminal coiled-coil and a carboxyl-terminal hydrophilic core stabilize the trimer. Individual mutations of conserved residues did not disrupt the TM trimer and minimally affected membrane fusion and infectivity. Major changes in the hydrophilic core, however, altered the antibody sensitivity of Env. These results show how a TM domain anchors, stabilizes, and modulates a viral envelope spike and suggest that its influence on Env conformation is an important consideration for HIV-1 immunogen design. PMID:27338706

  4. Glycosylation in HIV-1 envelope glycoprotein and its biological implications

    KAUST Repository

    Ho, Yung Shwen

    2013-08-01

    Glycosylation of HIV-1 envelope proteins (Env gp120/gp41) plays a vital role in viral evasion from the host immune response, which occurs through the masking of key neutralization epitopes and the presentation of the Env glycosylation as \\'self\\' to the host immune system. Env glycosylation is generally conserved, yet its continual evolution plays an important role in modulating viral infectivity and Env immunogenicity. Thus, it is believed that Env glycosylation, which is a vital part of the HIV-1 architecture, also controls intra- and inter-clade genetic variations. Discerning intra- and inter-clade glycosylation variations could therefore yield important information for understanding the molecular and biological differences between HIV clades and may assist in effectively designing Env-based immunogens and in clearly understanding HIV vaccines. This review provides an in-depth perspective of various aspects of Env glycosylation in the context of HIV-1 pathogenesis. © 2013 Future Medicine Ltd.

  5. Genotypic and functional properties of early infant HIV-1 envelopes

    Directory of Open Access Journals (Sweden)

    Sullivan John L

    2011-08-01

    Full Text Available Abstract Background Understanding the properties of HIV-1 variants that are transmitted from women to their infants is crucial to improving strategies to prevent transmission. In this study, 162 full-length envelope (env clones were generated from plasma RNA obtained from 5 HIV-1 Clade B infected mother-infant pairs. Following extensive genotypic and phylogenetic analyses, 35 representative clones were selected for functional studies. Results Infant quasispecies were highly homogeneous and generally represented minor maternal variants, consistent with transmission across a selective bottleneck. Infant clones did not differ from the maternal in env length, or glycosylation. All infant variants utilized the CCR5 co-receptor, but were not macrophage tropic. Relatively high levels (IC50 ≥ 100 μg/ml of autologous maternal plasma IgG were required to neutralize maternal and infant viruses; however, all infant viruses were neutralized by pooled sera from HIV-1 infected individuals, implying that they were not inherently neutralization-resistant. All infant viruses were sensitive to the HIV-1 entry inhibitors Enfuvirtide and soluble CD4; none were resistant to Maraviroc. Sensitivity to human monoclonal antibodies 4E10, 2F5, b12 and 2G12 varied. Conclusions This study provides extensive characterization of the genotypic and functional properties of HIV-1 env shortly after transmission. We present the first detailed comparisons of the macrophage tropism of infant and maternal env variants and their sensitivity to Maraviroc, the only CCR5 antagonist approved for therapeutic use. These findings may have implications for improving approaches to prevent mother-to-child HIV-1 transmission.

  6. Membrane topology analysis of HIV-1 envelope glycoprotein gp41

    Directory of Open Access Journals (Sweden)

    Xiao Dan

    2010-11-01

    Full Text Available Abstract Background The gp41 subunit of the HIV-1 envelope glycoprotein (Env has been widely regarded as a type I transmembrane protein with a single membrane-spanning domain (MSD. An alternative topology model suggested multiple MSDs. The major discrepancy between the two models is that the cytoplasmic Kennedy sequence in the single MSD model is assigned as the extracellular loop accessible to neutralizing antibodies in the other model. We examined the membrane topology of the gp41 subunit in both prokaryotic and mammalian systems. We attached topological markers to the C-termini of serially truncated gp41. In the prokaryotic system, we utilized a green fluorescent protein (GFP that is only active in the cytoplasm. The tag protein (HaloTag and a membrane-impermeable ligand specific to HaloTag was used in the mammalian system. Results In the absence of membrane fusion, both the prokaryotic and mammalian systems (293FT cells supported the single MSD model. In the presence of membrane fusion in mammalian cells (293CD4 cells, the data obtained seem to support the multiple MSD model. However, the region predicted to be a potential MSD is the highly hydrophilic Kennedy sequence and is least likely to become a MSD based on several algorithms. Further analysis revealed the induction of membrane permeability during membrane fusion, allowing the membrane-impermeable ligand and antibodies to cross the membrane. Therefore, we cannot completely rule out the possible artifacts. Addition of membrane fusion inhibitors or alterations of the MSD sequence decreased the induction of membrane permeability. Conclusions It is likely that a single MSD model for HIV-1 gp41 holds true even in the presence of membrane fusion. The degree of the augmentation of membrane permeability we observed was dependent on the membrane fusion and sequence of the MSD.

  7. Boosting of HIV-1 neutralizing antibody responses by a distally related retroviral envelope protein

    DEFF Research Database (Denmark)

    Uchtenhagen, Hannes; Schiffner, Torben; Bowles, Emma;

    2014-01-01

    Our knowledge of the binding sites for neutralizing Abs (NAb) that recognize a broad range of HIV-1 strains (bNAb) has substantially increased in recent years. However, gaps remain in our understanding of how to focus B cell responses to vulnerable conserved sites within the HIV-1 envelope...... glycoprotein (Env). In this article, we report an immunization strategy composed of a trivalent HIV-1 (clade B envs) DNA prime, followed by a SIVmac239 gp140 Env protein boost that aimed to focus the immune response to structurally conserved parts of the HIV-1 and simian immunodeficiency virus (SIV) Envs...

  8. Association of HIV-1 Envelope-Specific Breast Milk IgA Responses with Reduced Risk of Postnatal Mother-to-Child Transmission of HIV-1

    Science.gov (United States)

    Pollara, Justin; McGuire, Erin; Fouda, Genevieve G.; Rountree, Wes; Eudailey, Josh; Overman, R. Glenn; Seaton, Kelly E.; Deal, Aaron; Edwards, R. Whitney; Tegha, Gerald; Kamwendo, Deborah; Kumwenda, Jacob; Nelson, Julie A. E.; Liao, Hua-Xin; Brinkley, Christie; Denny, Thomas N.; Ochsenbauer, Christina; Ellington, Sascha; King, Caroline C.; Jamieson, Denise J.; van der Horst, Charles; Kourtis, Athena P.; Tomaras, Georgia D.; Ferrari, Guido

    2015-01-01

    ABSTRACT Infants born to HIV-1-infected mothers in resource-limited areas where replacement feeding is unsafe and impractical are repeatedly exposed to HIV-1 throughout breastfeeding. Despite this, the majority of infants do not contract HIV-1 postnatally, even in the absence of maternal antiretroviral therapy. This suggests that immune factors in breast milk of HIV-1-infected mothers help to limit vertical transmission. We compared the HIV-1 envelope-specific breast milk and plasma antibody responses of clade C HIV-1-infected postnatally transmitting and nontransmitting mothers in the control arm of the Malawi-based Breastfeeding Antiretrovirals and Nutrition Study using multivariable logistic regression modeling. We found no association between milk or plasma neutralization activity, antibody-dependent cell-mediated cytotoxicity, or HIV-1 envelope-specific IgG responses and postnatal transmission risk. While the envelope-specific breast milk and plasma IgA responses also did not reach significance in predicting postnatal transmission risk in the primary model after correction for multiple comparisons, subsequent exploratory analysis using two distinct assay methodologies demonstrated that the magnitudes of breast milk total and secretory IgA responses against a consensus HIV-1 envelope gp140 (B.con env03) were associated with reduced postnatal transmission risk. These results suggest a protective role for mucosal HIV-1 envelope-specific IgA responses in the context of postnatal virus transmission. This finding supports further investigations into the mechanisms by which mucosal IgA reduces risk of HIV-1 transmission via breast milk and into immune interventions aimed at enhancing this response. IMPORTANCE Infants born to HIV-1-infected mothers are repeatedly exposed to the virus in breast milk. Remarkably, the transmission rate is low, suggesting that immune factors in the breast milk of HIV-1-infected mothers help to limit transmission. We compared the antibody

  9. HIV-1 envelope subregion length variation during disease progression.

    Directory of Open Access Journals (Sweden)

    Marcel E Curlin

    Full Text Available The V3 loop of the HIV-1 Env protein is the primary determinant of viral coreceptor usage, whereas the V1V2 loop region is thought to influence coreceptor binding and participate in shielding of neutralization-sensitive regions of the Env glycoprotein gp120 from antibody responses. The functional properties and antigenicity of V1V2 are influenced by changes in amino acid sequence, sequence length and patterns of N-linked glycosylation. However, how these polymorphisms relate to HIV pathogenesis is not fully understood. We examined 5185 HIV-1 gp120 nucleotide sequence fragments and clinical data from 154 individuals (152 were infected with HIV-1 Subtype B. Sequences were aligned, translated, manually edited and separated into V1V2, C2, V3, C3, V4, C4 and V5 subregions. V1-V5 and subregion lengths were calculated, and potential N-linked glycosylation sites (PNLGS counted. Loop lengths and PNLGS were examined as a function of time since infection, CD4 count, viral load, and calendar year in cross-sectional and longitudinal analyses. V1V2 length and PNLGS increased significantly through chronic infection before declining in late-stage infection. In cross-sectional analyses, V1V2 length also increased by calendar year between 1984 and 2004 in subjects with early and mid-stage illness. Our observations suggest that there is little selection for loop length at the time of transmission; following infection, HIV-1 adapts to host immune responses through increased V1V2 length and/or addition of carbohydrate moieties at N-linked glycosylation sites. V1V2 shortening during early and late-stage infection may reflect ineffective host immunity. Transmission from donors with chronic illness may have caused the modest increase in V1V2 length observed during the course of the pandemic.

  10. IFITM Proteins Restrict HIV-1 Infection by Antagonizing the Envelope Glycoprotein

    Directory of Open Access Journals (Sweden)

    Jingyou Yu

    2015-10-01

    Full Text Available The interferon-induced transmembrane (IFITM proteins have been recently shown to restrict HIV-1 and other viruses. Here, we provide evidence that IFITM proteins, particularly IFITM2 and IFITM3, specifically antagonize the HIV-1 envelope glycoprotein (Env, thereby inhibiting viral infection. IFITM proteins interact with HIV-1 Env in viral producer cells, leading to impaired Env processing and virion incorporation. Notably, the level of IFITM incorporation into HIV-1 virions does not strictly correlate with the extent of inhibition. Prolonged passage of HIV-1 in IFITM-expressing T lymphocytes leads to emergence of Env mutants that overcome IFITM restriction. The ability of IFITMs to inhibit cell-to-cell infection can be extended to HIV-1 primary isolates, HIV-2 and SIVs; however, the extent of inhibition appears to be virus-strain dependent. Overall, our study uncovers a mechanism by which IFITM proteins specifically antagonize HIV-1 Env to restrict HIV-1 infection and provides insight into the specialized role of IFITMs in HIV infection.

  11. Phenotype and envelope gene diversity of nef-deleted HIV-1 isolated from long-term survivors infected from a single source

    Directory of Open Access Journals (Sweden)

    Sullivan John S

    2007-07-01

    Full Text Available Abstract Background The Sydney blood bank cohort (SBBC of long-term survivors consists of multiple individuals infected with attenuated, nef-deleted variants of human immunodeficiency virus type 1 (HIV-1 acquired from a single source. Long-term prospective studies have demonstrated that the SBBC now comprises slow progressors (SP as well as long-term nonprogressors (LTNP. Convergent evolution of nef sequences in SBBC SP and LTNP indicates the in vivo pathogenicity of HIV-1 in SBBC members is dictated by factors other than nef. To better understand mechanisms underlying the pathogenicity of nef-deleted HIV-1, we examined the phenotype and env sequence diversity of sequentially isolated viruses (n = 2 from 3 SBBC members. Results The viruses characterized here were isolated from two SP spanning a three or six year period during progressive HIV-1 infection (subjects D36 and C98, respectively and from a LTNP spanning a two year period during asymptomatic, nonprogressive infection (subject C18. Both isolates from D36 were R5X4 phenotype and, compared to control HIV-1 strains, replicated to low levels in peripheral blood mononuclear cells (PBMC. In contrast, both isolates from C98 and C18 were CCR5-restricted. Both viruses isolated from C98 replicated to barely detectable levels in PBMC, whereas both viruses isolated from C18 replicated to low levels, similar to those isolated from D36. Analysis of env by V1V2 and V3 heteroduplex tracking assay, V1V2 length polymorphisms, sequencing and phylogenetic analysis showed distinct intra- and inter-patient env evolution. Conclusion Independent evolution of env despite convergent evolution of nef may contribute to the in vivo pathogenicity of nef-deleted HIV-1 in SBBC members, which may not necessarily be associated with changes in replication capacity or viral coreceptor specificity.

  12. Uncleaved prefusion-optimized gp140 trimers derived from analysis of HIV-1 envelope metastability

    Science.gov (United States)

    Kong, Leopold; He, Linling; de Val, Natalia; Vora, Nemil; Morris, Charles D.; Azadnia, Parisa; Sok, Devin; Zhou, Bin; Burton, Dennis R.; Ward, Andrew B.; Wilson, Ian A.; Zhu, Jiang

    2016-06-01

    The trimeric HIV-1 envelope glycoprotein (Env) is critical for host immune recognition and neutralization. Despite advances in trimer design, the roots of Env trimer metastability remain elusive. Here we investigate the contribution of two Env regions to metastability. First, we computationally redesign a largely disordered bend in heptad region 1 (HR1) of SOSIP trimers that connects the long, central HR1 helix to the fusion peptide, substantially improving the yield of soluble, well-folded trimers. Structural and antigenic analyses of two distinct HR1 redesigns confirm that redesigned Env closely mimics the native, prefusion trimer with a more stable gp41. Next, we replace the cleavage site between gp120 and gp41 with various linkers in the context of an HR1 redesign. Electron microscopy reveals a potential fusion intermediate state for uncleaved trimers containing short but not long linkers. Together, these results outline a general approach for stabilization of Env trimers from diverse HIV-1 strains.

  13. Kinetic studies of HIV-1 and HIV-2 envelope glycoprotein-mediated fusion

    Directory of Open Access Journals (Sweden)

    Doms Robert W

    2006-12-01

    Full Text Available Abstract Background HIV envelope glycoprotein (Env-mediated fusion is driven by the concerted coalescence of the HIV gp41 N-helical and C-helical regions, which results in the formation of 6 helix bundles. Kinetics of HIV Env-mediated fusion is an important determinant of sensitivity to entry inhibitors and antibodies. However, the parameters that govern the HIV Env fusion cascade have yet to be fully elucidated. We address this issue by comparing the kinetics HIV-1IIIB Env with those mediated by HIV-2 from two strains with different affinities for CD4 and CXCR4. Results HIV-1 and HIV-2 Env-mediated cell fusion occurred with half times of about 60 and 30 min, respectively. Binding experiments of soluble HIV gp120 proteins to CD4 and co-receptor did not correlate with the differences in kinetics of fusion mediated by the three different HIV Envs. However, escape from inhibition by reagents that block gp120-CD4 binding, CD4-induced CXCR4 binding and 6-helix bundle formation, respectively, indicated large difference between HIV-1 and HIV-2 envelope glycoproteins in their CD4-induced rates of engagement with CXCR4. Conclusion The HIV-2 Env proteins studied here exhibited a significantly reduced window of time between the engagement of gp120 with CD4 and exposure of the CXCR4 binding site on gp120 as compared with HIV-1IIIB Env. The efficiency with which HIV-2 Env undergoes this CD4-induced conformational change is the major cause of the relatively rapid rate of HIV-2 Env mediated-fusion.

  14. DC-SIGN increases the affinity of HIV-1 envelope glycoprotein interaction with CD4.

    Directory of Open Access Journals (Sweden)

    Karolin Hijazi

    Full Text Available Mannose-binding C-type lectin receptors, expressed on Langerhans cells and subepithelial dendritic cells (DCs of cervico-vaginal tissues, play an important role in HIV-1 capture and subsequent dissemination to lymph nodes. DC-SIGN has been implicated in both productive infection of DCs and the DC-mediated trans infection of CD4(+ T cells that occurs in the absence of replication. However, the molecular events that underlie this efficient transmission have not been fully defined. In this study, we have examined the effect of the extracellular domains of DC-SIGN and Langerin on the stability of the interaction of the HIV-1 envelope glycoprotein with CD4 and also on replication in permissive cells. Surface plasmon resonance analysis showed that DC-SIGN increases the binding affinity of trimeric gp140 envelope glycoproteins to CD4. In contrast, Langerin had no effect on the stability of the gp140:CD4 complex. In vitro infection experiments to compare DC-SIGN enhancement of CD4-dependent and CD4-independent strains demonstrated significantly lower enhancement of the CD4-independent strain. In addition DC-SIGN increased the relative rate of infection of the CD4-dependent strain but had no effect on the CD4-independent strain. DC-SIGN binding to the HIV envelope protein effectively increases exposure of the CD4 binding site, which in turn contributes to enhancement of infection.

  15. Longitudinal Analysis of CCR5 and CXCR4 Usage in a Cohort of Antiretroviral Therapy-Naïve Subjects with Progressive HIV-1 Subtype C Infection

    DEFF Research Database (Denmark)

    Jakobsen, Martin Roelsgaard; Cashin, Kieran; Roche, Michael;

    2013-01-01

    HIV-1 subtype C (C-HIV) is responsible for most HIV-1 cases worldwide. Although the pathogenesis of C-HIV is thought to predominantly involve CCR5-restricted (R5) strains, we do not have a firm understanding of how frequently CXCR4-using (X4 and R5X4) variants emerge in subjects with progressive ...

  16. Use of silver nanoparticles increased inhibition of cell-associated HIV-1 infection by neutralizing antibodies developed against HIV-1 envelope proteins

    Directory of Open Access Journals (Sweden)

    Garza Treviño Elsa N

    2011-09-01

    Full Text Available Abstract Background HIV/AIDS pandemic is a worldwide public health issue. There is a need for new approaches to develop new antiviral compounds or other therapeutic strategies to limit viral transmission. The envelope glycoproteins gp120 and gp41 of HIV are the main targets for both silver nanoparticles (AgNPs and neutralizing antibodies. There is an urgency to optimize the efficiency of the neutralizing antibodies (NABs. In this study, we demonstrated that there is an additive effect between the four NABs and AgNPs when combined against cell-associated HIV-1 infection in vitro Results Four NABs (Monoclonal antibody to HIV-1 gp41 126-7, HIV-1 gp120 Antiserum PB1 Sub 2, HIV-1 gp120 Antiserum PB1, HIV-1 gp120 Monoclonal Antibody F425 B4e8 with or without AgNPs of 30-50 nm in size were tested against cell free and cell-associated HIVIIIB virus. All NABs inhibited HIV-1 cell free infection at a dose response manner, but with AgNPs an antiviral additive effect was not achieved Although there was no inhibition of infection with cell-associated virus by the NABs itself, AgNPs alone were able to inhibit cell associated virus infection and more importantly, when mixed together with NABs they inhibited the HIV-1 cell associated infection in an additive manner. Discussion The most attractive strategies to deal with the HIV problem are the development of a prophylactic vaccine and the development of effective topical vaginal microbicide. For two decades a potent vaccine that inhibits transmission of infection of HIV has been searched. There are vaccines that elicit NABs but none of them has the efficacy to stop transmission of HIV-1 infection. We propose that with the addition of AgNPs, NABs will have an additive effect and become more potent to inhibit cell-associated HIV-1 transmission/infection. Conclusions The addition of AgNPs to NABs has significantly increased the neutralizing potency of NABs in prevention of cell-associated HIV-1 transmission

  17. Cryoelectron tomography of HIV-1 envelope spikes: further evidence for tripod-like legs.

    Directory of Open Access Journals (Sweden)

    Ping Zhu

    2008-11-01

    Full Text Available A detailed understanding of the morphology of the HIV-1 envelope (Env spike is key to understanding viral pathogenesis and for informed vaccine design. We have previously presented a cryoelectron microscopic tomogram (cryoET of the Env spikes on SIV virions. Several structural features were noted in the gp120 head and gp41 stalk regions. Perhaps most notable was the presence of three splayed legs projecting obliquely from the base of the spike head toward the viral membrane. Subsequently, a second 3D image of SIV spikes, also obtained by cryoET, was published by another group which featured a compact vertical stalk. We now report the cryoET analysis of HIV-1 virion-associated Env spikes using enhanced analytical cryoET procedures. More than 2,000 Env spike volumes were initially selected, aligned, and sorted into structural classes using algorithms that compensate for the "missing wedge" and do not impose any symmetry. The results show varying morphologies between structural classes: some classes showed trimers in the head domains; nearly all showed two or three legs, though unambiguous three-fold symmetry was not observed either in the heads or the legs. Subsequently, clearer evidence of trimeric head domains and three splayed legs emerged when head and leg volumes were independently aligned and classified. These data show that HIV-1, like SIV, also displays the tripod-like leg configuration, and, unexpectedly, shows considerable gp41 leg flexibility/heteromorphology. The tripod-like model for gp41 is consistent with, and helps explain, many of the unique biophysical and immunological features of this region.

  18. Expanded breadth of the T-cell response to mosaic HIV-1 envelope DNA vaccination

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette [Los Alamos National Laboratory; Fischer, William [Los Alamos National Laboratory; Wallstrom, Timothy [Los Alamos National Laboratory

    2009-01-01

    An effective AIDS vaccine must control highly diverse circulating strains of HIV-1. Among HIV -I gene products, the envelope (Env) protein contains variable as well as conserved regions. In this report, an informatic approach to the design of T-cell vaccines directed to HIV -I Env M group global sequences was tested. Synthetic Env antigens were designed to express mosaics that maximize the inclusion of common potential Tcell epitope (PTE) 9-mers and minimize the inclusion of rare epitopes likely to elicit strain-specific responses. DNA vaccines were evaluated using intracellular cytokine staining (ICS) in inbred mice with a standardized panel of highly conserved 15-mer PTE peptides. I, 2 and 3 mosaic sets were developed that increased theoretical epitope coverage. The breadth and magnitude ofT-cell immunity stimulated by these vaccines were compared to natural strain Env's; additional comparisons were performed on mutant Env's, including gpl60 or gpl45 with or without V regions and gp41 deletions. Among them, the 2 or 3 mosaic Env sets elicited the optimal CD4 and CD8 responses. These responses were most evident in CD8 T cells; the 3 mosaic set elicited responses to an average of 8 peptide pools compared to 2 pools for a set of3 natural Env's. Synthetic mosaic HIV -I antigens can therefore induce T-cell responses with expanded breadth and may facilitate the development of effective T -cell-based HIV -1 vaccines.

  19. Elite suppressor-derived HIV-1 envelope glycoproteins exhibit reduced entry efficiency and kinetics.

    Directory of Open Access Journals (Sweden)

    Kara G Lassen

    2009-04-01

    Full Text Available Elite suppressors (ES are a rare subset of HIV-1-infected individuals who are able to maintain HIV-1 viral loads below the limit of detection by ultra-sensitive clinical assays in the absence of antiretroviral therapy. Mechanism(s responsible for this elite control are poorly understood but likely involve both host and viral factors. This study assesses ES plasma-derived envelope glycoprotein (env fitness as a function of entry efficiency as a possible contributor to viral suppression. Fitness of virus entry was first evaluated using a novel inducible cell line with controlled surface expression levels of CD4 (receptor and CCR5 (co-receptor. In the context of physiologic CCR5 and CD4 surface densities, ES envs exhibited significantly decreased entry efficiency relative to chronically infected viremic progressors. ES envs also demonstrated slow entry kinetics indicating the presence of virus with reduced entry fitness. Overall, ES env clones were less efficient at mediating entry than chronic progressor envs. Interestingly, acute infection envs exhibited an intermediate phenotypic pattern not distinctly different from ES or chronic progressor envs. These results imply that lower env fitness may be established early and may directly contribute to viral suppression in ES individuals.

  20. Contribution of intrinsic reactivity of the HIV-1 envelope glycoproteins to CD4-independent infection and global inhibitor sensitivity.

    Directory of Open Access Journals (Sweden)

    Hillel Haim

    2011-06-01

    Full Text Available Human immunodeficiency virus (HIV-1 enters cells following sequential activation of the high-potential-energy viral envelope glycoprotein trimer by target cell CD4 and coreceptor. HIV-1 variants differ in their requirements for CD4; viruses that can infect coreceptor-expressing cells that lack CD4 have been generated in the laboratory. These CD4-independent HIV-1 variants are sensitive to neutralization by multiple antibodies that recognize different envelope glycoprotein epitopes. The mechanisms underlying CD4 independence, global sensitivity to neutralization and the association between them are still unclear. By studying HIV-1 variants that differ in requirements for CD4, we investigated the contribution of CD4 binding to virus entry. CD4 engagement exposes the coreceptor-binding site and increases the "intrinsic reactivity" of the envelope glycoproteins; intrinsic reactivity describes the propensity of the envelope glycoproteins to negotiate transitions to lower-energy states upon stimulation. Coreceptor-binding site exposure and increased intrinsic reactivity promote formation/exposure of the HR1 coiled coil on the gp41 transmembrane glycoprotein and allow virus entry upon coreceptor binding. Intrinsic reactivity also dictates the global sensitivity of HIV-1 to perturbations such as exposure to cold and the binding of antibodies and small molecules. Accordingly, CD4 independence of HIV-1 was accompanied by increased susceptibility to inactivation by these factors. We investigated the role of intrinsic reactivity in determining the sensitivity of primary HIV-1 isolates to inhibition. Relative to the more common neutralization-resistant ("Tier 2-like" viruses, globally sensitive ("Tier 1" viruses exhibited increased intrinsic reactivity, i.e., were inactivated more efficiently by cold exposure or by a given level of antibody binding to the envelope glycoprotein trimer. Virus sensitivity to neutralization was dictated both by the efficiency of

  1. HIV-1 envelope, integrins and co-receptor use in mucosal transmission of HIV

    Directory of Open Access Journals (Sweden)

    Cicala Claudia

    2010-01-01

    Full Text Available Abstract It is well established that HIV-1 infection typically involves an interaction between the viral envelope protein gp120/41 and the CD4 molecule followed by a second interaction with a chemokine receptor, usually CCR5 or CXCR4. In the early stages of an HIV-1 infection CCR5 using viruses (R5 viruses predominate. In some viral subtypes there is a propensity to switch to CXCR4 usage (X4 viruses. The receptor switch occurs in ~ 40% of the infected individuals and is associated with faster disease progression. This holds for subtypes B and D, but occurs less frequently in subtypes A and C. There are several hypotheses to explain the preferential transmission of R5 viruses and the mechanisms that lead to switching of co-receptor usage; however, there is no definitive explanation for either. One important consideration regarding transmission is that signaling by R5 gp120 may facilitate transmission of R5 viruses by inducing a permissive environment for HIV replication. In the case of sexual transmission, infection by HIV requires the virus to breach the mucosal barrier to gain access to the immune cell targets that it infects; however, the immediate events that follow HIV exposure at genital mucosal sites are not well understood. Upon transmission, the HIV quasispecies that is replicating in an infected donor contracts through a “genetic bottleneck”, and often infection results from a single infectious event. Many details surrounding this initial infection remain unresolved. In mucosal tissues, CD4+ T cells express high levels of CCR5, and a subset of these CD4+/CCR5high cells express the integrin α4β7, the gut homing receptor. CD4+/CCR5high/ α4β7high T cells are highly susceptible to infection by HIV-1 and are ideal targets for an efficient productive infection at the point of transmission. In this context we have demonstrated that the HIV-1 envelope protein gp120 binds to α4β7 on CD4+ T cells. On CD4+/CCR5high/ α4β7high T cells,

  2. Genetic and functional analysis of a set of HIV-1 envelope genes obtained from biological clones with varying syncytium-inducing capacities.

    NARCIS (Netherlands)

    A.C. Andeweg (Arno); M. Groenink (Maarten); P. Leeflang; R.E.Y. de Goede; A.D.M.E. Osterhaus (Ab); M. Tersmette; M.L. Bosch (Marnix)

    1992-01-01

    textabstractTo study HIV-1 envelope-mediated syncytium formation we have amplified, cloned, expressed, and sequenced individual envelope genes from a set of eight biological HIV-1 clones. These clones were obtained from two patients and display either a syncytium-inducing (SI) or nonsyncytium-induci

  3. Envelope glycoproteins of HIV-1, HIV-2, and SIV purified with Galanthus nivalis agglutinin induce strong immune responses.

    Science.gov (United States)

    Gilljam, G

    1993-05-01

    Lectin affinity chromatography was used to purify in a single step the envelope glycoproteins of HIV-1, HIV-2, and SIV. Envelope glycoproteins carry the major determinants essential for protection by the humoral immune response. The purification of these proteins has previously been a laborious procedure. The glycoproteins were purified by a one-step procedure to a high level of purity by using Galanthus nivalis agglutinin (GNA). The purified glycoprotein had CD4-binding and antigenic reactivities. Strong immune responses to envelope proteins and peptides were seen in mice and primates after immunization with these preparations.

  4. Single genome amplification and standard bulk PCR yield HIV-1 envelope products with similar genotypic and phenotypic characteristics.

    Science.gov (United States)

    Etemad, Behzad; Ghulam-Smith, Melissa; Gonzalez, Oscar; White, Laura F; Sagar, Manish

    2015-03-01

    Recent studies suggest that single genome amplification (SGA) as compared to standard bulk PCR and virus stocks from 293T transfection versus short term passage in peripheral blood mononuclear cells (PBMC) yield a less biased representation of HIV-1 envelope characteristics. In 9 different subjects, genetic diversity, divergence, and population structure were not significantly different among SGA or bulk PCR amplified envelope V1-V3 segments. In these subjects, 293T transfection derived virus stocks with SGA or bulk PCR amplified envelopes have similar infectivity, replication kinetics, co-receptor usage, and neutralization susceptibility. While PBMC passage as compared to the 293T derived virus stocks had similar co-receptor usage, PBMC viruses were less neutralization susceptible to some specific antibodies. Our results suggest that the method of envelope sequence amplification, either SGA or bulk PCR, does not have a significant impact on the genotypic and phenotypic properties of the virus envelope quasispecies. PMID:25681527

  5. A sensitive HIV-1 envelope induced fusion assay identifies fusion enhancement of thrombin

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, De-Chun; Zhong, Guo-Cai; Su, Ju-Xiang [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Liu, Yan-Hong [Second Affiliated Hospital of Harbin Medical University, 246 Xuefu Road, Harbin, Heilongjiang 150081 (China); Li, Yan; Wang, Jia-Ye [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Hattori, Toshio [Department of Emerging Infectious Diseases, Division of Internal Medicine, Graduate School of Medicine, Tohoku University, Sendai 9808574 (Japan); Ling, Hong, E-mail: lingh@ems.hrbmu.edu.cn [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Department of Parasitology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Key Lab of Heilongjiang Province for Infection and Immunity, Key Lab of Heilongjiang Province Education Bureau for Etiology, Harbin, Heilongjiang 150081 (China); Zhang, Feng-Min, E-mail: fengminzhang@yahoo.com.cn [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Key Lab of Heilongjiang Province for Infection and Immunity, Key Lab of Heilongjiang Province Education Bureau for Etiology, Harbin, Heilongjiang 150081 (China)

    2010-01-22

    To evaluate the interaction between HIV-1 envelope glycoprotein (Env) and target cell receptors, various cell-cell-fusion assays have been developed. In the present study, we established a novel fusion system. In this system, the expression of the sensitive reporter gene, firefly luciferase (FL) gene, in the target cells was used to evaluate cell fusion event. Simultaneously, constitutively expressed Renilla luciferase (RL) gene was used to monitor effector cell number and viability. FL gave a wider dynamic range than other known reporters and the introduction of RL made the assay accurate and reproducible. This system is especially beneficial for investigation of potential entry-influencing agents, for its power of ruling out the false inhibition or enhancement caused by the artificial cell-number variation. As a case study, we applied this fusion system to observe the effect of a serine protease, thrombin, on HIV Env-mediated cell-cell fusion and have found the fusion enhancement activity of thrombin over two R5-tropic HIV strains.

  6. Composition and Antigenic Effects of Individual Glycan Sites of a Trimeric HIV-1 Envelope Glycoprotein

    Directory of Open Access Journals (Sweden)

    Anna-Janina Behrens

    2016-03-01

    Full Text Available The HIV-1 envelope glycoprotein trimer is covered by an array of N-linked glycans that shield it from immune surveillance. The high density of glycans on the trimer surface imposes steric constraints limiting the actions of glycan-processing enzymes, so that multiple under-processed structures remain on specific areas. These oligomannose glycans are recognized by broadly neutralizing antibodies (bNAbs that are not thwarted by the glycan shield but, paradoxically, target it. Our site-specific glycosylation analysis of a soluble, recombinant trimer (BG505 SOSIP.664 maps the extremes of simplicity and diversity of glycan processing at individual sites and reveals a mosaic of dense clusters of oligomannose glycans on the outer domain. Although individual sites usually minimally affect the global integrity of the glycan shield, we identify examples of how deleting some glycans can subtly influence neutralization by bNAbs that bind at distant sites. The network of bNAb-targeted glycans should be preserved on vaccine antigens.

  7. Composition and Antigenic Effects of Individual Glycan Sites of a Trimeric HIV-1 Envelope Glycoprotein

    Science.gov (United States)

    Behrens, Anna-Janina; Vasiljevic, Snezana; Pritchard, Laura K.; Harvey, David J.; Andev, Rajinder S.; Krumm, Stefanie A.; Struwe, Weston B.; Cupo, Albert; Kumar, Abhinav; Zitzmann, Nicole; Seabright, Gemma E.; Kramer, Holger B.; Spencer, Daniel I.R.; Royle, Louise; Lee, Jeong Hyun; Klasse, Per J.; Burton, Dennis R.; Wilson, Ian A.; Ward, Andrew B.; Sanders, Rogier W.; Moore, John P.; Doores, Katie J.; Crispin, Max

    2016-01-01

    Summary The HIV-1 envelope glycoprotein trimer is covered by an array of N-linked glycans that shield it from immune surveillance. The high density of glycans on the trimer surface imposes steric constraints limiting the actions of glycan-processing enzymes, so that multiple under-processed structures remain on specific areas. These oligomannose glycans are recognized by broadly neutralizing antibodies (bNAbs) that are not thwarted by the glycan shield but, paradoxically, target it. Our site-specific glycosylation analysis of a soluble, recombinant trimer (BG505 SOSIP.664) maps the extremes of simplicity and diversity of glycan processing at individual sites and reveals a mosaic of dense clusters of oligomannose glycans on the outer domain. Although individual sites usually minimally affect the global integrity of the glycan shield, we identify examples of how deleting some glycans can subtly influence neutralization by bNAbs that bind at distant sites. The network of bNAb-targeted glycans should be preserved on vaccine antigens. PMID:26972002

  8. Molecular motions and conformational transition between different conformational states of HIV-1 gp120 envelope glycoprotein

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The HIV-1 gp120 exterior envelope glycoprotein undergoes a series of conformational rearrangements while sequentially interacting with the receptor CD4 and coreceptor CCR5 or CXCR4 on the surface of host cells to initiate virus entry. Both the crystal structures of the HIV-1 gp120 core bound by the CD4 and antigen 17b and the SIV gp120 core prebound by CD4 are known. Despite the wealth of knowledge on these static snapshots of molecular conformations, the details of molecular motions involved in conformational transition that are crucial to intervention remain elusive. We presented comprehensive comparative analyses of the dynamics behaviors of the gp120 in its CD4-complexed, CD4-free and CD4-unliganded states based on the homology models with modeled V3 and V4 loops by means of CONCOORD computer simulation to generate ensembles of feasible protein structures that were subsequently analysed by essential dynamics analyses to identify preferred concerted motions. The revealed collective fluctuations are dominated by complex modes of combinational motions of the rotation/twisting, flexing/closure, and shortness/elongation between or within the inner, outer, and bridging-sheet domains, and these modes are related to the CD4 association and HIV neutralization avoidance. Further essential subspace overlap analyses were performed to quantitatively distinguish the preference for conformational transitions between the three states, revealing that the unliganded gp120 has a greater potential to translate its conformation into the conformational state adopted by the CD4-complexed gp120 than by the CD4-free gp120, whereas the CD4-free gp120 has a greater potential to translate its conformation into the unliganded state than the CD4-complexed gp120 does. These dy-namics data of gp120 in its different conformations are helpful in understanding the relationship be-tween the molecular motion/conformational transition and the function of gp120, and in gp120-structure-based subunit

  9. Temporal expression of HIV-1 envelope proteins in baculovirus-infected insect cells: Implications for glycosylation and CD4 binding

    International Nuclear Information System (INIS)

    Three different human immunodeficiency virus type I (HIV-1) envelope derived recombinant proteins and the full length human CD4 polypeptide were expressed in Spodoptera frugiperda (Sf9) cells. DNA constructs encoding CD4, gp120, gp160, and gp160 delta were cloned into the baculovirus expression vector pVL941 or a derivative and used to generate recombinant viruses in a cotransfection with DNA from Autographa californica nuclear polyhedrosis virus (AcMNPV). Western blotting of cell extracts of the recombinant HIV-1 proteins showed that for each construct two major bands specifically reacted with anti-HIV-1 envelope antiserum. These bands corresponded to glycosylated and nonglycosylated versions of the HIV proteins as determined by 3H-mannose labeling and tunicamycin treatment of infected cells. A time course of HIV envelope expression revealed that at early times post-infection (24 hours) the proteins were fully glycosylated and soluble in nonionic detergents. However, at later times postinfection (48 hours), expression levels of recombinant protein reached a maximum but most of the increase was due to a rise in the level of the nonglycosylated species, which was largely insoluble in nonionic detergents. Thus, it appears that Sf9 cells cannot process large amounts of glycosylated recombinant proteins efficiently. As a measure of biological activity, the CD4 binding ability of both glycosylated and nonglycosylated recombinant HIV envelope proteins was tested in a coimmunoprecipitation assay. The results showed that CD4 and the glycosylated versions of recombinant gp120 or gp160 delta specifically associated with one another in this analysis. Nonglycosylated gp120 or gp160 delta proteins from tunicamycin-treated cultures did immunoprecipitate with anti-HIV-1 antiserum but did not interact with CD4

  10. HIV-1 Envelope Proteins Complete Their Folding into Six-helix Bundles Immediately after Fusion Pore Formation

    OpenAIRE

    Markosyan, Ruben M; Cohen, Fredric S.; Melikyan, Grigory B.

    2003-01-01

    Fusion proteins of many viruses, including HIV-1 envelope protein (Env), fold into six-helix bundle structures. Fusion between individual Env-expressing cells and target cells was studied by fluorescence microscopy, and a temperature jump technique, to determine whether folding of Env into a bundle is complete by the time fusion pores have formed. Lowering temperature to 4°C immediately after a pore opened halted pore growth, which quickly resumed when temperature was raised again. HIV gp41-d...

  11. The intracellular production and secretion of HIV-1 envelope protein in the methylotrophic yeast Pichia pastoris.

    Science.gov (United States)

    Scorer, C A; Buckholz, R G; Clare, J J; Romanos, M A

    1993-12-22

    The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein, gp120 (ENV), is required in large quantities for immunological studies and as a potential vaccine component. We have expressed the DNA encoding gp120 in a highly efficient expression system based on the methylotrophic yeast, Pichia pastoris. The native gene was found to contain a sequence which resembled a Saccharomyces cerevisiae polyadenylation consensus and acted as a premature polyadenylation site in P. pastoris, resulting in the production of truncated mRNA. As full-length mRNA was produced in S. cerevisiae, this indicates differences in mRNA 3'-end formation between the two yeasts. Inactivation of this site by site-directed mutagenesis revealed several additional fortuitous polyadenylation sites within the gene. We have designed and constructed a 69%-synthetic gene with increased G + C content which overcomes this transcriptional problem, giving rise to full-length mRNA. High levels of intracellular, insoluble, unglycosylated ENV were produced [1.25 mg/ml in high-density (2 x 10(10) cells per ml) fermentations]. ENV also was secreted from P. pastoris using the S. cerevisiae alpha-factor prepro secretion leader and the S. cerevisiae invertase signal sequence. However, a high proportion of the secreted product was found to be hyperglycosylated, in contrast to other foreign proteins secreted from P. pastoris. There also was substantial proteolytic degradation, but this was minimized by maintaining a low pH on induction. Insoluble, yeast-derived ENV proteins are being considered as vaccine antigens and the P. pastoris system offers an efficient method of production. PMID:8293993

  12. An evolutionary-network model reveals stratified interactions in the V3 loop of the HIV-1 envelope.

    Directory of Open Access Journals (Sweden)

    Art F Y Poon

    2007-11-01

    Full Text Available The third variable loop (V3 of the human immunodeficiency virus type 1 (HIV-1 envelope is a principal determinant of antibody neutralization and progression to AIDS. Although it is undoubtedly an important target for vaccine research, extensive genetic variation in V3 remains an obstacle to the development of an effective vaccine. Comparative methods that exploit the abundance of sequence data can detect interactions between residues of rapidly evolving proteins such as the HIV-1 envelope, revealing biological constraints on their variability. However, previous studies have relied implicitly on two biologically unrealistic assumptions: (1 that founder effects in the evolutionary history of the sequences can be ignored, and; (2 that statistical associations between residues occur exclusively in pairs. We show that comparative methods that neglect the evolutionary history of extant sequences are susceptible to a high rate of false positives (20%-40%. Therefore, we propose a new method to detect interactions that relaxes both of these assumptions. First, we reconstruct the evolutionary history of extant sequences by maximum likelihood, shifting focus from extant sequence variation to the underlying substitution events. Second, we analyze the joint distribution of substitution events among positions in the sequence as a Bayesian graphical model, in which each branch in the phylogeny is a unit of observation. We perform extensive validation of our models using both simulations and a control case of known interactions in HIV-1 protease, and apply this method to detect interactions within V3 from a sample of 1,154 HIV-1 envelope sequences. Our method greatly reduces the number of false positives due to founder effects, while capturing several higher-order interactions among V3 residues. By mapping these interactions to a structural model of the V3 loop, we find that the loop is stratified into distinct evolutionary clusters. We extend our model to

  13. Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques

    Directory of Open Access Journals (Sweden)

    Roger Le Grand

    2013-07-01

    Full Text Available HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb. We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

  14. Functional stability of unliganded envelope glycoprotein spikes among isolates of human immunodeficiency virus type 1 (HIV-1.

    Directory of Open Access Journals (Sweden)

    Nitish Agrawal

    Full Text Available The HIV-1 envelope glycoprotein (Env spike is challenging to study at the molecular level, due in part to its genetic variability, structural heterogeneity and lability. However, the extent of lability in Env function, particularly for primary isolates across clades, has not been explored. Here, we probe stability of function for variant Envs of a range of isolates from chronic and acute infection, and from clades A, B and C, all on a constant virus backbone. Stability is elucidated in terms of the sensitivity of isolate infectivity to destabilizing conditions. A heat-gradient assay was used to determine T(90 values, the temperature at which HIV-1 infectivity is decreased by 90% in 1 h, which ranged between ∼40 to 49°C (n = 34. For select Envs (n = 10, the half-lives of infectivity decay at 37°C were also determined and these correlated significantly with the T(90 (p = 0.029, though two 'outliers' were identified. Specificity in functional Env stability was also evident. For example, Env variant HIV-1(ADA was found to be labile to heat, 37°C decay, and guanidinium hydrochloride but not to urea or extremes of pH, when compared to its thermostable counterpart, HIV-1(JR-CSF. Blue native PAGE analyses revealed that Env-dependent viral inactivation preceded complete dissociation of Env trimers. The viral membrane and membrane-proximal external region (MPER of gp41 were also shown to be important for maintaining trimer stability at physiological temperature. Overall, our results indicate that primary HIV-1 Envs can have diverse sensitivities to functional inactivation in vitro, including at physiological temperature, and suggest that parameters of functional Env stability may be helpful in the study and optimization of native Env mimetics and vaccines.

  15. Broader HIV-1 neutralizing antibody responses induced by envelope glycoprotein mutants based on the EIAV attenuated vaccine

    Directory of Open Access Journals (Sweden)

    Liu Lianxing

    2010-09-01

    Full Text Available Abstract Background In order to induce a potent and cross-reactive neutralizing antibody (nAb, an effective envelope immunogen is crucial for many viral vaccines, including the vaccine for the human immunodeficiency virus (HIV. The Chinese equine infectious anemia virus (EIAV attenuated vaccine has controlled the epidemic of this virus after its vaccination in over 70 million equine animals during the last 3 decades in China. Data from our past studies demonstrate that the Env protein of this vaccine plays a pivotal role in protecting horses from both homologous and heterogeneous EIAV challenges. Therefore, the amino acid sequence information from the Chinese EIAV attenuated vaccine, in comparison with the parental wild-type EIAV strains, was applied to modify the corresponding region of the envelope glycoprotein of HIV-1 CN54. The direction of the mutations was made towards the amino acids conserved in the two EIAV vaccine strains, distinguishing them from the two wild-type strains. The purpose of the modification was to enhance the immunogenicity of the HIV Env. Results The induced nAb by the modified HIV Env neutralized HIV-1 B and B'/C viruses at the highest titer of 1:270. Further studies showed that a single amino acid change in the C1 region accounts for the substantial enhancement in induction of anti-HIV-1 neutralizing antibodies. Conclusions This study shows that an HIV envelope modified by the information of another lentivirus vaccine induces effective broadly neutralizing antibodies. A single amino acid mutation was found to increase the immunogenicity of the HIV Env.

  16. Rapid screening and characterization of functional HIV-1 gp160 envelope genes%HIV-1功能性膜蛋白基因gp160的快速筛选和鉴定

    Institute of Scientific and Technical Information of China (English)

    胡园园; 朱雷; 赵春红; 郝金娟; 任莉; 邵一鸣; 洪坤学

    2013-01-01

    Objective To rapid screen and characterize functional HIV-1 envelope genes for HIV-1 neutralization test by pseudovirus infection.Methods HIV-1 gp160 genes were amplified from the blood sampls of the infected subjects.HIV-1 clade was determined by sequencing and phylogenetic analysis.HIV-1 pseudoviruses were prepared by transfection of functional env gp160 clone with plasmid pSG3Env,and the pseudovirus infectivity was also characterized.Results Nine HIV-1 gp160 genes were successfully cloned from HIV-1 infected patients using the HIV-1 pseudovirus infection assay.Sequencing and phylogenetic analysis indicated there were 4 CRF_07BC,2 CRF_01AE and 3 B viruses.Functional analysis demonstrated the pseudoviruses derived from these gp160 clones were infectious.Conclusion The present study has established an assay for rapid screening and characterization of functional gp160 clones of different HIV-1 subtypes,which will be useful in measurement of HIV-1 neutralizing antibody response.%目的 应用假病毒感染实验快速筛选可用于HIV-1中和抗体测定的功能性膜蛋白基因.方法 从HIV感染样品中扩增全长膜蛋白基因gp160,通过系统进化树分析确定其基因亚型,将HIV-1gp160阳性克隆与pSG3△Env质粒共转染293T细胞制备假病毒并对其感染能力进行分析,筛选功能性膜蛋白基因.结果 克隆和鉴定了我国HIV-1流行毒株的9个功能性膜蛋白基因,系统进化树分析表明其中包括4个CRF07_BC、2个CRF01_AE和3个B亚型毒株,这些gp160膜蛋白基因所制备的假病毒具有良好的感染性.结论 不同亚型HIV-1功能性膜蛋白gp160克隆为选择HIV-1中和抗体测定毒株提供了有价值的实验材料.

  17. Phase I randomised clinical trial of an HIV-1(CN54, clade C, trimeric envelope vaccine candidate delivered vaginally.

    Directory of Open Access Journals (Sweden)

    David J Lewis

    Full Text Available UNLABELLED: We conducted a phase 1 double-blind randomised controlled trial (RCT of a HIV-1 envelope protein (CN54 gp140 candidate vaccine delivered vaginally to assess immunogenicity and safety. It was hypothesised that repeated delivery of gp140 may facilitate antigen uptake and presentation at this mucosal surface. Twenty two healthy female volunteers aged 18-45 years were entered into the trial, the first receiving open-label active product. Subsequently, 16 women were randomised to receive 9 doses of 100 µg of gp140 in 3 ml of a Carbopol 974P based gel, 5 were randomised to placebo solution in the same gel, delivered vaginally via an applicator. Participants delivered the vaccine three times a week over three weeks during one menstrual cycle, and were followed up for two further months. There were no serious adverse events, and the vaccine was well tolerated. No sustained systemic or local IgG, IgA, or T cell responses to the gp140 were detected following vaginal immunisations. Repeated vaginal immunisation with a HIV-1 envelope protein alone formulated in Carbopol gel was safe, but did not induce local or systemic immune responses in healthy women. TRIAL REGISTRATION: ClinicalTrials.gov NCT00637962.

  18. Vaccine-induced plasma IgA specific for the C1 region of the HIV-1 envelope blocks binding and effector function of IgG

    OpenAIRE

    Tomaras, Georgia D.; Ferrari, Guido; Shen, Xiaoying; Alam, S. Munir; Liao, Hua-Xin; Pollara, Justin; Bonsignori, Mattia; Moody, M. Anthony; Fong, Youyi; Chen, Xi; Poling, Brigid; Nicholson, Cindo O; Zhang, Ruijun; Lu, Xiaozhi; Parks, Robert

    2013-01-01

    Analysis of correlates of risk of infection in the RV144 HIV-1 vaccine efficacy trial demonstrated that plasma IgG against the HIV-1 envelope (Env) variable region 1 and 2 inversely correlated with risk, whereas HIV-1 Env-specific plasma IgA responses directly correlated with risk. In the secondary analysis, antibody-dependent cellular cytotoxicity (ADCC) was another inverse correlate of risk, but only in the presence of low plasma IgA Env-specific antibodies. Thus, we investigated the hypoth...

  19. Infection of human and non-human cells by a highly fusogenic primary CD4-independent HIV-1 isolate with a truncated envelope cytoplasmic tail

    International Nuclear Information System (INIS)

    Truncation of the envelope cytoplasmic tail has enabled FIV, SIV, and some laboratory HIV-1 strains to acquire broader cellular tropism and enhanced fusogenicity. Here we have characterized a primary CD4-independent HIV-1 isolate (92UG046-T8) with a truncated cytoplasmic tail that was able to infect and induce syncytia in primary lymphocytes from human, chimpanzee, and monkey, as well as CD4-negative cell lines from human and monkey. Increased syncytia were also noticeable with 293 cells expressing the cloned envelope from the 92UG046-T8 isolate suggesting envelope-mediated cellular fusion. Except pooled serum from HIV-1-infected individuals, monoclonal anti-envelope antibodies or antibodies/antagonists against CD4, CXCR4, and CCR5 were not able to prevent infection by the 92UG046-T8 isolate. This is the first report showing a primary HIV-1 variant with truncated cytoplasmic tail which is highly fusogenic and can infect a broad range of cells from human and non-human origins. In vivo evolution of similar HIV-1 mutants may have important implications in AIDS pathogenesis

  20. Chimeric HIV-1 envelope glycoproteins with potent intrinsic granulocyte-macrophage colony-stimulating factor (GM-CSF activity.

    Directory of Open Access Journals (Sweden)

    Gözde Isik

    Full Text Available HIV-1 acquisition can be prevented by broadly neutralizing antibodies (BrNAbs that target the envelope glycoprotein complex (Env. An ideal vaccine should therefore be able to induce BrNAbs that can provide immunity over a prolonged period of time, but the low intrinsic immunogenicity of HIV-1 Env makes the elicitation of such BrNAbs challenging. Co-stimulatory molecules can increase the immunogenicity of Env and we have engineered a soluble chimeric Env trimer with an embedded granulocyte-macrophage colony-stimulating factor (GM-CSF domain. This chimeric molecule induced enhanced B and helper T cell responses in mice compared to Env without GM-CSF. We studied whether we could optimize the activity of the embedded GM-CSF as well as the antigenic structure of the Env component of the chimeric molecule. We assessed the effect of truncating GM-CSF, removing glycosylation-sites in GM-CSF, and adjusting the linker length between GM-CSF and Env. One of our designed Env(GM-CSF chimeras improved GM-CSF-dependent cell proliferation by 6-fold, reaching the same activity as soluble recombinant GM-CSF. In addition, we incorporated GM-CSF into a cleavable Env trimer and found that insertion of GM-CSF did not compromise Env cleavage, while Env cleavage did not compromise GM-CSF activity. Importantly, these optimized Env(GM-CSF proteins were able to differentiate human monocytes into cells with a macrophage-like phenotype. Chimeric Env(GM-CSF should be useful for improving humoral immunity against HIV-1 and these studies should inform the design of other chimeric proteins.

  1. An alternative conformation of the gp41 heptad repeat 1 region coiled coil exists in the human immunodeficiency virus (HIV-1) envelope glycoprotein precursor

    International Nuclear Information System (INIS)

    The human immunodeficiency virus (HIV-1) transmembrane envelope glycoprotein, gp41, which mediates virus-cell fusion, exists in at least three different conformations within the trimeric envelope glycoprotein complex. The structures of the prefusogenic and intermediate states are unknown; structures representing the postfusion state have been solved. In the postfusion conformation, three helical heptad repeat 2 (HR2) regions pack in an antiparallel fashion into the hydrophobic grooves on the surface of a triple-helical coiled coil formed by the heptad repeat 1 (HR1) regions. We studied the prefusogenic conformation of gp41 by mutagenic alteration of membrane-anchored and soluble forms of the HIV-1 envelope glycoproteins. Our results indicate that, in the HIV-1 envelope glycoprotein precursor, the gp41 HR1 region is in a conformation distinct from that of a trimeric coiled coil. Thus, the central gp41 coiled coil is formed during the transition of the HIV-1 envelope glycoproteins from the precursor state to the receptor-bound intermediate

  2. ASPP2 involvement in p53-mediated HIV-1 envelope glycoprotein gp120 neurotoxicity in mice cerebrocortical neurons

    Science.gov (United States)

    Liu, Zhiying; Zang, Yunjin; Qiao, Luxin; Liu, Kai; Ouyang, Yabo; Zhang, Yulin; Chen, Dexi

    2016-01-01

    The mechanisms behind HIV-1-associated neurocognitive disorders are still unclear. Apoptosis-stimulating protein 2 of p53 (ASPP2) is a damage-inducible p53-binding protein that stimulates p53-mediated apoptosis and transactivates proapoptotic and cell cycle regulatory genes. It has been reported that ASPP2 has a specific regulatory function in the death of retinal ganglion cells and the development of Alzheimer’s disease. In this study, we used p53 and ASPP2 knockout mice and primary cerebrocortical neuron culture to analyze the role of the interaction between ASPP2 with p53 in HIV-1 envelope glycoprotein gp120-induced neurotoxicity. The results showed that 10 ng/mL gp120 protein might stimulate p53 overexpression and translocation to the nucleus, and 30 ng/mL gp120 protein could stimulate both p53 and ASPP2 translocation to the nucleus, but only with p53 overexpression. The primary cultured neurons of p53−/−ASPP2+/− mice had a higher survival rate than p53−/− mice under gp120 protein stress. The interaction of ASPP2 with p53 induced by a high dose of gp120 stimulated Bax transcription and contributed to caspase-3 cleavage, and ASPP2-siRNA attenuated gp120 induced neuron death through inhibition of Bax expression. These results suggest that ASPP2 plays an important role in p53-mediated neuronal apoptosis under gp120 stress. PMID:27625111

  3. Incompatible Natures of the HIV-1 Envelope in Resistance to the CCR5 Antagonist Cenicriviroc and to Neutralizing Antibodies.

    Science.gov (United States)

    Kuwata, Takeo; Enomoto, Ikumi; Baba, Masanori; Matsushita, Shuzo

    2015-11-02

    Cenicriviroc is a CCR5 antagonist which prevents human immunodeficiency virus type 1 (HIV-1) from cellular entry. The CCR5-binding regions of the HIV-1 envelope glycoprotein are important targets for neutralizing antibodies (NAbs), and mutations conferring cenicriviroc resistance may therefore affect sensitivity to NAbs. Here, we used the in vitro induction of HIV-1 variants resistant to cenicriviroc or NAbs to examine the relationship between resistance to cenicriviroc and resistance to NAbs. The cenicriviroc-resistant variant KK652-67 (strain KK passaged 67 times in the presence of increasing concentrations of cenicriviroc) was sensitive to neutralization by NAbs against the V3 loop, the CD4-induced (CD4i) region, and the CD4-binding site (CD4bs), whereas the wild-type (WT) parental HIV-1 strain KKWT from which cenicriviroc-resistant strain KK652-67 was obtained was resistant to these NAbs. The V3 region of KK652-67 was important for cenicriviroc resistance and critical to the high sensitivity of the V3, CD4i, and CD4bs epitopes to NAbs. Moreover, induction of variants resistant to anti-V3 NAb 0.5γ and anti-CD4i NAb 4E9C from cenicriviroc-resistant strain KK652-67 resulted in reversion to the cenicriviroc-sensitive phenotype comparable to that of the parental strain, KKWT. Resistance to 0.5γ and 4E9C was caused by the novel substitutions R315K, G324R, and E381K in the V3 and C3 regions near the substitutions conferring cenicriviroc resistance. Importantly, these amino acid changes in the CCR5-binding region were also responsible for reversion to the cenicriviroc-sensitive phenotype. These results suggest the presence of key amino acid residues where resistance to cenicriviroc is incompatible with resistance to NAbs. This implies that cenicriviroc and neutralizing antibodies may restrict the emergence of variants resistant to each other.

  4. Early infection HIV-1 envelope V1-V2 genotypes do not enhance binding or replication in cells expressing high levels of α4β7 integrin.

    Science.gov (United States)

    Etemad, Behzad; Gonzalez, Oscar A; McDonough, Sean; Pena-Cruz, Victor; Sagar, Manish

    2013-11-01

    It has been postulated that HIV-1 envelope properties, such as shorter and less-glycosylated V1-V2 loops commonly observed among non-subtype B early-transmitted viruses, promote utilization of the gut homing integrin α4β7. This property potentially confers an advantage to some HIV-1 variants early after acquisition. We found that replication-competent recombinant viruses incorporating HIV-1 subtype A compact and less-glycosylated early versus chronic phase V1-V2 loops demonstrated no significant difference in binding to α4β7 high CD8⁺ T cells or replication in α4β7 high CD4⁺ T cells. Integrin α4β7 usage does not select for shorter less-glycosylated envelopes during transmission. PMID:23797693

  5. Evolutionary and Structural Features of the C2, V3 and C3 Envelope Regions Underlying the Differences in HIV-1 and HIV-2 Biology and Infection

    Science.gov (United States)

    Bártolo, Inês; Marcelino, José Maria; Família, Carlos; Quintas, Alexandre; Taveira, Nuno

    2011-01-01

    Background Unlike in HIV-1 infection, the majority of HIV-2 patients produce broadly reactive neutralizing antibodies, control viral replication and survive as elite controllers. The identification of the molecular, structural and evolutionary footprints underlying these very distinct immunological and clinical outcomes may lead to the development of new strategies for the prevention and treatment of HIV infection. Methodology/Principal Findings We performed a side-by-side molecular, evolutionary and structural comparison of the C2, V3 and C3 envelope regions from HIV-1 and HIV-2. These regions contain major antigenic targets and are important for receptor binding. In HIV-2, these regions also have immune modulatory properties. We found that these regions are significantly more variable in HIV-1 than in HIV-2. Within each virus, C3 is the most entropic region followed by either C2 (HIV-2) or V3 (HIV-1). The C3 region is well exposed in the HIV-2 envelope and is under strong diversifying selection suggesting that, like in HIV-1, it may harbour neutralizing epitopes. Notably, however, extreme diversification of C2 and C3 seems to be deleterious for HIV-2 and prevent its transmission. Computer modelling simulations showed that in HIV-2 the V3 loop is much less exposed than C2 and C3 and has a retractile conformation due to a physical interaction with both C2 and C3. The concealed and conserved nature of V3 in the HIV-2 is consistent with its lack of immunodominancy in vivo and with its role in preventing immune activation. In contrast, HIV-1 had an extended and accessible V3 loop that is consistent with its immunodominant and neutralizing nature. Conclusions/Significance We identify significant structural and functional constrains to the diversification and evolution of C2, V3 and C3 in the HIV-2 envelope but not in HIV-1. These studies highlight fundamental differences in the biology and infection of HIV-1 and HIV-2 and in their mode of interaction with the human

  6. Evolutionary and structural features of the C2, V3 and C3 envelope regions underlying the differences in HIV-1 and HIV-2 biology and infection.

    Directory of Open Access Journals (Sweden)

    Helena Barroso

    Full Text Available BACKGROUND: Unlike in HIV-1 infection, the majority of HIV-2 patients produce broadly reactive neutralizing antibodies, control viral replication and survive as elite controllers. The identification of the molecular, structural and evolutionary footprints underlying these very distinct immunological and clinical outcomes may lead to the development of new strategies for the prevention and treatment of HIV infection. METHODOLOGY/PRINCIPAL FINDINGS: We performed a side-by-side molecular, evolutionary and structural comparison of the C2, V3 and C3 envelope regions from HIV-1 and HIV-2. These regions contain major antigenic targets and are important for receptor binding. In HIV-2, these regions also have immune modulatory properties. We found that these regions are significantly more variable in HIV-1 than in HIV-2. Within each virus, C3 is the most entropic region followed by either C2 (HIV-2 or V3 (HIV-1. The C3 region is well exposed in the HIV-2 envelope and is under strong diversifying selection suggesting that, like in HIV-1, it may harbour neutralizing epitopes. Notably, however, extreme diversification of C2 and C3 seems to be deleterious for HIV-2 and prevent its transmission. Computer modelling simulations showed that in HIV-2 the V3 loop is much less exposed than C2 and C3 and has a retractile conformation due to a physical interaction with both C2 and C3. The concealed and conserved nature of V3 in the HIV-2 is consistent with its lack of immunodominancy in vivo and with its role in preventing immune activation. In contrast, HIV-1 had an extended and accessible V3 loop that is consistent with its immunodominant and neutralizing nature. CONCLUSIONS/SIGNIFICANCE: We identify significant structural and functional constrains to the diversification and evolution of C2, V3 and C3 in the HIV-2 envelope but not in HIV-1. These studies highlight fundamental differences in the biology and infection of HIV-1 and HIV-2 and in their mode of

  7. Characterization of a monoclonal antibody to a novel glycan-dependent epitope in the V1/V2 domain of the HIV-1 envelope protein, gp120.

    Science.gov (United States)

    Doran, Rachel C; Morales, Javier F; To, Briana; Morin, Trevor J; Theolis, Richard; O'Rourke, Sara M; Yu, Bin; Mesa, Kathryn A; Berman, Phillip W

    2014-11-01

    Recent studies have described several broadly neutralizing monoclonal antibodies (bN-mAbs) that recognize glycan-dependent epitopes (GDEs) in the HIV-1 envelope protein, gp120. These were recovered from HIV-1 infected subjects, and several (e.g., PG9, PG16, CH01, CH03) target glycans in the first and second variable (V1/V2) domain of gp120. The V1/V2 domain is thought to play an important role in conformational masking, and antibodies to the V1/V2 domain were recently identified as the only immune response that correlated with protection in the RV144 HIV-1 vaccine trial. While the importance of antibodies to polymeric glycans is well established for vaccines targeting bacterial diseases, the importance of antibodies to glycans in vaccines targeting HIV has only recently been recognized. Antibodies to GDEs may be particularly significant in HIV vaccines based on gp120, where 50% of the molecular mass of the envelope protein is contributed by N-linked carbohydrate. However, few studies have reported antibodies to GDEs in humans or animals immunized with candidate HIV-1 vaccines. In this report, we describe the isolation of a mouse mAb, 4B6, after immunization with the extracellular domain of the HIV-1 envelope protein, gp140. Epitope mapping using glycopeptide fragments and in vitro mutagenesis showed that binding of this antibody depends on N-linked glycosylation at asparagine N130 (HXB2 numbering) in the gp120 V1/V2 domain. Our results demonstrate that, in addition to natural HIV-1 infection, immunization with recombinant proteins can elicit antibodies to the GDEs in the V1/V2 domain of gp120. Although little is known regarding conditions that favor antibody responses to GDEs, our studies demonstrate that these antibodies can arise from a short-term immunization regimen. Our results suggest that antibodies to GDEs are more common than previously suspected, and that further analysis of antibody responses to the HIV-1 envelope protein will lead to the discovery of

  8. Evidence that Vpu modulates HIV-1 Gag-envelope interaction towards envelope incorporation and infectivity in a cell type dependent manner.

    Directory of Open Access Journals (Sweden)

    Archana Gautam

    Full Text Available The HIV-1 Vpu is required for efficient virus particle release from the plasma membrane and intracellular CD4 degradation in infected cells. In the present study, we found that the loss of virus infectivity as a result of envelope (Env incorporation defect caused by a Gag matrix (MA mutation (L30E was significantly alleviated by introducing a start codon mutation in vpu. Inactivation of Vpu partially restored the Env incorporation defect imposed by L30E substitution in MA. This effect was found to be comparable in cell types such as 293T, HeLa, NP2 and GHOST as well as in peripheral blood mononuclear cells (PBMC and monocyte-derived macrophages (MDM. However, in HeLa cells BST-2 knockdown was found to further alleviate the effect of Vpu inactivation on infectivity of L30E mutant. Our data demonstrated that the impaired infectivity of virus particles due to Env incorporation defect caused by MA mutation was modulated by start codon mutation in Vpu.

  9. Comprehensive Analysis of Contributions from Protein Conformational Stability and Major Histocompatibility Complex Class II-Peptide Binding Affinity to CD4+ Epitope Immunogenicity in HIV-1 Envelope Glycoprotein

    OpenAIRE

    Li, Tingfeng; Steede, N. Kalaya; Nguyen, Hong-Nam P.; Freytag, Lucy C.; McLachlan, James B.; Mettu, Ramgopal R.; Robinson, James E.; Landry, Samuel J.

    2014-01-01

    Helper T-cell epitope dominance in human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 is not adequately explained by peptide binding to major histocompatibility complex (MHC) proteins. Antigen processing potentially influences epitope dominance, but few, if any, studies have attempted to reconcile the influences of antigen processing and MHC protein binding for all helper T-cell epitopes of an antigen. Epitopes of gp120 identified in both humans and mice occur on the C-te...

  10. Recurrent signature patterns in HIV-1 B clade envelope glycoproteins associated with either early or chronic infections.

    Directory of Open Access Journals (Sweden)

    S Gnanakaran

    2011-09-01

    Full Text Available Here we have identified HIV-1 B clade Envelope (Env amino acid signatures from early in infection that may be favored at transmission, as well as patterns of recurrent mutation in chronic infection that may reflect common pathways of immune evasion. To accomplish this, we compared thousands of sequences derived by single genome amplification from several hundred individuals that were sampled either early in infection or were chronically infected. Samples were divided at the outset into hypothesis-forming and validation sets, and we used phylogenetically corrected statistical strategies to identify signatures, systematically scanning all of Env. Signatures included single amino acids, glycosylation motifs, and multi-site patterns based on functional or structural groupings of amino acids. We identified signatures near the CCR5 co-receptor-binding region, near the CD4 binding site, and in the signal peptide and cytoplasmic domain, which may influence Env expression and processing. Two signatures patterns associated with transmission were particularly interesting. The first was the most statistically robust signature, located in position 12 in the signal peptide. The second was the loss of an N-linked glycosylation site at positions 413-415; the presence of this site has been recently found to be associated with escape from potent and broad neutralizing antibodies, consistent with enabling a common pathway for immune escape during chronic infection. Its recurrent loss in early infection suggests it may impact fitness at the time of transmission or during early viral expansion. The signature patterns we identified implicate Env expression levels in selection at viral transmission or in early expansion, and suggest that immune evasion patterns that recur in many individuals during chronic infection when antibodies are present can be selected against when the infection is being established prior to the adaptive immune response.

  11. Comparative evaluation of trimeric envelope glycoproteins derived from subtype C and B HIV-1 R5 isolates.

    Science.gov (United States)

    Srivastava, Indresh K; Kan, Elaine; Sun, Yide; Sharma, Victoria A; Cisto, Jimna; Burke, Brian; Lian, Ying; Hilt, Susan; Biron, Zohar; Hartog, Karin; Stamatatos, Leonidas; Diaz-Avalos, Ruben; Cheng, R Holland; Ulmer, Jeffrey B; Barnett, Susan W

    2008-03-15

    We previously reported that an envelope (Env) glycoprotein immunogen (o-gp140DeltaV2SF162) containing a partial deletion in the second variable loop (V2) derived from the R5-tropic HIV-1 isolate SF162 partially protected vaccinated rhesus macaques against pathogenic SHIV(SF162P4) virus. Extending our studies to subtype C isolate TV1, we have purified o-gp140DeltaV2TV1 (subtype C DeltaV2 trimer) to homogeneity, performed glycosylation analysis, and determined its ability to bind CD4, as well as a panel of well-characterized neutralizing monoclonal antibodies (mAb). In general, critical epitopes are preserved on the subtype C DeltaV2 trimer; however, we did not observe significant binding for the b12 mAb. The molecular mass of subtype C DeltaV2 trimer was found to be 450 kDa, and the hydrodynamic radius was found to be 10.87 nm. Our data suggest that subtype C DeltaV2 trimer binds to CD4 with an affinity comparable to o-gp140DeltaV2SF162 (subtype B DeltaV2 trimer). Using isothermal titration calorimetric (ITC) analysis, we demonstrated that all three CD4 binding sites (CD4-BS) in both subtype C and B trimers are exposed and accessible. However, compared to subtype B trimer, the three CD4-BS in subtype C trimer have different affinities for CD4, suggesting a cooperativity of CD4 binding in subtype C trimer but not in subtype B trimer. Negative staining electron microscopy of the subtype C DeltaV2 trimer has demonstrated that it is in fact a trimer. These results highlight the importance of studying subtype C Env, and also of developing appropriate subtype C-specific reagents that may be used for better immunological characterization of subtype C Env for developing an AIDS vaccine.

  12. Longitudinal Analysis of CCR5 and CXCR4 Usage in a Cohort of Antiretroviral Therapy-Naive Subjects with Progressive HIV-1 Subtype C Infection.

    Directory of Open Access Journals (Sweden)

    Martin R Jakobsen

    Full Text Available HIV-1 subtype C (C-HIV is responsible for most HIV-1 cases worldwide. Although the pathogenesis of C-HIV is thought to predominantly involve CCR5-restricted (R5 strains, we do not have a firm understanding of how frequently CXCR4-using (X4 and R5X4 variants emerge in subjects with progressive C-HIV infection. Nor do we completely understand the molecular determinants of coreceptor switching by C-HIV variants. Here, we characterized a panel of HIV-1 envelope glycoproteins (Envs (n = 300 cloned sequentially from plasma of 21 antiretroviral therapy (ART-naïve subjects who experienced progression from chronic to advanced stages of C-HIV infection, and show that CXCR4-using C-HIV variants emerged in only one individual. Mutagenesis studies and structural models suggest that the evolution of R5 to X4 variants in this subject principally involved acquisition of an "Ile-Gly" insertion in the gp120 V3 loop and replacement of the V3 "Gly-Pro-Gly" crown with a "Gly-Arg-Gly" motif, but that the accumulation of additional gp120 "scaffold" mutations was required for these V3 loop changes to confer functional effects. In this context, either of the V3 loop changes could confer possible transitional R5X4 phenotypes, but when present together they completely abolished CCR5 usage and conferred the X4 phenotype. Our results show that the emergence of CXCR4-using strains is rare in this cohort of untreated individuals with advanced C-HIV infection. In the subject where X4 variants did emerge, alterations in the gp120 V3 loop were necessary but not sufficient to confer CXCR4 usage.

  13. Fusion proteins of HIV-1 envelope glycoprotein gp120 with CD4-induced antibodies showed enhanced binding to CD4 and CD4 binding site antibodies

    International Nuclear Information System (INIS)

    Highlights: ► Some recombinant HIV-1 gp120s do not preserve their conformations on gp140s. ► We hypothesize that CD4i antibodies could induce conformational changes in gp120. ► CD4i antibodies enhance binding of CD4 and CD4bs antibodies to gp120. ► CD4i antibody-gp120 fusion proteins could have potential as vaccine immunogens. -- Abstract: Development of successful AIDS vaccine immunogens continues to be a major challenge. One of the mechanisms by which HIV-1 evades antibody-mediated neutralizing responses is the remarkable conformational flexibility of its envelope glycoprotein (Env) gp120. Some recombinant gp120s do not preserve their conformations on gp140s and functional viral spikes, and exhibit decreased recognition by CD4 and neutralizing antibodies. CD4 binding induces conformational changes in gp120 leading to exposure of the coreceptor-binding site (CoRbs). In this study, we test our hypothesis that CD4-induced (CD4i) antibodies, which target the CoRbs, could also induce conformational changes in gp120 leading to better exposed conserved neutralizing antibody epitopes including the CD4-binding site (CD4bs). We found that a mixture of CD4i antibodies with gp120 only weakly enhanced CD4 binding. However, such interactions in single-chain fusion proteins resulted in gp120 conformations which bound to CD4 and CD4bs antibodies better than the original or mutagenically stabilized gp120s. Moreover, the two molecules in the fusion proteins synergized with each other in neutralizing HIV-1. Therefore, fusion proteins of gp120 with CD4i antibodies could have potential as components of HIV-1 vaccines and inhibitors of HIV-1 entry, and could be used as reagents to explore the conformational flexibility of gp120 and mechanisms of entry and immune evasion.

  14. Variations in the Biological Functions of HIV-1 Clade C Envelope in a SHIV-Infected Rhesus Macaque during Disease Progression.

    Directory of Open Access Journals (Sweden)

    For Yue Tso

    Full Text Available A better understanding of how the biological functions of the HIV-1 envelope (Env changes during disease progression may aid the design of an efficacious anti-HIV-1 vaccine. Although studies from patient had provided some insights on this issue, the differences in the study cohorts and methodology had make it difficult to reach a consensus of the variations in the HIV-1 Env functions during disease progression. To this end, an animal model that can be infected under controlled environment and reflect the disease course of HIV-1 infection in human will be beneficial. Such an animal model was previously demonstrated by the infection of macaque with SHIV, expressing HIV-1 clade C Env V1-V5 region. By using this model, we examined the changes in biological functions of Env in the infected animal over the entire disease course. Our data showed an increase in the neutralization resistance phenotype over time and coincided with the decrease in the net charges of the V1-V5 region. Infection of PBMC with provirus expressing various Env clones, isolated from the infected animal over time, showed a surprisingly better replicative fitness for viruses expressing the Env from early time point. Biotinylation and ELISA data also indicated a decrease of cell-surface-associated Env and virion-associated gp120 content with disease progression. This decrease did not affect the CD4-binding capability of Env, but were positively correlated with the decrease of Env fusion ability. Interestingly, some of these changes in biological functions reverted to the pre-AIDS level during advance AIDS. These data suggested a dynamic relationship between the Env V1-V5 region with the host immune pressure. The observed changes of biological functions in this setting might reflect and predict those occurring during natural disease progression in human.

  15. Comparison on Virulence and Immunogenicity of Two Recombinant Vaccinia Vaccines, Tian Tan and Guang9 Strains, Expressing the HIV-1 Envelope Gene

    OpenAIRE

    Rong Zhu; Weijin Huang; Wenbo Wang; Qiang Liu; Jianhui Nie; Shufang Meng; Yongxin Yu; Youchun Wang

    2012-01-01

    BACKGROUND: The vaccinia virus Guang9 strain (VG9), derived from the vaccinia virus Tian Tan strain (VTT) has been found to be less virulent than VTT. METHODOLOGY/PRINCIPAL FINDINGS: To investigate whether VG9 could be a potential replicating virus vector, the TK genes in VG9 and VTT were replaced with the HIV-1 envelope gene via homologous recombination, resulting in the recombinant viruses, VG9-E and VTT-E. The biology, virulence, humoral and cellular immunological responses of VG9-E and VT...

  16. Variation in HIV-1 R5 macrophage-tropism correlates with sensitivity to reagents that block envelope: CD4 interactions but not with sensitivity to other entry inhibitors

    Directory of Open Access Journals (Sweden)

    Simmonds Peter

    2008-01-01

    Full Text Available Abstract Background HIV-1 R5 viruses cause most of the AIDS cases worldwide and are preferentially transmitted compared to CXCR4-using viruses. Furthermore, R5 viruses vary extensively in capacity to infect macrophages and highly macrophage-tropic variants are frequently identified in the brains of patients with dementia. Here, we investigated the sensitivity of R5 envelopes to a range of inhibitors and antibodies that block HIV entry. We studied a large panel of R5 envelopes, derived by PCR amplification without culture from brain, lymph node, blood and semen. These R5 envelopes conferred a wide range of macrophage tropism and included highly macrophage-tropic variants from brain and non-macrophage-tropic variants from lymph node. Results R5 macrophage-tropism correlated with sensitivity to inhibition by reagents that inhibited gp120:CD4 interactions. Thus, increasing macrophage-tropism was associated with increased sensitivity to soluble CD4 and to IgG-CD4 (PRO 542, but with increased resistance to the anti-CD4 monoclonal antibody (mab, Q4120. These observations were highly significant and are consistent with an increased affinity of envelope for CD4 for macrophage-tropic envelopes. No overall correlations were noted between R5 macrophage-tropism and sensitivity to CCR5 antagonists or to gp41 specific reagents. Intriguingly, there was a relationship between increasing macrophage-tropism and increased sensitivity to the CD4 binding site mab, b12, but decreased sensitivity to 2G12, a mab that binds a glycan complex on gp120. Conclusion Variation in R5 macrophage-tropism is caused by envelope variation that predominantly influences sensitivity to reagents that block gp120:CD4 interactions. Such variation has important implications for therapy using viral entry inhibitors and for the design of envelope antigens for vaccines.

  17. Postnatally-transmitted HIV-1 Envelope variants have similar neutralization-sensitivity and function to that of nontransmitted breast milk variants

    Directory of Open Access Journals (Sweden)

    Fouda Genevieve G

    2013-01-01

    Full Text Available Abstract Background Breastfeeding is a leading cause of infant HIV-1 infection in the developing world, yet only a minority of infants exposed to HIV-1 via breastfeeding become infected. As a genetic bottleneck severely restricts the number of postnatally-transmitted variants, genetic or phenotypic properties of the virus Envelope (Env could be important for the establishment of infant infection. We examined the efficiency of virologic functions required for initiation of infection in the gastrointestinal tract and the neutralization sensitivity of HIV-1 Env variants isolated from milk of three postnatally-transmitting mothers (n=13 viruses, five clinically-matched nontransmitting mothers (n=16 viruses, and seven postnatally-infected infants (n = 7 postnatally-transmitted/founder (T/F viruses. Results There was no difference in the efficiency of epithelial cell interactions between Env virus variants from the breast milk of transmitting and nontransmitting mothers. Moreover, there was similar efficiency of DC-mediated trans-infection, CCR5-usage, target cell fusion, and infectivity between HIV-1 Env-pseudoviruses from nontransmitting mothers and postnatal T/F viruses. Milk Env-pseudoviruses were generally sensitive to neutralization by autologous maternal plasma and resistant to breast milk neutralization. Infant T/F Env-pseudoviruses were equally sensitive to neutralization by broadly-neutralizing monoclonal and polyclonal antibodies as compared to nontransmitted breast milk Env variants. Conclusion Postnatally-T/F Env variants do not appear to possess a superior ability to interact with and cross a mucosal barrier or an exceptional resistance to neutralization that define their capability to initiate infection across the infant gastrointestinal tract in the setting of preexisting maternal antibodies.

  18. Hyperimmune bovine colostrum as a low-cost, large-scale source of antibodies with broad neutralizing activity for HIV-1 envelope with potential use in microbicides.

    Science.gov (United States)

    Kramski, Marit; Center, Rob J; Wheatley, Adam K; Jacobson, Jonathan C; Alexander, Marina R; Rawlin, Grant; Purcell, Damian F J

    2012-08-01

    Bovine colostrum (first milk) contains very high concentrations of IgG, and on average 1 kg (500 g/liter) of IgG can be harvested from each immunized cow immediately after calving. We used a modified vaccination strategy together with established production systems from the dairy food industry for the large-scale manufacture of broadly neutralizing HIV-1 IgG. This approach provides a low-cost mucosal HIV preventive agent potentially suitable for a topical microbicide. Four cows were vaccinated pre- and/or postconception with recombinant HIV-1 gp140 envelope (Env) oligomers of clade B or A, B, and C. Colostrum and purified colostrum IgG were assessed for cross-clade binding and neutralization against a panel of 27 Env-pseudotyped reporter viruses. Vaccination elicited high anti-gp140 IgG titers in serum and colostrum with reciprocal endpoint titers of up to 1 × 10(5). While nonimmune colostrum showed some intrinsic neutralizing activity, colostrum from 2 cows receiving a longer-duration vaccination regimen demonstrated broad HIV-1-neutralizing activity. Colostrum-purified polyclonal IgG retained gp140 reactivity and neutralization activity and blocked the binding of the b12 monoclonal antibody to gp140, showing specificity for the CD4 binding site. Colostrum-derived anti-HIV antibodies offer a cost-effective option for preparing the substantial quantities of broadly neutralizing antibodies that would be needed in a low-cost topical combination HIV-1 microbicide. PMID:22664963

  19. Elicitation of neutralizing antibodies directed against CD4-induced epitope(s using a CD4 mimetic cross-linked to a HIV-1 envelope glycoprotein.

    Directory of Open Access Journals (Sweden)

    Antu K Dey

    Full Text Available The identification of HIV-1 envelope glycoprotein (Env structures that can generate broadly neutralizing antibodies (BNAbs is pivotal to the development of a successful vaccine against HIV-1 aimed at eliciting effective humoral immune responses. To that end, the production of novel Env structure(s that might induce BNAbs by presentation of conserved epitopes, which are otherwise occluded, is critical. Here, we focus on a structure that stabilizes Env in a conformation representative of its primary (CD4 receptor-bound state, thereby exposing highly conserved "CD4 induced" (CD4i epitope(s known to be important for co-receptor binding and subsequent virus infection. A CD4-mimetic miniprotein, miniCD4 (M64U1-SH, was produced and covalently complexed to recombinant, trimeric gp140 envelope glycoprotein (gp140 using site-specific disulfide linkages. The resulting gp140-miniCD4 (gp140-S-S-M64U1 complex was recognized by CD4i antibodies and the HIV-1 co-receptor, CCR5. The gp140-miniCD4 complex elicited the highest titers of CD4i binding antibodies as well as enhanced neutralizing antibodies against Tier 1 viruses as compared to gp140 protein alone following immunization of rabbits. Neutralization against HIV-2(7312/V434M and additional serum mapping confirm the specific elicitation of antibodies directed to the CD4i epitope(s. These results demonstrate the utility of structure-based approach in improving immunogenic response against specific region, such as the CD4i epitope(s here, and its potential role in vaccine application.

  20. Conformational alterations in the CD4 binding cavity of HIV-1 gp120 influencing gp120-CD4 interactions and fusogenicity of HIV-1 envelopes derived from brain and other tissues

    Directory of Open Access Journals (Sweden)

    Ramsland Paul A

    2011-06-01

    Full Text Available Abstract Background CD4-binding site (CD4bs alterations in gp120 contribute to HIV-1 envelope (Env mediated fusogenicity and the ability of gp120 to utilize low levels of cell-surface CD4. In a recent study, we constructed three-dimensional models of gp120 to illustrate CD4bs conformations associated with enhanced fusogenicity and enhanced CD4-usage of a modestly-sized panel of blood-derived HIV-1 Envs (n = 16. These conformations were characterized by a wider aperture of the CD4bs cavity, as constrained by the inner-most atoms at the gp120 V1V2 stem and the V5 loop. Here, we sought to provide further validation of the utility of these models for understanding mechanisms that influence Env function, by characterizing the structure-function relationships of a larger panel of Envs derived from brain and other tissues (n = 81. Findings Three-dimensional models of gp120 were generated by our recently validated homology modelling protocol. Analysis of predicted CD4bs structures showed correlations between the aperture width of the CD4bs cavity and ability of the Envs to mediate cell-cell fusion, scavenge low-levels of cell-surface CD4, bind directly to soluble CD4, and bind to the Env mAb IgG1b12 whose epitope overlaps the gp120 CD4bs. These structural alterations in the CD4bs cavity were associated with repositioning of the V5 loop. Conclusions Using a large, independent panel of Envs, we can confirm the utility of three-dimensional gp120 structural models for illustrating CD4bs alterations that can affect Env function. Furthermore, we now provide new evidence that these CD4bs alterations augment the ability of gp120 to interact with CD4 by increasing the exposure of the CD4bs.

  1. Second site escape of a T20-dependent HIV-1 variant by a single amino acid change in the CD4 binding region of the envelope glycoprotein

    Directory of Open Access Journals (Sweden)

    Berkhout Ben

    2006-11-01

    Full Text Available Abstract Background We previously described the selection of a T20-dependent human immunodeficiency virus type-1 (HIV-1 variant in a patient on T20 therapy. The fusion inhibitor T20 targets the viral envelope (Env protein by blocking a conformational switch that is critical for viral entry into the host cell. T20-dependent viral entry is the result of 2 mutations in Env (GIA-SKY, creating a protein that undergoes a premature conformational switch, and the presence of T20 prevents this premature switch and rescues viral entry. In the present study, we performed 6 independent evolution experiments with the T20-dependent HIV-1 variant in the absence of T20, with the aim to identify second site compensatory changes, which may provide new mechanistic insights into Env function and the T20-dependence mechanism. Results Escape variants with improved replication capacity appeared within 42 days in 5 evolution cultures. Strikingly, 3 cultures revealed the same single amino acid change in the CD4 binding region of Env (glycine at position 431 substituted for arginine: G431R. This mutation was sufficient to abolish the T20-dependence phenotype and restore viral replication in the absence of T20. The GIA-SKY-G431R escape variant produces an Env protein that exhibits reduced syncytia formation and reduced cell-cell fusion activity. The escape variant was more sensitive to an antibody acting on an early gp41 intermediate, suggesting that the G431R mutation helps preserve a pre-fusion Env conformation, similar to T20 action. The escape variant was also less sensitive to soluble CD4, suggesting a reduced CD4 receptor affinity. Conclusion The forced evolution experiments indicate that the premature conformational switch of the T20-dependent HIV-1 Env variant (GIA-SKY can be corrected by a second site mutation in Env (GIA-SKY-G431R that affects the interaction with the CD4 receptor.

  2. Sequential and Simultaneous Immunization of Rabbits with HIV-1 Envelope Glycoprotein SOSIP.664 Trimers from Clades A, B and C.

    Science.gov (United States)

    Klasse, P J; LaBranche, Celia C; Ketas, Thomas J; Ozorowski, Gabriel; Cupo, Albert; Pugach, Pavel; Ringe, Rajesh P; Golabek, Michael; van Gils, Marit J; Guttman, Miklos; Lee, Kelly K; Wilson, Ian A; Butera, Salvatore T; Ward, Andrew B; Montefiori, David C; Sanders, Rogier W; Moore, John P

    2016-09-01

    We have investigated the immunogenicity in rabbits of native-like, soluble, recombinant SOSIP.664 trimers based on the env genes of four isolates of human immunodeficiency virus type 1 (HIV-1); specifically BG505 (clade A), B41 (clade B), CZA97 (clade C) and DU422 (clade C). The various trimers were delivered either simultaneously (as a mixture of clade A + B trimers) or sequentially over a 73-week period. Autologous, Tier-2 neutralizing antibody (NAb) responses were generated to the clade A and clade B trimers in the bivalent mixture. When delivered as boosting immunogens to rabbits immunized with the clade A and/or clade B trimers, the clade C trimers also generated autologous Tier-2 NAb responses, the CZA97 trimers doing so more strongly and consistently than the DU422 trimers. The clade C trimers also cross-boosted the pre-existing NAb responses to clade A and B trimers. We observed heterologous Tier-2 NAb responses albeit inconsistently, and with limited overall breath. However, cross-neutralization of the clade A BG505.T332N virus was consistently observed in rabbits immunized only with clade B trimers and then boosted with clade C trimers. The autologous NAbs induced by the BG505, B41 and CZA97 trimers predominantly recognized specific holes in the glycan shields of the cognate virus. The shared location of some of these holes may account for the observed cross-boosting effects and the heterologous neutralization of the BG505.T332N virus. These findings will guide the design of further experiments to determine whether and how multiple Env trimers can together induce more broadly neutralizing antibody responses. PMID:27627672

  3. Multimeric scaffolds displaying the HIV-1 envelope MPER induce MPER-specific antibodies and cross-neutralizing antibodies when co-immunized with gp160 DNA.

    Directory of Open Access Journals (Sweden)

    Shelly J Krebs

    Full Text Available Developing a vaccine that overcomes the diversity of HIV-1 is likely to require a strategy that directs antibody (Ab responses toward conserved regions of the viral Envelope (Env. However, the generation of neutralizing Abs (NAbs targeting these regions through vaccination has proven to be difficult. One conserved region of particular interest is the membrane proximal external region (MPER of Env located within the gp41 ectodomain. In order to direct the immune response to this region, the MPER and gp41 ectodomain were expressed separately as N-terminal fusions to the E2 protein of Geobacillus stearothermophilus. The E2 protein acts as a scaffold by self-assembling into 60-mer particles, displaying up to 60 copies of the fused target on the surface. Rabbits were immunized with E2 particles displaying MPER and/or the gp41 ectodomain in conjunction with DNA encoding full-length gp160. Only vaccines including E2 particles displaying MPER elicited MPER-specific Ab responses. NAbs were elicited after two immunizations that largely targeted the V3 loop. To overcome V3 immunodominance in the DNA component, E2 particles displaying MPER were used in conjunction with gp160 DNA lacking hypervariable regions V2, V3, or combined V1V2V3. All rabbits had HIV binding Ab responses and NAbs following the second vaccination. Using HIV-2/HIV-1 MPER chimeric viruses as targets, NAbs were detected in 12/16 rabbits after three immunizations. Low levels of NAbs specific for Tier 1 and 2 viruses were observed in all groups. This study provides evidence that co-immunizing E2 particles displaying MPER and gp160 DNA can focus Ab responses toward conserved regions of Env.

  4. A sensitive radioimmunoprecipitation assay for the detection and quantitation of antibodies to the envelope glycoprotein gp120 of the human immunodeficiency virus (HIV-1)

    International Nuclear Information System (INIS)

    A radioimmunoprecipitation (RIP) assay was developed to detect antibodies to the envelope glycoprotein gp120 of the human immunodeficiency virus (HIV-1). The assay, which utilized recombinant gp120 (rgp120), was quantitative, reproducible, and specific for antibodies to rgp120 or antibodies to native gp120 resulting from natural infection with HIV. Polyethylene glycol-8000 (PEG), used in the assay at a final concentration of 10% to precipitate immune complexes, was demonstrated to be effective in titering sera from different animal species. Provided samples were diluted at least 1:100, antibody titers could be determined either by the classical dilution method or by interpolation from a calibration curve prepared with a positive serum. The humoral response of animals immunized with rgp120 was monitored and a positive correlation was found between titers determined in the RIP assay and the ability of the sera to neutralize. In addition, RIP titers of HIV-positive human sera correlated very well with reactivity obtained in a commercial HIV immunoblot assay. The assay has the advantage of quantitation, fast turnaround time, and versatility

  5. HIV-1 gp41 envelope IgA is frequently elicited after transmission but has an initial short response half-life

    OpenAIRE

    Yates, N L; Stacey, A R; Nolen, T L; Vandergrift, N A; Moody, M.A.; Montefiori, D C; Weinhold, K J; Blattner, W. A.; Borrow, P; Shattock, R.; Cohen, M.S.; Haynes, B. F.; Tomaras, G.D.

    2013-01-01

    Prevention of HIV-1 transmission at mucosal surfaces will likely require durable pre-existing mucosal anti-HIV-1 antibodies (Abs). Defining the ontogeny, specificities and potentially protective nature of the initial mucosal virus-specific B-cell response will be critical for understanding how to induce protective Ab responses by vaccination. Genital fluids from patients within the earliest stages of acute HIV-1 infection (Fiebig I–VI) were examined for multiple anti-HIV specificities. Gp41 (...

  6. Selective induction of cell-mediated immunity and protection of rhesus macaques from chronic SHIVKU2 infection by prophylactic vaccination with a conserved HIV-1 envelope peptide-cocktail

    International Nuclear Information System (INIS)

    Infection of Indian-origin rhesus macaques by the simian human immunodeficiency virus (SHIV) is considered to be a suitable preclinical model for directly testing efficacy of vaccine candidates based on the HIV-1 envelope. We used this model for prophylactic vaccination with a peptide-cocktail comprised of highly conserved HIV-1 envelope sequences immunogenic/antigenic in macaques and humans. Separate groups of macaques were immunized with the peptide-cocktail by intravenous and subcutaneous routes using autologous dendritic cells (DC) and Freund's adjuvant, respectively. The vaccine elicited antigen specific IFN-γ-producing cells and T-cell proliferation, but not HIV-neutralizing antibodies. The vaccinated animals also exhibited efficient cross-clade cytolytic activity against target cells expressing envelope proteins corresponding to HIV-1 strains representative of multiple clades that increased after intravenous challenge with pathogenic SHIVKU2. Virus-neutralizing antibodies were either undetectable or present only transiently at low levels in the control as well as vaccinated monkeys after infection. Significant control of plasma viremia leading to undetectable levels was achieved in majority of vaccinated monkeys compared to mock-vaccinated controls. Monkeys vaccinated with the peptide-cocktail using autologous DC, compared to Freund's adjuvant, and the mock-vaccinated animals, showed significantly higher IFN-γ production, higher levels of vaccine-specific IFN-γ producing CD4+ cells and significant control of plasma viremia. These results support DC-based vaccine delivery and the utility of the conserved HIV-1 envelope peptide-cocktail, capable of priming strong cell-mediated immunity, for potential inclusion in HIV vaccination strategies

  7. HIV-1 envelope glycoprotein resistance to monoclonal antibody 2G12 is subject-specific and context-dependent in macaques and humans.

    Directory of Open Access Journals (Sweden)

    Delphine C Malherbe

    Full Text Available HIV-1 Envelope (Env protein is the sole target of neutralizing antibodies (NAbs that arise during infection to neutralize autologous variants. Under this immune pressure, HIV escape variants are continuously selected and over the course of infection Env becomes more neutralization resistant. Many common alterations are known to affect sensitivity to NAbs, including residues encoding potential N-linked glycosylation sites (PNGS. Knowledge of Env motifs associated with neutralization resistance is valuable for the design of an effective Env-based vaccine so we characterized Envs isolated longitudinally from a SHIV(SF162P4 infected macaque for sensitivity to neutralizing monoclonal antibodies (MAbs B12, 2G12, 4E10 and 2F5. The early Env, isolated from plasma at day 56 after infection, was the most sensitive and the late Env, from day 670, was the most resistant to MAbs. We identified four PNGS in these Envs that accumulated over time at positions 130, 139, 160 and 397. We determined that removal of these PNGS significantly increased neutralization sensitivity to 2G12, and conversely, we identified mutations by in silico analyses that contributed resistance to 2G12 neutralization. In order to expand our understanding of these PNGS, we analyzed Envs from clade B HIV-infected human subjects and identified additional glycan and amino acid changes that could affect neutralization by 2G12 in a context-dependent manner. Taken together, these in vitro and in silico analyses of clade B Envs revealed that 2G12 resistance is achieved by previously unrecognized PNGS substitutions in a context-dependent manner and by subject-specific pathways.

  8. The Envelope Cytoplasmic Tail of HIV-1 Subtype C Contributes to Poor Replication Capacity through Low Viral Infectivity and Cell-to-Cell Transmission

    Science.gov (United States)

    Lemaire, Morgane; Masquelier, Cécile; Beraud, Cyprien; Rybicki, Arkadiusz; Servais, Jean-Yves; Iserentant, Gilles; Schmit, Jean-Claude; Seguin-Devaux, Carole; Perez Bercoff, Danielle

    2016-01-01

    The cytoplasmic tail (gp41CT) of the HIV-1 envelope (Env) mediates Env incorporation into virions and regulates Env intracellular trafficking. Little is known about the functional impact of variability in this domain. To address this issue, we compared the replication of recombinant virus pairs carrying the full Env (Env viruses) or the Env ectodomain fused to the gp41CT of NL4.3 (EnvEC viruses) (12 subtype C and 10 subtype B pairs) in primary CD4+ T-cells and monocyte-derived-macrophages (MDMs). In CD4+ T-cells, replication was as follows: B-EnvEC = B-Env>C-EnvEC>C-Env, indicating that the gp41CT of subtype C contributes to the low replicative capacity of this subtype. In MDMs, in contrast, replication capacity was comparable for all viruses regardless of subtype and of gp41CT. In CD4+ T-cells, viral entry, viral release and viral gene expression were similar. However, infectivity of free virions and cell-to-cell transmission of C-Env viruses released by CD4+ T-cells was lower, suggestive of lower Env incorporation into virions. Subtype C matrix only minimally rescued viral replication and failed to restore infectivity of free viruses and cell-to-cell transmission. Taken together, these results show that polymorphisms in the gp41CT contribute to viral replication capacity and suggest that the number of Env spikes per virion may vary across subtypes. These findings should be taken into consideration in the design of vaccines. PMID:27598717

  9. Comprehensive Analysis of Contributions from Protein Conformational Stability and Major Histocompatibility Complex Class II-Peptide Binding Affinity to CD4+ Epitope Immunogenicity in HIV-1 Envelope Glycoprotein

    Science.gov (United States)

    Li, Tingfeng; Steede, N. Kalaya; Nguyen, Hong-Nam P.; Freytag, Lucy C.; McLachlan, James B.; Mettu, Ramgopal R.; Robinson, James E.

    2014-01-01

    ABSTRACT Helper T-cell epitope dominance in human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 is not adequately explained by peptide binding to major histocompatibility complex (MHC) proteins. Antigen processing potentially influences epitope dominance, but few, if any, studies have attempted to reconcile the influences of antigen processing and MHC protein binding for all helper T-cell epitopes of an antigen. Epitopes of gp120 identified in both humans and mice occur on the C-terminal flanks of flexible segments that are likely to be proteolytic cleavage sites. In this study, the influence of gp120 conformation on the dominance pattern in gp120 from HIV strain 89.6 was examined in CBA mice, whose MHC class II protein has one of the most well defined peptide-binding preferences. Only one of six dominant epitopes contained the most conserved element of the I-Ak binding motif, an aspartic acid. Destabilization of the gp120 conformation by deletion of single disulfide bonds preferentially enhanced responses to the cryptic I-Ak motif-containing sequences, as reported by T-cell proliferation or cytokine secretion. Conversely, inclusion of CpG in the adjuvant with gp120 enhanced responses to the dominant CD4+ T-cell epitopes. The gp120 destabilization affected secretion of some cytokines more than others, suggesting that antigen conformation could modulate T-cell functions through mechanisms of antigen processing. IMPORTANCE CD4+ helper T cells play an essential role in protection against HIV and other pathogens. Thus, the sites of helper T-cell recognition, the dominant epitopes, are targets for vaccine design; and the corresponding T cells may provide markers for monitoring infection and immunity. However, T-cell epitopes are difficult to identify and predict. It is also unclear whether CD4+ T cells specific for one epitope are more protective than T cells specific for other epitopes. This work shows that the three-dimensional (3D) structure of an

  10. Specific interaction of CXCR4 with CD4 and CD8α: Functional analysis of the CD4/CXCR4 interaction in the context of HIV-1 envelope glycoprotein-mediated membrane fusion

    International Nuclear Information System (INIS)

    We investigated possible interactions between HIV-1 receptor (CD4) and the main coreceptors CXCR4 and CCR5. We found that CD4 and CXCR4 coexpressed in 293T cells form a complex that can be immunoprecipitated with antibodies directed against the extracellular domain of either protein. Mutagenesis revealed that the CD4/CXCR4 interaction maps to two previously uncharacterized basic motifs in the cytoplasmic domain of CD4. HIV-1 envelope glycoprotein-mediated membrane fusion was found to be independent of the ability of CD4 and CXCR4 to interact, whether fusion was studied in a virus-cell or a cell-cell model. However, this interaction might explain the adaptation of HIV-1 to CXCR4 as an alternative to CCR5. We found that CXCR4 also interacts with the cytoplasmic domain of CD8α in a way that is similar to the CD4/CXCR4 interaction. The CD4/CXCR4 and CD8α/CXCR4 interactions may thus be involved in cellular signaling pathways shared by the CD4 and CD8α molecules

  11. Correlation between carbohydrate structures on the envelope glycoprotein gp120 of HIV-1 and HIV-2 and syncytium inhibition with lectins

    DEFF Research Database (Denmark)

    Hansen, J E; Nielsen, C M; Nielsen, C;

    1989-01-01

    The binding of 13 different lectins to gp120 partially purified from two HIV-1 isolates and one HIV-2 isolate was studied by in situ staining on electrophoretically separated and electroblotted HIV antigens. The lectins concanavalin A, wheat germ agglutinin, Lens culinaris agglutinin, Vicia faba ...

  12. An HIV-1 envelope immunogen with W427S mutation in CD4 binding site induced more T follicular helper memory cells and reduced non-specific antibody responses.

    Directory of Open Access Journals (Sweden)

    Hao-Tong Yu

    Full Text Available The CD4 binding site (CD4BS of the HIV-1 envelope glycoprotein (Env contains epitopes for broadly neutralizing antibody (nAb and is the target for the vaccine development. However, the CD4BS core including residues 425-430 overlaps the B cell superantigen site and may be related to B cell exhaustion in HIV-1 infection. Furthermore, production of nAb and high-affinity plasma cells needs germinal center reaction and the help of T follicular helper (Tfh cells. We believe that strengthening the ability of Env CD4BS in inducing Tfh response and decreasing the effects of the superantigen are the strategies for eliciting nAb and development of HIV-1 vaccine. We constructed a gp120 mutant W427S of an HIV-1 primary R5 strain and examined its ability in the elicitation of Ab and the production of Tfh by immunization of BALB/c mice. We found that the trimeric wild-type gp120 can induce more non-specific antibody-secreting plasma cells, higher serum IgG secretion, and more Tfh cells by splenocyte. The modified W427S gp120 elicits higher levels of specific binding antibodies as well as nAbs though it produces less Tfh cells. Furthermore, higher Tfh cell frequency does not correlate to the specific binding Abs or nAbs indicating that the wild-type gp120 induced some non-specific Tfh that did not contribute to the production of specific Abs. This gp120 mutant led to more memory Tfh production, especially, the effector memory Tfh cells. Taken together, W427S gp120 could induce higher level of specific binding and neutralizing Ab production that may be associated with the reduction of non-specific Tfh but strengthening of the memory Tfh.

  13. Evolutionary and Structural Features of the C2, V3 and C3 Envelope Regions Underlying the Differences in HIV-1 and HIV-2 Biology and Infection

    OpenAIRE

    Helena Barroso; Pedro Borrego; Inês Bártolo; José Maria Marcelino; Carlos Família; Alexandre Quintas; Nuno Taveira

    2011-01-01

    This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Users must also make clear the license terms under which the work was published. Background: Unlike in HIV-1 infection, the majority of HIV-2 patients produce broadly reactive neutralizing antibodies, control viral replication and survive as elite con...

  14. Correlation between carbohydrate structures on the envelope glycoprotein gp120 of HIV-1 and HIV-2 and syncytium inhibition with lectins

    DEFF Research Database (Denmark)

    Hansen, J E; Nielsen, C M; Nielsen, C;

    1989-01-01

    The binding of 13 different lectins to gp120 partially purified from two HIV-1 isolates and one HIV-2 isolate was studied by in situ staining on electrophoretically separated and electroblotted HIV antigens. The lectins concanavalin A, wheat germ agglutinin, Lens culinaris agglutinin, Vicia faba...... agglutinin, Pisum sativum agglutinin and phytohaem(erythro)agglutinin bound to gp120 of all three isolates. The carbohydrate of gp120 recognized by lectins was thus arranged in at least four types of glycans: a high mannose type glycan, a bisected hybrid or complex type glycan, a biantennary fucosylated...

  15. Conformational instability governed by disulfide bonds partitions the dominant from subdominant helper T-cell responses specific for HIV-1 envelope glycoprotein gp120

    OpenAIRE

    Nguyen, Hong-Nam P.; Steede, N. Kalaya; Robinson, James E.; Landry, Samuel J.

    2015-01-01

    Most individuals infected with human immunodeficiency virus type 1 (HIV-1) generate a CD4+ T-cell response that is dominated by a few epitopes. Immunodominance may be counterproductive because a broad CD4+ T-cell response is associated with reduced viral load. Previous studies indicated that antigen three-dimensional structure controls antigen processing and presentation and therefore CD4+ T-cell epitope dominance. Dominant epitopes occur adjacent to the V1-V2, V3, and V4 loops because proteo...

  16. Structural analysis of the unmutated ancestor of the HIV-1 envelope V2 region antibody CH58 isolated from an RV144 vaccine efficacy trial vaccinee

    Directory of Open Access Journals (Sweden)

    Nathan I. Nicely

    2015-07-01

    Full Text Available Human monoclonal antibody CH58 isolated from an RV144 vaccinee binds at Lys169 of the HIV-1 Env gp120 V2 region, a site of vaccine-induced immune pressure. CH58 neutralizes HIV-1 CRF_01 AE strain 92TH023 and mediates ADCC against CD4+ T cell targets infected with CRF_01 AE tier 2 virus. CH58 and other antibodies that bind to a gp120 V2 epitope have a second light chain complementarity determining region (LCDR2 bearing a glutamic acid, aspartic acid (ED motif involved in forming salt bridges with polar, basic side amino acid side chains in V2. In an effort to learn how V2 responses develop, we determined the crystal structures of the CH58-UA antibody unliganded and bound to V2 peptide. The structures showed an LCDR2 structurally pre-conformed from germline to interact with V2 residue Lys169. LCDR3 was subject to conformational selection through the affinity maturation process. Kinetic analyses demonstrate that only a few contacts were responsible for a 2000-fold increase in KD through maturation, and this effect was predominantly due to an improvement in off-rate. This study shows that preconformation and preconfiguration can work in concert to produce antibodies with desired immunogenic properties.

  17. A rev1-vpu polymorphism unique to HIV-1 subtype A and C strains impairs envelope glycoprotein expression from rev-vpu-env cassettes and reduces virion infectivity in pseudotyping assays

    International Nuclear Information System (INIS)

    Functional studies of HIV-1 envelope glycoproteins (Envs) commonly include the generation of pseudoviruses, which are produced by co-transfection of rev-vpu-env cassettes with an env-deficient provirus. Here, we describe six Env constructs from transmitted/founder HIV-1 that were defective in the pseudotyping assay, although two produced infectious virions when expressed from their cognate proviruses. All of these constructs exhibited an unusual gene arrangement in which the first exon of rev (rev1) and vpu were in the same reading frame without an intervening stop codon. Disruption of the rev1-vpu fusion gene by frameshift mutation, stop codon, or abrogation of the rev initiation codon restored pseudovirion infectivity. Introduction of the fusion gene into wildtype Env cassettes severely compromised their function. The defect was not due to altered env and rev transcription or a dominant negative effect of the expressed fusion protein, but seemed to be caused by inefficient translation at the env initiation codon. Although the rev1-vpu polymorphism affects Env expression only in vitro, it can cause problems in studies requiring Env complementation, such as analyses of co-receptor usage and neutralization properties, since 3% of subtype A, 20% of subtype C and 5% of CRF01A/E viruses encode the fusion gene. A solution is to eliminate the rev initiation codon when amplifying rev-vpu-env cassettes since this increases Env expression irrespective of the presence of the polymorphism.

  18. HIV-1 adaptation to low levels of CCR5 results in V3 and V2 loop changes that increase envelope pathogenicity, CCR5 affinity and decrease susceptibility to Maraviroc.

    Science.gov (United States)

    Garg, Himanshu; Lee, Raphael T C; Maurer-Stroh, Sebastian; Joshi, Anjali

    2016-06-01

    Variability in CCR5 levels in the human population is suggested to affect virus evolution, fitness and the course of HIV disease. We previously demonstrated that cell surface CCR5 levels directly affect HIV Envelope mediated bystander apoptosis. In this study, we attempted to understand HIV evolution in the presence of low levels of CCR5, mimicking the limiting CCR5 levels inherent to the host. HIV-1 adaptation in a T cell line expressing low levels of CCR5 resulted in two specific mutations; N302Y and E172K. The N302Y mutation led to accelerated virus replication, increase in Maraviroc IC50 and an increase in Envelope mediated bystander apoptosis in low CCR5 expressing cells. Analysis of subtype B sequences showed that N302Y is over-represented in CXCR4 tropic viruses in comparison to CCR5 tropic isolates. Considering the variability in CCR5 levels between individuals, our findings have implications for virus evolution, MVC susceptibility as well as HIV pathogenesis.

  19. Induction of humoral and cellular immune responses against the HIV-1 envelope protein using γ-retroviral virus-like particles

    Directory of Open Access Journals (Sweden)

    Purcell Damian FJ

    2011-08-01

    Full Text Available Abstract This study evaluates the immunogenicity of the HIV envelope protein (env in mice presented either attached to γ-retroviral virus-like-particles (VLPs, associated with cell-derived microsomes or as solubilized recombinant protein (gp160. The magnitude and polyfunctionality of the cellular immune response was enhanced when delivering HIV env in the VLP or microsome form compared to recombinant gp160. Humoral responses measured by antibody titres were comparable across the groups and low levels of antibody neutralization were observed. Lastly, we identified stronger IgG2a class switching in the two particle-delivered antigen vaccinations modalities compared to recombinant gp160.

  20. Conformational instability governed by disulfide bonds partitions the dominant from subdominant helper T-cell responses specific for HIV-1 envelope glycoprotein gp120

    Science.gov (United States)

    Nguyen, Hong-Nam P.; Steede, N. Kalaya; Robinson, James E.; Landry, Samuel J.

    2015-01-01

    Most individuals infected with human immunodeficiency virus type 1 (HIV-1) generate a CD4+ T-cell response that is dominated by a few epitopes. Immunodominance may be counterproductive because a broad CD4+ T-cell response is associated with reduced viral load. Previous studies indicated that antigen three-dimensional structure controls antigen processing and presentation and therefore CD4+ T-cell epitope dominance. Dominant epitopes occur adjacent to the V1-V2, V3, and V4 loops because proteolytic antigen processing in the loops promotes presentation of adjacent sequences. In this study, three gp120 (strain JR-FL) variants were constructed, in which deletions of single outer-domain disulfide bonds were expected to introduce local conformational flexibility and promote presentation of additional CD4+ T-cell epitopes. Following mucosal immunization of C57BL/6 mice with wild-type or variant gp120 lacking the V3-flanking disulfide bond, the typical pattern of dominant epitopes was observed, suggesting that the disulfide bond posed no barrier to antigen presentation. In mice that lacked gamma interferoninducible lysosomal thioreductase (GILT), proliferative responses to the typically dominant epitopes of gp120 were selectively depressed, and the dominance pattern was rearranged. Deletion of the V3-flanking disulfide bond or one of the V4-flanking disulfide bonds partially restored highly proliferative responses to the typically dominant epitopes. These results reveal an acute dependence of dominant CD4+ T-cell responses on the native gp120 conformation. PMID:25944298

  1. Psychoneuroimmunology and HIV-1.

    Science.gov (United States)

    Antoni, Michael H.; And Others

    1990-01-01

    Presents evidence describing benefits of behavioral interventions such as aerobic exercise training on both psychological and immunological functioning among high risk human immunodeficiency virus-Type 1 (HIV-1) seronegative and very early stage seropositive homosexual men. HIV-1 infection is cast as chronic disease for which early…

  2. Identification of the gC1qR sites for the HIV-1 viral envelope protein gp41 and the HCV core protein: Implications in viral-specific pathogenesis and therapy.

    Science.gov (United States)

    Pednekar, Lina; Valentino, Alisa; Ji, Yan; Tumma, Nithin; Valentino, Christopher; Kadoor, Adarsh; Hosszu, Kinga K; Ramadass, Mahalakshmi; Kew, Richard R; Kishore, Uday; Peerschke, Ellinor I B; Ghebrehiwet, Berhane

    2016-06-01

    A substantial body of evidence accumulated over the past 20 years supports the concept that gC1qR is a major pathogen-associated pattern recognition receptor (PRR). This conclusion is based on the fact that, a wide range of bacterial and viral ligands are able to exploit gC1qR to either suppress the host's immune response and thus enhance their survival, or to gain access into cells to initiate disease. Of the extensive array of viral ligands that have affinity for gC1qR, the HIV-1 envelope glycoprotein gp41, and the core protein of hepatitis C virus (HCV) are of major interest as they are known to contribute to the high morbidity and mortality caused by these pathogens. While the HCV core protein binds gC1qR and suppresses T cell proliferation resulting in a significantly diminished immune response, the gp41 employs gC1qR to induce the surface expression of the NK cell ligand, NKp44L, on uninfected CD4(+) T cells, thereby rendering them susceptible to autologous destruction by NKp44 receptor expressing NK cells. Because of the potential for the design of peptide-based or antibody-based therapeutic options, the present studies were undertaken to define the gC1qR interaction sites for these pathogen-associated molecular ligands. Employing a solid phase microplate-binding assay, we examined the binding of each viral ligand to wild type gC1qR and 11 gC1qR deletion mutants. The results obtained from these studies have identified two major HCV core protein sites on a domain of gC1qR comprising of residues 144-148 and 196-202. Domain 196-202 in turn, is located in the last half of the larger gC1qR segment encoded by exons IV-VI (residues 159-282), which was proposed previously to contain the site for HCV core protein. The major gC1qR site for gp41 on the other hand, was found to be in a highly conserved region encoded by exon IV and comprises of residues 174-180. Interestingly, gC1qR residues 174-180 also constitute the cell surface-binding site for soluble gC1qR (sgC1q

  3. Aggressive HIV-1?

    OpenAIRE

    van der Hoek Lia; de Ronde Anthony; Berkhout Ben

    2005-01-01

    Abstract New York City health officials announced on February 11, 2005 that a patient rapidly developed full-blown AIDS shortly after being diagnosed with a rare, drug-resistant strain of HIV-1. The New York City Department of Health issued an alert to all hospitals and doctors and a press conference was held to announce the emergence of an aggressive HIV-1 strain that may be difficult to treat and that appears to trigger rapid progression to AIDS. Is the panic justified?

  4. Artificial 64-Residue HIV-1 Enhancer-Binding Peptide Is a Potent Inhibitor of Viral Replication in HIV-1-Infected Cells

    OpenAIRE

    Mouhssin Oufir; Bisset, Leslie R.; Hoffmann, Stefan R. K.; Gongda Xue; Stephan Klauser; Bianca Bergamaschi; Alain Gervaix; Jürg Böni; Jörg Schüpbach; Bernd Gutte

    2011-01-01

    An artificial HIV-1 enhancer-binding peptide was extended by nine consecutive arginine residues at the C-terminus and by the nuclear localization signal of SV40 large T antigen at the N-terminus. The resulting synthetic 64-residue peptide was found to bind to the two enhancers of the HIV-1 long terminal repeat, cross the plasma membrane and the nuclear envelope of human cells, and suppress the HIV-1 enhancer-controlled expression of a green fluorescent protein reporter gene. Moreover, HIV-1 r...

  5. Phenotypic Knockout of HIV-1 Chemokine Coreceptor CXCR4 and CCR5 by Intrakines for Blocking HIV-1 Infection

    Institute of Scientific and Technical Information of China (English)

    张颖; 张岩; 王平忠; 王九平; 黄长形; 孙永涛; 白雪帆

    2004-01-01

    To investigate the phenotypic knockout of HIV-1 chemokine coreceptor CXCR4 and CCR5 by intrakines and its inhibitory effect on HIV-1 infection. Primary human PBLs were transduced with the recombinant vector pLNCX-R-K-S-K(△NGFR), followed by anti-NGFR/anti-IgG-magnetic bead method selection and FCM detection. The transduced PBLs were infected with DP1 HIV-1 virus thereafter envelope-mediated syncytium formation and p24 detection were carried out to study the blockage of HIV-1 infection by co-inactivation of CCR5 and CXCR4. pLNCX-R-K-S-K (△NGFR)-transduced PBILs were isolated with an anti-NGFR/anti-IgG-magnetic bead method. After isolation, about 70% of the PBLs were positive for the NGFR marker. When the transduced PBLs were infected with DP1 HIV-1 virus, envelop-mediated syncytium formation was almost completely inhibited by pLNCX-R-K-S-K(△NGFR) transfection. Also, p24 antigen was very low in the cultures of pLNCX-R-K-S-K (△NGFR) transduced PBLs. pLNCX-R-K-S-K(△NGFR) transduction inhibited the production of DP1 p24 antigen by 15%, 43% and 19% on days 4, 7 and 10 respectively. The lymphocytes with the phenotypic knockout of CCR5 and CXCR4 could protect primary human PBLs from DP1 HIV-1 virus infection.

  6. Morphogenesis of the infectious HIV-1 virion

    Directory of Open Access Journals (Sweden)

    Jun-Ichi eSakuragi

    2011-12-01

    Full Text Available The virion of HIV-1 is spherical and viral glycoprotein spikes (gp120, gp41 protrude from its envelope. The characteristic cone-shaped core exists within the virion, caging the ribonucleoprotein (RNP complex, which is comprised of viral RNA, nucleocapsid (NC and viral enzymes. The HIV-1 virion is budded and released from the infected cell as an immature donut-shaped particle. During or immediately after release, viral protease (PR is activated and subsequently processes the viral structural protein Gag. Through this maturation process, virions acquire infectivity, but its mechanism and transition of morphology largely remain unclear. Recent technological advances in experimental devices and techniques have made it possible to closely dissect the viral production site on the cell, the exterior – or even the interior – of an individual virion, and many new aspects on virion morphology and maturation. In this manuscript, I review the morphogenesis of HIV-1 virions. I focus on several studies, including some of our recent findings, which examined virion formation and/or maturation processes. The story of novel compound, which inhibits virion maturation, and the importance of maturation research are also discussed.

  7. HIV-1 Antiretroviral Drug Therapy

    OpenAIRE

    Arts, Eric J.; Hazuda, Daria J.

    2012-01-01

    The most significant advance in the medical management of HIV-1 infection has been the treatment of patients with antiviral drugs, which can suppress HIV-1 replication to undetectable levels. The discovery of HIV-1 as the causative agent of AIDS together with an ever-increasing understanding of the virus replication cycle have been instrumental in this effort by providing researchers with the knowledge and tools required to prosecute drug discovery efforts focused on targeted inhibition with ...

  8. Transplanting supersites of HIV-1 vulnerability.

    Directory of Open Access Journals (Sweden)

    Tongqing Zhou

    Full Text Available One strategy for isolating or eliciting antibodies against a specific target region on the envelope glycoprotein trimer (Env of the human immunodeficiency virus type 1 (HIV-1 involves the creation of site transplants, which present the target region on a heterologous protein scaffold with preserved antibody-binding properties. If the target region is a supersite of HIV-1 vulnerability, recognized by a collection of broadly neutralizing antibodies, this strategy affords the creation of "supersite transplants", capable of binding (and potentially eliciting antibodies similar to the template collection of effective antibodies. Here we transplant three supersites of HIV-1 vulnerability, each targeted by effective neutralizing antibodies from multiple donors. To implement our strategy, we chose a single representative antibody against each of the target supersites: antibody 10E8, which recognizes the membrane-proximal external region (MPER on the HIV-1 gp41 glycoprotein; antibody PG9, which recognizes variable regions one and two (V1V2 on the HIV-1 gp120 glycoprotein; and antibody PGT128 which recognizes a glycopeptide supersite in variable region 3 (glycan V3 on gp120. We used a structural alignment algorithm to identify suitable acceptor proteins, and then designed, expressed, and tested antigenically over 100-supersite transplants in a 96-well microtiter-plate format. The majority of the supersite transplants failed to maintain the antigenic properties of their respective template supersite. However, seven of the glycan V3-supersite transplants exhibited nanomolar affinity to effective neutralizing antibodies from at least three donors and recapitulated the mannose9-N-linked glycan requirement of the template supersite. The binding of these transplants could be further enhanced by placement into self-assembling nanoparticles. Essential elements of the glycan V3 supersite, embodied by as few as 3 N-linked glycans and ∼ 25 Env residues, can be

  9. Monoclonal Antibodies Recognizing HIV-1 gp41 Could Inhibit Env-Mediated Syncytium Formation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Geng; CHEN Yinghua

    2005-01-01

    Some monoclonal antibodies (mAbs) could inhibit infection by HIV-1. In this study, four mAbs against HIV-1 gp41 were prepared in mice. All four mAbs could bind to the recombinant soluble gp41 and recognize the native envelope glycoprotein gp160 expressed on the HIV-Env+ CHO-WT cell in flow cytometry analysis. Interestingly, the results show that all four mAbs purified by affinity chromatography could inhibit HIV-1 Env-mediated membrane fusion (syncytium formation) by 40%-60% at 10 μg/mL, which implies potential inhibitory activities against HIV-1.

  10. Phylodynamics of HIV-1 from a Phase III AIDS vaccine trial in North America

    OpenAIRE

    Perez-Losada, M.; Jobes, D. V.; Sinangil, F.; Crandall, K. A.; Posada, D; Berman, P.W.

    2010-01-01

    In 2003, a phase III placebo-controlled trial (VAX004) of a candidate HIV-1 vaccine (AIDSVAX B/B) was completed in 5,403 volunteers at high risk for HIV-1 infection from North America and the Netherlands. A total of 368 individuals became infected with HIV-1 during the trial. The envelope glycoprotein gene (gp120) from the HIV-1 subtype B viruses infecting 349 patients was sequenced from clinical samples taken as close as possible to the time of diagnosis, rendering a final data set of 1,047 ...

  11. Estimating the Impact of Plasma HIV-1 RNA Reductions on Heterosexual HIV-1 Transmission Risk

    OpenAIRE

    Lingappa, Jairam R.; Hughes, James P.; Wang, Richard S.; BAETEN, Jared M.; Connie Celum; Gray, Glenda E.; Stevens, Wendy S.; Deborah Donnell; Campbell, Mary S.; Carey Farquhar; Essex, M.; Mullins, James I.; Coombs, Robert W.; Helen Rees; Lawrence Corey

    2010-01-01

    BACKGROUND: The risk of sexual transmission of HIV-1 is strongly associated with the level of HIV-1 RNA in plasma making reduction in HIV-1 plasma levels an important target for HIV-1 prevention interventions. A quantitative understanding of the relationship of plasma HIV-1 RNA and HIV-1 transmission risk could help predict the impact of candidate HIV-1 prevention interventions that operate by reducing plasma HIV-1 levels, such as antiretroviral therapy (ART), therapeutic vaccines, and other ...

  12. Hyperthermia stimulates HIV-1 replication.

    Directory of Open Access Journals (Sweden)

    Ferdinand Roesch

    Full Text Available HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C and Heat Shock Proteins (HSPs modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

  13. Developing strategies for HIV-1 eradication

    OpenAIRE

    Durand, Christine M.; Blankson, Joel N.; Siliciano, Robert F.

    2012-01-01

    Highly active antiretroviral therapy (HAART) suppresses HIV-1 replication, transforming the outlook for infected patients. However, reservoirs of replication-competent forms of the virus persist during HAART, and when treatment is stopped, high rates of HIV-1 replication return. Recent insights into HIV-1 latency, as well as a report that HIV-1 infection was eradicated in one individual, have renewed interest in finding a cure for HIV-1 infection. Strategies for HIV-1 eradication include gene...

  14. Hyperthermia stimulates HIV-1 replication.

    OpenAIRE

    Ferdinand Roesch; Oussama Meziane; Anna Kula; Sébastien Nisole; Françoise Porrot; Ian Anderson; Fabrizio Mammano; Ariberto Fassati; Alessandro Marcello; Monsef Benkirane; Olivier Schwartz

    2012-01-01

    International audience HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C) and Heat Shock Proteins (HSPs) modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C) on HIV-1 infection has not been extensively inve...

  15. Fucoidans as Potential Inhibitors of HIV-1

    Directory of Open Access Journals (Sweden)

    Vladimir S. Prassolov

    2013-08-01

    Full Text Available The antiviral activity of different structure fucoidans (α-l-fucans and galactofucans was studied using two model viral systems based on a lentiviral vectors and a replication competent Moloney murine leukemia virus (Mo-MuLV. It was found that investigated fucoidans have no cytotoxic effects on Jurkat and SC-1cell at the concentration range of 0.001–100 µg/mL. Fucoidans with different efficiency suppressed transduction of Jurkat cell line by pseudo-HIV-1 particles carrying the envelope protein of HIV-1 and infection of SC-1 cells by Mo-MuLV. According to our data, all natural fucoidans can be considered as potential anti-HIV agents regardless of their carbohydrate backbone and degree of sulfating, since their activity is shown at low concentrations (0.001–0.05 µg/mL. High molecular weight fucoidans isolated from Saccharina cichorioides (1.3-α-l-fucan, and S. japonica (galactofucan were the most effective inhibitors.

  16. Fucoidans as potential inhibitors of HIV-1.

    Science.gov (United States)

    Prokofjeva, Maria M; Imbs, Tatyana I; Shevchenko, Natalya M; Spirin, Pavel V; Horn, Stefan; Fehse, Boris; Zvyagintseva, Tatyana N; Prassolov, Vladimir S

    2013-08-19

    The antiviral activity of different structure fucoidans (α-l-fucans and galactofucans) was studied using two model viral systems based on a lentiviral vectors and a replication competent Moloney murine leukemia virus (Mo-MuLV). It was found that investigated fucoidans have no cytotoxic effects on Jurkat and SC-1cell at the concentration range of 0.001-100 µg/mL. Fucoidans with different efficiency suppressed transduction of Jurkat cell line by pseudo-HIV-1 particles carrying the envelope protein of HIV-1 and infection of SC-1 cells by Mo-MuLV. According to our data, all natural fucoidans can be considered as potential anti-HIV agents regardless of their carbohydrate backbone and degree of sulfating, since their activity is shown at low concentrations (0.001-0.05 µg/mL). High molecular weight fucoidans isolated from Saccharina cichorioides (1.3-α-l-fucan), and S. japonica (galactofucan) were the most effective inhibitors.

  17. RNA Control of HIV-1 Particle Size Polydispersity

    CERN Document Server

    Faivre-Moskalenko, Cendrine; Thomas, Audrey; Tartour, Kevin; Beck, Yvonne; Iazykov, Maksym; Danial, John; Lourdin, Morgane; Muriaux, Delphine; Castelnovo, Martin

    2014-01-01

    HIV-1, an enveloped RNA virus, produces viral particles that are known to be much more heterogeneous in size than is typical of non-enveloped viruses. We present here a novel strategy to study HIV-1 Viral Like Particles (VLP) assembly by measuring the size distribution of these purified VLPs and subsequent viral cores thanks to Atomic Force Microscopy imaging and statistical analysis. This strategy allowed us to identify whether the presence of viral RNA acts as a modulator for VLPs and cores size heterogeneity in a large population of particles. These results are analyzed in the light of a recently proposed statistical physics model for the self-assembly process. In particular, our results reveal that the modulation of size distribution by the presence of viral RNA is qualitatively reproduced, suggesting therefore an entropic origin for the modulation of RNA uptake by the nascent VLP.

  18. SHIV-1157i and passaged progeny viruses encoding R5 HIV-1 clade C env cause AIDS in rhesus monkeys

    OpenAIRE

    Siddappa Nagadenahalli B; Kramer Victor G; Chenine Agnès L; Sharma Prachi; Ong Helena; Song Ruijiang; Rasmussen Robert A; Humbert Michael; Xu Weidong; Else James G; Novembre Francis J; Strobert Elizabeth; O'Neil Shawn P; Ruprecht Ruth M

    2008-01-01

    Abstract Background Infection of nonhuman primates with simian immunodeficiency virus (SIV) or chimeric simian-human immunodeficiency virus (SHIV) strains is widely used to study lentiviral pathogenesis, antiviral immunity and the efficacy of AIDS vaccine candidates. SHIV challenges allow assessment of anti-HIV-1 envelope responses in primates. As such, SHIVs should mimic natural HIV-1 infection in humans and, to address the pandemic, encode HIV-1 Env components representing major viral subty...

  19. Maternal HIV-1 envelope–specific antibody responses and reduced risk of perinatal transmission

    Science.gov (United States)

    Permar, Sallie R.; Fong, Youyi; Vandergrift, Nathan; Fouda, Genevieve G.; Gilbert, Peter; Parks, Robert; Jaeger, Frederick H.; Pollara, Justin; Martelli, Amanda; Liebl, Brooke E.; Lloyd, Krissey; Yates, Nicole L.; Overman, R. Glenn; Shen, Xiaoying; Whitaker, Kaylan; Chen, Haiyan; Pritchett, Jamie; Solomon, Erika; Friberg, Emma; Marshall, Dawn J.; Whitesides, John F.; Gurley, Thaddeus C.; Von Holle, Tarra; Martinez, David R.; Cai, Fangping; Kumar, Amit; Xia, Shi-Mao; Lu, Xiaozhi; Louzao, Raul; Wilkes, Samantha; Datta, Saheli; Sarzotti-Kelsoe, Marcella; Liao, Hua-Xin; Ferrari, Guido; Alam, S. Munir; Montefiori, David C.; Denny, Thomas N.; Moody, M. Anthony; Tomaras, Georgia D.; Gao, Feng; Haynes, Barton F.

    2015-01-01

    Despite the wide availability of antiretroviral drugs, more than 250,000 infants are vertically infected with HIV-1 annually, emphasizing the need for additional interventions to eliminate pediatric HIV-1 infections. Here, we aimed to define humoral immune correlates of risk of mother-to-child transmission (MTCT) of HIV-1, including responses associated with protection in the RV144 vaccine trial. Eighty-three untreated, HIV-1–transmitting mothers and 165 propensity score–matched nontransmitting mothers were selected from the Women and Infants Transmission Study (WITS) of US nonbreastfeeding, HIV-1–infected mothers. In a multivariable logistic regression model, the magnitude of the maternal IgG responses specific for the third variable loop (V3) of the HIV-1 envelope was predictive of a reduced risk of MTCT. Neutralizing Ab responses against easy-to-neutralize (tier 1) HIV-1 strains also predicted a reduced risk of peripartum transmission in secondary analyses. Moreover, recombinant maternal V3–specific IgG mAbs mediated neutralization of autologous HIV-1 isolates. Thus, common V3-specific Ab responses in maternal plasma predicted a reduced risk of MTCT and mediated autologous virus neutralization, suggesting that boosting these maternal Ab responses may further reduce HIV-1 MTCT. PMID:26053661

  20. Escherichia coli surface display of single-chain antibody VRC01 against HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lin-Xu [Nebraska Center for Virology, Lincoln, NE (United States); School of Biological Sciences, University of Nebraska—Lincoln, Lincoln, NE 68583 (United States); Mellon, Michael [Nebraska Center for Virology, Lincoln, NE (United States); School of Veterinary Medicine and Biomedical Sciences, Lincoln, NE (United States); Bowder, Dane [Nebraska Center for Virology, Lincoln, NE (United States); School of Biological Sciences, University of Nebraska—Lincoln, Lincoln, NE 68583 (United States); Quinn, Meghan [Nebraska Center for Virology, Lincoln, NE (United States); School of Veterinary Medicine and Biomedical Sciences, Lincoln, NE (United States); Shea, Danielle; Wood, Charles [Nebraska Center for Virology, Lincoln, NE (United States); School of Biological Sciences, University of Nebraska—Lincoln, Lincoln, NE 68583 (United States); Xiang, Shi-Hua, E-mail: sxiang2@unl.edu [Nebraska Center for Virology, Lincoln, NE (United States); School of Veterinary Medicine and Biomedical Sciences, Lincoln, NE (United States)

    2015-01-15

    Human immunodeficiency virus type 1 (HIV-1) transmission and infection occur mainly via the mucosal surfaces. The commensal bacteria residing in these surfaces can potentially be employed as a vehicle for delivering inhibitors to prevent HIV-1 infection. In this study, we have employed a bacteria-based strategy to display a broadly neutralizing antibody VRC01, which could potentially be used to prevent HIV-1 infection. The VRC01 antibody mimics CD4-binding to gp120 and has broadly neutralization activities against HIV-1. We have designed a construct that can express the fusion peptide of the scFv-VRC01 antibody together with the autotransporter β-barrel domain of IgAP gene from Neisseria gonorrhoeae, which enabled surface display of the antibody molecule. Our results indicate that the scFv-VRC01 antibody molecule was displayed on the surface of the bacteria as demonstrated by flow cytometry and immunofluorescence microscopy. The engineered bacteria can capture HIV-1 particles via surface-binding and inhibit HIV-1 infection in cell culture. - Highlights: • Designed single-chain VRC01 antibody was demonstrated to bind HIV-1 envelope gp120. • Single-chain VRC01 antibody was successfully displayed on the surface of E. coli. • Engineered bacteria can absorb HIV-1 particles and prevent HIV-1 infection in cell culture.

  1. Application of a case–control study design to investigate genotypic signatures of HIV-1 transmission

    OpenAIRE

    Mota Talia M; Murray John M; Center Rob J; Purcell Damian F J; McCaw James M

    2012-01-01

    Abstract Background The characterization of HIV-1 transmission strains may inform the design of an effective vaccine. Shorter variable loops with fewer predicted glycosites have been suggested as signatures enriched in envelope sequences derived during acute HIV-1 infection. Specifically, a transmission-linked lack of glycosites within the V1 and V2 loops of gp120 provides greater access to an α4β7 binding motif, which promotes the establishment of infection. Also, a histidine at position 12 ...

  2. N-terminal Slit2 inhibits HIV-1 replication by regulating the actin cytoskeleton

    Directory of Open Access Journals (Sweden)

    Anand Appakkudal R

    2013-01-01

    Full Text Available Abstract Background Slit2 is a ~ 200 kDa secreted glycoprotein that has been recently shown to regulate immune functions. However, not much is known about its role in HIV (human immunodeficiency virus-1 pathogenesis. Results In the present study, we have shown that the N-terminal fragment of Slit2 (Slit2N (~120 kDa inhibits replication of both CXCR4 and CCR5-tropic HIV-1 viruses in T-cell lines and peripheral blood T-cells. Furthermore, we demonstrated inhibition of HIV-1 infection in resting CD4+ T-cells. In addition, we showed that Slit2N blocks cell-to-cell transmission of HIV-1. We have shown that Slit2N inhibits HIV-1 infection by blocking viral entry into T-cells. We also ruled out Slit2N-mediated inhibition of various other steps in the life cycle including binding, integration and viral transcription. Elucidation of the molecular mechanism revealed that Slit2N mediates its functional effects by binding to Robo1 receptor. Furthermore, we found that Slit2N inhibited Gp120-induced Robo1-actin association suggesting that Slit2N may inhibit cytoskeletal rearrangements facilitating HIV-1 entry. Studies into the mechanism of inhibition of HIV-1 revealed that Slit2N abrogated HIV-1 envelope-induced actin cytoskeletal dynamics in both T-cell lines and primary T-cells. We further showed that Slit2N specifically attenuated the HIV-1 envelope-induced signaling pathway consisting of Rac1, LIMK and cofilin that regulates actin polymerization. Conclusions Taken together, our results show that Slit2N inhibits HIV-1 replication through novel mechanisms involving modulation of cytoskeletal dynamics. Our study, thus, provides insights into the role of Slit2N in HIV-1 infection and underscores its potential in limiting viral replication in T-cells.

  3. Dimeric 2G12 as a potent protection against HIV-1.

    Directory of Open Access Journals (Sweden)

    Xin M Luo

    Full Text Available We previously showed that broadly neutralizing anti-HIV-1 antibody 2G12 (human IgG1 naturally forms dimers that are more potent than monomeric 2G12 in in vitro neutralization of various strains of HIV-1. In this study, we have investigated the protective effects of monomeric versus dimeric 2G12 against HIV-1 infection in vivo using a humanized mouse model. Our results showed that passively transferred, purified 2G12 dimer is more potent than 2G12 monomer at preventing CD4 T cell loss and suppressing the increase of viral load following HIV-1 infection of humanized mice. Using humanized mice bearing IgG "backpack" tumors that provided 2G12 antibodies continuously, we found that a sustained dimer concentration of 5-25 µg/ml during the course of infection provides effective protection against HIV-1. Importantly, 2G12 dimer at this concentration does not favor mutations of the HIV-1 envelope that would cause the virus to completely escape 2G12 neutralization. We have therefore identified dimeric 2G12 as a potent prophylactic reagent against HIV-1 in vivo, which could be used as part of an antibody cocktail to prevent HIV-1 infection.

  4. Curcumin derivatives as HIV-1 protease inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Z.; Li, J.; Craik, C.S.; Ortiz de Montellano, P.R. [Univ. of California, San Francisco, CA (United States)

    1993-12-31

    Curcumin, a non-toxic natural compound from Curcuma longa, has been found to be an HIV-1 protease inhibitor. Some of its derivatives were synthesized and their inhibitory activity against the HIV-1 protease was tested. Curcumin analogues containing boron enhanced the inhibitory activity. At least of the the synthesized compounds irreversibly inhibits the HIV-1 protease.

  5. Methylation: a regulator of HIV-1 replication?

    OpenAIRE

    Jeang Kuan-Teh; Yedavalli Venkat RK

    2007-01-01

    Abstract Recent characterizations of methyl transferases as regulators of cellular processes have spurred investigations into how methylation events might influence the HIV-1 life cycle. Emerging evidence suggests that protein-methylation can positively and negatively regulate HIV-1 replication. How DNA- and RNA- methylation might impact HIV-1 is also discussed.

  6. Diagnostik af HIV-1 infektionen

    DEFF Research Database (Denmark)

    Christiansen, C B; Dickmeiss, E; Bygbjerg, Ib Christian

    1991-01-01

    Different methods have been developed for the diagnosis of HIV infection, i.e. detection of antibodies, antigen and proviral DNA. ELISA methods for detecting HIV-1 antibodies are widely used as screening assays. A sample which is repeatedly positive with ELISA is re-tested with a confirmatory test......, e.g. western blot. Antibodies to HIV-1 are not detectable until 2-3 months after infection, but antigens may be detectable during the last weeks of this initial period, though they disappear with the appearance of the antibodies. In the later stages of HIV infection, HIV antigen is again detectable...... in a proportion of patients. Detection and quantitation of HIV antigen are used as indicators of disease progression and for monitoring the antiviral efficacy of therapeutic interventions. When no antibodies or antigens can be detected in persons suspected of having HIV infection, culture of HIV can be performed...

  7. The C-terminal sequence of IFITM1 regulates its anti-HIV-1 activity.

    Directory of Open Access Journals (Sweden)

    Rui Jia

    Full Text Available The interferon-inducible transmembrane (IFITM proteins inhibit a wide range of viruses. We previously reported the inhibition of human immunodeficiency virus type 1 (HIV-1 strain BH10 by human IFITM1, 2 and 3. It is unknown whether other HIV-1 strains are similarly inhibited by IFITMs and whether there exists viral countermeasure to overcome IFITM inhibition. We report here that the HIV-1 NL4-3 strain (HIV-1NL4-3 is not restricted by IFITM1 and its viral envelope glycoprotein is partly responsible for this insensitivity. However, HIV-1NL4-3 is profoundly inhibited by an IFITM1 mutant, known as Δ(117-125, which is deleted of 9 amino acids at the C-terminus. In contrast to the wild type IFITM1, which does not affect HIV-1 entry, the Δ(117-125 mutant diminishes HIV-1NL4-3 entry by 3-fold. This inhibition correlates with the predominant localization of Δ(117-125 to the plasma membrane where HIV-1 entry occurs. In spite of strong conservation of IFITM1 among most species, mouse IFITM1 is 19 amino acids shorter at its C-terminus as compared to human IFITM1 and, like the human IFITM1 mutant Δ(117-125, mouse IFITM1 also inhibits HIV-1 entry. This is the first report illustrating the role of viral envelope protein in overcoming IFITM1 restriction. The results also demonstrate the importance of the C-terminal region of IFITM1 in modulating the antiviral function through controlling protein subcellular localization.

  8. The Presence and Anti-HIV-1 Function of Tenascin C in Breast Milk and Genital Fluids

    Science.gov (United States)

    Jaeger, Frederick; McGuire, Erin; Fouda, Genevieve; Amos, Joshua; Barbas, Kimberly; Ohashi, Tomoo; Alam, S. Munir; Erickson, Harold; Permar, Sallie R.

    2016-01-01

    Tenascin-C (TNC) is a newly identified innate HIV-1-neutralizing protein present in breast milk, yet its presence and potential HIV-inhibitory function in other mucosal fluids is unknown. In this study, we identified TNC as a component of semen and cervical fluid of HIV-1-infected and uninfected individuals, although it is present at a significantly lower concentration and frequency compared to that of colostrum and mature breast milk, potentially due to genital fluid protease degradation. However, TNC was able to neutralize HIV-1 after exposure to low pH, suggesting that TNC could be active at low pH in the vaginal compartment. As mucosal fluids are complex and contain a number of proteins known to interact with the HIV-1 envelope, we further studied the relationship between the concentration of TNC and neutralizing activity in breast milk. The amount of TNC correlated only weakly with the overall innate HIV-1-neutralizing activity of breast milk of uninfected women and negatively correlated with neutralizing activity in milk of HIV-1 infected women, indicating that the amount of TNC in mucosal fluids is not adequate to impede HIV-1 transmission. Moreover, the presence of polyclonal IgG from milk of HIV-1 infected women, but not other HIV-1 envelope-binding milk proteins or monoclonal antibodies, blocked the neutralizing activity of TNC. Finally, as exogenous administration of TNC would be necessary for it to mediate measurable HIV-1 neutralizing activity in mucosal compartments, we established that recombinantly produced TNC has neutralizing activity against transmitted/founder HIV-1 strains that mimic that of purified TNC. Thus, we conclude that endogenous TNC concentration in mucosal fluids is likely inadequate to block HIV-1 transmission to uninfected individuals. PMID:27182834

  9. The Presence and Anti-HIV-1 Function of Tenascin C in Breast Milk and Genital Fluids.

    Directory of Open Access Journals (Sweden)

    Robin G Mansour

    Full Text Available Tenascin-C (TNC is a newly identified innate HIV-1-neutralizing protein present in breast milk, yet its presence and potential HIV-inhibitory function in other mucosal fluids is unknown. In this study, we identified TNC as a component of semen and cervical fluid of HIV-1-infected and uninfected individuals, although it is present at a significantly lower concentration and frequency compared to that of colostrum and mature breast milk, potentially due to genital fluid protease degradation. However, TNC was able to neutralize HIV-1 after exposure to low pH, suggesting that TNC could be active at low pH in the vaginal compartment. As mucosal fluids are complex and contain a number of proteins known to interact with the HIV-1 envelope, we further studied the relationship between the concentration of TNC and neutralizing activity in breast milk. The amount of TNC correlated only weakly with the overall innate HIV-1-neutralizing activity of breast milk of uninfected women and negatively correlated with neutralizing activity in milk of HIV-1 infected women, indicating that the amount of TNC in mucosal fluids is not adequate to impede HIV-1 transmission. Moreover, the presence of polyclonal IgG from milk of HIV-1 infected women, but not other HIV-1 envelope-binding milk proteins or monoclonal antibodies, blocked the neutralizing activity of TNC. Finally, as exogenous administration of TNC would be necessary for it to mediate measurable HIV-1 neutralizing activity in mucosal compartments, we established that recombinantly produced TNC has neutralizing activity against transmitted/founder HIV-1 strains that mimic that of purified TNC. Thus, we conclude that endogenous TNC concentration in mucosal fluids is likely inadequate to block HIV-1 transmission to uninfected individuals.

  10. A single HIV-1 cluster and a skewed immune homeostasis drive the early spread of HIV among resting CD4+ cell subsets within one month post-infection.

    Science.gov (United States)

    Bacchus, Charline; Cheret, Antoine; Avettand-Fenoël, Véronique; Nembot, Georges; Mélard, Adeline; Blanc, Catherine; Lascoux-Combe, Caroline; Slama, Laurence; Allegre, Thierry; Allavena, Clotilde; Yazdanpanah, Yazdan; Duvivier, Claudine; Katlama, Christine; Goujard, Cécile; Seksik, Bao Chau Phung; Leplatois, Anne; Molina, Jean-Michel; Meyer, Laurence; Autran, Brigitte; Rouzioux, Christine

    2013-01-01

    Optimizing therapeutic strategies for an HIV cure requires better understanding the characteristics of early HIV-1 spread among resting CD4+ cells within the first month of primary HIV-1 infection (PHI). We studied the immune distribution, diversity, and inducibility of total HIV-DNA among the following cell subsets: monocytes, peripheral blood activated and resting CD4 T cells, long-lived (naive [TN] and central-memory [TCM]) and short-lived (transitional-memory [TTM] and effector-memory cells [TEM]) resting CD4+T cells from 12 acutely-infected individuals recruited at a median 36 days from infection. Cells were sorted for total HIV-DNA quantification, phylogenetic analysis and inducibility, all studied in relation to activation status and cell signaling. One month post-infection, a single CCR5-restricted viral cluster was massively distributed in all resting CD4+ subsets from 88% subjects, while one subject showed a slight diversity. High levels of total HIV-DNA were measured among TN (median 3.4 log copies/million cells), although 10-fold less (p = 0.0005) than in equally infected TCM (4.5), TTM (4.7) and TEM (4.6) cells. CD3-CD4+ monocytes harbored a low viral burden (median 2.3 log copies/million cells), unlike equally infected resting and activated CD4+ T cells (4.5 log copies/million cells). The skewed repartition of resting CD4 subsets influenced their contribution to the pool of resting infected CD4+T cells, two thirds of which consisted of short-lived TTM and TEM subsets, whereas long-lived TN and TCM subsets contributed the balance. Each resting CD4 subset produced HIV in vitro after stimulation with anti-CD3/anti-CD28+IL-2 with kinetics and magnitude varying according to subset differentiation, while IL-7 preferentially induced virus production from long-lived resting TN cells. In conclusion, within a month of infection, a clonal HIV-1 cluster is massively distributed among resting CD4 T-cell subsets with a flexible inducibility, suggesting that

  11. Clinical significance of HIV-1 coreceptor usage

    Directory of Open Access Journals (Sweden)

    Lusso Paolo

    2010-01-01

    Full Text Available Abstract The identification of phenotypically distinct HIV-1 variants with different prevalence during the progression of the disease has been one of the earliest discoveries in HIV-1 biology, but its relevance to AIDS pathogenesis remains only partially understood. The physiological basis for the phenotypic variability of HIV-1 was elucidated with the discovery of distinct coreceptors employed by the virus to infect susceptible cells. The role of the viral phenotype in the variable clinical course and treatment outcome of HIV-1 infection has been extensively investigated over the past two decades. In this review, we summarize the major findings on the clinical significance of the HIV-1 coreceptor usage.

  12. Regional differences in prevalence of HIV-1 discordance in Africa and enrollment of HIV-1 discordant couples into an HIV-1 prevention trial.

    Directory of Open Access Journals (Sweden)

    Jairam R Lingappa

    Full Text Available BACKGROUND: Most HIV-1 transmission in Africa occurs among HIV-1-discordant couples (one partner HIV-1 infected and one uninfected who are unaware of their discordant HIV-1 serostatus. Given the high HIV-1 incidence among HIV-1 discordant couples and to assess efficacy of interventions for reducing HIV-1 transmission, HIV-1 discordant couples represent a critical target population for HIV-1 prevention interventions and prevention trials. Substantial regional differences exist in HIV-1 prevalence in Africa, but regional differences in HIV-1 discordance among African couples, has not previously been reported. METHODOLOGY/PRINCIPAL FINDINGS: The Partners in Prevention HSV-2/HIV-1 Transmission Trial ("Partners HSV-2 Study", the first large HIV-1 prevention trial in Africa involving HIV-1 discordant couples, completed enrollment in May 2007. Partners HSV-2 Study recruitment data from 12 sites from East and Southern Africa were used to assess HIV-1 discordance among couples accessing couples HIV-1 counseling and testing, and to correlate with enrollment of HIV-1 discordant couples. HIV-1 discordance at Partners HSV-2 Study sites ranged from 8-31% of couples tested from the community. Across all study sites and, among all couples with one HIV-1 infected partner, almost half (49% of couples were HIV-1 discordant. Site-specific monthly enrollment of HIV-1 discordant couples into the clinical trial was not directly associated with prevalence of HIV-1 discordance, but was modestly correlated with national HIV-1 counseling and testing rates and access to palliative care/basic health care (r = 0.74, p = 0.09. CONCLUSIONS/SIGNIFICANCE: HIV-1 discordant couples are a critical target for HIV-1 prevention in Africa. In addition to community prevalence of HIV-1 discordance, national infrastructure for HIV-1 testing and healthcare delivery and effective community outreach strategies impact recruitment of HIV-1 discordant couples into HIV-1 prevention trials.

  13. Maturation Pathways of Cross-Reactive HIV-1 Neutralizing Antibodies

    Directory of Open Access Journals (Sweden)

    Dimiter S. Dimitrov

    2009-11-01

    Full Text Available Several human monoclonal antibodies (hmAbs and antibody fragments, including the best characterized in terms of structure-function b12 and Fab X5, exhibit relatively potent and broad HIV-1 neutralizing activity. However, the elicitation of b12 or b12-like antibodies in vivo by vaccine immunogens based on the HIV-1 envelope glycoprotein (Env has not been successful. B12 is highly divergent from the closest corresponding germline antibody while X5 is less divergent. We have hypothesized that the relatively high degree of specific somatic hypermutations may preclude binding of the HIV-1 envelope glycoprotein (Env to closest germline antibodies, and that identifying antibodies that are intermediates in the pathways to maturation could help design novel vaccine immunogens to guide the immune system for their enhanced elicitation. In support of this hypothesis we have previously found that a germline-like b12 (monovalent and bivalent scFv as an Fc fusion protein or IgG lacks measurable binding to an Env as measured by ELISA with a sensitivity in the μM range [1]; here we present evidence confirming and expanding these findings for a panel of Envs. In contrast, a germline-like scFv X5 bound Env with high (nM affinity. To begin to explore the maturation pathways of these antibodies we identified several possible b12 intermediate antibodies and tested their neutralizing activity. These intermediate antibodies neutralized only some HIV-1 isolates and with relatively weak potency. In contrast, germline-like scFv X5 neutralized a subset of the tested HIV-1 isolates with comparable efficiencies to that of the mature X5. These results could help explain the relatively high immunogenicity of the coreceptor binding site on gp120 and the abundance of CD4-induced (CD4i antibodies in HIV-1-infected patients (X5 is a CD4i antibody as well as the maturation pathway of X5. They also can help identify antigens that can bind specifically to b12 germline and

  14. Estimating the impact of plasma HIV-1 RNA reductions on heterosexual HIV-1 transmission risk.

    Directory of Open Access Journals (Sweden)

    Jairam R Lingappa

    Full Text Available BACKGROUND: The risk of sexual transmission of HIV-1 is strongly associated with the level of HIV-1 RNA in plasma making reduction in HIV-1 plasma levels an important target for HIV-1 prevention interventions. A quantitative understanding of the relationship of plasma HIV-1 RNA and HIV-1 transmission risk could help predict the impact of candidate HIV-1 prevention interventions that operate by reducing plasma HIV-1 levels, such as antiretroviral therapy (ART, therapeutic vaccines, and other non-ART interventions. METHODOLOGY/PRINCIPAL FINDINGS: We use prospective data collected from 2004 to 2008 in East and Southern African HIV-1 serodiscordant couples to model the relationship of plasma HIV-1 RNA levels and heterosexual transmission risk with confirmation of HIV-1 transmission events by HIV-1 sequencing. The model is based on follow-up of 3381 HIV-1 serodiscordant couples over 5017 person-years encompassing 108 genetically-linked HIV-1 transmission events. HIV-1 transmission risk was 2.27 per 100 person-years with a log-linear relationship to log(10 plasma HIV-1 RNA. The model predicts that a decrease in average plasma HIV-1 RNA of 0.74 log(10 copies/mL (95% CI 0.60 to 0.97 reduces heterosexual transmission risk by 50%, regardless of the average starting plasma HIV-1 level in the population and independent of other HIV-1-related population characteristics. In a simulated population with a similar plasma HIV-1 RNA distribution the model estimates that 90% of overall HIV-1 infections averted by a 0.74 copies/mL reduction in plasma HIV-1 RNA could be achieved by targeting this reduction to the 58% of the cohort with plasma HIV-1 levels ≥4 log(10 copies/mL. CONCLUSIONS/SIGNIFICANCE: This log-linear model of plasma HIV-1 levels and risk of sexual HIV-1 transmission may help estimate the impact on HIV-1 transmission and infections averted from candidate interventions that reduce plasma HIV-1 RNA levels.

  15. Targeted infection of HIV-1 Env expressing cells by HIV(CD4/CXCR4 vectors reveals a potential new rationale for HIV-1 mediated down-modulation of CD4

    Directory of Open Access Journals (Sweden)

    Harmison George G

    2005-12-01

    Full Text Available Abstract Background Efficient targeted gene transfer and cell type specific transgene expression are important for the safe and effective expression of transgenes in vivo. Enveloped viral vectors allow insertion of exogenous membrane proteins into their envelopes, which could potentially aid in the targeted transduction of specific cell types. Our goal was to specifically target cells that express the T cell tropic HIV-1 envelope protein (Env using the highly specific interaction of Env with its cellular receptor (CD4 inserted into the envelope of an HIV-1-based viral vector. Results To generate HIV-1-based vectors carrying the CD4 molecule in their envelope, the CD4 ectodomain was fused to diverse membrane anchors and inserted together with the HIV-1 coreceptor CXCR4 into the envelopes of HIV-1 vector particles. Independent of the type of CD4 anchor, all chimeric CD4 proteins inserted into HIV-1 vector envelopes and the resultant HIV(CD4/CXCR4 particles were able to selectively confer neomycin resistance to cells expressing the fusogenic T cell tropic HIV-1 Env protein. Unexpectedly, in the absence of Env on the target cells, all vector particles carrying the CD4 ectodomain anchored in their envelope adhered to various cell types without infecting these cells. This cell adhesion was very avid. It was independent of the presence of Env on the target cell, the type of CD4 anchor or the presence of CXCR4 on the particle. In mixed cell populations with defined ratios of Env+/Env- cells, the targeted transduction of Env+ cells by HIV(CD4/CXCR4 particles was diminished in proportion to the number of Env- cells. Conclusion Vector diversion caused by a strong, non-selective cell binding of CD4+-vector particles effectively prevents the targeted transduction of HIV-1 Env expressing cells in mixed cell populations. This Env-independent cell adhesion severely limits the effective use of targeted HIV(CD4/CXCR4 vectors designed to interfere with HIV-1

  16. Genotypic and phenotypic characterization of HIV-1 virus found early in infection

    OpenAIRE

    Freitas, Inês Trindade de, 1986-

    2010-01-01

    Tese de mestrado. Biologia (Biologia Molecular e Humana). Universidade de Lisboa, Faculdade de Ciências, 2010 In this study we raised full-length envelope sequences from HIV-1 infected patients in early phases of infection, up to three month of viral acquisition, and from their transmitting partners, who were in later stages of infection, to assess any genotypic signature(s) that would distinguish the envelope sequences that were being transmitted and correlate those signatures with viral ...

  17. HIV-1 vaccine development: constrained peptide immunogens show improved binding to the anti-HIV-1 gp41 MAb.

    Science.gov (United States)

    McGaughey, G B; Citron, M; Danzeisen, R C; Freidinger, R M; Garsky, V M; Hurni, W M; Joyce, J G; Liang, X; Miller, M; Shiver, J; Bogusky, M J

    2003-03-25

    The human immunodeficiency virus type I (HIV-1) transmembrane glycoprotein gp41 mediates viral entry through fusion of the target cellular and viral membranes. A segment of gp41 containing the sequence Glu-Leu-Asp-Lys-Trp-Ala has previously been identified as the epitope of the HIV-1 neutralizing human monoclonal antibody 2F5 (MAb 2F5). The 2F5 epitope is highly conserved among HIV-1 envelope glycoproteins. Antibodies directed at the 2F5 epitope have neutralizing effects on a broad range of laboratory-adapted HIV-1 variants and primary isolates. Recently, a crystal structure of the epitope bound to the Fab fragment of MAb 2F5 has shown that the 2F5 peptide adopts a beta-turn conformation [Pai, E. F., Klein, M. H., Chong, P., and Pedyczak, A. (2000) World Intellectual Property Organization Patent WO-00/61618]. We have designed cyclic peptides to adopt beta-turn conformations by the incorporation of a side-chain to side-chain lactam bridge between the i and i + 4 residues containing the Asp-Lys-Trp segment. Synthesis of extended, nonconstrained peptides encompassing the 2F5 epitope revealed that the 13 amino acid sequence, Glu-Leu-Leu-Glu-Leu-Asp-Lys-Trp-Ala-Ser-Leu-Trp-Asn, maximized MAb 2F5 binding. Constrained analogues of this sequence were explored to optimize 2F5 binding affinity. The solution conformations of the constrained peptides have been characterized by NMR spectroscopy and molecular modeling techniques. The results presented here demonstrate that both inclusion of the lactam constraint and extension of the 2F5 segment are necessary to elicit optimal antibody binding activity. The ability of these peptide immunogens to stimulate a high titer, peptide-specific immune response incapable of viral neutralization is discussed in regard to developing an HIV-1 vaccine designed to elicit a 2F5-like immune response. PMID:12641452

  18. Identification of a Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Variant Resistant to Cold Inactivation▿ †

    OpenAIRE

    Kassa, Aemro; Finzi, Andrés; Pancera, Marie; Courter, Joel R.; Amos B Smith; Sodroski, Joseph

    2009-01-01

    The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein trimer consists of gp120 and gp41 subunits and undergoes a series of conformational changes upon binding to the receptors, CD4 and CCR5/CXCR4, that promote virus entry. Surprisingly, we found that the envelope glycoproteins of some HIV-1 strains are functionally inactivated by prolonged incubation on ice. Serial exposure of HIV-1 to extremes of temperature, followed by expansion of replication-competent viruses, allowed sel...

  19. Structural Basis for Broad and Potent Neutralization of HIV-1 by Antibody VRC01

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Tongqing; Georgiev, Ivelin; Wu, Xueling; Yang, Zhi-Yong; Dai, Kaifan; Finzi, Andrés; Kwon, Young Do; Scheid, Johannes F.; Shi, Wei; Xu, Ling; Yang, Yongping; Zhu, Jiang; Nussenzweig, Michel C.; Sodroski, Joseph; Shapiro, Lawrence; Nabel, Gary J.; Mascola, John R.; Kwong, Peter D. (NIH); (Rockefeller); (DFCI)

    2010-08-26

    During HIV-1 infection, antibodies are generated against the region of the viral gp120 envelope glycoprotein that binds CD4, the primary receptor for HIV-1. Among these antibodies, VRC01 achieves broad neutralization of diverse viral strains. We determined the crystal structure of VRC01 in complex with a human immunodeficiency virus HIV-1 gp120 core. VRC01 partially mimics CD4 interaction with gp120. A shift from the CD4-defined orientation, however, focuses VRC01 onto the vulnerable site of initial CD4 attachment, allowing it to overcome the glycan and conformational masking that diminishes the neutralization potency of most CD4-binding-site antibodies. To achieve this recognition, VRC01 contacts gp120 mainly through immunoglobulin V-gene regions substantially altered from their genomic precursors. Partial receptor mimicry and extensive affinity maturation thus facilitate neutralization of HIV-1 by natural human antibodies.

  20. Selected HIV-1 Env trimeric formulations act as potent immunogens in a rabbit vaccination model

    DEFF Research Database (Denmark)

    Heyndrickx, Leo; Stewart-Jones, Guillaume; Jansson, Marianne Bendixen;

    2013-01-01

    Ten to 30% of HIV-1 infected subjects develop broadly neutralizing antibodies (bNAbs) during chronic infection. We hypothesized that immunizing rabbits with viral envelope glycoproteins (Envs) from these patients may induce bNAbs, when formulated as a trimeric protein and in the presence...

  1. Quantifying Ongoing HIV-1 Exposure in HIV-1–Serodiscordant Couples to Identify Individuals With Potential Host Resistance to HIV-1

    OpenAIRE

    Mackelprang, Romel D.; Jared M Baeten; Donnell, Deborah; Celum, Connie; Farquhar, Carey; de Bruyn, Guy; Essex, Max; McElrath, M. Juliana; NAKKU-JOLOBA, Edith; Lingappa, Jairam R.

    2012-01-01

    Background. Immunogenetic correlates of resistance to HIV-1 in HIV-1–exposed seronegative (HESN) individuals with consistently high exposure may inform HIV-1 prevention strategies. We developed a novel approach for quantifying HIV-1 exposure to identify individuals remaining HIV-1 uninfected despite persistent high exposure.

  2. Binding of HIV-1 virions to α4β7 expressing cells and impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells

    Institute of Scientific and Technical Information of China (English)

    Chang; Li; Wei; Jin; Tao; Du; Biao; Wu; Yalan; Liu; Robin; J; Shattock; Qinxue; Hu

    2014-01-01

    HIV-1 envelope glycoprotein is reported to interact with α4β7, an integrin mediating the homing of lymphocytes to gut-associated lymphoid tissue, but the significance of α4β7 in HIV-1 infection remains controversial. Here, using HIV-1 strain Ba L, the gp120 of which was previously shown to be capable of interacting with α4β7, we demonstrated that α4β7 can mediate the binding of whole HIV-1 virions to α4β7-expressing transfectants. We further constructed a cell line stably expressing α4β7 and confirmed the α4β7-mediated HIV-1 binding. In primary lymphocytes with activated α4β7 expression, we also observed significant virus binding which can be inhibited by an anti-α4β7 antibody. Moreover, we investigated the impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells. In α4β7-activated CD4+ T cells, both anti-α4β7 antibodies and introduction of shorthairpin RNAs specifically targeting α4β7 resulted in a decreased HIV-1 infection. Our findings indicate that α4β7 may serve as an attachment factor at least for some HIV-1 strains. The established approach provides a promising means for the investigation of other viral strains to understand the potential roles of α4β7 in HIV-1 infection.

  3. GB Virus Type C E2 Protein Inhibits Human Immunodeficiency Virus Type 1 Assembly Through Interference With HIV-1 Gag Plasma Membrane Targeting

    OpenAIRE

    Timmons, Christine L.; Shao, Qiujia; Wang, Chenliang; Liu, Ling; Liu, Huanliang; Dong, Xinhong; Liu, Bindong

    2013-01-01

    GB virus type C (GBV-C) is a single-stranded positive-sense RNA virus classified in the Flaviviridae family. Persistent coinfection with GBV-C is associated with lower human immunodeficiency virus type 1 (HIV-1) load, higher CD4+ T-cell count, and prolonged survival in HIV-1 coinfected patients. The GBV-C envelope glycoprotein E2 has been reported to interfere with HIV-1 entry. In this study, we showed that the expression of GBV-C E2 inhibited HIV-1 Gag assembly and release. Expression of gly...

  4. Male reproduction and HIV-1 infection

    NARCIS (Netherlands)

    E. van Leeuwen

    2009-01-01

    From its initial presentation in the early nineteen eighties until 1996, HIV-1 infection almost inevitably led to AIDS, which was a death sentence. Because of the short life expectancy, patients were advised against pregnancy. The improved prognosis of patients with HIV-1 infection following the int

  5. HIV-1 Latency in Monocytes/Macrophages

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    2014-04-01

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 targets CD4+ T cells and cells of the monocyte/macrophage lineage. HIV pathogenesis is characterized by the depletion of T lymphocytes and by the presence of a population of cells in which latency has been established called the HIV-1 reservoir. Highly active antiretroviral therapy (HAART has significantly improved the life of HIV-1 infected patients. However, complete eradication of HIV-1 from infected individuals is not possible without targeting latent sources of infection. HIV-1 establishes latent infection in resting CD4+ T cells and findings indicate that latency can also be established in the cells of monocyte/macrophage lineage. Monocyte/macrophage lineage includes among others, monocytes, macrophages and brain resident macrophages. These cells are relatively more resistant to apoptosis induced by HIV-1, thus are important stable hideouts of the virus. Much effort has been made in the direction of eliminating HIV-1 resting CD4+ T-cell reservoirs. However, it is impossible to achieve a cure for HIV-1 without considering these neglected latent reservoirs, the cells of monocyte/macrophage lineage. In this review we will describe our current understanding of the mechanism of latency in monocyte/macrophage lineage and how such cells can be specifically eliminated from the infected host.

  6. Design and Characterization of a Peptide Mimotope of the HIV-1 gp120 Bridging Sheet

    Directory of Open Access Journals (Sweden)

    Guido Poli

    2012-05-01

    Full Text Available The Bridging Sheet domain of HIV-1 gp120 is highly conserved among the HIV-1 strains and allows HIV-1 binding to host cells via the HIV-1 coreceptors. Further, the bridging sheet domain is a major target to neutralize HIV-1 infection. We rationally designed four linear peptide epitopes that mimic the three-dimensional structure of bridging sheet by using molecular modeling. Chemically synthesized peptides BS3 and BS4 showed a fair degree of antigenicity when tested in ELISA with IgG purified from HIV+ broadly neutralizing sera while the production of synthetic peptides BS1 and BS2 failed due to their high degree of hydrophobicity. To overcome this limitation, we linked all four BS peptides to the COOH-terminus of GST protein to test both their antigenicity and immunogenicity. Only the BS1 peptide showed good antigenicity; however, no envelope specific antibodies were elicited upon mice immunization. Therefore we performed further analyses by linking BS1 peptide to the NH2-terminus of the E2 scaffold from the Geobacillus Stearothermophylus PDH complex. The E2-BS1 fusion peptide showed good antigenic results, however only one immunized rabbit elicited good antibody titers towards both the monomeric and oligomeric viral envelope glycoprotein (Env. In addition, moderate neutralizing antibodies response was elicited against two HIV-1 clade B and one clade C primary isolates. These preliminary data validate the peptide mimotope approach as a promising tool to obtain an effective HIV-1 vaccine.

  7. Readily Accessible Multiplane Microscopy: 3D Tracking the HIV-1 Genome in Living Cells.

    Science.gov (United States)

    Itano, Michelle S; Bleck, Marina; Johnson, Daniel S; Simon, Sanford M

    2016-02-01

    Human immunodeficiency virus (HIV)-1 infection and the associated disease AIDS are a major cause of human death worldwide with no vaccine or cure available. The trafficking of HIV-1 RNAs from sites of synthesis in the nucleus, through the cytoplasm, to sites of assembly at the plasma membrane are critical steps in HIV-1 viral replication, but are not well characterized. Here we present a broadly accessible microscopy method that captures multiple focal planes simultaneously, which allows us to image the trafficking of HIV-1 genomic RNAs with high precision. This method utilizes a customization of a commercial multichannel emission splitter that enables high-resolution 3D imaging with single-macromolecule sensitivity. We show with high temporal and spatial resolution that HIV-1 genomic RNAs are most mobile in the cytosol, and undergo confined mobility at sites along the nuclear envelope and in the nucleus and nucleolus. These provide important insights regarding the mechanism by which the HIV-1 RNA genome is transported to the sites of assembly of nascent virions.

  8. Challenges in the Design of a T Cell Vaccine in the Context of HIV-1 Diversity

    Directory of Open Access Journals (Sweden)

    Marcel Tongo

    2014-10-01

    Full Text Available The extraordinary variability of HIV-1 poses a major obstacle to vaccine development. The effectiveness of a vaccine is likely to vary dramatically in different populations infected with different HIV-1 subtypes, unless innovative vaccine immunogens are developed to protect against the range of HIV-1 diversity. Immunogen design for stimulating neutralizing antibody responses focuses on “breadth” – the targeting of a handful of highly conserved neutralizing determinants on the HIV-1 Envelope protein that can recognize the majority of viruses across all HIV-1 subtypes. An effective vaccine will likely require the generation of both broadly cross-neutralizing antibodies and non-neutralizing antibodies, as well as broadly cross-reactive T cells. Several approaches have been taken to design such broadly-reactive and cross-protective T cell immunogens. Artificial sequences have been designed that reduce the genetic distance between a vaccine strain and contemporary circulating viruses; “mosaic” immunogens extend this concept to contain multiple potential T cell epitope (PTE variants; and further efforts attempt to focus T cell immunity on highly conserved regions of the HIV-1 genome. Thus far, a number of pre-clinical and early clinical studies have been performed assessing these new immunogens. In this review, the potential use of these new immunogens is explored.

  9. Anti-gp120 minibody gene transfer to female genital epithelial cells protects against HIV-1 virus challenge in vitro.

    Directory of Open Access Journals (Sweden)

    Ussama M Abdel-Motal

    Full Text Available BACKGROUND: Although cervico-vaginal epithelial cells of the female lower genital tract provide the initial defense system against HIV-1 infection, the protection is sometimes incomplete. Thus, enhancing anti-HIV-1 humoral immunity at the mucosal cell surface by local expression of anti-HIV-1 broadly neutralizing antibodies (BnAb that block HIV-1 entry would provide an important new intervention that could slow the spread of HIV/AIDS. METHODS AND FINDINGS: This study tested the hypothesis that adeno-associated virus (AAV-BnAb gene transfer to cervico-vaginal epithelial cells will lead to protection against HIV-1. Accordingly, a recombinant AAV vector that encodes human b12 anti-HIV gp120 BnAb as a single-chain variable fragment Fc fusion (scFvFc, or "minibody" was constructed. The secreted b12 minibody was shown to be biologically functional in binding to virus envelope protein, neutralizing HIV-1 and importantly, blocking transfer and infectivity of HIV-1(bal in an organotypic human vaginal epithelial cell (VEC model. Furthermore, cervico-vaginal epithelial stem cells were found to be efficiently transduced by the optimal AAV serotype mediated expression of GFP. CONCLUSION: This study provides the foundation for a novel microbicide strategy to protect against sexual transmission of HIV-1 by AAV transfer of broadly neutralizing antibody genes to cervico-vaginal epithelial stem cells that could replenish b12 BnAb secreting cells through multiple menstrual cycles.

  10. Tenascin-C is an innate broad-spectrum, HIV-1–neutralizing protein in breast milk

    Science.gov (United States)

    Fouda, Genevieve G.; Jaeger, Frederick H.; Amos, Joshua D.; Ho, Carrie; Kunz, Erika L.; Anasti, Kara; Stamper, Lisa W.; Liebl, Brooke E.; Barbas, Kimberly H.; Ohashi, Tomoo; Moseley, Martin Arthur; Liao, Hua-Xin; Erickson, Harold P.; Alam, S. Munir; Permar, Sallie R.

    2013-01-01

    Achieving an AIDS-free generation will require elimination of postnatal transmission of HIV-1 while maintaining the nutritional and immunologic benefits of breastfeeding for infants in developing regions. Maternal/infant antiretroviral prophylaxis can reduce postnatal HIV-1 transmission, yet toxicities and the development of drug-resistant viral strains may limit the effectiveness of this strategy. Interestingly, in the absence of antiretroviral prophylaxis, greater than 90% of infants exposed to HIV-1 via breastfeeding remain uninfected, despite daily mucosal exposure to the virus for up to 2 y. Moreover, milk of uninfected women inherently neutralizes HIV-1 and prevents virus transmission in animal models, yet the factor(s) responsible for this anti-HIV activity is not well-defined. In this report, we identify a primary HIV-1–neutralizing protein in breast milk, Tenascin-C (TNC). TNC is an extracellular matrix protein important in fetal development and wound healing, yet its antimicrobial properties have not previously been established. Purified TNC captured and neutralized multiclade chronic and transmitted/founder HIV-1 variants, and depletion of TNC abolished the HIV-1–neutralizing activity of milk. TNC bound the HIV-1 Envelope protein at a site that is induced upon engagement of its primary receptor, CD4, and is blocked by V3 loop- (19B and F39F) and chemokine coreceptor binding site-directed (17B) monoclonal antibodies. Our results demonstrate the ability of an innate mucosal host protein found in milk to neutralize HIV-1 via binding to the chemokine coreceptor site, potentially explaining why the majority of HIV-1–exposed breastfed infants are protected against mucosal HIV-1 transmission. PMID:24145401

  11. Cytoplasmic Dynein Promotes HIV-1 Uncoating

    Directory of Open Access Journals (Sweden)

    Paulina Pawlica

    2014-11-01

    Full Text Available Retroviral capsid (CA cores undergo uncoating during their retrograde transport (toward the nucleus, and/or after reaching the nuclear membrane. However, whether HIV-1 CA core uncoating is dependent upon its transport is not understood. There is some evidence that HIV-1 cores retrograde transport involves cytoplasmic dynein complexes translocating on microtubules. Here we investigate the role of dynein-dependent transport in HIV-1 uncoating. To interfere with dynein function, we depleted dynein heavy chain (DHC using RNA interference, and we over-expressed p50/dynamitin. In immunofluorescence microscopy experiments, DHC depletion caused an accumulation of CA foci in HIV-1 infected cells. Using a biochemical assay to monitor HIV-1 CA core disassembly in infected cells, we observed an increase in amounts of intact (pelletable CA cores upon DHC depletion or p50 over-expression. Results from these two complementary assays suggest that inhibiting dynein-mediated transport interferes with HIV-1 uncoating in infected cells, indicating the existence of a functional link between HIV-1 transport and uncoating.

  12. HIV-1 RNA quantification in CRF02_AG HIV-1 infection: too easy to make mistakes.

    Science.gov (United States)

    Tatarelli, Paola; Taramasso, Lucia; Di Biagio, Antonio; Sticchi, Laura; Nigro, Nicola; Barresi, Renata; Viscoli, Claudio; Bruzzone, Bianca

    2016-04-01

    The number of patients newly infected by HIV-1 non-B subtypes and circulating recombinant forms (CRFs) is increasing worldwide, including in the western countries. We report on a primary HIV-1 infection in a Caucasian patient. A routine quantitative assay (Nuclisens EasyQ HIV-1 2.0, BioMérieux SA) showed 6,700 HIV-1 RNA copies/ml. A combined antiretroviral therapy (cART) consistent with low baseline HIV-1 RNA was started. Few days later, the analysis performed with REGA HIV-1 Subtyping Tool - Version 3.0 attributed the HIV-1 sequence to the CRF02_AG recombinant form. Therefore, a second real-time PCR assay was performed, using the Versant HIV-1 RNA 1.0 Assay (kPCR) (Siemens HealthCare Diagnostics) which revealed a HIV-1 RNA of 230,000 copies/ml. Consequently, the ongoing cART was potentiated. This case suggests that the wide genetic variability of HIV-1 subtypes may affect the capability of the commonly used assays to detect and accurately quantify HIV-1 RNA in non-B subtypes and CRFs. In presence of CRFs different commercial HIV-1 RNA tests should be performed to find the most reliable for viral load quantification at the diagnosis, because it influences the choice of cART, and during the follow-up. Indeed, international guidelines for HIV-1 infection management suggest to monitor patient' HIV-RNA with the same assay over the course of treatment. As different commercial tests can be performed in the same laboratory with considerable difficulty, the laboratory should select an assay that is suitable not only for the more prevalent strain, but also for less frequent ones that, nevertheless, can occur. Then, knowing and investigating the spread of non-B strains has essential clinical and laboratory implications. PMID:27196556

  13. Blocking of HIV-1 Infectivity by a Soluble, Secreted Form of the CD4 Antigen

    Science.gov (United States)

    Smith, Douglas H.; Byrn, Randal A.; Marsters, Scot A.; Gregory, Timothy; Groopman, Jerome E.; Capon, Daniel J.

    1987-12-01

    The initial event in the infection of human T lymphocytes, macrophages, and other cells by human immunodeficiency virus (HIV-1) is the attachment of the HIV-1 envelope glycoprotein gp120 to its cellular receptor, CD4. As a step toward designing antagonists of this binding event, soluble, secreted forms of CD4 were produced by transfection of mammalian cells with vectors encoding versions of CD4 lacking its transmembrane and cytoplasmic domains. The soluble CD4 so produced binds gp120 with an affinity and specificity comparable to intact CD4 and is capable of neutralizing the infectivity of HIV-1. These studies reveal that the high-affinity CD4-gp120 interaction does not require other cell or viral components and may establish a novel basis for therapeutic intervention in the acquired immune deficiency syndrome (AIDS).

  14. HIV-1自然感染中的中和抗体反应%Neutralizing antibodies responses during natural HIV-1 infection

    Institute of Scientific and Technical Information of China (English)

    任彩云; 李妍; 凌虹

    2012-01-01

    中和抗体(Nab)可以防止I型人类免疫缺陷病毒(HIV-1)侵入靶细胞.HIV-1感染数周后即可诱导产生Nab,这些早期抗体只能特异性地中和自体病毒但不能中和异源性病毒.在一些慢性感染者体内则可以检测到可同时中和同源性和异源性病毒的广谱中和抗体(BNab).BNab的靶点通常位于包膜蛋白的保守区域.HIV-1 BNab的产生还受到病毒变异及结构遮盖等因素的限制,同时Nab的中和广度与病毒载量具有相关性.%Neutralizing antibodies can protect a host against the infection by human immunodeficiency virus type 1 (HIV-1).Neutralizing antibodies can be induced several weeks after infection.However,the antibodies induced in the early stage can neutralize only the autologous but not heterologous viruses.Nevertheless,broad neutralizing antibodies,which can neutralize both autologous and heterologous viruses,have been found in some chronic patients.Inaddition,broad neutralizing antibodies usually target the conserved regions of HIV-1 envelope glycoprotein.However,the envelope glycoprotein mutation and its structure shielding limit the induction of these antibodies.

  15. Molecular Understanding of HIV-1 Latency

    Directory of Open Access Journals (Sweden)

    W. Abbas

    2012-01-01

    Full Text Available The introduction of highly active antiretroviral therapy (HAART has been an important breakthrough in the treatment of HIV-1 infection and has also a powerful tool to upset the equilibrium of viral production and HIV-1 pathogenesis. Despite the advent of potent combinations of this therapy, the long-lived HIV-1 reservoirs like cells from monocyte-macrophage lineage and resting memory CD4+ T cells which are established early during primary infection constitute a major obstacle to virus eradication. Further HAART interruption leads to immediate rebound viremia from latent reservoirs. This paper focuses on the essentials of the molecular mechanisms for the establishment of HIV-1 latency with special concern to present and future possible treatment strategies to completely purge and target viral persistence in the reservoirs.

  16. Small animal model for HIV-1 Disease

    Institute of Scientific and Technical Information of China (English)

    Yoshio; Koyanagi

    2005-01-01

    Development of a viral infection model of the humanimmune systemusingsmall animalsis animportant goal in biomedi-cal research,especiallyinstudiesof HIV-1infection.Thisis particularlyimportant since susceptibilityto HIV-1islimit-edto humans.The C.B-17-scid/scid-mouselacks mature Tand Bcells dueto a defective rearrangement of the Tcell re-ceptor andimmunoglobulin genes.Twotypes of humanlymphoid chimeras have been establishedin scid-mice.The firstsuccess withthe human mouse chimera was achieved.Human fetal liv...

  17. Exosomes: Implications in HIV-1 Pathogenesis.

    Science.gov (United States)

    Madison, Marisa N; Okeoma, Chioma M

    2015-07-20

    Exosomes are membranous nanovesicles of endocytic origin that carry host and pathogen derived genomic, proteomic, and lipid cargos. Exosomes are secreted by most cell types into the extracellular milieu and are subsequently internalized by recipient cells. Upon internalization, exosomes condition recipient cells by donating their cargos and/or activating various signal transduction pathways, consequently regulating physiological and pathophysiological processes. The role of exosomes in viral pathogenesis, especially human immunodeficiency virus type 1 [HIV-1] is beginning to unravel. Recent research reports suggest that exosomes from various sources play important but different roles in the pathogenesis of HIV-1. From these reports, it appears that the source of exosomes is the defining factor for the exosomal effect on HIV-1. In this review, we will describe how HIV-1 infection is modulated by exosomes and in turn how exosomes are targeted by HIV-1 factors. Finally, we will discuss potentially emerging therapeutic options based on exosomal cargos that may have promise in preventing HIV-1 transmission.

  18. HIV-1 transmission linkage in an HIV-1 prevention clinical trial

    Energy Technology Data Exchange (ETDEWEB)

    Leitner, Thomas [Los Alamos National Laboratory; Campbell, Mary S [UNIV OF WASHINGTON; Mullins, James I [UNIV OF WASHINGTON; Hughes, James P [UNIV OF WASHINGTON; Wong, Kim G [UNIV OF WASHINGTON; Raugi, Dana N [UNIV OF WASHINGTON; Scrensen, Stefanie [UNIV OF WASHINGTON

    2009-01-01

    HIV-1 sequencing has been used extensively in epidemiologic and forensic studies to investigate patterns of HIV-1 transmission. However, the criteria for establishing genetic linkage between HIV-1 strains in HIV-1 prevention trials have not been formalized. The Partners in Prevention HSV/HIV Transmission Study (ClinicaITrials.gov NCT00194519) enrolled 3408 HIV-1 serodiscordant heterosexual African couples to determine the efficacy of genital herpes suppression with acyclovir in reducing HIV-1 transmission. The trial analysis required laboratory confirmation of HIV-1 linkage between enrolled partners in couples in which seroconversion occurred. Here we describe the process and results from HIV-1 sequencing studies used to perform transmission linkage determination in this clinical trial. Consensus Sanger sequencing of env (C2-V3-C3) and gag (p17-p24) genes was performed on plasma HIV-1 RNA from both partners within 3 months of seroconversion; env single molecule or pyrosequencing was also performed in some cases. For linkage, we required monophyletic clustering between HIV-1 sequences in the transmitting and seroconverting partners, and developed a Bayesian algorithm using genetic distances to evaluate the posterior probability of linkage of participants sequences. Adjudicators classified transmissions as linked, unlinked, or indeterminate. Among 151 seroconversion events, we found 108 (71.5%) linked, 40 (26.5%) unlinked, and 3 (2.0%) to have indeterminate transmissions. Nine (8.3%) were linked by consensus gag sequencing only and 8 (7.4%) required deep sequencing of env. In this first use of HIV-1 sequencing to establish endpoints in a large clinical trial, more than one-fourth of transmissions were unlinked to the enrolled partner, illustrating the relevance of these methods in the design of future HIV-1 prevention trials in serodiscordant couples. A hierarchy of sequencing techniques, analysis methods, and expert adjudication contributed to the linkage

  19. Humoral Immune Pressure Selects for HIV-1 CXC-chemokine Receptor 4-using Variants.

    Science.gov (United States)

    Lin, Nina; Gonzalez, Oscar A; Registre, Ludy; Becerril, Carlos; Etemad, Behzad; Lu, Hong; Wu, Xueling; Lockman, Shahin; Essex, Myron; Moyo, Sikhulile; Kuritzkes, Daniel R; Sagar, Manish

    2016-06-01

    Although both C-C chemokine receptor 5 (CCR5)- and CXC chemokine receptor 4 (CXCR4)-using HIV-1 strains cause AIDS, the emergence of CXCR4-utilizing variants is associated with an accelerated decline in CD4+ T cells. It remains uncertain if CXCR4-using viruses hasten disease or if these variants only emerge after profound immunological damage. We show that exclusively CXCR4- as compared to cocirculating CCR5-utilizing variants are less sensitive to neutralization by both contemporaneous autologous plasma and plasma pools from individuals that harbor only CCR5-using HIV-1. The CXCR4-utilizing variants, however, do not have a global antigenic change because they remain equivalently susceptible to antibodies that do not target coreceptor binding domains. Studies with envelope V3 loop directed antibodies and chimeric envelopes suggest that the neutralization susceptibility differences are potentially influenced by the V3 loop. In vitro passage of a neutralization sensitive CCR5-using virus in the presence of autologous plasma and activated CD4+ T cells led to the emergence of a CXCR4-utilizing virus in 1 of 3 cases. These results suggest that in some but not necessarily all HIV-1 infected individuals humoral immune pressure against the autologous virus selects for CXCR4-using variants, which potentially accelerates disease progression. Our observations have implications for using antibodies for HIV-1 immune therapy. PMID:27428434

  20. Humoral Immune Pressure Selects for HIV-1 CXC-chemokine Receptor 4-using Variants

    Directory of Open Access Journals (Sweden)

    Nina Lin

    2016-06-01

    Full Text Available Although both C-C chemokine receptor 5 (CCR5- and CXC chemokine receptor 4 (CXCR4-using HIV-1 strains cause AIDS, the emergence of CXCR4-utilizing variants is associated with an accelerated decline in CD4+ T cells. It remains uncertain if CXCR4-using viruses hasten disease or if these variants only emerge after profound immunological damage. We show that exclusively CXCR4- as compared to cocirculating CCR5-utilizing variants are less sensitive to neutralization by both contemporaneous autologous plasma and plasma pools from individuals that harbor only CCR5-using HIV-1. The CXCR4-utilizing variants, however, do not have a global antigenic change because they remain equivalently susceptible to antibodies that do not target coreceptor binding domains. Studies with envelope V3 loop directed antibodies and chimeric envelopes suggest that the neutralization susceptibility differences are potentially influenced by the V3 loop. In vitro passage of a neutralization sensitive CCR5-using virus in the presence of autologous plasma and activated CD4+ T cells led to the emergence of a CXCR4-utilizing virus in 1 of 3 cases. These results suggest that in some but not necessarily all HIV-1 infected individuals humoral immune pressure against the autologous virus selects for CXCR4-using variants, which potentially accelerates disease progression. Our observations have implications for using antibodies for HIV-1 immune therapy.

  1. Infected Cell Killing by HIV-1 Protease Promotes NF-κB Dependent HIV-1 Replication

    OpenAIRE

    Bren, Gary D.; Joe Whitman; Nathan Cummins; Brett Shepard; Rizza, Stacey A; Trushin, Sergey A.; Badley, Andrew D

    2008-01-01

    Acute HIV-1 infection of CD4 T cells often results in apoptotic death of infected cells, yet it is unclear what evolutionary advantage this offers to HIV-1. Given the independent observations that acute T cell HIV-1 infection results in (1) NF-kappaB activation, (2) caspase 8 dependent apoptosis, and that (3) caspase 8 directly activates NF-kappaB, we questioned whether these three events might be interrelated. We first show that HIV-1 infected T cell apoptosis, NF-kappaB activation, and casp...

  2. Appreciating HIV-1 diversity: subtypic differences in ENV

    Energy Technology Data Exchange (ETDEWEB)

    Gnanakaran, S [Los Alamos National Laboratory; Shen, Tongye [Los Alamos National Laboratory; Lynch, Rebecca M [NON LANL; Derdeyn, Cynthia A [NON LANL

    2008-01-01

    Human immunodeficiency virus type 1 (HIV-1) group M is responsible for the current AIDS pandemic and exhibits exceedingly high levels of viral genetic diversity around the world, necessitating categorization of viruses into distinct lineages, or subtypes. These subtypes can differ by around 35% in the envelope (Env) glycoproteins of the virus, which are displayed on the surface of the virion and are targets for both neutralizing antibody and cell-mediated immune responses. This diversity reflects the remarkable ability of the virus to adapt to selective pressures, the bulk of which is applied by the host immune response, and represents a serious obstacle for developing an effective vaccine with broad coverage. Thus, it is important to understand the underlying biological consequences of inter-subtype diversity. Recent studies have revealed that the HIV-1 subtypes exhibit phenotypic differences that result from subtle differences in Env structure, particularly within the highly immunogenic V3 domain, which participates directly in viral entry. This review will therefore explore current research that describes subtypic differences in Env at the genetic and phenotypic level, focusing in particular on V3, and highlighting recent discoveries about the unique features of subtype C Env, which is the most prevalent subtype globally.

  3. Heterologous protection elicited by candidate monomeric recombinant HIV-1 gp120 vaccine in the absence of cross neutralising antibodies in a macaque model

    Directory of Open Access Journals (Sweden)

    Page Mark

    2012-07-01

    Full Text Available Abstract Background Current data suggest that an efficacious human immunodeficiency virus type 1 (HIV-1 vaccine should elicit both adaptive humoral and cell mediated immune responses. Such a vaccine will also need to protect against infection from a range of heterologous viral variants. Here we have developed a simian-human immunodeficiency virus (SHIV based model in cynomolgus macaques to investigate the breadth of protection conferred by HIV-1W61D recombinant gp120 vaccination against SHIVsbg and SHIVSF33 challenge, and to identify correlates of protection. Results High titres of anti-envelope antibodies were detected in all vaccinees. The antibodies reacted with both the homologous HIV-1W61D and heterologous HIV-1IIIB envelope rgp120 which has an identical sequence to the SHIVsbg challenge virus. Significant titres of virus neutralising antibodies were detected against SHIVW61D expressing an envelope homologous with the vaccine, but only limited cross neutralisation against SHIVsbg, SHIV-4 and SHIVSF33 was observed. Protection against SHIVsbg infection was observed in vaccinated animals but none was observed against SHIVSF33 challenge. Transfer of immune sera from vaccinated macaques to naive recipients did not confer protection against SHIVsbg challenge. In a follow-up study, T cell proliferative responses detected after immunisation with the same vaccine against a single peptide present in the second conserved region 2 of HIV-1 W61D and HIV-1 IIIB gp120, but not SF33 gp120. Conclusions Following extended vaccination with a HIV-1 rgp120 vaccine, protection was observed against heterologous virus challenge with SHIVsbg, but not SHIVSF33. Protection did not correlate with serological responses generated by vaccination, but might be associated with T cell proliferative responses against an epitope in the second constant region of HIV-1 gp120. Broader protection may be obtained with recombinant HIV-1 envelope based vaccines formulated with

  4. Tyrosine-sulfated V2 peptides inhibit HIV-1 infection via coreceptor mimicry.

    Science.gov (United States)

    Cimbro, Raffaello; Peterson, Francis C; Liu, Qingbo; Guzzo, Christina; Zhang, Peng; Miao, Huiyi; Van Ryk, Donald; Ambroggio, Xavier; Hurt, Darrell E; De Gioia, Luca; Volkman, Brian F; Dolan, Michael A; Lusso, Paolo

    2016-08-01

    Tyrosine sulfation is a post-translational modification that facilitates protein-protein interaction. Two sulfated tyrosines (Tys173 and Tys177) were recently identified within the second variable (V2) loop of the major HIV-1 envelope glycoprotein, gp120, and shown to contribute to stabilizing the intramolecular interaction between V2 and the third variable (V3) loop. Here, we report that tyrosine-sulfated peptides derived from V2 act as structural and functional mimics of the CCR5 N-terminus and potently block HIV-1 infection. Nuclear magnetic and surface plasmon resonance analyses indicate that a tyrosine-sulfated V2 peptide (pV2α-Tys) adopts a CCR5-like helical conformation and directly interacts with gp120 in a CD4-dependent fashion, competing with a CCR5 N-terminal peptide. Sulfated V2 mimics, but not their non-sulfated counterparts, inhibit HIV-1 entry and fusion by preventing coreceptor utilization, with the highly conserved C-terminal sulfotyrosine, Tys177, playing a dominant role. Unlike CCR5 N-terminal peptides, V2 mimics inhibit a broad range of HIV-1 strains irrespective of their coreceptor tropism, highlighting the overall structural conservation of the coreceptor-binding site in gp120. These results document the use of receptor mimicry by a retrovirus to occlude a key neutralization target site and provide leads for the design of therapeutic strategies against HIV-1. PMID:27389109

  5. RRE-dependent HIV-1 Env RNA effects on Gag protein expression, assembly and release

    Energy Technology Data Exchange (ETDEWEB)

    López, Claudia S., E-mail: lopezcl@ohsu.edu [Departments of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 (United States); Sloan, Rachel; Cylinder, Isabel [Departments of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 (United States); Kozak, Susan L.; Kabat, David [Biochemistry and Molecular Biology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 (United States); Barklis, Eric, E-mail: barklis@ohsu.edu [Departments of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 (United States)

    2014-08-15

    The HIV-1 Gag proteins are translated from the full-length HIV-1 viral RNA (vRNA), whereas the envelope (Env) protein is translated from incompletely spliced Env mRNAs. Nuclear export of vRNAs and Env mRNAs is mediated by the Rev accessory protein which binds to the rev-responsive element (RRE) present on these RNAs. Evidence has shown there is a direct or indirect interaction between the Gag protein, and the cytoplasmic tail (CT) of the Env protein. Our current work shows that env gene expression impacts HIV-1 Gag expression and function in two ways. At the protein level, full-length Env expression altered Gag protein expression, while Env CT-deletion proteins did not. At the RNA level, RRE-containing Env mRNA expression reduced Gag expression, processing, and virus particle release from cells. Our results support models in which Gag is influenced by the Env CT, and Env mRNAs compete with vRNAs for nuclear export. - Highlights: • At the protein level, full-length HIV-1 Env alters Gag protein expression. • HIV-1 Env RNA expression reduces Gag levels and virus release. • Env RNA effects on Gag are dependent on the RRE. • RRE-containing Env RNAs compete with vRNAs for nuclear export.

  6. Psoralen/UV inactivation of HIV-1-infected cells for use in cytologic and immunologic procedures

    Energy Technology Data Exchange (ETDEWEB)

    Watson, A.J.; Klaniecki, J.; Hanson, C.V. (Oncogen Corporation, Seattle, WA (USA))

    1990-04-01

    A rapid procedure for the inactivation of HIV-1-infected cells using psoralen and ultraviolet (UV) light is described. Exposure of HIV-1-infected cells to 5 micrograms/ml psoralen followed by UV irradiation (320-380 nm) for 5 minutes yields cells that are noninfectious as assessed by extended infectivity assays. The psoralen/UV inactivation procedure described is effective with cells chronically or acutely infected with HIV-1 and is unaffected by cell densities up to 12 x 10(6)/ml. At 5 micrograms/ml psoralen does little damage to cellular permeability as shown by the ability of treated cells to exclude trypan blue and propidium iodide. Psoralen/UV treatment of HIV-1-infected cells does not cause a significant decrease in the reactivity of HIV-1 core and envelope antigens or cellular antigens to monoclonal antibodies. Experiments are presented demonstrating the use of these cells for flow cytometry studies and for cell surface labeling using the lactoperoxidase {sup 125}I iodination procedure.

  7. Specific Elimination of Latently HIV-1 Infected Cells Using HIV-1 Protease-Sensitive Toxin Nanocapsules.

    Science.gov (United States)

    Wen, Jing; Yan, Ming; Liu, Yang; Li, Jie; Xie, Yiming; Lu, Yunfeng; Kamata, Masakazu; Chen, Irvin S Y

    2016-01-01

    Anti-retroviral drugs suppress HIV-1 plasma viremia to undetectable levels; however, latent HIV-1 persists in reservoirs within HIV-1-infected patients. The silent provirus can be activated through the use of drugs, including protein kinase C activators and histone deacetylase inhibitors. This "shock" approach is then followed by "kill" of the producing cells either through direct HIV-1-induced cell death or natural immune mechanisms. However, these mechanisms are relatively slow and effectiveness is unclear. Here, we develop an approach to specifically target and kill cells that are activated early in the process of virus production. We utilize a novel nanocapsule technology whereby the ricin A chain is encapsulated in an inactive form within a polymer shell. Specificity for release of the ricin A toxin is conferred by peptide crosslinkers that are sensitive to cleavage by HIV-1 protease. By using well-established latent infection models, J-Lat and U1 cells, we demonstrate that only within an HIV-1-producing cell expressing functional HIV-1 protease will the nanocapsule release its ricin A cargo, shutting down viral and cellular protein synthesis, and ultimately leading to rapid death of the producer cell. Thus, we provide proof of principle for a novel technology to kill HIV-1-producing cells without effects on non-target cells.

  8. N6-methyladenosine of HIV-1 RNA regulates viral infection and HIV-1 Gag protein expression

    Science.gov (United States)

    Tirumuru, Nagaraja; Zhao, Boxuan Simen; Lu, Wuxun; Lu, Zhike; He, Chuan; Wu, Li

    2016-01-01

    The internal N6-methyladenosine (m6A) methylation of eukaryotic nuclear RNA controls post-transcriptional gene expression, which is regulated by methyltransferases (writers), demethylases (erasers), and m6A-binding proteins (readers) in cells. The YTH domain family proteins (YTHDF1–3) bind to m6A-modified cellular RNAs and affect RNA metabolism and processing. Here, we show that YTHDF1–3 proteins recognize m6A-modified HIV-1 RNA and inhibit HIV-1 infection in cell lines and primary CD4+ T-cells. We further mapped the YTHDF1–3 binding sites in HIV-1 RNA from infected cells. We found that the overexpression of YTHDF proteins in cells inhibited HIV-1 infection mainly by decreasing HIV-1 reverse transcription, while knockdown of YTHDF1–3 in cells had the opposite effects. Moreover, silencing the m6A writers decreased HIV-1 Gag protein expression in virus-producing cells, while silencing the m6A erasers increased Gag expression. Our findings suggest an important role of m6A modification of HIV-1 RNA in viral infection and HIV-1 protein synthesis. DOI: http://dx.doi.org/10.7554/eLife.15528.001 PMID:27371828

  9. Specific Elimination of Latently HIV-1 Infected Cells Using HIV-1 Protease-Sensitive Toxin Nanocapsules.

    Directory of Open Access Journals (Sweden)

    Jing Wen

    Full Text Available Anti-retroviral drugs suppress HIV-1 plasma viremia to undetectable levels; however, latent HIV-1 persists in reservoirs within HIV-1-infected patients. The silent provirus can be activated through the use of drugs, including protein kinase C activators and histone deacetylase inhibitors. This "shock" approach is then followed by "kill" of the producing cells either through direct HIV-1-induced cell death or natural immune mechanisms. However, these mechanisms are relatively slow and effectiveness is unclear. Here, we develop an approach to specifically target and kill cells that are activated early in the process of virus production. We utilize a novel nanocapsule technology whereby the ricin A chain is encapsulated in an inactive form within a polymer shell. Specificity for release of the ricin A toxin is conferred by peptide crosslinkers that are sensitive to cleavage by HIV-1 protease. By using well-established latent infection models, J-Lat and U1 cells, we demonstrate that only within an HIV-1-producing cell expressing functional HIV-1 protease will the nanocapsule release its ricin A cargo, shutting down viral and cellular protein synthesis, and ultimately leading to rapid death of the producer cell. Thus, we provide proof of principle for a novel technology to kill HIV-1-producing cells without effects on non-target cells.

  10. Can HIV-1 infection be cured?%HIV-1感染能治愈吗?

    Institute of Scientific and Technical Information of China (English)

    张兴权

    2013-01-01

    A functional HIV-1 cure has been possible now.The ideal functional HIV-1 cure should get HIV-1 infected patients to the point where drugs are not needed after combination therapy and HIV-1 RNA cannot be detected in some patients.However,a functional HIV-1 cure is not equal to a cure for HIV-1,because HIV-1 RNA can still be detected in patients' latent infected cells and related symptoms have not been resolved completely.An era of eradication cure for HIV infection will be coming with further basic and clinical studies,especially when cleaning virus reservoirs by gene modifications successfully.%目前,HIV-1感染治疗已发展到“功能性治愈”阶段,即采用联合化疗一段时间后停止用药几年内,可以使部分患者体内的病毒达到检测不出的水平.然而,这还不是治愈,因为患者的静止淋巴细胞内仍可查到病毒痕迹,患者临床症状也并未完全消失.真正的治愈还须进行更深入的基础和临床研究,特别是通过基因修饰清除病毒的藏身之地.

  11. The hunt for HIV-1 integrase inhibitors.

    Science.gov (United States)

    Lataillade, Max; Kozal, Michael J

    2006-07-01

    Currently, there are three distinct mechanistic classes of antiretrovirals: inhibitors of the HIV- 1 reverse transcriptase and protease enzymes and inhibitors of HIV entry, including receptor and coreceptor binding and cell fusion. A new drug class that inhibits the HIV-1 integrase enzyme (IN) is in development and may soon be available in the clinic. IN is an attractive drug target because it is essential for a stable and productive HIV-1 infection and there is no mammalian homologue of IN. Inhibitors of integrase enzyme (INI) block the integration of viral double-stranded DNA into the host cell's chromosomal DNA. HIV-1 integration has many potential steps that can be inhibited and several new compounds that target specific integration steps have been identified by drug developers. Recently, two INIs, GS-9137 and MK-0518, demonstrated promising early clinical trial results and have been advanced into later stage trials. In this review, we describe how IN facilitates HIV-1 integration, the needed enzyme cofactors, and the resultant byproducts created during integration. Furthermore, we review the different INIs under development, their mechanism of actions, site of IN inhibition, potency, resistance patterns, and discuss the early clinical trial results. PMID:16839248

  12. The hunt for HIV-1 integrase inhibitors.

    Science.gov (United States)

    Lataillade, Max; Kozal, Michael J

    2006-07-01

    Currently, there are three distinct mechanistic classes of antiretrovirals: inhibitors of the HIV- 1 reverse transcriptase and protease enzymes and inhibitors of HIV entry, including receptor and coreceptor binding and cell fusion. A new drug class that inhibits the HIV-1 integrase enzyme (IN) is in development and may soon be available in the clinic. IN is an attractive drug target because it is essential for a stable and productive HIV-1 infection and there is no mammalian homologue of IN. Inhibitors of integrase enzyme (INI) block the integration of viral double-stranded DNA into the host cell's chromosomal DNA. HIV-1 integration has many potential steps that can be inhibited and several new compounds that target specific integration steps have been identified by drug developers. Recently, two INIs, GS-9137 and MK-0518, demonstrated promising early clinical trial results and have been advanced into later stage trials. In this review, we describe how IN facilitates HIV-1 integration, the needed enzyme cofactors, and the resultant byproducts created during integration. Furthermore, we review the different INIs under development, their mechanism of actions, site of IN inhibition, potency, resistance patterns, and discuss the early clinical trial results.

  13. HLA-C increases HIV-1 infectivity and is associated with gp120

    Directory of Open Access Journals (Sweden)

    Beretta Alberto

    2008-08-01

    Full Text Available Abstract Background A recently identified genetic polymorphism located in the 5' region of the HLA-C gene is associated with individual variations in HIV-1 viral load and with differences in HLA-C expression levels. HLA-C has the potential to restrict HIV-1 by presenting epitopes to cytotoxic T cells but it is also a potent inhibitor of NK cells. In addition, HLA-C molecules incorporated within the HIV-1 envelope have been shown to bind to the envelope glycoprotein gp120 and enhance viral infectivity. We investigated this last property in cell fusion assays where the expression of HLA-C was silenced by small interfering RNA sequences. Syncytia formation was analyzed by co-cultivating cell lines expressing HIV-1 gp120/gp41 from different laboratory and primary isolates with target cells expressing different HIV-1 co-receptors. Virus infectivity was analyzed using pseudoviruses. Molecular complexes generated during cell fusion (fusion complexes were purified and analyzed for their HLA-C content. Results HLA-C positive cells co-expressing HIV-1 gp120/gp41 fused more rapidly and produced larger syncytia than HLA-C negative cells. Transient transfection of gp120/gp41 from different primary isolates in HLA-C positive cells resulted in a significant cell fusion increase. Fusion efficiency was reduced in HLA-C silenced cells compared to non-silenced cells when co-cultivated with different target cell lines expressing HIV-1 co-receptors. Similarly, pseudoviruses produced from HLA-C silenced cells were significantly less infectious. HLA-C was co-purified with gp120 from cells before and after fusion and was associated with the fusion complex. Conclusion Virionic HLA-C molecules associate to Env and increase the infectivity of both R5 and X4 viruses. Genetic polymorphisms associated to variations in HLA-C expression levels may therefore influence the individual viral set point not only by means of a regulation of the virus-specific immune response but also

  14. Viremic Control and Viral Coreceptor Usage in Two HIV-1-Infected Persons Homozygous for CCR5 Δ32

    Science.gov (United States)

    Henrich, Timothy J.; Hanhauser, Emily; Hu, Zixin; Stellbrink, Hans-Jürgen; Noah, Christian; Martin, Jeffrey N.; Deeks, Steven G.; Kuritzkes, Daniel R.; Pereyra, Florencia

    2015-01-01

    Objectives To determine viral and immune factors involved in transmission and control of HIV-1 infection in persons without functional CCR5 Design Understanding transmission and control of HIV-1 in persons homozygous for CCR5Δ32 is important given efforts to develop HIV-1 curative therapies aimed at modifying or disrupting CCR5 expression. Methods We identified two HIV-infected CCR5Δ32/Δ32 individuals among a cohort of patients with spontaneous control of HIV-1 infection without antiretroviral therapy and determined co-receptor usage of the infecting viruses. We assessed genetic evolution of full-length HIV-1 envelope sequences by single-genome analysis from one participant and his sexual partner, and explored HIV-1 immune responses and HIV-1 mutations following virologic escape and disease progression. Results Both participants experienced viremia of less than 4,000 RNA copies/ml with preserved CD4+ T cell counts off ART for at least 3.3 and 4.6 years after diagnosis, respectively. One participant had phenotypic evidence of X4 virus, had no known favorable HLA alleles, and appeared to be infected by minority X4 virus from a pool that predominately used CCR5 for entry. The second participant had virus that was unable to use CXCR4 for entry in phenotypic assay but was able to engage alternative viral coreceptors (e.g. CXCR6) in vitro. Conclusions Our study demonstrates that individuals may be infected by minority X4 viruses from a population that predominately uses CCR5 for entry, and that viruses may bypass traditional HIV-1 coreceptors (CCR5 and CXCR4) completely by engaging alternative coreceptors to establish and propagate HIV-1 infection. PMID:25730507

  15. Predicting Pregnancy in HIV-1-Discordant Couples

    OpenAIRE

    Guthrie, Brandon L.; Choi, Robert Y.; Bosire, Rose; Kiarie, James N.; Mackelprang, Romel D.; Gatuguta, Anne; John-Stewart, Grace C.; FARQUHAR, Carey

    2010-01-01

    This study examines the incidence and predictors of pregnancy in HIV-1-discordant couples from Nairobi, Kenya. Women from 454 discordant couples were followed for up to 2 years. One-year cumulative incidence of pregnancy was 9.7%. Pregnancy rates did not differ significantly between HIV-1-infected and uninfected women (HR = 1.46). The majority of pregnancies occurred among women < 30 years old reporting a desire for future children (1-year incidence 22.2%). Pregnancy rates may be high among d...

  16. Intercompartmental Recombination of HIV-1 Contributes to env Intrahost Diversity and Modulates Viral Tropism and Sensitivity to Entry Inhibitors▿†‡

    OpenAIRE

    Brown, Richard J. P.; Peters, Paul J; Caron, Catherine; Gonzalez-Perez, Maria Paz; Stones, Leanne; Ankghuambom, Chiambah; Pondei, Kemebradikumo; McClure, C. Patrick; Alemnji, George; Taylor, Stephen; Sharp, Paul M.; Clapham, Paul R.; Ball, Jonathan K.

    2011-01-01

    HIV-1 circulates within an infected host as a genetically heterogeneous viral population. Viral intrahost diversity is shaped by substitutional evolution and recombination. Although many studies have speculated that recombination could have a significant impact on viral phenotype, this has never been definitively demonstrated. We report here phylogenetic and subsequent phenotypic analyses of envelope genes obtained from HIV-1 populations present in different anatomical compartments. Assessmen...

  17. The RNA helicase DDX1 is involved in restricted HIV-1 Rev function in human astrocytes

    International Nuclear Information System (INIS)

    Productive infection by human immunodeficiency virus type I (HIV-1) in the central nervous system (CNS) involves mainly macrophages and microglial cells. A frequency of less than 10% of human astrocytes is estimated to be infectable with HIV-1. Nonetheless, this relatively low percentage of infected astrocytes, but associated with a large total number of astrocytic cells in the CNS, makes human astrocytes a critical part in the analyses of potential HIV-1 reservoirs in vivo. Investigations in astrocytic cell lines and primary human fetal astrocytes revealed that limited HIV-1 replication in these cells resulted from low-level viral entry, transcription, viral protein processing, and virion maturation. Of note, a low ratio of unspliced versus spliced HIV-1-specific RNA was also investigated, as Rev appeared to act aberrantly in astrocytes, via loss of nuclear and/or nucleolar localization and diminished Rev-mediated function. Host cellular machinery enabling Rev function has become critical for elucidation of diminished Rev activity, especially for those factors leading to RNA metabolism. We have recently identified a DEAD-box protein, DDX1, as a Rev cellular co-factor and now have explored its potential importance in astrocytes. Cells were infected with HIV-1 pseudotyped with envelope glycoproteins of amphotropic murine leukemia viruses (MLV). Semi-quantitative reverse transcriptase-polymerase chain reactions (RT-PCR) for unspliced, singly-spliced, and multiply-spliced RNA clearly showed a lower ratio of unspliced/singly-spliced over multiply-spliced HIV-1-specific RNA in human astrocytes as compared to Rev-permissive, non-glial control cells. As well, the cellular localization of Rev in astrocytes was cytoplasmically dominant as compared to that of Rev-permissive, non-glial controls. This endogenous level of DDX1 expression in astrocytes was demonstrated directly to lead to a shift of Rev sub-cellular distribution dominance from nuclear and/or nucleolar to

  18. Uterine epithelial cell regulation of DC-SIGN expression inhibits transmitted/founder HIV-1 trans infection by immature dendritic cells.

    Directory of Open Access Journals (Sweden)

    Daniel O Ochiel

    Full Text Available BACKGROUND: Sexual transmission accounts for the majority of HIV-1 infections. In over 75% of cases, infection is initiated by a single variant (transmitted/founder virus. However, the determinants of virus selection during transmission are unknown. Host cell-cell interactions in the mucosa may be critical in regulating susceptibility to infection. We hypothesized in this study that specific immune modulators secreted by uterine epithelial cells modulate susceptibility of dendritic cells (DC to infection with HIV-1. METHODOLOGY/PRINCIPAL FINDINGS: Here we report that uterine epithelial cell secretions (i.e. conditioned medium, CM decreased DC-SIGN expression on immature dendritic cells via a transforming growth factor beta (TGF-β mechanism. Further, CM inhibited dendritic cell-mediated trans infection of HIV-1 expressing envelope proteins of prototypic reference. Similarly, CM inhibited trans infection of HIV-1 constructs expressing envelopes of transmitted/founder viruses, variants that are selected during sexual transmission. In contrast, whereas recombinant TGF- β1 inhibited trans infection of prototypic reference HIV-1 by dendritic cells, TGF-β1 had a minimal effect on trans infection of transmitted/founder variants irrespective of the reporter system used to measure trans infection. CONCLUSIONS/SIGNIFICANCE: Our results provide the first direct evidence for uterine epithelial cell regulation of dendritic cell transmission of infection with reference and transmitted/founder HIV-1 variants. These findings have immediate implications for designing strategies to prevent sexual transmission of HIV-1.

  19. The NRTIs Lamivudine, Stavudine and Zidovudine Have Reduced HIV-1 Inhibitory Activity in Astrocytes

    Science.gov (United States)

    Gray, Lachlan R.; Tachedjian, Gilda; Ellett, Anne M.; Roche, Michael J.; Cheng, Wan-Jung; Guillemin, Gilles J.; Brew, Bruce J.; Turville, Stuart G.; Wesselingh, Steve L.; Gorry, Paul R.; Churchill, Melissa J.

    2013-01-01

    HIV-1 establishes infection in astrocytes and macroage-lineage cells of the central nervous system (CNS). Certain antiretroviral drugs (ARVs) can penetrate the CNS, and are therefore often used in neurologically active combined antiretroviral therapy (Neuro-cART) regimens, but their relative activity in the different susceptible CNS cell populations is unknown. Here, we determined the HIV-1 inhibitory activity of CNS-penetrating ARVs in astrocytes and macrophage-lineage cells. Primary human fetal astrocytes (PFA) and the SVG human astrocyte cell line were used as in vitro models for astrocyte infection, and monocyte-derived macrophages (MDM) were used as an in vitro model for infection of macrophage-lineage cells. The CNS-penetrating ARVs tested were the nucleoside reverse transcriptase inhibitors (NRTIs) abacavir (ABC), lamivudine (3TC), stavudine (d4T) and zidovudine (ZDV), the non-NRTIs efavirenz (EFV), etravirine (ETR) and nevirapine (NVP), and the integrase inhibitor raltegravir (RAL). Drug inhibition assays were performed using single-round HIV-1 entry assays with luciferase viruses pseudotyped with HIV-1 YU-2 envelope or vesicular stomatitis virus G protein (VSV-G). All the ARVs tested could effectively inhibit HIV-1 infection in macrophages, with EC90s below concentrations known to be achievable in the cerebral spinal fluid (CSF). Most of the ARVs had similar potency in astrocytes, however the NRTIs 3TC, d4T and ZDV had insufficient HIV-1 inhibitory activity in astrocytes, with EC90s 12-, 187- and 110-fold greater than achievable CSF concentrations, respectively. Our data suggest that 3TC, d4T and ZDV may not adequately target astrocyte infection in vivo, which has potential implications for their inclusion in Neuro-cART regimens. PMID:23614033

  20. Early low-titer neutralizing antibodies impede HIV-1 replication and select for virus escape.

    Directory of Open Access Journals (Sweden)

    Katharine J Bar

    Full Text Available Single genome sequencing of early HIV-1 genomes provides a sensitive, dynamic assessment of virus evolution and insight into the earliest anti-viral immune responses in vivo. By using this approach, together with deep sequencing, site-directed mutagenesis, antibody adsorptions and virus-entry assays, we found evidence in three subjects of neutralizing antibody (Nab responses as early as 2 weeks post-seroconversion, with Nab titers as low as 1∶20 to 1∶50 (IC(50 selecting for virus escape. In each of the subjects, Nabs targeted different regions of the HIV-1 envelope (Env in a strain-specific, conformationally sensitive manner. In subject CH40, virus escape was first mediated by mutations in the V1 region of the Env, followed by V3. HIV-1 specific monoclonal antibodies from this subject mapped to an immunodominant region at the base of V3 and exhibited neutralizing patterns indistinguishable from polyclonal antibody responses, indicating V1-V3 interactions within the Env trimer. In subject CH77, escape mutations mapped to the V2 region of Env, several of which selected for alterations of glycosylation. And in subject CH58, escape mutations mapped to the Env outer domain. In all three subjects, initial Nab recognition was followed by sequential rounds of virus escape and Nab elicitation, with Nab escape variants exhibiting variable costs to replication fitness. Although delayed in comparison with autologous CD8 T-cell responses, our findings show that Nabs appear earlier in HIV-1 infection than previously recognized, target diverse sites on HIV-1 Env, and impede virus replication at surprisingly low titers. The unexpected in vivo sensitivity of early transmitted/founder virus to Nabs raises the possibility that similarly low concentrations of vaccine-induced Nabs could impair virus acquisition in natural HIV-1 transmission, where the risk of infection is low and the number of viruses responsible for transmission and productive clinical

  1. Extensive complement-dependent enhancement of HIV-1 by autologous non-neutralising antibodies at early stages of infection

    Directory of Open Access Journals (Sweden)

    Williams Ian

    2011-03-01

    Full Text Available Abstract Background Non-neutralising antibodies to the envelope glycoprotein are elicited during acute HIV-1 infection and are abundant throughout the course of disease progression. Although these antibodies appear to have negligible effects on HIV-1 infection when assayed in standard neutralisation assays, they have the potential to exert either inhibitory or enhancing effects through interactions with complement and/or Fc receptors. Here we report that non-neutralising antibodies produced early in response to HIV-1 infection can enhance viral infectivity. Results We investigated this complement-mediated antibody-dependent enhancement (C'-ADE of early HIV infection by carrying out longitudinal studies with primary viruses and autologous sera derived sequentially from recently infected individuals, using a T cell line naturally expressing the complement receptor 2 (CR2; CD21. The C'-ADE was consistently observed and in some cases achieved infection-enhancing levels of greater than 350-fold, converting a low-level infection to a highly destructive one. C'-ADE activity declined as a neutralising response to the early virus emerged, but later virus isolates that had escaped the neutralising response demonstrated an increased capacity for enhanced infection by autologous antibodies. Moreover, sera with autologous enhancing activity were capable of C'ADE of heterologous viral isolates, suggesting the targeting of conserved epitopes on the envelope glycoprotein. Ectopic expression of CR2 on cell lines expressing HIV-1 receptors was sufficient to render them sensitive to C'ADE. Conclusions Taken together, these results suggest that non-neutralising antibodies to the HIV-1 envelope that arise during acute infection are not 'passive', but in concert with complement and complement receptors may have consequences for HIV-1 dissemination and pathogenesis.

  2. Immunodeficient Parameters in the HIV-1 Transgenic Rat Model

    OpenAIRE

    Chang, Sulie L.; Frank Ocasio; Joseq A. Beltran

    2007-01-01

    Recently an HIV-1 transgenic (HIV-1Tg) rat model was created that carries a gag-pol-deleted HIV-1 genome under the control of the HIV-1 viral promoter. However, other viral proteins are expressed in most organs and tissues, and are found in the circulating blood. Since HIV-1 targets the immune system in humans, we examined two immunological parameters, leukocyte-endothelial adhesion (LEA) and inflammatory cytokine production, in 5 mo old HIV-1Tg rats to identify immune functions that may be i...

  3. Critical involvement of the ATM-dependent DNA damage response in the apoptotic demise of HIV-1-elicited syncytia.

    Directory of Open Access Journals (Sweden)

    Jean-Luc Perfettini

    Full Text Available DNA damage can activate the oncosuppressor protein ataxia telangiectasia mutated (ATM, which phosphorylates the histone H2AX within characteristic DNA damage foci. Here, we show that ATM undergoes an activating phosphorylation in syncytia elicited by the envelope glycoprotein complex (Env of human immunodeficiency virus-1 (HIV-1 in vitro. This was accompanied by aggregation of ATM in discrete nuclear foci that also contained phospho-histone H2AX. DNA damage foci containing phosphorylated ATM and H2AX were detectable in syncytia present in the brain or lymph nodes from patients with HIV-1 infection, as well as in a fraction of blood leukocytes, correlating with viral status. Knockdown of ATM or of its obligate activating factor NBS1 (Nijmegen breakage syndrome 1 protein, as well as pharmacological inhibition of ATM with KU-55933, inhibited H2AX phosphorylation and prevented Env-elicited syncytia from undergoing apoptosis. ATM was found indispensable for the activation of MAP kinase p38, which catalyzes the activating phosphorylation of p53 on serine 46, thereby causing p53 dependent apoptosis. Both wild type HIV-1 and an HIV-1 mutant lacking integrase activity induced syncytial apoptosis, which could be suppressed by inhibiting ATM. HIV-1-infected T lymphoblasts from patients with inactivating ATM or NBS1 mutations also exhibited reduced syncytial apoptosis. Altogether these results indicate that apoptosis induced by a fusogenic HIV-1 Env follows a pro-apoptotic pathway involving the sequential activation of ATM, p38MAPK and p53.

  4. Functional organization of the HIV lipid envelope

    Science.gov (United States)

    Huarte, Nerea; Carravilla, Pablo; Cruz, Antonio; Lorizate, Maier; Nieto-Garai, Jon A.; Kräusslich, Hans-Georg; Pérez-Gil, Jesús; Requejo-Isidro, Jose; Nieva, José L.

    2016-01-01

    The chemical composition of the human immunodeficiency virus type 1 (HIV-1) membrane is critical for fusion and entry into target cells, suggesting that preservation of a functional lipid bilayer organization may be required for efficient infection. HIV-1 acquires its envelope from the host cell plasma membrane at sites enriched in raft-type lipids. Furthermore, infectious particles display aminophospholipids on their surface, indicative of dissipation of the inter-leaflet lipid asymmetry metabolically generated at cellular membranes. By combining two-photon excited Laurdan fluorescence imaging and atomic force microscopy, we have obtained unprecedented insights into the phase state of membranes reconstituted from viral lipids (i.e., extracted from infectious HIV-1 particles), established the role played by the different specimens in the mixtures, and characterized the effects of membrane-active virucidal agents on membrane organization. In determining the molecular basis underlying lipid packing and lateral heterogeneity of the HIV-1 membrane, our results may help develop compounds with antiviral activity acting by perturbing the functional organization of the lipid envelope. PMID:27678107

  5. Picomolar dichotomous activity of gnidimacrin against HIV-1.

    Directory of Open Access Journals (Sweden)

    Li Huang

    Full Text Available Highly active antiretroviral therapy (HAART has offered a promising approach for controlling HIV-1 replication in infected individuals. However, with HARRT, HIV-1 is suppressed rather than eradicated due to persistence of HIV-1 in latent viral reservoirs. Thus, purging the virus from latent reservoirs is an important strategy toward eradicating HIV-1 infection. In this study, we discovered that the daphnane diterpene gnidimacrin, which was previously reported to have potent anti-cancer cell activity, activated HIV-1 replication and killed persistently-infected cells at picomolar concentrations. In addition to its potential to purge HIV-1 from latently infected cells, gnidimacrin potently inhibited a panel of HIV-1 R5 virus infection of peripheral blood mononuclear cells (PBMCs at an average concentration lower than 10 pM. In contrast, gnidimacrin only partially inhibited HIV-1 ×4 virus infection of PBMCs. The strong anti-HIV-1 R5 virus activity of gnidimacrin was correlated with its effect on down-regulation of the HIV-1 coreceptor CCR5. The anti-R5 virus activity of gnidimacrin was completely abrogated by a selective protein kinase C beta inhibitor enzastaurin, which suggests that protein kinase C beta plays a key role in the potent anti-HIV-1 activity of gnidimacrin in PBMCs. In summary, these results suggest that gnidimacrin could activate latent HIV-1, specifically kill HIV-1 persistently infected cells, and inhibit R5 viruses at picomolar concentrations.

  6. Harnessing the protective potential of HIV-1 neutralizing antibodies [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    S Abigail Smith

    2016-01-01

    Full Text Available Recent biological, structural, and technical advances are converging within the HIV-1 vaccine field to harness the power of antibodies for prevention and therapy. Numerous monoclonal antibodies with broad neutralizing activity against diverse HIV-1 isolates have now been identified, revealing at least five sites of vulnerability on the envelope (Env glycoproteins. While there are practical and technological barriers blocking a clear path from broadly neutralizing antibodies (bNAb to a protective vaccine, this is not a dead end. Scientists are revisiting old approaches with new technology, cutting new trails through unexplored territory, and paving new roads in the hopes of preventing HIV-1 infection. Other promising avenues to capitalize on the power of bNAbs are also being pursued, such as passive antibody immunotherapy and gene therapy approaches. Moreover, non-neutralizing antibodies have inhibitory activities that could have protective potential, alone or in combination with bNAbs. With a new generation of bNAbs, and a clinical trial that associated antibodies with reduced acquisition, the field is closer than ever to developing strategies to use antibodies against HIV-1.

  7. Molecular Gymnastics: Mechanisms of HIV-1 Resistance to CCR5 Antagonists and Impact on Virus Phenotypes.

    Science.gov (United States)

    Roche, Michael; Borm, Katharina; Flynn, Jacqueline K; Lewin, Sharon R; Churchill, Melissa J; Gorry, Paul R

    2016-01-01

    Human immunodeficiency virus type 1 (HIV-1) enters host cells through the binding of its envelope glycoproteins (Env) to the host cell receptor CD4 and then subsequent binding to a chemokine coreceptor, either CCR5 or CXCR4. CCR5 antagonists are a relatively recent class addition to the armamentarium of anti-HIV-1 drugs. These compounds act by binding to a hydrophobic pocket formed by the transmembrane helices of CCR5 and altering the conformation of the extracellular domains, such that they are no longer recognized by Env. Maraviroc is the first drug within this class to be licenced for use in HIV-1 therapy regimens. HIV resistance to CCR5 antagonists occurs either through outgrowth of pre-existing CXCR4-using viruses, or through acquisition of the ability of CCR5-using HIV-1 to use the antagonist bound form of CCR5. In the latter scenario, the mechanism underlying resistance is through complex alterations in the way that resistant Envs engage CCR5. These significant changes are unlikely to occur without consequence to the viral entry phenotype and may also open up new avenues to target CCR5 antagonist resistant viruses. This review discusses the mechanism of action of CCR5 antagonists, how HIV resistance to CCR5 antagonists occurs, and the subsequent effects on Env function. PMID:26324043

  8. CIB1 and CIB2 are HIV-1 helper factors involved in viral entry.

    Science.gov (United States)

    Godinho-Santos, Ana; Hance, Allan J; Gonçalves, João; Mammano, Fabrizio

    2016-01-01

    HIV-1 relies on the host-cell machinery to accomplish its replication cycle, and characterization of these helper factors contributes to a better understanding of HIV-host interactions and can identify potential novel antiviral targets. Here we explored the contribution of CIB2, previously identified by RNAi screening as a potential helper factor, and its homolog, CIB1. Knockdown of either CIB1 or CIB2 strongly impaired viral replication in Jurkat cells and in primary CD4+ T-lymphocytes, identifying these proteins as non-redundant helper factors. Knockdown of CIB1 and CIB2 impaired envelope-mediated viral entry for both for X4- and R5-tropic HIV-1, and both cell-free and cell-associated entry pathways were affected. In contrast, the level of CIB1 and CIB2 expression did not influence cell viability, cell proliferation, receptor-independent viral binding to the cell surface, or later steps in the viral replication cycle. CIB1 and CIB2 knockdown was found to reduce the expression of surface molecules implicated in HIV-1 infection, including CXCR4, CCR5 and integrin α4β7, suggesting at least one mechanism through which these proteins promote viral infection. Thus, this study identifies CIB1 and CIB2 as host helper factors for HIV-1 replication that are required for optimal receptor-mediated viral entry. PMID:27489023

  9. CIB1 and CIB2 are HIV-1 helper factors involved in viral entry

    Science.gov (United States)

    Godinho-Santos, Ana; Hance, Allan J.; Gonçalves, João; Mammano, Fabrizio

    2016-01-01

    HIV-1 relies on the host-cell machinery to accomplish its replication cycle, and characterization of these helper factors contributes to a better understanding of HIV-host interactions and can identify potential novel antiviral targets. Here we explored the contribution of CIB2, previously identified by RNAi screening as a potential helper factor, and its homolog, CIB1. Knockdown of either CIB1 or CIB2 strongly impaired viral replication in Jurkat cells and in primary CD4+ T-lymphocytes, identifying these proteins as non-redundant helper factors. Knockdown of CIB1 and CIB2 impaired envelope-mediated viral entry for both for X4- and R5-tropic HIV-1, and both cell-free and cell-associated entry pathways were affected. In contrast, the level of CIB1 and CIB2 expression did not influence cell viability, cell proliferation, receptor-independent viral binding to the cell surface, or later steps in the viral replication cycle. CIB1 and CIB2 knockdown was found to reduce the expression of surface molecules implicated in HIV-1 infection, including CXCR4, CCR5 and integrin α4β7, suggesting at least one mechanism through which these proteins promote viral infection. Thus, this study identifies CIB1 and CIB2 as host helper factors for HIV-1 replication that are required for optimal receptor-mediated viral entry. PMID:27489023

  10. Molecular Gymnastics: Mechanisms of HIV-1 Resistance to CCR5 Antagonists and Impact on Virus Phenotypes.

    Science.gov (United States)

    Roche, Michael; Borm, Katharina; Flynn, Jacqueline K; Lewin, Sharon R; Churchill, Melissa J; Gorry, Paul R

    2016-01-01

    Human immunodeficiency virus type 1 (HIV-1) enters host cells through the binding of its envelope glycoproteins (Env) to the host cell receptor CD4 and then subsequent binding to a chemokine coreceptor, either CCR5 or CXCR4. CCR5 antagonists are a relatively recent class addition to the armamentarium of anti-HIV-1 drugs. These compounds act by binding to a hydrophobic pocket formed by the transmembrane helices of CCR5 and altering the conformation of the extracellular domains, such that they are no longer recognized by Env. Maraviroc is the first drug within this class to be licenced for use in HIV-1 therapy regimens. HIV resistance to CCR5 antagonists occurs either through outgrowth of pre-existing CXCR4-using viruses, or through acquisition of the ability of CCR5-using HIV-1 to use the antagonist bound form of CCR5. In the latter scenario, the mechanism underlying resistance is through complex alterations in the way that resistant Envs engage CCR5. These significant changes are unlikely to occur without consequence to the viral entry phenotype and may also open up new avenues to target CCR5 antagonist resistant viruses. This review discusses the mechanism of action of CCR5 antagonists, how HIV resistance to CCR5 antagonists occurs, and the subsequent effects on Env function.

  11. Racing with HIV-1: Challenges and Hope

    Institute of Scientific and Technical Information of China (English)

    刘树林; 郑鑫; 王玲; 凌虹; 刘桂荣

    2004-01-01

    We are racing with HIV-1, the etiologic agent for AIDS in human beings [1,2], with two possible end consequences: if we win, HIV-1 will be under our control by immunologic or therapeutic measures; if HIV-1 wins, the SIVAfrican monkeys' story would repeat in humans, i.e., only the few individuals that are not killed by the virus

  12. HIV-1 vaccine design: Learning from natural infection

    NARCIS (Netherlands)

    T.L.G.M. van den Kerkhof

    2016-01-01

    Het humane immuundeficiëntie virus type 1 (hiv-1) is het virus dat aids veroorzaakt. Er is nog steeds geen bescherming tegen een hiv-1 infectie en de beëindiging van de wereldwijde epidemie kan waarschijnlijk alleen worden bereikt met behulp van een vaccin. Een hiv-1 vaccin zal bescherming moeten bi

  13. Intestinal microbiota and HIV-1 infection

    Directory of Open Access Journals (Sweden)

    E. B. S. M. Trindade

    2007-01-01

    Full Text Available The intestinal microbiota consists of a qualitatively and quantitatively diverse range of microorganisms dynamically interacting with the host. It is remarkably stable with regard to the presence of microorganisms and their roles which, however, can be altered due to pathological conditions, diet composition, gastrointestinal disturbances and/or drug ingestion. The present review aimed at contributing to the discussion about changes in the intestinal microbiota due to HIV-1 infection, focusing on the triad infection-microbiota-nutrition as factors that promote intestinal bacterial imbalance. Intestinal microbiota alterations can be due to the HIV-1 infection as a primary factor or the pharmacotherapy employed, or they can be one of the consequences of the disease.

  14. NKT cells in HIV-1 infection

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Natural killer T (NKT) cells are a unique T cell population that have important immunoregulatory functions and have been shown to be involved in host immunity against a range of microorganisms. It also emerges that they might play a role in HIV-1 infection, and therefore be selectively depleted during the early stages of infection. Recent studies are reviewed regarding the dynamics of NKT depletion during HIV-I infection and their recovery under highly active antiretrovirai treatment (HAART). Possible mechanisms for these changes are proposed based on the recent developments in HIV pathogenesis. Further discussions are focused on HIV's disruption of NKT activation by downregulating CDId expression on antigen presentation cells (APC). HIV-1 protein Nefis found to play the major role by interrupting the intraceilular trafficking of nascent and recycling CDId molecules.

  15. Nanochemistry-based immunotherapy for HIV-1.

    Science.gov (United States)

    Lori, F; Calarota, S A; Lisziewicz, J

    2007-01-01

    Highly active antiretroviral treatment (HAART), i.e. the combination of three or more drugs against human immunodeficiency virus type 1 (HIV-1), has greatly improved the clinical outcome of HIV-1-infected individuals. However, HAART is unable to reconstitute HIV-specific immunity and eradicate the virus. Several observations in primate models and in humans support the notion that cell-mediated immunity can control viral replication and slow disease progression. Thus, besides drugs, an immunotherapy that induces long-lasting HIV-specific T-cell responses could play a role in the treatment of HIV/AIDS. To induce such immune responses, DermaVir Patch has been developed. DermaVir consists of an HIV-1 antigen-encoding plasmid DNA that is chemically formulated in a nanoparticle. DermaVir is administered under a patch after a skin preparation that supports the delivery of the nanoparticle to Langerhans cells (LC). Epidermal LC trap and transport the nanomedicine to draining lymph nodes. While in transit, LC mature into dendritic cells (DC), which can efficiently present the DNA-encoded antigens to naïve T-cells for the induction of cellular immunity. Pre-clinical studies and Phase I clinical testing of DermaVir in HIV-1-infected individuals have demonstrated the safety and tolerability of DermaVir Patch. To further modulate cellular immunity, molecular adjuvants might be added into the nanoparticle. DermaVir Patch represents a new nanomedicine platform for immunotherapy of HIV/AIDS. In this review, the antiviral activity of DermaVir-induced cellular immunity is discussed. Furthermore, the action of some cytokines currently being tested as adjuvants are highlighted and the adjuvant effect of cytokine plasmid DNA included in the DermaVir nanoparticle is reviewed.

  16. Persistent HIV-1 replication during antiretroviral therapy

    OpenAIRE

    Martinez-Picado, Javier; Deeks, Steven G

    2016-01-01

    Purpose of review The present review will highlight some of the recent findings regarding the capacity of HIV-1 to replicate during antiretroviral therapy (ART). Recent findings Although ART is highly effective at inhibiting HIV replication, it is not curative. Several mechanisms contribute to HIV persistence during ART, including HIV latency, immune dysfunction, and perhaps persistent low-level spread of the virus to uninfected cells (replication). The success in curing HIV will depend on ef...

  17. Induction of multi-epitope specific antibodies against HIV-1 by multi-epitope vaccines

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Some neutralizing antibodies against HIV-1 envelope proteins were highly effective to inhibit the infection of different strains in vitro, and existed in the infected individuals with very low levels. We suggested multi-epitope-vaccine as a new strategy to increase levels of neutralizing antibodies and the abilities against HIV mutation in vivo. Two candidate multi-epitope-vaccines induced antibodies with predefined multi-epitope-specificity in rhesus macaque. These antibodies recognized corresponding neutralizing epitopes on epitope-peptides, gp41 peptides, V3 loop peptide, rsgp41 and rgp120. Besides, three candidate epitope-vaccines in combination (another kind of multi-epitopevaccines) showed similar potency to induce predefined multiple immune responses in rabbits. These results suggest that multi-epitope-vaccines may be a new strategy to induce multi-antiviral activities against HIV-1 infection and mutafions.

  18. Conserved Structural Elements in the V3 Crown of HIV-1 gp120

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, X.; Burke, V; Totrov, M; Williams, C; Cardozo, T; Gorny, M; Zolla-Pazner, S; Kong, X

    2010-01-01

    Binding of the third variable region (V3) of the HIV-1 envelope glycoprotein gp120 to the cell-surface coreceptors CCR5 or CXCR4 during viral entry suggests that there are conserved structural elements in this sequence-variable region. These conserved elements could serve as epitopes to be targeted by a vaccine against HIV-1. Here we perform a systematic structural analysis of representative human anti-V3 monoclonal antibodies in complex with V3 peptides, revealing that the crown of V3 has four conserved structural elements: an arch, a band, a hydrophobic core and the peptide backbone. These are either unaffected by or are subject to minimal sequence variation. As these regions are targeted by cross-clade neutralizing human antibodies, they provide a blueprint for the design of vaccine immunogens that could elicit broadly cross-reactive protective antibodies.

  19. Methamphetamine Inhibits HIV-1 Replication in CD4+ T Cells by Modulating Anti–HIV-1 miRNA Expression

    OpenAIRE

    Mantri, Chinmay K.; Mantri, Jyoti V.; Pandhare, Jui; Dash, Chandravanu

    2014-01-01

    Methamphetamine is the second most frequently used illicit drug in the United States. Methamphetamine abuse is associated with increased risk of HIV-1 acquisition, higher viral loads, and enhanced HIV-1 pathogenesis. Although a direct link between methamphetamine abuse and HIV-1 pathogenesis remains to be established in patients, methamphetamine has been shown to increase HIV-1 replication in macrophages, dendritic cells, and cells of HIV transgenic mice. Intriguingly, the effects of methamph...

  20. Nup153 and Nup98 bind the HIV-1 core and contribute to the early steps of HIV-1 replication

    Energy Technology Data Exchange (ETDEWEB)

    Di Nunzio, Francesca, E-mail: francesca.di-nunzio@pasteur.fr [Molecular Virology and Vaccinology unit, CNRS URA 3015, Department of Virology, Institut Pasteur, 25-28 rue du Dr. Roux, 75015 Paris (France); Fricke, Thomas [Department of Microbiology and Immunology, Albert Einstein College of Medicine Bronx, NY 10461 (United States); Miccio, Annarita [University of Modena e Reggio Emilia, Centro di Medicina Rigenerativa, Modena (Italy); Valle-Casuso, Jose Carlos; Perez, Patricio [Department of Microbiology and Immunology, Albert Einstein College of Medicine Bronx, NY 10461 (United States); Souque, Philippe [Molecular Virology and Vaccinology unit, CNRS URA 3015, Department of Virology, Institut Pasteur, 25-28 rue du Dr. Roux, 75015 Paris (France); Rizzi, Ermanno; Severgnini, Marco [Institute of Biomedical Technologies, CNR, Milano (Italy); Mavilio, Fulvio [University of Modena e Reggio Emilia, Centro di Medicina Rigenerativa, Modena (Italy); Genethon, Evry (France); Charneau, Pierre [Molecular Virology and Vaccinology unit, CNRS URA 3015, Department of Virology, Institut Pasteur, 25-28 rue du Dr. Roux, 75015 Paris (France); Diaz-Griffero, Felipe, E-mail: felipe.diaz-griffero@einstein.yu.edu [Department of Microbiology and Immunology, Albert Einstein College of Medicine Bronx, NY 10461 (United States)

    2013-05-25

    The early steps of HIV-1 replication involve the entry of HIV-1 into the nucleus, which is characterized by viral interactions with nuclear pore components. HIV-1 developed an evolutionary strategy to usurp the nuclear pore machinery and chromatin in order to integrate and efficiently express viral genes. In the current work, we studied the role of nucleoporins 153 and 98 (Nup153 and Nup98) in infection of human Jurkat lymphocytes by HIV-1. We showed that Nup153-depleted cells exhibited a defect in nuclear import, while depletion of Nup 98 caused a slight defect in HIV integration. To explore the biochemical viral determinants for the requirement of Nup153 and Nup98 during HIV-1 infection, we tested the ability of these nucleoporins to interact with HIV-1 cores. Our findings showed that both nucleoporins bind HIV-1 cores suggesting that this interaction is important for HIV-1 nuclear import and/or integration. Distribution analysis of integration sites in Nup153-depleted cells revealed a reduced tendency of HIV-1 to integrate in intragenic sites, which in part could account for the large infectivity defect observed in Nup153-depleted cells. Our work strongly supports a role for Nup153 in HIV-1 nuclear import and integration. - Highlights: ► We studied the role of Nup98 and Nup153 in HIV-1 infection. ► Nup98 binds the HIV-1 core and is involved in HIV-1 integration. ► Nup153 binds the HIV-1 core and is involved in HIV-1 nuclear import. ► Depletion of Nup153 decreased the integration of HIV-1 in transcriptionally active sites.

  1. Immunodeficient Parameters in the HIV-1 Transgenic Rat Model

    Directory of Open Access Journals (Sweden)

    Sulie L. Chang

    2007-01-01

    Full Text Available Recently an HIV-1 transgenic (HIV-1Tg rat model was created that carries a gag-pol-deleted HIV-1 genome under the control of the HIV-1 viral promoter. However, other viral proteins are expressed in most organs and tissues, and are found in the circulating blood. Since HIV-1 targets the immune system in humans, we examined two immunological parameters, leukocyte-endothelial adhesion (LEA and inflammatory cytokine production, in 5 mo old HIV-1Tg rats to identify immune functions that may be impaired even before the onset of symptoms of HIV-1 infection. We administered a single injection (i.p. of the bacterial endotoxin, lipopolysaccharide (LPS, 250 ug/kg, to 5 mo old HIV-1Tg rats, age-matched transgenic control (Tg rats, and F344/NHsd (F344 control background strain rats. LPS induced an LEA response in both the Tg control and F344 control animals. However, in the HIV-1Tg rats, there was no LEA response to LPS. Following LPS administration, there was significantly greater serum levels of TNF-α and IL-1β, two pro-inflammatory cytokines, in the HIV-1Tg rats compared to the control animals. In contrast, the serum level of IL-10, an anti-inflammatory cytokine, was comparable in the HIV-1Tg, Tg control, and F344 control rats. Our data show that, in the HIV-1Tg rat, there is a negative correlation between the LEA response and the induction of pro-inflammatory cytokines in response to bacterial endotoxin. These findings suggest that the persistent presence of viral proteins may be, at least, partially responsible for the immunodeficiency that occurs with HIV-1 infection, and that the HIV-1Tg rat could be a valid rodent model in which to study various aspects of HIV-1 infection.

  2. Suppression of HIV-1 Infectivity by Human Glioma Cells.

    Science.gov (United States)

    Hoque, Sheikh Ariful; Tanaka, Atsushi; Islam, Salequl; Ahsan, Gias Uddin; Jinno-Oue, Atsushi; Hoshino, Hiroo

    2016-05-01

    HIV-1 infection to the central nervous system (CNS) is very common in AIDS patients. The predominant cell types infected in the brain are monocytes and macrophages, which are surrounded by several HIV-1-resistant cell types, such as astrocytes, oligodendrocytes, neurons, and microvascular cells. The effect of these HIV-1-resistant cells on HIV-1 infection is largely unknown. In this study, we examined the stability of HIV-1 cultured with several human glioblastoma cell lines, for example, NP-2, U87MG, T98G, and A172, to determine whether these HIV-1-resistant brain cells could enhance or suppress HIV-1 infection and thus modulate HIV-1 infection in the CNS. The HIV-1 titer was determined using the MAGIC-5A indicator cell line as well as naturally occurring CD4(+) T cells. We found that the stability of HIV-1 incubated with NP-2 or U87MG cells at 37°C was significantly shorter (half-life, 2.5-4 h) compared to that of HIV-1 incubated with T98G or A172 cells or in culture medium without cells (half-life, 8-18 h). The spent culture media (SCM) of NP-2 and U87MG cells had the ability to suppress both R5- and X4-HIV-1 infection by inhibiting HIV-1 attachment to target cells. This inhibitory effect was eliminated by the treatment of the SCM with chondroitinase ABC but not heparinase, suggesting that the inhibitory factor(s) secreted by NP-2 and U87MG cells was chiefly mediated by chondroitin sulfate (CS) or CS-like moiety. Thus, this study reveals that some but not all glioma cells secrete inhibitory molecules to HIV-1 infection that may contribute in lowering HIV-1 infection in the CNS in vivo.

  3. Viral linkage in HIV-1 seroconverters and their partners in an HIV-1 prevention clinical trial.

    Directory of Open Access Journals (Sweden)

    Mary S Campbell

    Full Text Available BACKGROUND: Characterization of viruses in HIV-1 transmission pairs will help identify biological determinants of infectiousness and evaluate candidate interventions to reduce transmission. Although HIV-1 sequencing is frequently used to substantiate linkage between newly HIV-1 infected individuals and their sexual partners in epidemiologic and forensic studies, viral sequencing is seldom applied in HIV-1 prevention trials. The Partners in Prevention HSV/HIV Transmission Study (ClinicalTrials.gov #NCT00194519 was a prospective randomized placebo-controlled trial that enrolled serodiscordant heterosexual couples to determine the efficacy of genital herpes suppression in reducing HIV-1 transmission; as part of the study analysis, HIV-1 sequences were examined for genetic linkage between seroconverters and their enrolled partners. METHODOLOGY/PRINCIPAL FINDINGS: We obtained partial consensus HIV-1 env and gag sequences from blood plasma for 151 transmission pairs and performed deep sequencing of env in some cases. We analyzed sequences with phylogenetic techniques and developed a Bayesian algorithm to evaluate the probability of linkage. For linkage, we required monophyletic clustering between enrolled partners' sequences and a Bayesian posterior probability of ≥ 50%. Adjudicators classified each seroconversion, finding 108 (71.5% linked, 40 (26.5% unlinked, and 3 (2.0% indeterminate transmissions, with linkage determined by consensus env sequencing in 91 (84%. Male seroconverters had a higher frequency of unlinked transmissions than female seroconverters. The likelihood of transmission from the enrolled partner was related to time on study, with increasing numbers of unlinked transmissions occurring after longer observation periods. Finally, baseline viral load was found to be significantly higher among linked transmitters. CONCLUSIONS/SIGNIFICANCE: In this first use of HIV-1 sequencing to establish endpoints in a large clinical trial, more than

  4. Common principles and intermediates of viral protein-mediated fusion: the HIV-1 paradigm

    Directory of Open Access Journals (Sweden)

    Melikyan Gregory B

    2008-12-01

    Full Text Available Abstract Enveloped viruses encode specialized fusion proteins which promote the merger of viral and cell membranes, permitting the cytosolic release of the viral cores. Understanding the molecular details of this process is essential for antiviral strategies. Recent structural studies revealed a stunning diversity of viral fusion proteins in their native state. In spite of this diversity, the post-fusion structures of these proteins share a common trimeric hairpin motif in which the amino- and carboxy-terminal hydrophobic domains are positioned at the same end of a rod-shaped molecule. The converging hairpin motif, along with biochemical and functional data, implies that disparate viral proteins promote membrane merger via a universal "cast-and-fold" mechanism. According to this model, fusion proteins first anchor themselves to the target membrane through their hydrophobic segments and then fold back, bringing the viral and cellular membranes together and forcing their merger. However, the pathways of protein refolding and the mechanism by which this refolding is coupled to membrane rearrangements are still not understood. The availability of specific inhibitors targeting distinct steps of HIV-1 entry permitted the identification of key conformational states of its envelope glycoprotein en route to fusion. These studies provided functional evidence for the direct engagement of the target membrane by HIV-1 envelope glycoprotein prior to fusion and revealed the role of partially folded pre-hairpin conformations in promoting the pore formation.

  5. Three Candidate Epitope-Vaccines in Combination Inducing High Levels of Multiantibodies Against HIV-1

    Institute of Scientific and Technical Information of China (English)

    刘祖强; 田海军; 王颖; 陈应华

    2003-01-01

    HIV-1 mutation results in immune evasion, which presents a serious challenge for conventional strategies for developing effective vaccines.So far, much experimental evidence indicates that HIV-1 particles in the blood of patients can be cleaned principally by neutralizing antibodies.Based on these facts, we prepared triple combination of epitope-vaccines with the objective of inducing antibodies with predefined multi-epitope-specificity against HIV-1.According to the sequences of three neutralizing epitopes (RILAVERYLKD, ELDKWA and GPGRAFY, designated E1, E2, and E3, respectively) on HIV-1 envelope proteins, three epitope-peptides ((E1)2: C-(RILAVERYLKDG)2; (E2)4: C-(ELDKWAG)4; and (E3)2: C-(GPGRAFY)2) were synthesized and then conjugated with carrier protein keyhole limpet hemocyanin (KLH) or bovine serum albumin (BSA), and used for immunizing rabbits.After the vaccine course, the triple combination of epitope-vaccines induced high levels of predefined multi-epitope-specific antibodies.An immunoblotting-analysis demonstrated that the antibodies could recognize the native epitopes on both gp41 protein and V3 loop peptide.Furthermore, we compared the immune responses of three doses of epitope-peptides in the candidate epitope-vaccine.Strong antibody responses to three epitopes were observed in a dose dependent manner, with increasing dose raising the immune response.This result indicated that immunotolerance did not occur using an epitope vaccine dose of 80 μg.Thus, our results demonstrate that epitope-vaccines in combination can synchronously induce high levels of antibodies with predefined multi-epitope-specificity against HIV-1, and may be used to develop effective vaccines against HIV as a new strategy.

  6. KIF5B and Nup358 Cooperatively Mediate the Nuclear Import of HIV-1 during Infection.

    Science.gov (United States)

    Dharan, Adarsh; Talley, Sarah; Tripathi, Abhishek; Mamede, João I; Majetschak, Matthias; Hope, Thomas J; Campbell, Edward M

    2016-06-01

    Following envelope mediated fusion, the HIV-1 core is released into the cytoplasm of the target cell and undergoes a series of trafficking and replicative steps that result in the nuclear import of the viral genome, which ultimately leads to the integration of the proviral DNA into the host cell genome. Previous studies have found that disruption of microtubules, or depletion of dynein or kinesin motors, perturb the normal uncoating and trafficking of the viral genome. Here, we show that the Kinesin-1 motor, KIF5B, induces a relocalization of the nuclear pore component Nup358 into the cytoplasm during HIV-1 infection. This relocalization of NUP358 is dependent on HIV-1 capsid, and NUP358 directly associates with viral cores following cytoplasmic translocation. This interaction between NUP358 and the HIV-1 core is dependent on multiple capsid binding surfaces, as this association is not observed following infection with capsid mutants in which a conserved hydrophobic binding pocket (N74D) or the cyclophilin A binding loop (P90A) is disrupted. KIF5B knockdown also prevents the nuclear entry and infection by HIV-1, but does not exert a similar effect on the N74D or P90A capsid mutants which do not rely on Nup358 for nuclear import. Finally, we observe that the relocalization of Nup358 in response to CA is dependent on cleavage protein and polyadenylation factor 6 (CPSF6), but independent of cyclophilin A. Collectively, these observations identify a previously unappreciated role for KIF5B in mediating the Nup358 dependent nuclear import of the viral genome during infection. PMID:27327622

  7. KIF5B and Nup358 Cooperatively Mediate the Nuclear Import of HIV-1 during Infection.

    Directory of Open Access Journals (Sweden)

    Adarsh Dharan

    2016-06-01

    Full Text Available Following envelope mediated fusion, the HIV-1 core is released into the cytoplasm of the target cell and undergoes a series of trafficking and replicative steps that result in the nuclear import of the viral genome, which ultimately leads to the integration of the proviral DNA into the host cell genome. Previous studies have found that disruption of microtubules, or depletion of dynein or kinesin motors, perturb the normal uncoating and trafficking of the viral genome. Here, we show that the Kinesin-1 motor, KIF5B, induces a relocalization of the nuclear pore component Nup358 into the cytoplasm during HIV-1 infection. This relocalization of NUP358 is dependent on HIV-1 capsid, and NUP358 directly associates with viral cores following cytoplasmic translocation. This interaction between NUP358 and the HIV-1 core is dependent on multiple capsid binding surfaces, as this association is not observed following infection with capsid mutants in which a conserved hydrophobic binding pocket (N74D or the cyclophilin A binding loop (P90A is disrupted. KIF5B knockdown also prevents the nuclear entry and infection by HIV-1, but does not exert a similar effect on the N74D or P90A capsid mutants which do not rely on Nup358 for nuclear import. Finally, we observe that the relocalization of Nup358 in response to CA is dependent on cleavage protein and polyadenylation factor 6 (CPSF6, but independent of cyclophilin A. Collectively, these observations identify a previously unappreciated role for KIF5B in mediating the Nup358 dependent nuclear import of the viral genome during infection.

  8. Raman spectroscopy of HIV-1 antigen and antibody

    Science.gov (United States)

    Zinin, Pavel V.; Hu, Ningjie; Kamemoto, Lori E.; Yu, Qigui; Misra, Anupam K.; Sharma, Shiv K.

    2011-05-01

    Raman spectra of anti-HIV-1 antibody, HIV-1 antigen (p24), and HIV-1 antibody-antigen complex have been measured in near-infrared and UV regions: 785 nm; 830 nm; and 244 nm laser excitations. The spectrum of the HIV-1 antigen was excited with an infrared laser and contains numerous Raman peaks. The most prominent peaks are broad bands at 1343, 1449, 1609 and 1655 cm-1, which are characteristic of the Raman spectra of biological cells. The UV Raman spectrum of the HIV-1 antigen has a completely different structure. It has two strong peaks at 1613 cm-1 and 1173 cm-1. The peak at 1613 cm-1 is associated with vibrations of the aromatic amino acids tyrosine (Tyr) and tryptophan (Try). The second strongest peak at 1173 cm-1 is associated with the vibration of Tyr. The Raman peak pattern of the HIV-1 antigen-antibody complex is very similar to that of the HIV-1 antigen. The only difference is that the peak at 1007 cm-1 of the Raman spectrum of the HIV-1 antigen-antibody complex is slightly enhanced compared to that of the HIV-1 antigen. This indicates that the peaks of the HIV-1 antigen dominate the Raman spectrum of the HIV-1 antigen-antibody complex.

  9. Tannin inhibits HIV-1 entry by targeting gp41

    Institute of Scientific and Technical Information of China (English)

    Lin L(U); Shu-wen LIU; Shi-bo JIANG; Shu-guang WU

    2004-01-01

    AIM: To investigate the mechanism by which tannin inhibits HIV-1 entry into target cells. METHODS: The inhibitory activity of tannin on HIV-1 replication and entry was detected by p24 production and HIV-1-mediated cell fusion, respectively. The inhibitory activity on the gp41 six-helix bundle formation was determined by an improved sandwich ELISA. RESULTS: Tannins from different sources showed potent inhibitory activity on HIV-1 replication,HIV-1-mediated cell fusion, and the gp4 six-helix bundle formation. CONCLUSION: Tannin inhibits HIV-1 entry into target cells by interfering with the gp41 six-helix bundle formation, thus blocking HIV-1 fusion with the target cell.

  10. Broad activation of latent HIV-1 in vivo

    DEFF Research Database (Denmark)

    Barton, Kirston; Hiener, Bonnie; Winckelmann, Anni;

    2016-01-01

    The 'shock and kill' approach to cure human immunodeficiency virus (HIV) includes transcriptional induction of latent HIV-1 proviruses using latency-reversing agents (LRAs) with targeted immunotherapy to purge infected cells. The administration of LRAs (panobinostat or vorinostat) to HIV-1-infected...... individuals on antiretroviral therapy induces a significant increase in cell-associated unspliced (CA-US) HIV-1 RNA from CD4(+) T cells. However, it is important to discern whether the increases in CA-US HIV-1 RNA are due to limited or broad activation of HIV-1 proviruses. Here we use single-genome sequencing...... to find that the RNA transcripts observed following LRA administration are genetically diverse, indicating activation of transcription from an extensive range of proviruses. Defective sequences are more frequently found in CA HIV-1 RNA than in HIV-1 DNA, which has implications for developing an accurate...

  11. Significant impact of non-B HIV-1 variants genetic diversity in Gabon on plasma HIV-1 RNA quantitation.

    Science.gov (United States)

    Mouinga-Ondémé, Augustin; Mabika-Mabika, Arsène; Alalade, Patrick; Mongo, Arnaud Delis; Sica, Jeanne; Liégeois, Florian; Rouet, François

    2014-01-01

    Evaluations of HIV-1 RNA viral load assays are lacking in Central Africa. The main objective of our study was to assess the reliability of HIV-1 RNA results obtained with three different assays for samples collected in Gabon. A total of 137 plasma specimens were assessed for HIV-1 RNA using the Abbott RealTime HIV-1® and Nuclisens HIV-1 EasyQ® version 2.0 assays. It included HIV-1 non-B samples (n = 113) representing six subtypes, 10 CRFs and 18 URFs from patients infected with HIV-1 and treated with antiretrovirals that were found HIV-1 RNA positive (≥300 copies/ml) with the Generic HIV viral load® assay; and samples (n = 24) from untreated individuals infected with HIV-1 but showing undetectable (<300 copies/ml) results with the Biocentric kit. For samples found positive with the Generic HIV viral load® test, correlation coefficients obtained between the three techniques were relatively low (R = 0.65 between Generic HIV viral load® and Abbott RealTime HIV-1®, 0.50 between Generic HIV viral load® and Nuclisens HIV-1 EasyQ®, and 0.66 between Abbott RealTime HIV-1® and Nuclisens HIV-1 EasyQ®). Discrepancies by at least one log10 were obtained for 19.6%, 33.7%, and 20% of samples, respectively, irrespective of genotype. Most of samples (22/24) from untreated study patients, found negative with the Biocentric kit, were also found negative with the two other techniques. In Central Africa, HIV-1 genetic diversity remains challenging for viral load testing. Further studies are required in the same area to confirm the presence of HIV-1 strains that are not amplified with at least two different viral load assays.

  12. Plasmacytoid dendritic cells suppress HIV-1 replication but contribute to HIV-1 induced immunopathogenesis in humanized mice.

    Directory of Open Access Journals (Sweden)

    Guangming Li

    2014-07-01

    Full Text Available The role of plasmacytoid dendritic cells (pDC in human immunodeficiency virus type 1 (HIV-1 infection and pathogenesis remains unclear. HIV-1 infection in the humanized mouse model leads to persistent HIV-1 infection and immunopathogenesis, including type I interferons (IFN-I induction, immune-activation and depletion of human leukocytes, including CD4 T cells. We developed a monoclonal antibody that specifically depletes human pDC in all lymphoid organs in humanized mice. When pDC were depleted prior to HIV-1 infection, the induction of IFN-I and interferon-stimulated genes (ISGs were abolished during acute HIV-1 infection with either a highly pathogenic CCR5/CXCR4-dual tropic HIV-1 or a standard CCR5-tropic HIV-1 isolate. Consistent with the anti-viral role of IFN-I, HIV-1 replication was significantly up-regulated in pDC-depleted mice. Interestingly, the cell death induced by the highly pathogenic HIV-1 isolate was severely reduced in pDC-depleted mice. During chronic HIV-1 infection, depletion of pDC also severely reduced the induction of IFN-I and ISGs, associated with elevated HIV-1 replication. Surprisingly, HIV-1 induced depletion of human immune cells including T cells in lymphoid organs, but not the blood, was reduced in spite of the increased viral replication. The increased cell number in lymphoid organs was associated with a reduced level of HIV-induced cell death in human leukocytes including CD4 T cells. We conclude that pDC play opposing roles in suppressing HIV-1 replication and in promoting HIV-1 induced immunopathogenesis. These findings suggest that pDC-depletion and IFN-I blockade will provide novel strategies for treating those HIV-1 immune non-responsive patients with persistent immune activation despite effective anti-retrovirus treatment.

  13. Antiviral mechanism of polyanionic carbosilane dendrimers against HIV-1

    Science.gov (United States)

    Vacas-Córdoba, Enrique; Maly, Marek; De la Mata, Francisco J; Gómez, Rafael; Pion, Marjorie; Muñoz-Fernández, Mª Ángeles

    2016-01-01

    Nanotechnology-derived platforms, such as dendrimers, are very attractive in several biological applications. In the case of human immunodeficiency virus (HIV) infection, polyanionic carbosilane dendrimers have shown great potential as antiviral agents in the development of novel microbicides to prevent the sexual transmission of HIV-1. In this work, we studied the mechanism of two sulfated and naphthylsulfonated functionalized carbosilane dendrimers, G3-S16 and G2-NF16. They are able to inhibit viral infection at fusion and thus at the entry step. Both compounds impede the binding of viral particles to target cell surface and membrane fusion through the blockage of gp120–CD4 interaction. In addition, and for the first time, we demonstrate that dendrimers can inhibit cell-to-cell HIV transmission and difficult infectious synapse formation. Thus, carbosilane dendrimers’ mode of action is a multifactorial process targeting several proteins from viral envelope and from host cells that could block HIV infection at different stages during the first step of infection. PMID:27103798

  14. Role of endolysosomes in HIV-1 Tat-induced neurotoxicity

    Directory of Open Access Journals (Sweden)

    Liang Hui

    2012-06-01

    Full Text Available Combined anti-retroviral therapeutic drugs effectively increase the lifespan of HIV-1-infected individuals who then have a higher prevalence of HAND (HIV-1 associated neurocognitive disorder. Soluble factors including HIV-1 proteins released from HIV-1-infected cells have been implicated in the pathogenesis of HAND, and particular attention has been paid to the HIV-1 Tat (transactivator of transcription protein because of its ability to directly excite neurons and cause neuronal cell death. Since HIV-1 Tat enters cells by receptor-mediated endocytosis and since endolysosomes play an important role in neuronal cell life and death, we tested here the hypothesis that HIV-1 Tat neurotoxicity is associated with changes in the endolysosome structure and function and also autophagy. Following the treatment of primary cultured rat hippocampal neurons with HIV-1 Tat or as controls mutant-Tat or PBS, neuronal viability was determined using a triple staining method. Preceding observations of HIV-1 Tat-induced neuronal cell death, we observed statistically significant changes in the structure and membrane integrity of endolysosomes, endolysosome pH and autophagy. As early as 24 h after HIV-1 Tat was applied to neurons, HIV-1 Tat accumulated in endolysosomes, endolysosome morphology was affected and their size increased, endolysosome membrane integrity was disrupted, endolysosome pH increased, specific activities of endolysosome enzymes decreased and autophagy was inhibited, as indicated by the significant changes in three markers for autophagy. In contrast, statistically significant levels of HIV-1 Tat-induced neuronal cell death were observed only after 48 h of HIV-1 Tat treatment. Our findings suggest that endolysosomes are involved in HIV-1 Tat-induced neurotoxicity and may represent a target for therapeutic intervention against HAND.

  15. Strain-specific V3 and CD4 binding site autologous HIV-1 neutralizing antibodies select neutralization-resistant viruses

    Science.gov (United States)

    Moody, M. Anthony; Gao, Feng; Gurley, Thaddeus C.; Amos, Joshua D.; Kumar, Amit; Hora, Bhavna; Marshall, Dawn J.; Whitesides, John F.; Xia, Shi-Mao; Parks, Robert; Lloyd, Krissey E.; Hwang, Kwan-Ki; Lu, Xiaozhi; Bonsignori, Mattia; Finzi, Andrés; Vandergrift, Nathan A.; Alam, S. Munir; Ferrari, Guido; Shen, Xiaoying; Tomaras, Georgia D.; Kamanga, Gift; Cohen, Myron S.; Sam, Noel E.; Kapiga, Saidi; Gray, Elin S.; Tumba, Nancy L.; Morris, Lynn; Zolla-Pazner, Susan; Gorny, Miroslaw K.; Mascola, John R.; Hahn, Beatrice; Shaw, George M.; Sodroski, Joseph G.; Liao, Hua-Xin; Montefiori, David C.; Hraber, Peter T.; Korber, Bette T.; Haynes, Barton F.

    2015-01-01

    Summary The third variable (V3) loop and the CD4 binding site (CD4bs) of the HIV-1 envelope are frequently targeted by neutralizing antibodies (nAbs) in infected individuals. In chronic infection, HIV-1 escape mutants repopulate the plasma, and V3 and CD4bs nAbs emerge that can neutralize heterologous tier 1 easy-to-neutralize, but not tier 2 difficult-to-neutralize HIV-1 isolates. However, neutralization sensitivity of autologous plasma viruses to this type of nAb response has not been studied. We describe the development and evolution in vivo of antibodies distinguished by their target specificity for V3and CD4bs epitopes on autologous tier 2 viruses but not on heterologous tier 2 viruses. A surprisingly high fraction of autologous circulating viruses was sensitive to these antibodies. These findings demonstrate a role for V3 and CD4bs antibodies in constraining the native envelope trimer in vivo to a neutralization-resistant phenotype, explaining why HIV-1 transmission generally occurs by tier 2 neutralization-resistant viruses. PMID:26355218

  16. HbAHP-25, an In-Silico Designed Peptide, Inhibits HIV-1 Entry by Blocking gp120 Binding to CD4 Receptor.

    Directory of Open Access Journals (Sweden)

    Tahir Bashir

    Full Text Available Human Immunodeficiency Virus (HIV-1 poses a serious threat to the developing world and sexual transmission continues to be the major source of new infections. Therefore, the development of molecules, which prevent new HIV-1 infections, is highly warranted. In the present study, a panel of human hemoglobin (Hb-α subunit derived peptides and their analogues, with an ability to bind gp120, were designed in-silico and their anti-HIV-1 activity was evaluated. Of these peptides, HbAHP-25, an analogue of Hb-α derived peptide, demonstrated significant anti-HIV-1 activity. HbAHP-25 was found to be active against CCR5-tropic HIV-1 strains (ADA5 and BaL and CXCR4-tropic HIV-1 strains (IIIB and NL4-3. Surface plasmon resonance (SPR and ELISA revealed direct interaction between HbAHP-25 and HIV-1 envelope protein, gp120. The peptide prevented binding of CD4 to gp120 and blocked subsequent steps leading to entry and/or fusion or both. Anti-HIV activity of HbAHP-25 appeared to be specific as it failed to inhibit the entry of HIV-1 pseudotyped virus (HIV-1 VSV. Further, HbAHP-25 was found to be non-cytotoxic to TZM-bl cells, VK2/E6E7 cells, CEM-GFP cells and PBMCs, even at higher concentrations. Moreover, HbAHP-25 retained its anti-HIV activity in presence of seminal plasma and vaginal fluid. In brief, the study identified HbAHP-25, a novel anti-HIV peptide, which directly interacts with gp120 and thus has a potential to inhibit early stages of HIV-1 infection.

  17. Structures of HIV-1 RT-DNA complexes before and after incorporation of the anti-AIDS drug tenofovir

    Institute of Scientific and Technical Information of China (English)

    Tuske,S; Sarafianos,SG; Clark,AD; Ding,JP; Naeger,LK; White,KL; Miller,MD; Gibbs,CS; Boyer,PL; Clark,P; Wang,G; Gaffney,BL; Jones,RA; Jerina,DM; Hughes,SH; Arnold,E

    2005-01-01

    Tenofovir, also known as PMPA, R-9-(2-(phosphonomethoxypropyl)adenine, is a nucleotide reverse transcriptas e(RT) inhibitor. We have determined the crystal structures of two related complexes ofHIV-1 RT with template primer and tenofovir: (i) a ternary complex at a resolution of 3.0 Angstrom of RT crosslinked to a dideoxy-terminated DNA with tenofovir-diphosphate bound as the incoming substrate; and (ii) a RT DNA complex at a resolution of 3,1 Angstrom with tenofovir at the 3 primer terminus. The tenofovir nucleotide in the tenofovir-terminated structure seems to adopt multiple conformations. Some nucleoside reverse transcriptase inhibitors, including 3TC and AZT, have dements (handles) that project beyond the corresponding elements on normal dNTPs (the substrate envelope). HIV-1 RT resistance mechanisms to AZT and 3TC take advantage of these handles; tenofovir's structure lacks handles that could protrude through the substrate envelope to cause resistance.

  18. Short Communication: Circulating Plasma HIV-1 Viral Protein R in Dual HIV-1/Tuberculosis Infection

    OpenAIRE

    Toossi, Zahra; Liu, Shigou; Wu, Mianda; Mayanja-Kizza, Harriet; Hirsch, Christina S.

    2014-01-01

    Circulating free HIV-1 viral protein R (Vpr) is found in up to one third of subjects with HIV-1 infection. Free Vpr presumably shares some of the immunopathogenic effects of cell-associated Vpr. Here we assessed Vpr in plasma and pleural fluid from HIV/tuberculosis (TB) dually infected subjects with pleural TB and from plasma of patients with pulmonary HIV/TB. Vpr was assessed by western blot analysis. In plasma from HIV/TB subjects with pulmonary TB free Vpr could be detected in 47%. Only on...

  19. A conditionally replicating HIV-1 vector interferes with wild-type HIV-1 replication and spread.

    OpenAIRE

    Dropulić, B; Hĕrmánková, M; Pitha, P M

    1996-01-01

    Defective-interfering viruses are known to modulate virus pathogenicity. We describe conditionally replicating HIV-1 (crHIV) vectors that interfere with wild-type HIV-1 (wt-HIV) replication and spread. crHIV vectors are defective-interfering HIV genomes that do not encode viral proteins and replicate only in the presence of wt-HIV helper virus. In cells that contain both wt-HIV and crHIV genomes, the latter are shown to have a selective advantage for packaging into progeny virions because the...

  20. Varied sensitivity to therapy of HIV-1 strains in CD4+ lymphocyte sub-populations upon ART initiation

    Directory of Open Access Journals (Sweden)

    Paxton William A

    2010-12-01

    Full Text Available Abstract Background Although antiretroviral therapy (ART has proven its success against HIV-1, the long lifespan of infected cells and viral latency prevent eradication. In this study we analyzed the sensitivity to ART of HIV-1 strains in naïve, central memory and effector memory CD4+ lymphocyte subsets. Methods From five patients cellular HIV-1 infection levels were quantified before and after initiation of therapy (2-5 weeks. Through sequencing the C2V3 region of the HIV-1 gp120 envelope, we studied the effect of short-term therapy on virus variants derived from naïve, central memory and effector memory CD4+ lymphocyte subsets. Results During short-term ART, HIV-1 infection levels declined in all lymphocyte subsets but not as much as RNA levels in serum. Virus diversity in the naïve and central memory lymphocyte populations remained unchanged, whilst diversity decreased in serum and the effector memory lymphocytes. ART differentially affected the virus populations co-circulating in one individual harboring a dual HIV-1 infection. Changes in V3 charge were found in all individuals after ART initiation with increases within the effector memory subset and decreases found in the naïve cell population. Conclusions During early ART virus diversity is affected mainly in the serum and effector memory cell compartments. Differential alterations in V3 charge were observed between effector memory and naïve populations. While certain cell populations can be targeted preferentially during early ART, some virus strains demonstrate varied sensitivity to therapy, as shown from studying two strains within a dual HIV-1 infected individual.

  1. HIV-1 genetic variants in Kyrgyzstan

    Directory of Open Access Journals (Sweden)

    V Laga

    2012-11-01

    Full Text Available Objectives: During the last two decades, HIV-1 has been spreading rapidly in former Soviet Union republics including Kyrgyzstan. The current molecular monitoring of HIV-infection epidemic is carried out in Russia only with no or limited data from the other FSU countries. The aim of this work was to investigate the prevalence of HIV-1 genetic variants circulating in Kyrgyzstan. Methods: Blood collection from the HIV-infected patients was carried out by local specialists with the informed consent and the questionnaire was answered by each of the patients. The total number of samples was 100. The washed cell pellets were transferred to Moscow following with proviral DNA extraction, PCR amplification and gag, pol and env genes sequencing. The phylogenetic analysis of nucleotide sequences using neighbor-joining method was carried out by MEGA 3 program. The preliminary data were obtained in 22 samples isolated from PBMC of HIV-infected patients from Kyrgyzstan. Results: Among the samples studied 6 (27.3% samples belonged to a subtype CRF02_AG, 16 samples - to subtype A (A1. One of the samples belonging to CRF02_AG, probably, is a recombinant between CRF02_AG and A1. There was no major drug resistance mutations in the samples studied. The minor mutations were presented in small proportions: 1 in PR (L10I, 6 in RT (A62V - in 3 samples, V108G, E138A, Y181F, M184I, L210M - on one sample and 1 in IN (L74M. It was impossible to associate the distribution of mutations with HIV-1 genetic variant. The V3 loop (env gene in 17 samples was analyzed for tropism using geno2pheno program; all samples were found to be R5-viruses. Conclusion: The HIV-1 subtype A seems to dominate in Kyrgyzstan like in other FSU countries. The recombinant CRF02_AG epidemiologically linked to Uzbekistan is quite widespread. The rest of Kyrgyzstan collection is under investigation and the data will be refined soon.

  2. Rigidity analysis of HIV-1 protease

    Energy Technology Data Exchange (ETDEWEB)

    Heal, J W [MOAC Doctoral Training Centre, University of Warwick, Coventry, CV4 7AL (United Kingdom); Wells, S A; Jimenez-Roldan, E; Roemer, R A [Department of Physics and Centre for Scientific Computing, University of Warwick, Coventry, CV4 7AL (United Kingdom); Freedman, R F, E-mail: jack.heal@warwick.ac.uk [School of Life Sciences, University of Warwick, Coventry, CV4 7AL (United Kingdom)

    2011-03-01

    We present a rigidity analysis on a large number of X-ray crystal structures of the enzyme HIV-1 protease using the 'pebble game' algorithm of the software FIRST. We find that although the rigidity profile remains similar across a comprehensive set of high resolution structures, the profile changes significantly in the presence of an inhibitor. Our study shows that the action of the inhibitors is to restrict the flexibility of the {beta}-hairpin flaps which allow access to the active site. The results are discussed in the context of full molecular dynamics simulations as well as data from NMR experiments.

  3. Mechanism of HIV-1 recombination%HIV-1重组机制

    Institute of Scientific and Technical Information of China (English)

    姚瑾; 李佩璐; 张驰宇

    2013-01-01

    HIV is a retrovirus, which contains two copies of plus-strand RNA genome. During synthesis of provirus DNA, the reverse transcriptase template switching that causes HIV genetic recombination occurs between two genomic RNAs. This genetic recombination plays a central role in shaping HIV diversity, and brings great challenges in HIV diagnosis, therapy and vaccine development. Here, we review the recent advances on HIV-1 recombination and discuss the effects on HIV-1 prevention and control.%人类免疫缺陷病毒(HIV)属于逆转录病毒,包含2个正链的RNA基因组.其复制过程需要逆转录酶发生模板转换,这样极容易导致重组.重组是导致HIV多样性的重要原因,给病毒的诊断、治疗以及疫苗研发带来巨大困难.本文综述了HIV-1重组的条件、机制、特性以及重组对于HIV-1防控和疫苗研究的影响.

  4. Biomimetic Envelopes

    Directory of Open Access Journals (Sweden)

    Ilaria Mazzoleni

    2010-06-01

    Full Text Available How to translate the lessons learned from the analysis and observation of the animal world is the design learning experience presented in this article. Skin is a complex and incredibly sophisticated organ that performs various functions, including protection, sensation and heat and water regulation. In a similar way building envelopes serve multiple roles, as they are the interface between the building inhabitants and environmental elements. The resulting architectural building envelopes proto-architectural research and design projects here presented, inspired by the study of animal skins, perform and respond; they take into consideration various dynamic local environmental conditions, enhancing and supporting them rather than exploiting them, creating a more sustainable way of building and living.

  5. INTERNAL ENVELOPES

    CERN Multimedia

    Mail Office

    2001-01-01

    Internal mail envelopes often finish up in large piles in certain offices, thus creating a shortage for other users of the mail service, who would be grateful if everyone with an unused stock could deposit them in their mail box, after attaching them together with an elastic band or piece of string. The messengers will then collect them so that the Mail Office can put them back in circulation. Thank you for your understanding and collaboration.

  6. RRE-dependent HIV-1 Env RNA effects on Gag protein expression, assembly and release.

    Science.gov (United States)

    López, Claudia S; Sloan, Rachel; Cylinder, Isabel; Kozak, Susan L; Kabat, David; Barklis, Eric

    2014-08-01

    The HIV-1 Gag proteins are translated from the full-length HIV-1 viral RNA (vRNA), whereas the envelope (Env) protein is translated from incompletely spliced Env mRNAs. Nuclear export of vRNAs and Env mRNAs is mediated by the Rev accessory protein which binds to the rev-responsive element (RRE) present on these RNAs. Evidence has shown there is a direct or indirect interaction between the Gag protein, and the cytoplasmic tail (CT) of the Env protein. Our current work shows that env gene expression impacts HIV-1 Gag expression and function in two ways. At the protein level, full-length Env expression altered Gag protein expression, while Env CT-deletion proteins did not. At the RNA level, RRE-containing Env mRNA expression reduced Gag expression, processing, and virus particle release from cells. Our results support models in which Gag is influenced by the Env CT, and Env mRNAs compete with vRNAs for nuclear export. PMID:24971705

  7. Slit2/Robo4 signaling modulates HIV-1 gp120-induced lymphatic hyperpermeability.

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhang

    2012-01-01

    Full Text Available Dissemination of HIV in the host involves transit of the virus and virus-infected cells across the lymphatic endothelium. HIV may alter lymphatic endothelial permeability to foster dissemination, but the mechanism is largely unexplored. Using a primary human lymphatic endothelial cell model, we found that HIV-1 envelope protein gp120 induced lymphatic hyperpermeability by disturbing the normal function of Robo4, a novel regulator of endothelial permeability. HIV-1 gp120 induced fibronectin expression and integrin α₅β₁ phosphorylation, which led to the complexing of these three proteins, and their subsequent interaction with Robo4 through its fibronectin type III repeats. Moreover, pretreatment with an active N-terminus fragment of Slit2, a Robo4 agonist, protected lymphatic endothelial cells from HIV-1 gp120-induced hyperpermeability by inhibiting c-Src kinase activation. Our results indicate that targeting Slit2/Robo4 signaling may protect the integrity of the lymphatic barrier and limit the dissemination of HIV in the host.

  8. Cleavage-Independent HIV-1 Env Trimers Engineered as Soluble Native Spike Mimetics for Vaccine Design

    Directory of Open Access Journals (Sweden)

    Shailendra Kumar Sharma

    2015-04-01

    Full Text Available Viral glycoproteins mediate entry by pH-activated or receptor-engaged activation and exist in metastable pre-fusogenic states that may be stabilized by directed rational design. As recently reported, the conformationally fixed HIV-1 envelope glycoprotein (Env trimers in the pre-fusion state (SOSIP display molecular homogeneity and structural integrity at relatively high levels of resolution. However, the SOSIPs necessitate full Env precursor cleavage, which requires endogenous furin overexpression. Here, we developed an alternative strategy using flexible peptide covalent linkage of Env subdomains to produce soluble, homogeneous, and cleavage-independent Env mimics, called native flexibly linked (NFL trimers, as vaccine candidates. This simplified design avoids the need for furin co-expression and, in one case, antibody affinity purification to accelerate trimer scale-up for preclinical and clinical applications. We have successfully translated the NFL design to multiple HIV-1 subtypes, establishing the potential to become a general method of producing native-like, well-ordered Env trimers for HIV-1 or other viruses.

  9. A homogeneous time-resolved fluorescence assay to identify inhibitors of HIV-1 fusion.

    Science.gov (United States)

    Smeulders, Liesbet; Bunkens, Lieve; Vereycken, Inge; Van Acker, Koen; Holemans, Pascale; Gustin, Emmanuel; Van Loock, Marnix; Dams, Géry

    2013-01-01

    The human immunodeficiency virus type 1 (HIV-1) initiates infection through sequential interactions with CD4 and chemokine coreceptors unmasking the gp41 subunit of the viral envelope protein. Consequently, the N-terminal heptad repeats of gp41 form a trimeric coiled-coil groove in which the C-terminal heptad repeats collapse, generating a stable six-helix bundle. This brings the viral and cell membrane in close proximity enabling fusion and the release of viral genome in the cytosol of the host cell. In this chapter, we describe a homogeneous time-resolved fluorescence assay to identify inhibitors of HIV-1 fusion, based on the ability of soluble peptides, derived from the N- and C-terminal domains of gp41, to form a stable six-helix bundle in vitro. Labeling of the peptides with allophycocyanin and the lanthanide europium results in a Föster resonance energy transfer (FRET) signal upon formation of the six-helix bundle. Compounds interfering with the six-helix bundle formation inhibit the HIV-1 fusion process and suppress the FRET signal. PMID:23821256

  10. Dual role of autophagy in HIV-1 replication and pathogenesis

    OpenAIRE

    Killian M

    2012-01-01

    Abstract Autophagy, the major mechanism for degrading long-lived intracellular proteins and organelles, is essential for eukaryotic cell homeostasis. Autophagy also defends the cell against invasion by microorganisms and has important roles in innate and adaptive immunity. Increasingly evident is that HIV-1 replication is dependent on select components of autophagy. Fittingly, HIV-1 proteins are able to modulate autophagy to maximize virus production. At the same time, HIV-1 proteins appear t...

  11. Purinergic Receptors: Key Mediators of HIV-1 Infection and Inflammation

    OpenAIRE

    Swartz, Talia H.; Dubyak, George R.; Chen, Benjamin K.

    2015-01-01

    Human immunodeficiency virus type 1 (HIV-1) causes a chronic infection that afflicts more than 30 million individuals worldwide. While the infection can be suppressed with potent antiretroviral therapies, individuals infected with HIV-1 have elevated levels of inflammation as indicated by increased T cell activation, soluble biomarkers, and associated morbidity and mortality. A single mechanism linking HIV-1 pathogenesis to this inflammation has yet to be identified. Purinergic receptors are ...

  12. Human erythrocytes selectively bind and enrich infectious HIV-1 virions.

    Directory of Open Access Journals (Sweden)

    Zoltan Beck

    Full Text Available Although CD4(+ cells represent the major target for HIV infection in blood, claims of complement-independent binding of HIV-1 to erythrocytes and the possible role of Duffy blood group antigen, have generated controversy. To examine the question of binding to erythrocytes, HIV-1 was incubated in vitro with erythrocytes from 30 healthy leukapheresis donors, and binding was determined by p24 analysis and adsorption of HIV-1 with reduction of infectivity for CD4(+ target cells. All of the cells, regardless of blood group type, bound HIV-1 p24. A typical preparation of erythrocytes bound <2.4% of the added p24, but erythrocytes selectively removed essentially all of the viral infectivity as determined by decreased infection of CD4(+ target cells; however, cell-associated HIV-1 was approximately 100-fold more efficient, via trans infection, than unadsorbed virus for infection of CD4(+ cells. All of the bound HIV-1 p24 was released by treatment of the cells with EDTA, and binding was optimized by adding Ca(2+ and Mg(2+ during the washing of erythrocytes containing bound HIV-1. Although the small number of contaminating leukocytes in the erythrocyte preparation also bound HIV-1 p24, there was no significant binding to CD4, and it thus appears that the binding occurred on leukocytes at non-CD4 sites. Furthermore, binding occurred to erythrocyte ghosts from which contaminating leukocytes had been previously removed. The results demonstrate that erythrocytes incubated in vitro with HIV-1 differentially adsorb all of the infectious HIV-1 virions (as opposed to non-infectious or degraded virions in the absence of complement and independent of blood group, and binding is dependent on divalent cations. By analogy with HIV-1 bound to DC-SIGN on dendritic cells, erythrocyte-bound HIV-1 might comprise an important surface reservoir for trans infection of permissive cells.

  13. Platelets and HIV-1 infection: old and new aspects.

    Science.gov (United States)

    Torre, Donato; Pugliese, Agostino

    2008-09-01

    In this review we summarize the data on interaction of platelets with HIV-1 infection. Thrombocytopenia is a common finding among HIV-1 infected patients; several combined factors contribute to low peripheral platelet counts, which are present during all the stages of the disease. In addition, a relationship between platelet count, plasma viral load and disease progression has been reported, and this shows the potential influence platelets may have on the natural history of HIV-1 disease. Several lines of evidence have shown that platelets are an integral part of inflammation, and can be also potent effector cells of innate immune response as well as of adaptive immunity. Thus, we rewieved the role of inflammatory cytokines, and chemokines as activators of platelets during HIV-1 infection. Moreover, platelets show a direct interaction with HIV-1 itself, through different pathogenic mechanisms as binding, engulfment, internalisation of HIV-1, playing a role in host defence during HIV-1 infection, by limiting viral spread and probably by inactivating viral particles. Platelets may also play an intriguing role on endothelial dysfunction present in HIV-1 infection, and this topic begins to receive systematic study, inasmuch as interaction between platelets and endothelial cells is important in the pathogenesis of atherosclerosis in HIV-1 infected patients, especially in those patients treated with antiretroviral drugs. Finally, this review attempts to better define the state of this emerging issue, to focus areas of potential clinical relevance, and to suggest several directions for future research.

  14. HIV-1 vaccine design: Learning from natural infection

    OpenAIRE

    Kerkhof, van den, T.L.G.M.

    2016-01-01

    Het humane immuundeficiëntie virus type 1 (hiv-1) is het virus dat aids veroorzaakt. Er is nog steeds geen bescherming tegen een hiv-1 infectie en de beëindiging van de wereldwijde epidemie kan waarschijnlijk alleen worden bereikt met behulp van een vaccin. Een hiv-1 vaccin zal bescherming moeten bieden tegen de verschillende subtypes die wereldwijd voorkomen. Ongeveer 10-30% van de hiv-1 geïnfecteerde patiënten ontwikkelen zogenoemde "breed-neutraliserende" antistoffen. Alhoewel deze antisto...

  15. HIV-1 vaccine design: Learning from natural infection

    OpenAIRE

    Schuitemaker, J.; Sanders, R W; Kerkhof, van den, T.L.G.M.

    2016-01-01

    Het humane immuundeficiëntie virus type 1 (hiv-1) is het virus dat aids veroorzaakt. Er is nog steeds geen bescherming tegen een hiv-1 infectie en de beëindiging van de wereldwijde epidemie kan waarschijnlijk alleen worden bereikt met behulp van een vaccin. Een hiv-1 vaccin zal bescherming moeten bieden tegen de verschillende subtypes die wereldwijd voorkomen. Ongeveer 10-30% van de hiv-1 geïnfecteerde patiënten ontwikkelen zogenoemde “breed-neutraliserende” antistoffen. Alhoewel deze antisto...

  16. Purification of HIV-1 gag virus-like particles and separation of other extracellular particles.

    Science.gov (United States)

    Steppert, Petra; Burgstaller, Daniel; Klausberger, Miriam; Berger, Eva; Aguilar, Patricia Pereira; Schneider, Tobias A; Kramberger, Petra; Tover, Andres; Nöbauer, Katharina; Razzazi-Fazeli, Ebrahim; Jungbauer, Alois

    2016-07-15

    Enveloped virus-like particles (VLPs) are increasingly used as vaccines and immunotherapeutics. Frequently, very time consuming density gradient centrifugation techniques are used for purification of VLPs. However, the progress towards optimized large-scale VLP production increased the demand for fast, cost efficient and scale able purification processes. We developed a chromatographic procedure for purification of HIV-1 gag VLPs produced in CHO cells. The clarified and filtered cell culture supernatant was directly processed on an anion-exchange monolith. The majority of host cell impurities passed through the column, whereas the VLPs were eluted by a linear or step salt gradient; the major fraction of DNA was eluted prior to VLPs and particles in the range of 100-200nm in diameter could be separated into two fractions. The earlier eluted fraction was enriched with extracellular particles associated to exosomes or microvesicles, whereas the late eluting fractions contained the majority of most pure HIV-1 gag VLPs. DNA content in the exosome-containing fraction could not be reduced by Benzonase treatment which indicated that the DNA was encapsulated. Many exosome markers were identified by proteomic analysis in this fraction. We present a laboratory method that could serve as a basis for rapid downstream processing of enveloped VLPs. Up to 2000 doses, each containing 1×10(9) particles, could be processed with a 1mL monolith within 47min. The method compared to density gradient centrifugation has a 220-fold improvement in productivity. PMID:27286649

  17. Labeling of multiple HIV-1 proteins with the biarsenical-tetracysteine system.

    Directory of Open Access Journals (Sweden)

    Cândida F Pereira

    Full Text Available Due to its small size and versatility, the biarsenical-tetracysteine system is an attractive way to label viral proteins for live cell imaging. This study describes the genetic labeling of the human immunodeficiency virus type 1 (HIV-1 structural proteins (matrix, capsid and nucleocapsid, enzymes (protease, reverse transcriptase, RNAse H and integrase and envelope glycoprotein 120 with a tetracysteine tag in the context of a full-length virus. We measure the impact of these modifications on the natural virus infection and, most importantly, present the first infectious HIV-1 construct containing a fluorescently-labeled nucleocapsid protein. Furthermore, due to the high background levels normally associated with the labeling of tetracysteine-tagged proteins we have also optimized a metabolic labeling system that produces infectious virus containing the natural envelope glycoproteins and specifically labeled tetracysteine-tagged proteins that can easily be detected after virus infection of T-lymphocytes. This approach can be adapted to other viral systems for the visualization of the interplay between virus and host cell during infection.

  18. Blood-Brain Barrier Abnormalities Caused by HIV-1 gp120: Mechanistic and Therapeutic Implications

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Louboutin

    2012-01-01

    Full Text Available The blood-brain barrier (BBB is compromised in many systemic and CNS diseases, including HIV-1 infection of the brain. We studied BBB disruption caused by HIV-1 envelope glycoprotein 120 (gp120 as a model. Exposure to gp120, whether acute [by direct intra-caudate-putamen (CP injection] or chronic [using SV(gp120, an experimental model of ongoing production of gp120] disrupted the BBB, and led to leakage of vascular contents. Gp120 was directly toxic to brain endothelial cells. Abnormalities of the BBB reflect the activity of matrix metalloproteinases (MMPs. These target laminin and attack the tight junctions between endothelial cells and BBB basal laminae. MMP-2 and MMP-9 were upregulated following gp120-injection. Gp120 reduced laminin and tight junction proteins. Reactive oxygen species (ROS activate MMPs. Injecting gp120 induced lipid peroxidation. Gene transfer of antioxidant enzymes protected against gp120-induced BBB abnormalities. NMDA upregulates the proform of MMP-9. Using the NMDA receptor (NMDAR-1 inhibitor, memantine, we observed partial protection from gp120-induced BBB injury. Thus, (1 HIV-envelope gp120 disrupts the BBB; (2 this occurs via lesions in brain microvessels, MMP activation and degradation of vascular basement membrane and vascular tight junctions; (3 NMDAR-1 activation plays a role in this BBB injury; and (4 antioxidant gene delivery as well as NMDAR-1 antagonists may protect the BBB.

  19. Decreased glial and synaptic glutamate uptake in the striatum of HIV-1 gp120 transgenic mice.

    Science.gov (United States)

    Melendez, Roberto I; Roman, Cristina; Capo-Velez, Coral M; Lasalde-Dominicci, Jose A

    2016-06-01

    The mechanisms leading to the neurocognitive deficits in humans with immunodeficiency virus type 1 (HIV-1) are not well resolved. A number of cell culture models have demonstrated that the HIV-envelope glycoprotein 120 (gp120) decreases the reuptake of glutamate, which is necessary for learning, memory, and synaptic plasticity. However, the impact of brain HIV-1 gp120 on glutamate uptake systems in vivo remains unknown. Notably, alterations in brain glutamate uptake systems are implicated in a number of neurodegenerative and neurocognitive disorders. We characterized the kinetic properties of system XAG (sodium-dependent) and systems xc- (sodium-independent) [3H]-L-glutamate uptake in the striatum and hippocampus of HIV-1 gp120 transgenic mice, an established model of HIV neuropathology. We determined the kinetic constant Vmax (maximal velocity) and Km (affinity) of both systems XAG and xc- using subcellular preparations derived from neurons and glial cells. We show significant (30-35 %) reductions in the Vmax of systems XAG and xc- in both neuronal and glial preparations derived from the striatum, but not from the hippocampus of gp120 mice relative to wild-type (WT) controls. Moreover, immunoblot analysis showed that the protein expression of glutamate transporter subtype-1 (GLT-1), the predominant brain glutamate transporter, was significantly reduced in the striatum but not in the hippocampus of gp120 mice. These extensive and region-specific deficits of glutamate uptake likely contribute to the development and/or severity of HIV-associated neurocognitive disorders. Understanding the role of striatal glutamate uptake systems in HIV-1 gp120 may advance the development of new therapeutic strategies to prevent neuronal damage and improve cognitive function in HIV patients. PMID:26567011

  20. Engineering Recombinant Reoviruses To Display gp41 Membrane-Proximal External-Region Epitopes from HIV-1

    Science.gov (United States)

    Boehme, Karl W.; Ikizler, Mine'; Iskarpatyoti, Jason A.; Wetzel, J. Denise; Willis, Jordan; Crowe, James E.; LaBranche, Celia C.; Montefiori, David C.

    2016-01-01

    . Antibodies that neutralize genetically diverse strains of HIV-1 bind to discrete regions of the envelope glycoproteins, including the gp41 MPER. We engineered recombinant reoviruses that displayed MPER epitopes in attachment protein σ1 (REO-MPER vectors). The REO-MPER vectors replicated with wild-type efficiency, were genetically stable, and retained native antigenicity. However, we did not detect HIV-1-specific immune responses following inoculation of the REO-MPER vectors into small animals. This work provides proof of principle for engineering reovirus to express antigenic epitopes and illustrates the difficulty in eliciting MPER-specific immune responses. PMID:27303748

  1. HIV-1进入抑制剂的研究近况%Progress in HIV-1 Entry Inhibitors

    Institute of Scientific and Technical Information of China (English)

    李淼; 黄山

    2007-01-01

    分类综述靶向病毒进入宿主细胞过程各环节的HIV-1进入抑制剂,包括HIV-1附着抑制剂、HIV-1辅助受体抑制剂、HIV-1融合抑制剂以及氧化还原酶蛋白二硫化物异构酶抑制剂的作用机制和疗效研究及其开发.

  2. HIV-1 infection of in vitro cultured human monocytes: early events and influence of anti HIV-1 antibodies

    DEFF Research Database (Denmark)

    Arendrup, M; Olofsson, S; Nielsen, Jens Ole;

    1994-01-01

    To characterize the role of the humoral immune response on HIV-1 infection of monocytes and macrophages (M phi s) we examined the susceptibility of in vitro cultured monocyte/M phi s to various HIV-1 isolates and the influence of heterologous and particularly autologous anti HIV-1 sera...... on this infection. Depending on the period of in vitro cultivation and the virus isolate used different patterns of susceptibility were detected. One week old monocyte/M phi s were highly susceptible to HIV-1 infection, in contrast to monocyte/M phi s cultured 4 weeks. The infection by virus isolated immediately...

  3. Evaluation of the potency of the anti-idiotypic antibody Ab2/3H6 mimicking gp41 as an HIV-1 vaccine in a rabbit prime/boost study.

    Directory of Open Access Journals (Sweden)

    Alexander Mader

    Full Text Available The HIV-1 envelope protein harbors several conserved epitopes that are recognized by broadly neutralizing antibodies. One of these neutralizing sites, the MPER region of gp41, is targeted by one of the most potent and broadly neutralizing monoclonal antibody, 2F5. Different vaccination strategies and a lot of efforts have been undertaken to induce MPER neutralizing antibodies but little success has been achieved so far. We tried to consider the alternative anti-idiotypic vaccination approach for induction of 2F5-like antibodies. The previously developed and characterized anti-idiotypic antibody Ab2/3H6 was expressed as antibody fragment fusion protein with C-terminally attached immune-modulators and used for immunization of rabbits to induce antibodies specific for HIV-1. Only those rabbits immunized with immunogens fused with the immune-modulators developed HIV-1 specific antibodies. Anti-anti-idiotypic antibodies were affinity purified using a two-step affinity purification protocol which revealed that only little amount of the total rabbit IgG fraction contained HIV-1 specific antibodies. The characterization of the induced anti-anti-idiotypic antibodies showed specificity for the linear epitope of 2F5 GGGELDKWASL and the HIV-1 envelope protein gp140. Despite specificity for the linear epitope and the truncated HIV-1 envelope protein these antibodies were not able to exhibit virus neutralization activities. These results suggest that Ab2/3H6 alone might not be suitable as a vaccine.

  4. SHIV-1157i and passaged progeny viruses encoding R5 HIV-1 clade C env cause AIDS in rhesus monkeys

    Directory of Open Access Journals (Sweden)

    Siddappa Nagadenahalli B

    2008-10-01

    Full Text Available Abstract Background Infection of nonhuman primates with simian immunodeficiency virus (SIV or chimeric simian-human immunodeficiency virus (SHIV strains is widely used to study lentiviral pathogenesis, antiviral immunity and the efficacy of AIDS vaccine candidates. SHIV challenges allow assessment of anti-HIV-1 envelope responses in primates. As such, SHIVs should mimic natural HIV-1 infection in humans and, to address the pandemic, encode HIV-1 Env components representing major viral subtypes worldwide. Results We have developed a panel of clade C R5-tropic SHIVs based upon env of a Zambian pediatric isolate of HIV-1 clade C, the world's most prevalent HIV-1 subtype. The parental infectious proviral clone, SHIV-1157i, was rapidly passaged through five rhesus monkeys. After AIDS developed in the first animal at week 123 post-inoculation, infected blood was infused into a sixth monkey. Virus reisolated at this late stage was still exclusively R5 tropic and mucosally transmissible. Here we describe the long-term follow-up of this initial cohort of six monkeys. Two have remained non-progressors, whereas the other four gradually progressed to AIDS within 123–270 weeks post-exposure. Two progressors succumbed to opportunistic infections, including a case of SV40 encephalitis. Conclusion These data document the disease progression induced by the first mucosally transmissible, pathogenic R5 non-clade B SHIV and suggest that SHIV-1157i-derived viruses, including the late-stage, highly replication-competent SHIV-1157ipd3N4 previously described (Song et al., 2006, display biological characteristics that mirror those of HIV-1 clade C and support their expanded use for AIDS vaccine studies in nonhuman primates.

  5. Anti-HIV-1 antibody-dependent cellular cytotoxicity mediated by hyperimmune bovine colostrum IgG.

    Science.gov (United States)

    Kramski, Marit; Lichtfuss, Gregor F; Navis, Marjon; Isitman, Gamze; Wren, Leia; Rawlin, Grant; Center, Rob J; Jaworowski, Anthony; Kent, Stephen J; Purcell, Damian F J

    2012-10-01

    Antibodies with antibody-dependent cellular cytotoxicity (ADCC) activity play an important role in protection against HIV-1 infection, but generating sufficient amounts of antibodies to study their protective efficacy is difficult. HIV-specific IgG can be easily and inexpensively produced in large quantities using bovine colostrum. We previously vaccinated cows with HIV-1 envelope gp140 and elicited high titers of anti-gp140-binding IgG in colostrum. In the present study, we determined whether bovine antibodies would also demonstrate specific cytotoxic activity. We found that bovine IgG bind to Fcγ-receptors (FcγRs) on human neutrophils, monocytes, and NK cells in a dose-dependent manner. Antibody-dependent killing was observed in the presence of anti-HIV-1 colostrum IgG but not nonimmune colostrum IgG. Killing was dependent on Fc and FcγR interaction since ADDC activity was not seen with F(ab')(2) fragments. ADCC activity was primarily mediated by CD14(+) monocytes with FcγRIIa (CD32a) as the major receptor responsible for monocyte-mediated ADCC in response to bovine IgG. In conclusion, we demonstrate that bovine anti-HIV colostrum IgG have robust HIV-1-specific ADCC activity and therefore offer a useful source of antibodies able to provide a rapid and potent response against HIV-1 infection. This could assist the development of novel Ab-mediated approaches for prevention of HIV-1 transmission. PMID:22730083

  6. Analysis of memory B cell responses and isolation of novel monoclonal antibodies with neutralizing breadth from HIV-1-infected individuals.

    Directory of Open Access Journals (Sweden)

    Davide Corti

    Full Text Available BACKGROUND: The isolation of human monoclonal antibodies (mAbs that neutralize a broad spectrum of primary HIV-1 isolates and the characterization of the human neutralizing antibody B cell response to HIV-1 infection are important goals that are central to the design of an effective antibody-based vaccine. METHODS AND FINDINGS: We immortalized IgG(+ memory B cells from individuals infected with diverse clades of HIV-1 and selected on the basis of plasma neutralization profiles that were cross-clade and relatively potent. Culture supernatants were screened using various recombinant forms of the envelope glycoproteins (Env in multiple parallel assays. We isolated 58 mAbs that were mapped to different Env surfaces, most of which showed neutralizing activity. One mAb in particular (HJ16 specific for a novel epitope proximal to the CD4 binding site on gp120 selectively neutralized a multi-clade panel of Tier-2 HIV-1 pseudoviruses, and demonstrated reactivity that was comparable in breadth, but distinct in neutralization specificity, to that of the other CD4 binding site-specific neutralizing mAb b12. A second mAb (HGN194 bound a conserved epitope in the V3 crown and neutralized all Tier-1 and a proportion of Tier-2 pseudoviruses tested, irrespective of clade. A third mAb (HK20 with broad neutralizing activity, particularly as a Fab fragment, recognized a highly conserved epitope in the HR-1 region of gp41, but showed striking assay-dependent selectivity in its activity. CONCLUSIONS: This study reveals that by using appropriate screening methods, a large proportion of memory B cells can be isolated that produce mAbs with HIV-1 neutralizing activity. Three of these mAbs show unusual breadth of neutralization and therefore add to the current panel of HIV-1 neutralizing antibodies with potential for passive protection and template-based vaccine design.

  7. Aqueous extracts from peppermint, sage and lemon balm leaves display potent anti-HIV-1 activity by increasing the virion density

    Directory of Open Access Journals (Sweden)

    Baumann Ingo

    2008-03-01

    Full Text Available Abstract Background Aqueous extracts from leaves of well known species of the Lamiaceae family were examined for their potency to inhibit infection by human immunodeficiency virus type 1 (HIV-1. Results Extracts from lemon balm (Melissa officinalis L., peppermint (Mentha × piperita L., and sage (Salvia officinalis L. exhibited a high and concentration-dependent activity against the infection of HIV-1 in T-cell lines, primary macrophages, and in ex vivo tonsil histocultures with 50% inhibitory concentrations as low as 0.004%. The aqueous Lamiaceae extracts did not or only at very high concentrations interfere with cell viability. Mechanistically, extract exposure of free virions potently and rapidly inhibited infection, while exposure of surface-bound virions or target cells alone had virtually no antiviral effect. In line with this observation, a virion-fusion assay demonstrated that HIV-1 entry was drastically impaired following treatment of particles with Lamiaceae extracts, and the magnitude of this effect at the early stage of infection correlated with the inhibitory potency on HIV-1 replication. Extracts were active against virions carrying diverse envelopes (X4 and R5 HIV-1, vesicular stomatitis virus, ecotropic murine leukemia virus, but not against a non-enveloped adenovirus. Following exposure to Lamiaceae extracts, the stability of virions as well as virion-associated levels of envelope glycoprotein and processed Gag protein were unaffected, while, surprisingly, sucrose-density equilibrium gradient analyses disclosed a marked increase of virion density. Conclusion Aqueous extracts from Lamiaceae can drastically and rapidly reduce the infectivity of HIV-1 virions at non-cytotoxic concentrations. An extract-induced enhancement of the virion's density prior to its surface engagement appears to be the most likely mode of action. By harbouring also a strong activity against herpes simplex virus type 2, these extracts may provide a basis

  8. Raltegravir with optimized background therapy for resistant HIV-1 infection

    DEFF Research Database (Denmark)

    Steigbigel, Roy T; Cooper, David A; Kumar, Princy N;

    2008-01-01

    BACKGROUND: Raltegravir (MK-0518) is an inhibitor of human immunodeficiency virus type 1 (HIV-1) integrase active against HIV-1 susceptible or resistant to older antiretroviral drugs. METHODS: We conducted two identical trials in different geographic regions to evaluate the safety and efficacy of...

  9. Antibody function in neutralization and protection against HIV-1

    NARCIS (Netherlands)

    Hessell, A.J.

    2009-01-01

    The ability to induce neutralizing antibodies is generally thought to be of great importance for vaccine efficacy. In HIV-1 research this quality has been elusive as the HIV-1 virus has evolved multiple mechanisms to evade neutralizing antibodies. This thesis traces studies with four broadly neutral

  10. Global human genetics of HIV-1 infection and China

    Institute of Scientific and Technical Information of China (English)

    Tuo Fu ZHU; Tie Jian FENG; Xin XIAO; Hui WANG; Bo Ping ZHOU

    2005-01-01

    Genetic polymorphisms in human genes can influence the risk for HIV-1 infection and disease progression, although the reported effects of these alleles have been inconsistent. This review highlights the recent discoveries on global and Chinese genetic polymorphisms and their association with HIV-1 transmission and disease progression.

  11. Varicella vaccination in HIV-1-infected children after immune reconstitution

    NARCIS (Netherlands)

    V. Bekker; G.H.A. Westerlaken; H. Scherpbier; S. Alders; H. Zaaijer; D. van Baarle; T. Kuijper

    2006-01-01

    Background: HIV-1-infected children have an increased risk of severe chickenpox. However, vaccination is not recommended in severely immunocompromised children. Objective: Can the live-attenuated varicella zoster virus (VZV) Oka strain be safely and effectively given to HIV-1-infected children despi

  12. The origin and emergence of an HIV-1 epidemic:

    DEFF Research Database (Denmark)

    Bruhn, Christian Anders Wathne; Audelin, Anne M.; Helleberg, Marie;

    2014-01-01

    To describe, at patient-level detail, the determining events and factors involved in the development of a country's HIV-1 epidemic.......To describe, at patient-level detail, the determining events and factors involved in the development of a country's HIV-1 epidemic....

  13. Molecular Mechanisms in Activation of Latent HIV-1

    NARCIS (Netherlands)

    H. Rafati (Haleh)

    2014-01-01

    markdownabstract__Abstract__ Finding a cure for the human immunodeficiency virus type 1 (HIV-1) is extremely challenging. Development of highly active anti-retroviral therapy (HAART), transformed HIV-1 infection from an acute syndrome into chronic disease. Although using HAART results in suppressio

  14. Structure and Dynamics of the Native HIV-1 Env Trimer

    OpenAIRE

    Munro, James B.; Mothes, Walther

    2015-01-01

    HIV-1/AIDS remains one of the worst pandemics in human history. Despite tremendous efforts, no effective vaccine has been found. Recent reports give new insights into the structure and dynamics of the HIV-1 Env trimer and renew hopes that a better understanding of Env will translate into new vaccine candidates and more-effective antiretroviral therapies.

  15. [A new unique HIV-1 recombinant form detected in Belarus].

    Science.gov (United States)

    Eremin, V F; Gasich, E L; Sosinovich, S V

    2012-01-01

    Republican Research-and-Practical Center for Epidemiology and Microbiology, Ministry of Health of Belarus, Minsk The paper presents data on the molecular genetic characteristics of a new HIV-1 recombinant form. The study has shown that the virus is referred to as HIV-1 subtype B in terms of the gag gene and HIV-1 subtype A in terms of the pol and env genes. At the same time the new isolate is closer, in terms of the gag gene, to the HIV-1 DQ207943 strain isolated in Georgia, in terms of the pol gene, to the HIV-1 AF413987.1 strain isolated in Ukraine and, in terms of the env gene to the HIV-1 AY500393 strain isolated in Russia. Thus, the described new HIV-1 recombinant form has the following structure: BgagApolAenv. The gag, pol, and env gene sequences from the new unique HIV-1 recombinant form have been registered in the international database EMBL/Genbank/DDBJ under accession numbers FR775442.1, FN995656.1, and FR775443.1.

  16. Survival of the fittest: positive selection of CD4+ T cells expressing a membrane-bound fusion inhibitor following HIV-1 infection.

    Directory of Open Access Journals (Sweden)

    Janine Kimpel

    Full Text Available Although a variety of genetic strategies have been developed to inhibit HIV replication, few direct comparisons of the efficacy of these inhibitors have been carried out. Moreover, most studies have not examined whether genetic inhibitors are able to induce a survival advantage that results in an expansion of genetically-modified cells following HIV infection. We evaluated the efficacy of three leading genetic strategies to inhibit HIV replication: 1 an HIV-1 tat/rev-specific small hairpin (sh RNA; 2 an RNA antisense gene specific for the HIV-1 envelope; and 3 a viral entry inhibitor, maC46. In stably transduced cell lines selected such that >95% of cells expressed the genetic inhibitor, the RNA antisense envelope and viral entry inhibitor maC46 provided the strongest inhibition of HIV-1 replication. However, when mixed populations of transduced and untransduced cells were challenged with HIV-1, the maC46 fusion inhibitor resulted in highly efficient positive selection of transduced cells, an effect that was evident even in mixed populations containing as few as 1% maC46-expressing cells. The selective advantage of the maC46 fusion inhibitor was also observed in HIV-1-infected cultures of primary T lymphocytes as well as in HIV-1-infected humanized mice. These results demonstrate robust inhibition of HIV replication with the fusion inhibitor maC46 and the antisense Env inhibitor, and importantly, a survival advantage of cells expressing the maC46 fusion inhibitor both in vitro and in vivo. Evaluation of the ability of genetic inhibitors of HIV-1 replication to confer a survival advantage on genetically-modified cells provides unique information not provided by standard techniques that may be important in the in vivo efficacy of these genes.

  17. Alterations in HIV-1 LTR promoter activity during AIDS progression

    International Nuclear Information System (INIS)

    HIV-1 variants evolving in AIDS patients frequently show increased replicative capacity compared to those present during early asymptomatic infection. It is known that late stage HIV-1 variants often show an expanded coreceptor tropism and altered Nef function. In the present study we investigated whether enhanced HIV-1 LTR promoter activity might also evolve during disease progression. Our results demonstrate increased LTR promoter activity after AIDS progression in 3 of 12 HIV-1-infected individuals studied. Further analysis revealed that multiple alterations in the U3 core-enhancer and in the transactivation-response (TAR) region seem to be responsible for the enhanced functional activity. Our findings show that in a subset of HIV-1-infected individuals enhanced LTR transcription contributes to the increased replicative potential of late stage virus isolates and might accelerate disease progression

  18. HIV-1 differentially modulates autophagy in neurons and astrocytes.

    Science.gov (United States)

    Mehla, Rajeev; Chauhan, Ashok

    2015-08-15

    Autophagy, a lysosomal degradative pathway that maintains cellular homeostasis, has emerged as an innate immune defense against pathogens. The role of autophagy in the deregulated HIV-infected central nervous system (CNS) is unclear. We have found that HIV-1-induced neuro-glial (neurons and astrocytes) damage involves modulation of the autophagy pathway. Neuro-glial stress induced by HIV-1 led to biochemical and morphological dysfunctions. X4 HIV-1 produced neuro-glial toxicity coupled with suppression of autophagy, while R5 HIV-1-induced toxicity was restricted to neurons. Rapamycin, a specific mTOR inhibitor (autophagy inducer) relieved the blockage of the autophagy pathway caused by HIV-1 and resulted in neuro-glial protection. Further understanding of the regulation of autophagy by cytokines and chemokines or other signaling events may lead to recognition of therapeutic targets for neurodegenerative diseases.

  19. Short Communication: HIV-1 Variants That Use Mouse CCR5 Reveal Critical Interactions of gp120's V3 Crown with CCR5 Extracellular Loop 1.

    Science.gov (United States)

    Platt, Emily J; Durnin, James P; Kabat, David

    2015-10-01

    The CCR5 coreceptor amino terminus and extracellular (ECL) loops 1 and 2 have been implicated in HIV-1 infections, with species differences in these regions inhibiting zoonoses. Interactions of gp120 with CD4 and CCR5 reduce constraints on metastable envelope subunit gp41, enabling gp41 conformational changes needed for infection. We previously selected HIV-1JRCSF variants that efficiently use CCR5(Δ18) with a deleted amino terminus or CCR5(HHMH) with ECL2 from an NIH/Swiss mouse. Unexpectedly, the adaptive gp120 mutations were nearly identical, suggesting that they function by weakening gp120's grip on gp41 and/or by increasing interactions with ECL1. To analyze this and further wean HIV-1 from human CCR5, we selected variants using CCR5(HMMH) with murine ECL1 and 2 sequences. HIV-1JRCSF mutations adaptive for CCR5(Δ18) and CCR5(HHMH) were generally maladaptive for CCR5(HMMH), whereas the converse was true for CCR5(HMMH) adaptations. The HIV-1JRCSF variant adapted to CCR5(HMMH) also weakly used intact NIH/Swiss mouse CCR5. Our results strongly suggest that HIV-1JRCSF makes functionally critical contacts with human ECL1 and that adaptation to murine ECL1 requires multiple mutations in the crown of gp120's V3 loop. PMID:26114311

  20. Broad-spectrum inhibition of HIV-1 by a monoclonal antibody directed against a gp120-induced epitope of CD4.

    Directory of Open Access Journals (Sweden)

    Samuele E Burastero

    Full Text Available To penetrate susceptible cells, HIV-1 sequentially interacts with two highly conserved cellular receptors, CD4 and a chemokine receptor like CCR5 or CXCR4. Monoclonal antibodies (MAbs directed against such receptors are currently under clinical investigation as potential preventive or therapeutic agents. We immunized Balb/c mice with molecular complexes of the native, trimeric HIV-1 envelope (Env bound to a soluble form of the human CD4 receptor. Sera from immunized mice were found to contain gp120-CD4 complex-enhanced antibodies and showed broad-spectrum HIV-1-inhibitory activity. A proportion of MAbs derived from these mice preferentially recognized complex-enhanced epitopes. In particular, a CD4-specific MAb designated DB81 (IgG1Κ was found to preferentially bind to a complex-enhanced epitope on the D2 domain of human CD4. MAb DB81 also recognized chimpanzee CD4, but not baboon or macaque CD4, which exhibit sequence divergence in the D2 domain. Functionally, MAb DB81 displayed broad HIV-1-inhibitory activity, but it did not exert suppressive effects on T-cell activation in vitro. The variable regions of the heavy and light chains of MAb DB81 were sequenced. Due to its broad-spectrum anti-HIV-1 activity and lack of immunosuppressive effects, a humanized derivative of MAb DB81 could provide a useful complement to current preventive or therapeutic strategies against HIV-1.

  1. Short Communication: HIV-1 Variants That Use Mouse CCR5 Reveal Critical Interactions of gp120's V3 Crown with CCR5 Extracellular Loop 1.

    Science.gov (United States)

    Platt, Emily J; Durnin, James P; Kabat, David

    2015-10-01

    The CCR5 coreceptor amino terminus and extracellular (ECL) loops 1 and 2 have been implicated in HIV-1 infections, with species differences in these regions inhibiting zoonoses. Interactions of gp120 with CD4 and CCR5 reduce constraints on metastable envelope subunit gp41, enabling gp41 conformational changes needed for infection. We previously selected HIV-1JRCSF variants that efficiently use CCR5(Δ18) with a deleted amino terminus or CCR5(HHMH) with ECL2 from an NIH/Swiss mouse. Unexpectedly, the adaptive gp120 mutations were nearly identical, suggesting that they function by weakening gp120's grip on gp41 and/or by increasing interactions with ECL1. To analyze this and further wean HIV-1 from human CCR5, we selected variants using CCR5(HMMH) with murine ECL1 and 2 sequences. HIV-1JRCSF mutations adaptive for CCR5(Δ18) and CCR5(HHMH) were generally maladaptive for CCR5(HMMH), whereas the converse was true for CCR5(HMMH) adaptations. The HIV-1JRCSF variant adapted to CCR5(HMMH) also weakly used intact NIH/Swiss mouse CCR5. Our results strongly suggest that HIV-1JRCSF makes functionally critical contacts with human ECL1 and that adaptation to murine ECL1 requires multiple mutations in the crown of gp120's V3 loop.

  2. Sexually transmitted infections among HIV-1-discordant couples.

    Directory of Open Access Journals (Sweden)

    Brandon L Guthrie

    Full Text Available INTRODUCTION: More new HIV-1 infections occur within stable HIV-1-discordant couples than in any other group in Africa, and sexually transmitted infections (STIs may increase transmission risk among discordant couples, accounting for a large proportion of new HIV-1 infections. Understanding correlates of STIs among discordant couples will aid in optimizing interventions to prevent HIV-1 transmission in these couples. METHODS: HIV-1-discordant couples in which HIV-1-infected partners were HSV-2-seropositive were tested for syphilis, chlamydia, gonorrhea, and trichomoniasis, and HIV-1-uninfected partners were tested for HSV-2. We assessed sociodemographic, behavioral, and biological correlates of a current STI. RESULTS: Of 416 couples enrolled, 16% were affected by a treatable STI, and among these both partners were infected in 17% of couples. A treatable STI was found in 46 (11% females and 30 (7% males. The most prevalent infections were trichomoniasis (5.9% and syphilis (2.6%. Participants were 5.9-fold more likely to have an STI if their partner had an STI (P<0.01, and STIs were more common among those reporting any unprotected sex (OR = 2.43; P<0.01 and those with low education (OR = 3.00; P<0.01. Among HIV-1-uninfected participants with an HSV-2-seropositive partner, females were significantly more likely to be HSV-2-seropositive than males (78% versus 50%, P<0.01. CONCLUSIONS: Treatable STIs were common among HIV-1-discordant couples and the majority of couples affected by an STI were discordant for the STI, with relatively high HSV-2 discordance. Awareness of STI correlates and treatment of both partners may reduce HIV-1 transmission. TRIAL REGISTRATION: ClinicalTrials.gov NCT00194519.

  3. Evaluation of the Aptima(®) HIV-1 Quant Dx assay for HIV-1 RNA viral load detection and quantitation in plasma of HIV-1-infected individuals: A comparison with Abbott RealTime HIV-1 assay.

    Science.gov (United States)

    Amendola, Alessandra; Pisciotta, Maria; Aleo, Loredana; Ferraioli, Valeria; Angeletti, Claudio; Capobianchi, Maria Rosaria

    2016-09-01

    The Hologic Aptima(®) HIV-1 Quant Dx assay (Aptima HIV) is a real-time transcription-mediated amplification method CE-approved for use in diagnosis and monitoring of HIV-1 infection. The analytical performance of this new assay was compared to the FDA-approved Abbott RealTime HIV-1 (RealTime). The evaluation was performed using 220 clinical plasma samples, the WHO 3rd HIV-1 International Standard, and the QCMD HIV-1 RNA EQA. Concordance on qualitative results, correlation between quantitative results, accuracy, and reproducibility of viral load data were analyzed. The ability to measure HIV-1 subtypes was assessed on the second WHO International Reference Preparation Panel for HIV-1 Subtypes. With clinical samples, inter-assay agreement for qualitative results was high (91.8%) with Cohen's kappa statistic equal to 0.836. For samples with quantitative results in both assays (n = 93), Lin's concordance correlation coefficient was 0.980 (P R(2)  > 0.970) and showed higher sensitivity compared to RealTime being able to detect HIV-1 RNA in 10 out of 10 replicates containing down to 7 cp/ml (20 IU/ml). Reproducibility was very high, even at low HIV-1 RNA values. The Aptima HIV was able to detect and accurately quantify all the main HIV-1 subtypes in both reference panels and clinical samples. Besides excellent performance, Aptima HIV shows full automation, ease of use, and improved workflow compared to RealTime. J. Med. Virol. 88:1535-1544, 2016. © 2016 Wiley Periodicals, Inc. PMID:26864171

  4. Intercompartmental recombination of HIV-1 contributes to env intrahost diversity and modulates viral tropism and sensitivity to entry inhibitors.

    Science.gov (United States)

    Brown, Richard J P; Peters, Paul J; Caron, Catherine; Gonzalez-Perez, Maria Paz; Stones, Leanne; Ankghuambom, Chiambah; Pondei, Kemebradikumo; McClure, C Patrick; Alemnji, George; Taylor, Stephen; Sharp, Paul M; Clapham, Paul R; Ball, Jonathan K

    2011-06-01

    HIV-1 circulates within an infected host as a genetically heterogeneous viral population. Viral intrahost diversity is shaped by substitutional evolution and recombination. Although many studies have speculated that recombination could have a significant impact on viral phenotype, this has never been definitively demonstrated. We report here phylogenetic and subsequent phenotypic analyses of envelope genes obtained from HIV-1 populations present in different anatomical compartments. Assessment of env compartmentalization from immunologically discrete tissues was assessed utilizing a single genome amplification approach, minimizing in vitro-generated artifacts. Genetic compartmentalization of variants was frequently observed. In addition, multiple incidences of intercompartment recombination, presumably facilitated by low-level migration of virus or infected cells between different anatomic sites and coinfection of susceptible cells by genetically divergent strains, were identified. These analyses demonstrate that intercompartment recombination is a fundamental evolutionary mechanism that helps to shape HIV-1 env intrahost diversity in natural infection. Analysis of the phenotypic consequences of these recombination events showed that genetic compartmentalization often correlates with phenotypic compartmentalization and that intercompartment recombination results in phenotype modulation. This represents definitive proof that recombination can generate novel combinations of phenotypic traits which differ subtly from those of parental strains, an important phenomenon that may have an impact on antiviral therapy and contribute to HIV-1 persistence in vivo. PMID:21471230

  5. Engineering and exploitation of a fluorescent HIV-1 gp120 for live cell CD4 binding assays

    International Nuclear Information System (INIS)

    The HIV-1 envelope glycoprotein, gp120, binds the host cell receptor, CD4, in the initial step of HIV viral entry and infection. This process is an appealing target for the development of inhibitory drugs and neutralizing antibodies. To study gp120 binding and intracellular trafficking, we engineered a fluorescent fusion of the humanized gp120 JRFL HIV-1 variant and GFP. Gp120-sfGFP is glycosylated with human sugars, robustly expressed, and secreted from cultured human cells. Protein dynamics, quality control, and trafficking can be visualized in live cells. The fusion protein can be readily modified with different gp120 variants or fluorescent proteins. Finally, secreted gp120-sfGFP enables a sensitive and easy binding assay that can quantitatively screen potential inhibitors of gp120-CD4 binding on live cells via fluorescence imaging or laser scanning cytometry. This adaptable research tool should aid in studies of gp120 cell biology and the development of novel anti-HIV drugs. - Highlights: • Development of fluorescent protein labeled HIV-1 envelope gp120. • Imaging of gp120 dynamics and trafficking in live cells. • Quantitative visual assay of antibody-mediated inhibition of gp120 binding to CD4 on live cells

  6. Identification of a conserved domain of the HIV-1 transmembrane protein gp41 which interacts with cholesteryl groups.

    Science.gov (United States)

    Vincent, Nadine; Genin, Christian; Malvoisin, Etienne

    2002-12-23

    A soluble form of the HIV-1 envelope glycoprotein gp160 devoid of the transmembrane anchor domain was found to bind to cholesteryl-hemisuccinate agarose. The external subunit gp120 failed to bind to the resin, suggesting that the site responsible for the binding to cholesterol was located in the transmembrane protein gp41. We constructed a series of maltose binding protein (MBP) fusion proteins representing overlapping fragments of the gp41 molecule and we studied their capacity to bind to cholesteryl beads. The domain responsible for binding to cholesterol was localised within the residues 668 to 684 immediately adjacent to the membrane spanning domain. We identified a short sequence (LWYIK, aa 678-683) comparable to the cholesterol interaction amino acid consensus pattern published by Li and Papadopoulos [Endocrinology 139 (1998) 4991]. We demonstrated that the sequence LWYIK synthesized fused to the MBP was able to bind to cholesteryl groups. A synthetic peptide containing the sequence LWYIK was found to inhibit the interaction between cholesteryl beads and MBP44, an MBP fusion HIV-1 envelope protein that contains the putative cholesterol binding domain. Human sera obtained from HIV-1 seropositive patients did not react in ELISA to the LWYIK sequence, suggesting that this region is not exposed to the immune system. The biological significance of the interaction between gp41 and cholesterol is discussed.

  7. Memory B cell antibodies to HIV-1 gp140 cloned from individuals infected with clade A and B viruses.

    Directory of Open Access Journals (Sweden)

    Hugo Mouquet

    Full Text Available Understanding the antibody response to HIV-1 in humans that show broad neutralizing serologic activity is a crucial step in trying to reproduce such responses by vaccination. Investigating antibodies with cross clade reactivity is particularly important as these antibodies may target conserved epitopes on the HIV envelope gp160 protein. To this end we have used a clade B YU-2 gp140 trimeric antigen and single-cell antibody cloning methods to obtain 189 new anti-gp140 antibodies representing 51 independent B cell clones from the IgG memory B cells of 3 patients infected with HIV-1 clade A or B viruses and exhibiting broad neutralizing serologic activity. Our results support previous findings showing a diverse antibody response to HIV gp140 envelope protein, characterized by differentially expanded B-cell clones producing highly hypermutated antibodies with heterogenous gp140-specificity and neutralizing activity. In addition to their high-affinity binding to the HIV spike, the vast majority of the new anti-gp140 antibodies are also polyreactive. Although none of the new antibodies are as broad or potent as VRC01 or PG9, two clonally-related antibodies isolated from a clade A HIV-1 infected donor, directed against the gp120 variable loop 3, rank in the top 5% of the neutralizers identified in our large collection of 185 unique gp140-specific antibodies in terms of breadth and potency.

  8. Engineering and exploitation of a fluorescent HIV-1 gp120 for live cell CD4 binding assays

    Energy Technology Data Exchange (ETDEWEB)

    Costantini, Lindsey M. [Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States); Irvin, Susan C. [Department of Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States); Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States); Kennedy, Steven C. [Department of Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States); Guo, Feng [Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States); Goldstein, Harris; Herold, Betsy C. [Department of Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States); Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States); Snapp, Erik L., E-mail: erik-lee.snapp@einstein.yu.edu [Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States)

    2015-02-15

    The HIV-1 envelope glycoprotein, gp120, binds the host cell receptor, CD4, in the initial step of HIV viral entry and infection. This process is an appealing target for the development of inhibitory drugs and neutralizing antibodies. To study gp120 binding and intracellular trafficking, we engineered a fluorescent fusion of the humanized gp120 JRFL HIV-1 variant and GFP. Gp120-sfGFP is glycosylated with human sugars, robustly expressed, and secreted from cultured human cells. Protein dynamics, quality control, and trafficking can be visualized in live cells. The fusion protein can be readily modified with different gp120 variants or fluorescent proteins. Finally, secreted gp120-sfGFP enables a sensitive and easy binding assay that can quantitatively screen potential inhibitors of gp120-CD4 binding on live cells via fluorescence imaging or laser scanning cytometry. This adaptable research tool should aid in studies of gp120 cell biology and the development of novel anti-HIV drugs. - Highlights: • Development of fluorescent protein labeled HIV-1 envelope gp120. • Imaging of gp120 dynamics and trafficking in live cells. • Quantitative visual assay of antibody-mediated inhibition of gp120 binding to CD4 on live cells.

  9. Molecular mechanisms of HIV-1 associated neurodegeneration

    Indian Academy of Sciences (India)

    Hakan Ozdener

    2005-06-01

    Since identification of the human immunodeficiency virus-1 (HIV-1), numerous studies suggest a link between neurological impairments, in particular dementia, with acquired immunodeficiency syndrome (AIDS) with alarming occurrence worldwide. Approximately, 60% of HIV-infected people show some form of neurological impairment, and neuropathological changes are found in 90% of autopsied cases. Approximately 30% of untreated HIV-infected persons may develop dementia. The mechanisms behind these pathological changes are still not understood. Mounting data obtained by in vivo and in vitro experiments suggest that neuronal apoptosis is a major feature of HIV associated dementia (HAD), which can occur in the absence of direct infection of neurons. The major pathway of neuronal apoptosis occurs indirectly through release of neurotoxins by activated cells in the central nervous system (CNS) involving the induction of excitotoxicity and oxidative stress. In addition a direct mechanism induced by viral proteins in the pathogenesis of HAD may also play a role. This review focuses on the molecular mechanisms of HIV-associated dementia and possible therapeutic strategies.

  10. Cyclophilin B enhances HIV-1 infection.

    Science.gov (United States)

    DeBoer, Jason; Madson, Christian J; Belshan, Michael

    2016-02-01

    Cyclophilin B (CypB) is a member of the immunophilin family and intracellular chaperone. It predominantly localizes to the ER, but also contains a nuclear localization signal and is secreted from cells. CypB has been shown to interact with the Gag protein of human immunodeficiency type 1 (HIV-1). Several proteomic and genetic studies identified it as a potential factor involved in HIV replication. Herein, we show that over-expression of CypB enhances HIV infection by increasing nuclear import of viral DNA. This enhancement was unaffected by cyclosporine treatment and requires the N-terminus of the protein. The N-terminus contains an ER leader sequence, putative nuclear localization signal, and is required for secretion. Deletion of the N-terminus resulted in mislocalization from the ER and suppression of HIV infection. Passive transfer experiments showed that secreted CypB did not impact HIV infection. Combined, these experiments show that intracellular CypB modulates a pathway of HIV nuclear import. PMID:26774171

  11. Anti-HIV-1 activity of flavonoid myricetin on HIV-1 infection in a dual-chamber in vitro model.

    Directory of Open Access Journals (Sweden)

    Silvana Pasetto

    Full Text Available HIV infection by sexual transmission remains an enormous global health concern. More than 1 million new infections among women occur annually. Microbicides represent a promising prevention strategy that women can easily control. Among emerging therapies, natural small molecules such as flavonoids are an important source of new active substances. In this study we report the in vitro cytotoxicity and anti-HIV-1 and microbicide activity of the following flavonoids: Myricetin, Quercetin and Pinocembrin. Cytotoxicity tests were conducted on TZM-bl, HeLa, PBMC, and H9 cell cultures using 0.01-100 µM concentrations. Myricetin presented the lowest toxic effect, with Quercetin and Pinocembrin relatively more toxic. The anti-HIV-1 activity was tested with TZM-bl cell plus HIV-1 BaL (R5 tropic, H9 and PBMC cells plus HIV-1 MN (X4 tropic, and the dual tropic (X4R5 HIV-1 89.6. All flavonoids showed anti-HIV activity, although Myricetin was more effective than Quercetin or Pinocembrin. In TZM-bl cells, Myricetin inhibited ≥90% of HIV-1 BaL infection. The results were confirmed by quantification of HIV-1 p24 antigen in supernatant from H9 and PBMC cells following flavonoid treatment. In H9 and PBMC cells infected by HIV-1 MN and HIV-1 89.6, Myricetin showed more than 80% anti-HIV activity. Quercetin and Pinocembrin presented modest anti-HIV activity in all experiments. Myricetin activity was tested against HIV-RT and inhibited the enzyme by 49%. Microbicide activities were evaluated using a dual-chamber female genital tract model. In the in vitro microbicide activity model, Myricetin showed promising results against different strains of HIV-1 while also showing insignificant cytotoxic effects. Further studies of Myricetin should be performed to identify its molecular targets in order to provide a solid biological foundation for translational research.

  12. HIV-1 Tat and HIV-associated Dementia%HIV-1Tat蛋白与艾滋病脑病

    Institute of Scientific and Technical Information of China (English)

    周勤华; 姚鑫; 惠斌

    2012-01-01

    HIV-1 gene expression requires the transcriptional activator protein Tal of human immunodeficiency virus-1 ( HIV-1) , which stimulates viral transcript elongation. A significant number of people infected with the HIV develop neurologic complications. HIV-1-associated dementia( HAD) is a severe central nervous system(CNS) disorder neurologically induced by HIV-1. HAD represents the most severe form of HIV-related neuropsychiatric impairment and is characterized by motor dysfunction and impaired cognitions and behaviors. HIV-1 trans-activator of transcription( Tat) is an important factor in viral pathogenesis. The Tat protein not only drives the regulatory regions of the virus, but also might be actively released from the cells and then interacts with the cell surface receptors of other uninfected cells in the brain leading to cellular dysfunction. Growing evidence indicates that HIV-1 Tat protein play a major role in pathogenesis of HAD. This article reviewed the pleomorphic actions of Tat protein and the evidence supporting its central role in the neuropathogenesis of HAD.%Tat蛋白是HIV-1编码的反式转录激活因子,其主要功能是反式激活HIV-1病毒基因组转录的起始和延伸,启动病毒复制,近年来研究发现,Tat蛋白在HIV-1感染所引起的严重中枢神经系统(CNS)并发症——艾滋病脑病中起重要作用,是艾滋病脑病发生与发展的重要致病因子.本文就HIV-1 Tat蛋白在艾滋病脑病中的研究进展作一综述.

  13. Defining the roles for Vpr in HIV-1-associated neuropathogenesis.

    Science.gov (United States)

    James, Tony; Nonnemacher, Michael R; Wigdahl, Brian; Krebs, Fred C

    2016-08-01

    It is increasingly evident that the human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) has a unique role in neuropathogenesis. Its ability to induce G2/M arrest coupled with its capacity to increase viral gene transcription gives it a unique role in sustaining viral replication and aiding in the establishment and maintenance of a systemic infection. The requirement of Vpr for HIV-1 infection and replication in cells of monocytic origin (a key lineage of cells involved in HIV-1 neuroinvasion) suggests an important role in establishing and sustaining infection in the central nervous system (CNS). Contributions of Vpr to neuropathogenesis can be expanded further through (i) naturally occurring HIV-1 sequence variation that results in functionally divergent Vpr variants; (ii) the dual activities of Vpr as a intracellular protein delivered and expressed during HIV-1 infection and as an extracellular protein that can act on neighboring, uninfected cells; (iii) cell type-dependent consequences of Vpr expression and exposure, including cell cycle arrest, metabolic dysregulation, and cytotoxicity; and (iv) the effects of Vpr on exosome-based intercellular communication in the CNS. Revealing that the effects of this pleiotropic viral protein is an essential part of a greater understanding of HIV-1-associated pathogenesis and potential approaches to treating and preventing disease caused by HIV-1 infection.

  14. Correlates of HIV-1 genital shedding in Tanzanian women.

    Directory of Open Access Journals (Sweden)

    Clare Tanton

    Full Text Available BACKGROUND: Understanding the correlates of HIV shedding is important to inform strategies to reduce HIV infectiousness. We examined correlates of genital HIV-1 RNA in women who were seropositive for both herpes simplex virus (HSV-2 and HIV-1 and who were enrolled in a randomised controlled trial of HSV suppressive therapy (aciclovir 400 mg b.i.d vs. placebo in Tanzania. METHODOLOGY: Samples, including a cervico-vaginal lavage, were collected and tested for genital HIV-1 and HSV and reproductive tract infections (RTIs at randomisation and 6, 12 and 24 months follow-up. Data from all women at randomisation and women in the placebo arm during follow-up were analysed using generalised estimating equations to determine the correlates of cervico-vaginal HIV-1 RNA detection and load. PRINCIPAL FINDINGS: Cervico-vaginal HIV-1 RNA was detected at 52.0% of 971 visits among 482 women, and was independently associated with plasma viral load, presence of genital ulcers, pregnancy, bloody cervical or vaginal discharge, abnormal vaginal discharge, cervical ectopy, Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, an intermediate bacterial vaginosis score and HSV DNA detection. Similar factors were associated with genital HIV-1 RNA load. CONCLUSIONS: RTIs were associated with increased presence and quantity of genital HIV-1 RNA in this population. These results highlight the importance of integrating effective RTI treatment into HIV care services.

  15. Defining the roles for Vpr in HIV-1-associated neuropathogenesis.

    Science.gov (United States)

    James, Tony; Nonnemacher, Michael R; Wigdahl, Brian; Krebs, Fred C

    2016-08-01

    It is increasingly evident that the human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) has a unique role in neuropathogenesis. Its ability to induce G2/M arrest coupled with its capacity to increase viral gene transcription gives it a unique role in sustaining viral replication and aiding in the establishment and maintenance of a systemic infection. The requirement of Vpr for HIV-1 infection and replication in cells of monocytic origin (a key lineage of cells involved in HIV-1 neuroinvasion) suggests an important role in establishing and sustaining infection in the central nervous system (CNS). Contributions of Vpr to neuropathogenesis can be expanded further through (i) naturally occurring HIV-1 sequence variation that results in functionally divergent Vpr variants; (ii) the dual activities of Vpr as a intracellular protein delivered and expressed during HIV-1 infection and as an extracellular protein that can act on neighboring, uninfected cells; (iii) cell type-dependent consequences of Vpr expression and exposure, including cell cycle arrest, metabolic dysregulation, and cytotoxicity; and (iv) the effects of Vpr on exosome-based intercellular communication in the CNS. Revealing that the effects of this pleiotropic viral protein is an essential part of a greater understanding of HIV-1-associated pathogenesis and potential approaches to treating and preventing disease caused by HIV-1 infection. PMID:27056720

  16. Efficient Gene Transfer Mediated by HIV-1-based Defective Lentivector and Inhibition of HIV-1 Replication

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Lentiviral vectors have drawn considerable attention recently and show great promise to become important delivery vehicles for future gene transfer manipulation. In the present study we have optimized a protocol for preparation of human immunodeficiency virus type-1 (HIV-1)-based defective lentiviral vectors (DLV) and characterized these vectors in terms of their transduction of different cells. Transient co-transfection of 293T packaging cells with DNA plasmids encoding lentiviral vector constituents resulted in production of high-titer DLV (0.5-1.2 × 107IU/mL), which can be further concentrated over 100-fold through a single step ultracentrifugation. These vectors were capable of transducing a variety of cells from both primate and non-primate sources and high transduction efficiency was achieved using concentrated vectors. Assessment of potential generation of RCV revealed no detection of infection by infectious particles in DLV-transduced CEM, SupT-1 and MT-2 cells. Long-term culture of transduced cells showed a stable expression of transgenes without apparent alteration in cellular morphology and growth kinetics. Vector mobilization to untransduced cells mediated by wild-type HIV-1 infection was confirmed in this test. Challenge of transduced human T-lymphocytes with wild-type HIV-1 showed these cells are totally resistant to the viral infection. Considering the effective gene transfer and stable gene expression, safety and anti-HIV activity, these DLV vectors warrant further exploration for their potential use as a gene transfer vehicle in the development of gene therapy protocols.

  17. HIV-1/HSV-2 co-infected adults in early HIV-1 infection have elevated CD4+ T cell counts.

    Directory of Open Access Journals (Sweden)

    Jason D Barbour

    Full Text Available INTRODUCTION: HIV-1 is often acquired in the presence of pre-existing co-infections, such as Herpes Simplex Virus 2 (HSV-2. We examined the impact of HSV-2 status at the time of HIV-1 acquisition for its impact on subsequent clinical course, and total CD4+ T cell phenotypes. METHODS: We assessed the relationship of HSV-1/HSV-2 co-infection status on CD4+ T cell counts and HIV-1 RNA levels over time prior in a cohort of 186 treatment naïve adults identified during early HIV-1 infection. We assessed the activation and differentiation state of total CD4+ T cells at study entry by HSV-2 status. RESULTS: Of 186 recently HIV-1 infected persons, 101 (54% were sero-positive for HSV-2. There was no difference in initial CD8+ T cell count, or differences between the groups for age, gender, or race based on HSV-2 status. Persons with HIV-1/HSV-2 co-infection sustained higher CD4+ T cell counts over time (+69 cells/ul greater (SD = 33.7, p = 0.04 than those with HIV-1 infection alone (Figure 1, after adjustment for HIV-1 RNA levels (-57 cells per 1 log(10 higher HIV-1 RNA, p<0.0001. We did not observe a relationship between HSV-2 infection status with plasma HIV-1 RNA levels over time. HSV-2 acquisition after HIV-1 acquisition had no impact on CD4+ count or viral load. We did not detect differences in CD4+ T cell activation or differentiation state by HSV-2+ status. DISCUSSION: We observed no effect of HSV-2 status on viral load. However, we did observe that treatment naïve, recently HIV-1 infected adults co-infected with HSV-2+ at the time of HIV-1 acquisition had higher CD4+ T cell counts over time. If verified in other cohorts, this result poses a striking paradox, and its public health implications are not immediately clear.

  18. HIV-1 Replication and the Cellular Eukaryotic Translation Apparatus

    Directory of Open Access Journals (Sweden)

    Santiago Guerrero

    2015-01-01

    Full Text Available Eukaryotic translation is a complex process composed of three main steps: initiation, elongation, and termination. During infections by RNA- and DNA-viruses, the eukaryotic translation machinery is used to assure optimal viral protein synthesis. Human immunodeficiency virus type I (HIV-1 uses several non-canonical pathways to translate its own proteins, such as leaky scanning, frameshifting, shunt, and cap-independent mechanisms. Moreover, HIV-1 modulates the host translation machinery by targeting key translation factors and overcomes different cellular obstacles that affect protein translation. In this review, we describe how HIV-1 proteins target several components of the eukaryotic translation machinery, which consequently improves viral translation and replication.

  19. HIV-1 replication and the cellular eukaryotic translation apparatus.

    Science.gov (United States)

    Guerrero, Santiago; Batisse, Julien; Libre, Camille; Bernacchi, Serena; Marquet, Roland; Paillart, Jean-Christophe

    2015-01-01

    Eukaryotic translation is a complex process composed of three main steps: initiation, elongation, and termination. During infections by RNA- and DNA-viruses, the eukaryotic translation machinery is used to assure optimal viral protein synthesis. Human immunodeficiency virus type I (HIV-1) uses several non-canonical pathways to translate its own proteins, such as leaky scanning, frameshifting, shunt, and cap-independent mechanisms. Moreover, HIV-1 modulates the host translation machinery by targeting key translation factors and overcomes different cellular obstacles that affect protein translation. In this review, we describe how HIV-1 proteins target several components of the eukaryotic translation machinery, which consequently improves viral translation and replication. PMID:25606970

  20. Persistent HIV-1 replication during antiretroviral therapy

    Science.gov (United States)

    Martinez-Picado, Javier; Deeks, Steven G.

    2016-01-01

    Purpose of review The present review will highlight some of the recent findings regarding the capacity of HIV-1 to replicate during antiretroviral therapy (ART). Recent findings Although ART is highly effective at inhibiting HIV replication, it is not curative. Several mechanisms contribute to HIV persistence during ART, including HIV latency, immune dysfunction, and perhaps persistent low-level spread of the virus to uninfected cells (replication). The success in curing HIV will depend on efficiently targeting these three aspects. The degree to which HIV replicates during ART remains controversial. Most studies have failed to find any evidence of HIV evolution in blood, even with samples collected over many years, although a recent very intensive study of three individuals suggested that the virus population does shift, at least during the first few months of therapy. Stronger but still not definitive evidence for replication comes from a series of studies in which standard regimens were intensified with an integration inhibitor, resulting in changes in episomal DNA (blood) and cell-associated RNA (tissue). Limited drug penetration within tissues and the presence of immune sanctuaries have been argued as potential mechanisms allowing HIV to spread during ART. Mathematical models suggest that HIV replication and evolution is possible even without the selection of fully drug-resistant variants. As persistent HIV replication could have clinical consequences and might limit the efficacy of curative interventions, determining if HIV replicates during ART and why, should remain a key focus of the HIV research community. Summary Residual viral replication likely persists in lymphoid tissues, at least in a subset of individuals. Abnormal levels of immune activation might contribute to sustain virus replication. PMID:27078619

  1. Impact of HIV-1, HIV-2 and HIV-1+2 dual infection on the outcome of tuberculosis

    DEFF Research Database (Denmark)

    Wejse, C; Patsche, C B; Kühle, A;

    2014-01-01

    BACKGROUND: HIV-1 infection has been shown to impact the outcome of patients with tuberculosis (TB), but data regarding the impact of HIV-2 on TB outcomes are limited. The aim of this study was to assess the impact of HIV types on mortality among TB patients in Guinea-Bissau and to examine the...... predictive ability of the TBscoreII, a clinical score used to assess disease severity. METHODS: In a prospective follow-up study, we examined the prevalence of HIV-1, HIV-2, and HIV-1+2 co-infection in TB patients in Guinea-Bissau, and the impact on outcomes at 12 months of follow-up. We included all adult...... seventy-nine patients were HIV-infected: 241 had HIV-1, 93 had HIV-2, and 45 were HIV-1+2 dual infected. The HIV type-associated risk of TB was 6-fold higher for HIV-1, 7-fold higher for HIV-1+2 dual infection, and 2-fold higher for HIV-2 compared with the HIV-uninfected. Of the patients included, 144 (11...

  2. Molecular epidemiology of HIV-1 transmission in a cohort of HIV-1 concordant heterosexual couples from Dakar, Senegal.

    Directory of Open Access Journals (Sweden)

    Wim Jennes

    Full Text Available BACKGROUND: A large number of HIV-1 infections in Africa occur in married couples. The predominant direction of intracouple transmission and the principal external origins of infection remain important issues of debate. METHODS: We investigated HIV-1 transmission in 46 HIV-1 concordant positive couples from Dakar, Senegal. Intracouple transmission was confirmed by maximum-likelihood phylogenetic analysis and pairwise distance comparisons of HIV-1 env gp41 sequences from both partners. Standardized interview data were used to deduce the direction as well as the external sources of the intracouple transmissions. RESULTS: Conservative molecular analyses showed linked viruses in 34 (74% couples, unlinked viruses in 6 (13% couples, and indeterminate results for 6 (13% couples. The interview data corresponded completely with the molecular analyses: all linked couples reported internal transmission and all unlinked couples reported external sources of infection. The majority of linked couples (93% reported the husband as internal source of infection. These husbands most frequently (82% reported an occasional sexual relationship as external source of infection. Pairwise comparisons of the CD4 count, antiretroviral therapy status, and the proportion of gp41 ambiguous base pairs within transmission pairs correlated with the reported order of infection events. CONCLUSIONS: In this suburban Senegalese population, a majority of HIV-1 concordant couples showed linked HIV-1 transmission with the husband as likely index partner. Our data emphasize the risk of married women for acquiring HIV-1 as a result of the occasional sexual relationships of their husbands.

  3. Knockdown of MAP4 and DNAL1 produces a post-fusion and pre-nuclear translocation impairment in HIV-1 replication

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, Daniel E., E-mail: d-gallo@northwestern.edu; Hope, Thomas J., E-mail: thope@northwestern.edu

    2012-01-05

    DNAL1 and MAP4 are both microtubule-associated proteins. These proteins were identified as HIV-1 dependency factors in a screen with wild-type HIV-1. In this study we demonstrate that knockdown using DNAL1 and MAP4 siRNAs and shRNAs inhibits HIV-1 infection regardless of envelope. Using a fusion assay, we show that DNAL1 and MAP4 do not impact fusion. By assaying for late reverse transcripts and 2-LTR circles, we show that DNAL1 and MAP4 inhibit both by approximately 50%. These results demonstrate that DNAL1 and MAP4 impact reverse transcription but not nuclear translocation. DNAL1 and MAP4 knockdown cells do not display cytoskeletal defects. Together these experiments indicate that DNAL1 and MAP4 may exert their functions in the HIV life cycle at reverse transcription, prior to nuclear translocation.

  4. Characteristics, Immunological Response & Treatment Outcomes of HIV-2 Compared with HIV-1 & Dual Infections (HIV 1/2) in Mumbai

    OpenAIRE

    Chiara, Montaldo; Rony, Zachariah; Homa, Mansoor; Bhanumati, Varghese; Ladomirska, Joanna; Manzi, M.; Wilson, N; Alaka, Deshpande; Harries, A. D.

    2010-01-01

    Background & objectives: Information available on HIV-2 and dual infection (HIV-1/2) is limited. This study was carried out among HIV positive individuals in an urban referral clinic in Khar, Mumbai, India, to report on relative proportions of HIV-1, HIV-2 and HIV-1/2 and baseline characteristics, response to and outcomes on antiretroviral treatment (ART). Methods: Retrospective analysis of programme data (May 2006-May 2009) at Khar HIV/AIDS clinic at Mumbai, India was done. Three test algori...

  5. Plasmacytoid Dendritic Cells Suppress HIV-1 Replication but Contribute to HIV-1 Induced Immunopathogenesis in Humanized Mice

    OpenAIRE

    Guangming Li; Menglan Cheng; Jun-Ichi Nunoya; Liang Cheng; Haitao Guo; Haisheng Yu; Yong-Jun Liu; Lishan Su; Liguo Zhang

    2014-01-01

    The role of plasmacytoid dendritic cells (pDC) in human immunodeficiency virus type 1 (HIV-1) infection and pathogenesis remains unclear. HIV-1 infection in the humanized mouse model leads to persistent HIV-1 infection and immunopathogenesis, including type I interferons (IFN-I) induction, immune-activation and depletion of human leukocytes, including CD4 T cells. We developed a monoclonal antibody that specifically depletes human pDC in all lymphoid organs in humanized mice. When pDC were de...

  6. Purinergic Receptors: Key Mediators of HIV-1 infection and inflammation

    Directory of Open Access Journals (Sweden)

    Talia H Swartz

    2015-11-01

    Full Text Available Human immunodeficiency virus (HIV-1 causes a chronic infection that afflicts more than 38 million individuals worldwide. While the infection can be suppressed with potent anti-retroviral therapies, individuals infected with HIV have elevated levels of inflammation as indicated by increased T cell activation, soluble biomarkers, and associated morbidity and mortality. A single mechanism linking HIV pathogenesis to this inflammation has yet to be identified. Purinergic receptors are known to mediate inflammation and have been shown to be required for HIV-1 infection at the level of HIV-1 membrane fusion. Here we review the literature on the role of purinergic receptors in HIV-1 infection and associated inflammation and describe a role for these receptors as potential therapeutic targets.

  7. Identification of a Small Molecular Anti - HIV - 1 Compound that Interferes with Formation of the Fusion - active gp41 Core

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The human immunodeficiency virus type 1 (HIV - 1 ) envelope glycoprotein gp41 plays a critical role in the fusion of viral and target cell membranes. The gp41 extracellular domain, which contains fusion peptide (FP), N - and C - terminal hydrophobic heptad repeats (NHR and CHR, respectively). Peptides derived from NHR and CHR regions,designated N- and C- peptides, respectively, can interact with each other to form a six - stranded coiled - coil domain, representing the fusion-active gp41 core. Our previous studies demonstrated that the C- peptides have potent inhibitory activity against HIV- 1 infection.These peptides inhibit HIV- 1 -mediated membrane fusion by binding to NHR regions for preventing the formation of fusion- active gp41 core. One of the C - peptides, T - 20, which is in the phase Ⅲ clinical trails, is expected to become the first peptide HIV fusion inhibitory drug in the near future. However, this peptide HIV fusion inhibitor lacks oral availability and is sensitive to the proteolytic digestion.Therefore, it is essential to develop small molecular non -peptide HIV fusion inhibitors having similar mechanism of action as the C- peptides. We have established an ELISA- based screening assay using a unique monoclonal antibody, NC- 1, which can specifically bind to a conformational epitope on the gp41 core domain. Using this screening assay, we have identified a small molecular anti- HIV- 1 compound,named ADS-Jl, which inhibits HIV- 1- mediated membrane fusion by blocking the interaction between the NHR and CHR regions to form the fusion - active gp41 core. This compound will be used as a lead to design and develop novel HIV fusion inhibitors as new drugs for the treatment of HIV infection and/or AIDS.

  8. Neutralization resistance of virological synapse-mediated HIV-1 Infection is regulated by the gp41 cytoplasmic tail.

    Science.gov (United States)

    Durham, Natasha D; Yewdall, Alice W; Chen, Ping; Lee, Rebecca; Zony, Chati; Robinson, James E; Chen, Benjamin K

    2012-07-01

    Human immunodeficiency virus type 1 (HIV-1) infection can spread efficiently from infected to uninfected T cells through adhesive contacts called virological synapses (VSs). In this process, cell-surface envelope glycoprotein (Env) initiates adhesion and viral transfer into an uninfected recipient cell. Previous studies have found some HIV-1-neutralizing patient sera to be less effective at blocking VS-mediated infection than infection with cell-free virus. Here we employ sensitive flow cytometry-based infection assays to measure the inhibitory potency of HIV-1-neutralizing monoclonal antibodies (MAb) and HIV-1-neutralizing patient sera against cell-free and VS-mediated infection. To various degrees, anti-Env MAbs exhibited significantly higher 50% inhibitory concentration (IC(50)s) against VS-mediated infection than cell-free infection. Notably, the MAb 17b, which binds a CD4-induced (CD4i) epitope on gp120, displayed a 72-fold reduced efficacy against VS-mediated inocula compared to cell-free inocula. A mutant with truncation mutation in the gp41 cytoplasmic tail (CT) which is unable to modulate Env fusogenicity in response to virus particle maturation but which can still engage in cell-to-cell infection was tested for the ability to resist neutralizing antibodies. The ΔCT mutation increased cell surface staining by neutralizing antibodies, significantly enhanced neutralization of VS-mediated infection, and had reduced or no effect on cell-free infection, depending upon the antibody. Our results suggest that the gp41 CT regulates the exposure of key neutralizing epitopes during cell-to-cell infection and plays an important role in immune evasion. Vaccine strategies should consider immunogens that reflect Env conformations exposed on the infected cell surface to enhance protection against VS-mediated HIV-1 spread. PMID:22553332

  9. Identification of an HIV-1 BG Intersubtype Recombinant Form (CRF73_BG), Partially Related to CRF14_BG, Which Is Circulating in Portugal and Spain.

    Science.gov (United States)

    Fernández-García, Aurora; Delgado, Elena; Cuevas, María Teresa; Vega, Yolanda; Montero, Vanessa; Sánchez, Mónica; Carrera, Cristina; López-Álvarez, María José; Miralles, Celia; Pérez-Castro, Sonia; Cilla, Gustavo; Hinojosa, Carmen; Pérez-Álvarez, Lucía; Thomson, Michael M

    2016-01-01

    HIV-1 exhibits a characteristically high genetic diversity, with the M group, responsible for the pandemic, being classified into nine subtypes, 72 circulating recombinant forms (CRFs) and numerous unique recombinant forms (URFs). Here we characterize the near full-length genome sequence of an HIV-1 BG intersubtype recombinant virus (X3208) collected in Galicia (Northwest Spain) which exhibits a mosaic structure coincident with that of a previously characterized BG recombinant virus (9601_01), collected in Germany and epidemiologically linked to Portugal, and different from currently defined CRFs. Similar recombination patterns were found in partial genome sequences from three other BG recombinant viruses, one newly derived, from a virus collected in Spain, and two retrieved from databases, collected in France and Portugal, respectively. Breakpoint coincidence and clustering in phylogenetic trees of these epidemiologically-unlinked viruses allow to define a new HIV-1 CRF (CRF73_BG). CRF73_BG shares one breakpoint in the envelope with CRF14_BG, which circulates in Portugal and Spain, and groups with it in a subtype B envelope fragment, but the greatest part of its genome does not appear to derive from CRF14_BG, although both CRFs share as parental strain the subtype G variant circulating in the Iberian Peninsula. Phylogenetic clustering of partial pol and env segments from viruses collected in Portugal and Spain with X3208 and 9691_01 indicates that CRF73_BG is circulating in both countries, with proportions of around 2-3% Portuguese database HIV-1 isolates clustering with CRF73_BG. The fact that an HIV-1 recombinant virus characterized ten years ago as a URF has been shown to represent a CRF suggests that the number of HIV-1 CRFs may be much greater than currently known.

  10. Curcumin inhibits HIV-1 by promoting Tat protein degradation

    OpenAIRE

    Amjad Ali; Banerjea, Akhil C

    2016-01-01

    HIV-1 Tat is an intrinsically unfolded protein playing a pivotal role in viral replication by associating with TAR region of viral LTR. Unfolded proteins are degraded by 20S proteasome in an ubiquitin independent manner. Curcumin is known to activate 20S proteasome and promotes the degradation of intrinsically unfolded p53 tumor suppressor protein. Since HIV-1 Tat protein is largerly unfolded, we hypothesized that Tat may also be targeted through this pathway. Curcumin treated Tat transfected...

  11. Interplay between the RNA interference machinery and HIV-1

    OpenAIRE

    Schopman, N.C.T.

    2012-01-01

    Resistente infecties zijn lastig te behandelen. Nick Schopman onderzocht een verbeterde RNA-interferentie (RNAi)-gebaseerde anti-hiv-1 gentherapie. Dit kan in de toekomst leiden tot een nieuwe aanpak van de behandeling van resistente infecties. Schopman beschrijft een nieuw ontwerp van een RNAi-molecuul dat een aanzienlijke verbetering is ten opzichte van het huidige ontwerp. Verder bekeek hij de impact van hiv-1-infectie op RNAi in verschillende celtypes. Het ontrafelen van het RNAi-mechanis...

  12. HIV-1 Replication and the Cellular Eukaryotic Translation Apparatus

    OpenAIRE

    Santiago Guerrero; Julien Batisse; Camille Libre; Serena Bernacchi; Roland Marquet; Jean-Christophe Paillart

    2015-01-01

    Eukaryotic translation is a complex process composed of three main steps: initiation, elongation, and termination. During infections by RNA- and DNA-viruses, the eukaryotic translation machinery is used to assure optimal viral protein synthesis. Human immunodeficiency virus type I (HIV-1) uses several non-canonical pathways to translate its own proteins, such as leaky scanning, frameshifting, shunt, and cap-independent mechanisms. Moreover, HIV-1 modulates the host translation machinery by ta...

  13. A multifaceted analysis of HIV-1 protease multidrug resistance phenotypes

    Directory of Open Access Journals (Sweden)

    Doherty Kathleen M

    2011-12-01

    Full Text Available Abstract Background Great strides have been made in the effective treatment of HIV-1 with the development of second-generation protease inhibitors (PIs that are effective against historically multi-PI-resistant HIV-1 variants. Nevertheless, mutation patterns that confer decreasing susceptibility to available PIs continue to arise within the population. Understanding the phenotypic and genotypic patterns responsible for multi-PI resistance is necessary for developing PIs that are active against clinically-relevant PI-resistant HIV-1 variants. Results In this work, we use globally optimal integer programming-based clustering techniques to elucidate multi-PI phenotypic resistance patterns using a data set of 398 HIV-1 protease sequences that have each been phenotyped for susceptibility toward the nine clinically-approved HIV-1 PIs. We validate the information content of the clusters by evaluating their ability to predict the level of decreased susceptibility to each of the available PIs using a cross validation procedure. We demonstrate the finding that as a result of phenotypic cross resistance, the considered clinical HIV-1 protease isolates are confined to ~6% or less of the clinically-relevant phenotypic space. Clustering and feature selection methods are used to find representative sequences and mutations for major resistance phenotypes to elucidate their genotypic signatures. We show that phenotypic similarity does not imply genotypic similarity, that different PI-resistance mutation patterns can give rise to HIV-1 isolates with similar phenotypic profiles. Conclusion Rather than characterizing HIV-1 susceptibility toward each PI individually, our study offers a unique perspective on the phenomenon of PI class resistance by uncovering major multidrug-resistant phenotypic patterns and their often diverse genotypic determinants, providing a methodology that can be applied to understand clinically-relevant phenotypic patterns to aid in the

  14. HLA-C Downmodulation by HIV-1 Vpu.

    Science.gov (United States)

    Barker, Edward; Evans, David T

    2016-05-11

    It is widely held that HIV-1 Nef downmodulates HLA-A and -B to protect infected cells from CD8(+) T cells but leaves HLA-C on the cell surface to inhibit NK cells. In this issue of Cell Host & Microbe, Apps et al. (2016) revise this model by showing that the Vpu protein of primary HIV-1 isolates downmodulate HLA-C.

  15. Dendritic cells exposed to MVA-based HIV-1 vaccine induce highly functional HIV-1-specific CD8(+ T cell responses in HIV-1-infected individuals.

    Directory of Open Access Journals (Sweden)

    Núria Climent

    Full Text Available Currently, MVA virus vectors carrying HIV-1 genes are being developed as HIV-1/AIDS prophylactic/therapeutic vaccines. Nevertheless, little is known about the impact of these vectors on human dendritic cells (DC and their capacity to present HIV-1 antigens to human HIV-specific T cells. This study aimed to characterize the interaction of MVA and MVA expressing the HIV-1 genes Env-Gag-Pol-Nef of clade B (referred to as MVA-B in human monocyte-derived dendritic cells (MDDC and the subsequent processes of HIV-1 antigen presentation and activation of memory HIV-1-specific T lymphocytes. For these purposes, we performed ex vivo assays with MDDC and autologous lymphocytes from asymptomatic HIV-infected patients. Infection of MDDC with MVA-B or MVA, at the optimal dose of 0.3 PFU/MDDC, induced by itself a moderate degree of maturation of MDDC, involving secretion of cytokines and chemokines (IL1-ra, IL-7, TNF-α, IL-6, IL-12, IL-15, IL-8, MCP-1, MIP-1α, MIP-1β, RANTES, IP-10, MIG, and IFN-α. MDDC infected with MVA or MVA-B and following a period of 48 h or 72 h of maturation were able to migrate toward CCL19 or CCL21 chemokine gradients. MVA-B infection induced apoptosis of the infected cells and the resulting apoptotic bodies were engulfed by the uninfected MDDC, which cross-presented HIV-1 antigens to autologous CD8(+ T lymphocytes. MVA-B-infected MDDC co-cultured with autologous T lymphocytes induced a highly functional HIV-specific CD8(+ T cell response including proliferation, secretion of IFN-γ, IL-2, TNF-α, MIP-1β, MIP-1α, RANTES and IL-6, and strong cytotoxic activity against autologous HIV-1-infected CD4(+ T lymphocytes. These results evidence the adjuvant role of the vector itself (MVA and support the clinical development of prophylactic and therapeutic anti-HIV vaccines based on MVA-B.

  16. CRISPR-mediated Activation of Latent HIV-1 Expression.

    Science.gov (United States)

    Limsirichai, Prajit; Gaj, Thomas; Schaffer, David V

    2016-03-01

    Complete eradication of HIV-1 infection is impeded by the existence of cells that harbor chromosomally integrated but transcriptionally inactive provirus. These cells can persist for years without producing viral progeny, rendering them refractory to immune surveillance and antiretroviral therapy and providing a permanent reservoir for the stochastic reactivation and reseeding of HIV-1. Strategies for purging this latent reservoir are thus needed to eradicate infection. Here, we show that engineered transcriptional activation systems based on CRISPR/Cas9 can be harnessed to activate viral gene expression in cell line models of HIV-1 latency. We further demonstrate that complementing Cas9 activators with latency-reversing compounds can enhance latent HIV-1 transcription and that epigenome modulation using CRISPR-based acetyltransferases can also promote viral gene activation. Collectively, these results demonstrate that CRISPR systems are potentially effective tools for inducing latent HIV-1 expression and that their use, in combination with antiretroviral therapy, could lead to improved therapies for HIV-1 infection. PMID:26607397

  17. Negative Feedback Regulation of HIV-1 by Gene Editing Strategy

    Science.gov (United States)

    Kaminski, Rafal; Chen, Yilan; Salkind, Julian; Bella, Ramona; Young, Won-bin; Ferrante, Pasquale; Karn, Jonathan; Malcolm, Thomas; Hu, Wenhui; Khalili, Kamel

    2016-01-01

    The CRISPR/Cas9 gene editing method is comprised of the guide RNA (gRNA) to target a specific DNA sequence for cleavage and the Cas9 endonuclease for introducing breaks in the double-stranded DNA identified by the gRNA. Co-expression of both a multiplex of HIV-1-specific gRNAs and Cas9 in cells results in the modification and/or excision of the segment of viral DNA, leading to replication-defective virus. In this study, we have personalized the activity of CRISPR/Cas9 by placing the gene encoding Cas9 under the control of a minimal promoter of HIV-1 that is activated by the HIV-1 Tat protein. We demonstrate that functional activation of CRISPR/Cas9 by Tat during the course of viral infection excises the designated segment of the integrated viral DNA and consequently suppresses viral expression. This strategy was also used in a latently infected CD4+ T-cell model after treatment with a variety of HIV-1 stimulating agents including PMA and TSA. Controlled expression of Cas9 by Tat offers a new strategy for safe implementation of the Cas9 technology for ablation of HIV-1 at a very early stage of HIV-1 replication during the course of the acute phase of infection and the reactivation of silent proviral DNA in latently infected cells. PMID:27528385

  18. DBR1 siRNA inhibition of HIV-1 replication

    Directory of Open Access Journals (Sweden)

    Naidu Yathi

    2005-10-01

    Full Text Available Abstract Background HIV-1 and all retroviruses are related to retroelements of simpler organisms such as the yeast Ty elements. Recent work has suggested that the yeast retroelement Ty1 replicates via an unexpected RNA lariat intermediate in cDNA synthesis. The putative genomic RNA lariat intermediate is formed by a 2'-5' phosphodiester bond, like that found in pre-mRNA intron lariats and it facilitates the minus-strand template switch during cDNA synthesis. We hypothesized that HIV-1 might also form a genomic RNA lariat and therefore that siRNA-mediated inhibition of expression of the human RNA lariat de-branching enzyme (DBR1 expression would specifically inhibit HIV-1 replication. Results We designed three short interfering RNA (siRNA molecules targeting DBR1, which were capable of reducing DBR1 mRNA expression by 80% and did not significantly affect cell viability. We assessed HIV-1 replication in the presence of DBR1 siRNA and found that DBR1 knockdown led to decreases in viral cDNA and protein production. These effects could be reversed by cotransfection of a DBR1 cDNA indicating that the inhibition of HIV-1 replication was a specific effect of DBR1 underexpression. Conclusion These data suggest that DBR1 function may be needed to debranch a putative HIV-1 genomic RNA lariat prior to completion of reverse transcription.

  19. Potent inhibition of HIV-1 replication by a Tat mutant.

    Science.gov (United States)

    Meredith, Luke W; Sivakumaran, Haran; Major, Lee; Suhrbier, Andreas; Harrich, David

    2009-11-10

    Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection.

  20. Potent inhibition of HIV-1 replication by a Tat mutant.

    Directory of Open Access Journals (Sweden)

    Luke W Meredith

    Full Text Available Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection.

  1. Quantitative Phosphoproteomics Reveals Extensive Cellular Reprogramming During HIV-1 Entry

    Science.gov (United States)

    Wojcechowskyj, Jason A.; Didigu, Chuka A.; Lee, Jessica Y.; Parrish, Nicholas F.; Sinha, Rohini; Hahn, Beatrice H.; Bushman, Frederic D.; Jensen, Shane T.; Seeholzer, Steven H.; Doms, Robert W.

    2014-01-01

    SUMMARY Receptor engagement by HIV-1 during host cell entry activates signaling pathways that can reprogram the cell for optimal viral replication. To obtain a global view of the signaling events induced during HIV-1 entry, we conducted a quantitative phosphoproteomics screen of primary human CD4+ T cell after infection with an HIV-1 strain that engages the receptors CD4 and CXCR4. We quantified 1,757 phosphorylation sites with high stringency. The abundance of 239 phosphorylation sites from 175 genes, including several proteins in pathways known to be impacted by HIV-receptor binding, changed significantly within a minute after HIV-1 exposure. Several previously uncharacterized HIV-1 host factors were also identified and confirmed through RNAi depletion studies. Surprisingly, 5 serine/arginine-rich (SR)-proteins involved in mRNA splicing, including the splicing factor SRm300 (SRRM2) were differentially phosophorylated. Mechanistic studies with SRRM2 suggest that HIV-1 modulates host cell alternative splicing machinery during entry in order to facilitate virus replication and release. PMID:23684312

  2. HIV-1, Methamphetamine and Astrocytes at Neuroinflammatory crossroads

    Directory of Open Access Journals (Sweden)

    Kathleen eBorgmann

    2015-10-01

    Full Text Available As a popular psychostimulant, methamphetamine (METH use leads to long-lasting, strong euphoric effects. While METH abuse is common in the general population, between 10-15% of human immunodeficiency virus-1 (HIV-1 patients report having abused METH. METH exacerbates the severity and onset of HIV-1-associated neurocognitive disorders (HAND through direct and indirect mechanisms. Repetitive METH use decreases adherence to antiretroviral drug regimens, increasing the likelihood of HIV-1 disease progression towards AIDS. METH exposure also directly affects both innate and adaptive immunity, altering lymphocyte number and activity, cytokine signaling, phagocytic function, and CNS infiltration through the blood brain barrier. Further, METH triggers the neuronal dopamine reward pathway and leads to altered neuronal activity and direct toxicity. Concurrently, METH and HIV-1 alter the neuroimmune balance and induce neuroinflammation. Neuroinflammation modulates a wide range of brain functions including neuronal signaling and activity, glial activation, viral infection, oxidative stress and excitotoxicity. Pathologically, glial activation is a hallmark of both HIV-1 and METH-associated neuroinflammation. Significant commonality exists in the neurotoxic mechanisms for both METH and HAND; however, the pathways dysregulated in astroglia during METH exposure are less clear. Thus alterations in astrocyte intracellular signaling pathways, gene expression and function during METH and HIV-1 comorbidity, neuroinflammation and HAND are carefully reviewed. Interventions targeting astrocytes in HAND and METH are presented as potential novel therapeutic approaches.

  3. Negative Feedback Regulation of HIV-1 by Gene Editing Strategy.

    Science.gov (United States)

    Kaminski, Rafal; Chen, Yilan; Salkind, Julian; Bella, Ramona; Young, Won-Bin; Ferrante, Pasquale; Karn, Jonathan; Malcolm, Thomas; Hu, Wenhui; Khalili, Kamel

    2016-01-01

    The CRISPR/Cas9 gene editing method is comprised of the guide RNA (gRNA) to target a specific DNA sequence for cleavage and the Cas9 endonuclease for introducing breaks in the double-stranded DNA identified by the gRNA. Co-expression of both a multiplex of HIV-1-specific gRNAs and Cas9 in cells results in the modification and/or excision of the segment of viral DNA, leading to replication-defective virus. In this study, we have personalized the activity of CRISPR/Cas9 by placing the gene encoding Cas9 under the control of a minimal promoter of HIV-1 that is activated by the HIV-1 Tat protein. We demonstrate that functional activation of CRISPR/Cas9 by Tat during the course of viral infection excises the designated segment of the integrated viral DNA and consequently suppresses viral expression. This strategy was also used in a latently infected CD4+ T-cell model after treatment with a variety of HIV-1 stimulating agents including PMA and TSA. Controlled expression of Cas9 by Tat offers a new strategy for safe implementation of the Cas9 technology for ablation of HIV-1 at a very early stage of HIV-1 replication during the course of the acute phase of infection and the reactivation of silent proviral DNA in latently infected cells. PMID:27528385

  4. Tetherin does not significantly restrict dendritic cell-mediated HIV-1 transmission and its expression is upregulated by newly synthesized HIV-1 Nef

    Directory of Open Access Journals (Sweden)

    Wu Li

    2011-04-01

    Full Text Available Abstract Background Dendritic cells (DCs are among the first cells to encounter HIV-1 and play important roles in viral transmission and pathogenesis. Immature DCs allow productive HIV-1 replication and long-term viral dissemination. The pro-inflammatory factor lipopolysaccharide (LPS induces DC maturation and enhances the efficiency of DC-mediated HIV-1 transmission. Type I interferon (IFN partially inhibits HIV-1 replication and cell-cell transmission in CD4+ T cells and macrophages. Tetherin is a type I IFN-inducible restriction factor that blocks HIV-1 release and modulates CD4+ T cell-mediated cell-to-cell transmission of HIV-1. However, the role of type I IFN and tetherin in HIV-1 infection of DCs and DC-mediated viral transmission remains unknown. Results We demonstrated that IFN-alpha (IFNα-induced mature DCs restricted HIV-1 replication and trans-infection of CD4+ T cells. Tetherin expression in monocyte-derived immature DCs was undetectable or very low. High levels of tetherin were transiently expressed in LPS- and IFNα-induced mature DCs, while HIV-1 localized into distinct patches in these DCs. Knockdown of induced tetherin in LPS- or IFNα-matured DCs modestly enhanced HIV-1 transmission to CD4+ T cells, but had no significant effect on wild-type HIV-1 replication in mature DCs. Intriguingly, we found that HIV-1 replication in immature DCs induced significant tetherin expression in a Nef-dependent manner. Conclusions The restriction of HIV-1 replication and transmission in IFNα-induced mature DCs indicates a potent anti-HIV-1 response; however, high levels of tetherin induced in mature DCs cannot significantly restrict wild-type HIV-1 release and DC-mediated HIV-1 transmission. Nef-dependent tetherin induction in HIV-1-infected immature DCs suggests an innate immune response of DCs to HIV-1 infection.

  5. HIV-1 specific IgA detected in vaginal secretions of HIV uninfected women participating in a microbicide trial in Southern Africa are primarily directed toward gp120 and gp140 specificities.

    Directory of Open Access Journals (Sweden)

    Kelly E Seaton

    Full Text Available BACKGROUND: Many participants in microbicide trials remain uninfected despite ongoing exposure to HIV-1. Determining the emergence and nature of mucosal HIV-specific immune responses in such women is important, since these responses may contribute to protection and could provide insight for the rational design of HIV-1 vaccines. METHODS AND FINDINGS: We first conducted a pilot study to compare three sampling devices (Dacron swabs, flocked nylon swabs and Merocel sponges for detection of HIV-1-specific IgG and IgA antibodies in vaginal secretions. IgG antibodies from HIV-1-positive women reacted broadly across the full panel of eight HIV-1 envelope (Env antigens tested, whereas IgA antibodies only reacted to the gp41 subunit. No Env-reactive antibodies were detected in the HIV-negative women. The three sampling devices yielded equal HIV-1-specific antibody titers, as well as total IgG and IgA concentrations. We then tested vaginal Dacron swabs archived from 57 HIV seronegative women who participated in a microbicide efficacy trial in Southern Africa (HPTN 035. We detected vaginal IgA antibodies directed at HIV-1 Env gp120/gp140 in six of these women, and at gp41 in another three women, but did not detect Env-specific IgG antibodies in any women. CONCLUSION: Vaginal secretions of HIV-1 infected women contained IgG reactivity to a broad range of Env antigens and IgA reactivity to gp41. In contrast, Env-binding antibodies in the vaginal secretions of HIV-1 uninfected women participating in the microbicide trial were restricted to the IgA subtype and were mostly directed at HIV-1 gp120/gp140.

  6. Genotypic alteration of HAART-persistent HIV-1 reservoirs in vivo

    International Nuclear Information System (INIS)

    Three HIV-1-infected individuals, on virally-suppressive highly active anti-retroviral therapy (HAART), were treated in vivo with anti-retroviral inhibitor intensification and cell stimulatory therapies in attempting to eradicate latent viral reservoirs. Afterwards, the patients ceased all anti-retroviral drugs. Sequences of the V3 region of HIV-1 envelope protein (ENV) from patient peripheral blood mononuclear cell (PBMC) proviral DNA, patient blood plasma viral RNA and virion-associated RNA from viruses amplified by patient cell co-culture, were obtained before, during, and certain times after the clinical regimen. As anticipated, the V3 loop sequencing results indicate diversity in viral strain complexity among the individual patients. However, the detection of unique V3 ENV signature sequences or V3 signatures of low frequency, relative to those observed prior to therapy, indicate that the expression of specific viruses, or viruses of low abundance, can be induced through stimulation in vivo. Furthermore, this stimulation or general immune activation therapy (IAT) approach, consisting of administration of the anti-T-cell receptor antibody, OKT3, and IL-2 in vivo, appeared to have subsequently altered the genotype of the persistent viral reservoir in peripheral blood cells for two of the three patients

  7. Intracellular mannose binding lectin mediates subcellular trafficking of HIV-1 gp120 in neurons.

    Science.gov (United States)

    Teodorof, C; Divakar, S; Soontornniyomkij, B; Achim, C L; Kaul, M; Singh, K K

    2014-09-01

    Human immunodeficiency virus-1 (HIV-1) enters the brain early during infection and leads to severe neuronal damage and central nervous system impairment. HIV-1 envelope glycoprotein 120 (gp120), a neurotoxin, undergoes intracellular trafficking and transport across neurons; however mechanisms of gp120 trafficking in neurons are unclear. Our results show that mannose binding lectin (MBL) that binds to the N-linked mannose residues on gp120, participates in intravesicular packaging of gp120 in neuronal subcellular organelles and also in subcellular trafficking of these vesicles in neuronal cells. Perinuclear MBL:gp120 vesicular complexes were observed and MBL facilitated the subcellular trafficking of gp120 via the endoplasmic reticulum (ER) and Golgi vesicles. The functional carbohydrate recognition domain of MBL was required for perinuclear organization, distribution and subcellular trafficking of MBL:gp120 vesicular complexes. Nocodazole, an agent that depolymerizes the microtubule network, abolished the trafficking of MBL:gp120 vesicles, suggesting that these vesicular complexes were transported along the microtubule network. Live cell imaging confirmed the association of the MBL:gp120 complexes with dynamic subcellular vesicles that underwent trafficking in neuronal soma and along the neurites. Thus, our findings suggest that intracellular MBL mediates subcellular trafficking and transport of viral glycoproteins in a microtubule-dependent mechanism in the neurons. PMID:24825317

  8. Intracellular mannose binding lectin mediates subcellular trafficking of HIV-1 gp120 in neurons.

    Science.gov (United States)

    Teodorof, C; Divakar, S; Soontornniyomkij, B; Achim, C L; Kaul, M; Singh, K K

    2014-09-01

    Human immunodeficiency virus-1 (HIV-1) enters the brain early during infection and leads to severe neuronal damage and central nervous system impairment. HIV-1 envelope glycoprotein 120 (gp120), a neurotoxin, undergoes intracellular trafficking and transport across neurons; however mechanisms of gp120 trafficking in neurons are unclear. Our results show that mannose binding lectin (MBL) that binds to the N-linked mannose residues on gp120, participates in intravesicular packaging of gp120 in neuronal subcellular organelles and also in subcellular trafficking of these vesicles in neuronal cells. Perinuclear MBL:gp120 vesicular complexes were observed and MBL facilitated the subcellular trafficking of gp120 via the endoplasmic reticulum (ER) and Golgi vesicles. The functional carbohydrate recognition domain of MBL was required for perinuclear organization, distribution and subcellular trafficking of MBL:gp120 vesicular complexes. Nocodazole, an agent that depolymerizes the microtubule network, abolished the trafficking of MBL:gp120 vesicles, suggesting that these vesicular complexes were transported along the microtubule network. Live cell imaging confirmed the association of the MBL:gp120 complexes with dynamic subcellular vesicles that underwent trafficking in neuronal soma and along the neurites. Thus, our findings suggest that intracellular MBL mediates subcellular trafficking and transport of viral glycoproteins in a microtubule-dependent mechanism in the neurons.

  9. 尿液HIV-1抗体检测技术%Urine HIV-1 antibody testing technology

    Institute of Scientific and Technical Information of China (English)

    纪秋宇; 何小维; 罗志刚

    2008-01-01

    艾滋病常规快速测定方法为检测血液中HIV抗体.尿液检测HIV-1因其具有安全、便捷、成本低等优势,是一种很有发展潜力的检测HIV的全新手段.本文就尿液中HIV-1抗体、尿液检测HIV-1优点以及影响检测的因素等作了综述,对尿液检测产品的的应用及生产现状做了简介.并对尿液HIV-1检测技术的发展前景进行了展望.

  10. Quantifying CD4/CCR5 Usage Efficiency of HIV-1 Env Using the Affinofile System.

    Science.gov (United States)

    Webb, Nicholas E; Lee, Benhur

    2016-01-01

    Entry of HIV-1 into target cells involves the interaction of the HIV envelope (Env) with both a primary receptor (CD4) and a coreceptor (CXCR4 or CCR5). The relative efficiency with which a particular Env uses these receptors is a major component of cellular tropism in the context of entry and is related to a variety of pathological Env phenotypes (Chikere et al. Virology 435:81-91, 2013). The protocols outlined in this chapter describe the use of the Affinofile system, a 293-based dual-inducible cell line that expresses up to 25 distinct combinations of CD4 and CCR5, as well as the associated Viral Entry Receptor Sensitivity Assay (VERSA) metrics used to summarize the CD4/CCR5-dependent infectivity results. This system allows for high-resolution profiling of CD4 and CCR5 usage efficiency in the context of unique viral phenotypes.

  11. TNPO3 is required for HIV-1 replication after nuclear import but prior to integration and binds the HIV-1 core.

    OpenAIRE

    Valle-Casuso, Jose Carlos; Di Nunzio, Francesca; Yang, Yang; Reszka, Natalia; Lienlaf, Maritza; Arhel, Nathalie; Perez, Patricio; Brass, Abraham L.; Diaz-Griffero, Felipe

    2012-01-01

    International audience TNPO3 is a nuclear importer required for HIV-1 infection. Here, we show that depletion of TNPO3 leads to an HIV-1 block after nuclear import but prior to integration. To investigate the mechanistic requirement of TNPO3 in HIV-1 infection, we tested the binding of TNPO3 to the HIV-1 core and found that TNPO3 binds to the HIV-1 core. Overall, this work suggests that TNPO3 interacts with the incoming HIV-1 core in the cytoplasm to assist a process that is important for ...

  12. Novel engineered HIV-1 East African Clade-A gp160 plasmid construct induces strong humoral and cell-mediated immune responses in vivo

    International Nuclear Information System (INIS)

    HIV-1 sequences are highly diverse due to the inaccuracy of the viral reverse transcriptase. This diversity has been studied and used to categorize HIV isolates into subtypes or clades, which are geographically distinct. To develop effective vaccines against HIV-1, immunogens representing different subtypes may be important for induction of cross-protective immunity, but little data exist describing and comparing the immunogenicity induced by different subtype-based vaccines. This issue is further complicated by poor expression of HIV structural antigens due to rev dependence. One costly approach is to codon optimize each subtype construct to be examined. Interestingly, cis-acting transcriptional elements (CTE) can also by pass rev restriction by a rev independent export pathway. We reasoned that rev+CTE constructs might have advantages for such expression studies. A subtype A envelope sequence from a viral isolate from east Africa was cloned into a eukaryotic expression vector under the control of the CMV-IE promoter. The utility of inclusion of the Mason-Pfizer monkey virus (MPV)-CTE with/without rev for driving envelope expression and immunogenicity was examined. Expression of envelope (gp120) was confirmed by immunoblot analysis and by pseudotype virus infectivity assays. The presence of rev and the CTE together increased envelope expression and viral infection. Furthermore the CTE+rev construct was significantly more immunogenic then CTE alone vector. Isotype analysis and cytokine profiles showed strong Th1 response in plasmid-immunized mice, which also demonstrated the superior nature of the rev+CTE construct. These responses were of similar or greater magnitude to a codon-optimized construct. The resulting cellular immune responses were highly cross-reactive with a HIV-1 envelope subtype B antigen. This study suggests a simple strategy for improving the expression and immunogenicity of HIV subtype-specific envelope antigens as plasmid or vector

  13. Role of Gag and lipids during HIV-1 assembly in CD4 T cells and Macrophages

    Directory of Open Access Journals (Sweden)

    Charlotte eMariani

    2014-06-01

    Full Text Available HIV-1 is an RNA enveloped virus that preferentiallyinfects CD4+ T lymphocytes andalso macrophages. In CD4+ T cells, HIV-1mainly buds from the host cell plasma membrane.The viral Gag polyprotein targets theplasma membrane and is the orchestrator ofthe HIV assembly as its expression is sufficientto promote the formation of virus-likeparticles particles carrying a lipidic envelopederiving from the host cell membrane. Certainlipids are enriched in the viral membraneand are thought to play a key role in theassembly process and the envelop composition.A large body of work performed oninfected CD4+ T cells has provided importantknowledge about the assembly process andthe membrane virus lipid composition. WhileHIV assembly and budding in macrophages isthought to follow the same general Gag-drivenmechanism as in T-lymphocytes, the HIV cyclein macrophage exhibits specific features.In these cells, new virions bud from the limitingmembrane of seemingly intracellular compartments,where they accumulate while remaininginfectious. These structures are now oftenreferred to as Virus Containing Compartments(VCCs. Recent studies suggest that VCCsrepresent intracellularly sequestered regionsof the plasma membrane, but their precisenature remains elusive. The proteomic andlipidomic characterization of virions producedby T cells or macrophages has highlightedthe similarity between their composition andthat of the plasma membrane of producercells, as well as their enrichment in acidiclipids, some components of raft lipids andin tetraspanin-enriched microdomains. Greatchances are that Gag promotes the coalescenceof these components into an assemblyplatform from which viral budding takesplace. How Gag exactly interacts with membranelipids and what are the mechanisms involvedin the interaction between the differentmembrane nanodomains within the assemblyplatform remains unclear. Here we review recentliterature regarding the role of Gag andlipids

  14. HIV-1C疫苗研究进展%Advances in the Research of HIV-1 Subtype C Vaccine

    Institute of Scientific and Technical Information of China (English)

    王晶晶; 寸韡

    2008-01-01

    对于HIV-1,抗逆转录病毒药物能显著改善HIV/AIDS病人的健康并延长其寿命.但高昂的费用和治疗条件令大多数HIV患者望而却步,尤其在感染水平高、公共资源极度匮乏的发展中国家.到2004年底,撒哈拉以南非洲地区有2540万HIV感染者,该地区迄今仍是HIV-1C感染最严重的地区.几种候选HIV-1C疫苗目前正在进行临床前和临床研究.这些候选疫苗的设计主要是来自HIV-1C的HIV-1调控蛋白和结构蛋白.本文重点介绍HIV-1C疫苗的研究进展.

  15. Cell-specific RNA aptamer against human CCR5 specifically targets HIV-1 susceptible cells and inhibits HIV-1 infectivity.

    Science.gov (United States)

    Zhou, Jiehua; Satheesan, Sangeetha; Li, Haitang; Weinberg, Marc S; Morris, Kevin V; Burnett, John C; Rossi, John J

    2015-03-19

    The C-C chemokine receptor type 5 (CCR5) is a receptor expressed by T cells and macrophages that serves as a coreceptor for macrophage-tropic HIV-1. Loss of CCR5 is associated with resistance to HIV-1. Here, we combine the live-cell-based SELEX with high-throughput sequencing technology to generate CCR5 RNA aptamers capable of specifically targeting HIV-1 susceptible cells (as small interfering RNA [siRNA] delivery agent) and inhibiting HIV-1 infectivity (as antiviral agent) via block of the CCR5 required for HIV-1 to enter cells. One of the best candidates, G-3, efficiently bound and was internalized into human CCR5-expressing cells. The G-3 specifically neutralized R5 virus infection in primary peripheral blood mononuclear cells, and in vivo generated human CD4(+) T cells with a nanomolar inhibitory concentration 50%. G-3 was also capable of transferring functional siRNAs to CCR5-expressing cells. Collectively, the cell-specific, internalizing, CCR5-targeted aptamers and aptamer-siRNA conjugates offer promise for overcoming some of the current challenges of drug resistance in HIV-1 by providing cell-type- or tissue-specific delivery of various therapeutic moieties.

  16. First Membrane Proximal External Region-Specific Anti-HIV1 Broadly Neutralizing Monoclonal IgA1 Presenting Short CDRH3 and Low Somatic Mutations.

    Science.gov (United States)

    Benjelloun, Fahd; Oruc, Zeliha; Thielens, Nicole; Verrier, Bernard; Champier, Gael; Vincent, Nadine; Rochereau, Nicolas; Girard, Alexandre; Jospin, Fabienne; Chanut, Blandine; Genin, Christian; Cogné, Michel; Paul, Stephane

    2016-09-01

    Mucosal HIV-1-specific IgA have been described as being able to neutralize HIV-1 and to block viral transcytosis. In serum and saliva, the anti-HIV IgA response is predominantly raised against the envelope of HIV-1. In this work, we describe the in vivo generation of gp41-specific IgA1 in humanized α1KI mice to produce chimeric IgA1. Mice were immunized with a conformational immunogenic gp41-transfected cell line. Among 2300 clones screened by immunofluorescence microscopy, six different gp41-specific IgA with strong recognition of gp41 were identified. Two of them have strong neutralizing activity against primary HIV-1 tier 1, 2, and 3 strains and present a low rate of somatic mutations and autoreactivity, unlike what was described for classical gp41-specific IgG. Epitopes were identified and located in the hepted repeat 2/membrane proximal external region. These Abs could be of interest in prophylactic treatment to block HIV-1 penetration in mucosa or in chronically infected patients in combination with antiretroviral therapy to reduce viral load and reservoir. PMID:27481846

  17. Reduced expression of glutamate transporter EAAT2 and impaired glutamate transport in human primary astrocytes exposed to HIV-1 or gp120

    International Nuclear Information System (INIS)

    L-Glutamate is the major excitatory neurotransmitter in the brain. Astrocytes maintain low levels of synaptic glutamate by high-affinity uptake and defects in this function may lead to neuronal cell death by excitotoxicity. We tested the effects of HIV-1 and its envelope glycoprotein gp120 upon glutamate uptake and expression of glutamate transporters EAAT1 and EAAT2 in fetal human astrocytes in vitro. Astrocytes isolated from fetal tissues between 16 and 19 weeks of gestation expressed EAAT1 and EAAT2 RNA and proteins as detected by Northern blot analysis and immunoblotting, respectively, and the cells were capable of specific glutamate uptake. Exposure of astrocytes to HIV-1 or gp120 significantly impaired glutamate uptake by the cells, with maximum inhibition within 6 h, followed by gradual decline during 3 days of observation. HIV-1-infected cells showed a 59% reduction in Vmax for glutamate transport, indicating a reduction in the number of active transporter sites on the cell surface. Impaired glutamate transport after HIV-1 infection or gp120 exposure correlated with a 40-70% decline in steady-state levels of EAAT2 RNA and protein. EAAT1 RNA and protein levels were less affected. Treatment of astrocytes with tumor necrosis factor-α (TNF-α) decreased the expression of both EAAT1 and EAAT2, but neither HIV-1 nor gp120 were found to induce TNF-α production by astrocytes. These findings demonstrate that HIV-1 and gp120 induce transcriptional downmodulation of the EAAT2 transporter gene in human astrocytes and coordinately attenuate glutamate transport by the cells. Reduction of the ability of HIV-1-infected astrocytes to take up glutamate may contribute to the development of neurological disease

  18. Phylodynamics of the HIV-1 epidemic in Cuba.

    Science.gov (United States)

    Delatorre, Edson; Bello, Gonzalo

    2013-01-01

    Previous studies have shown that the HIV-1 epidemic in Cuba displayed a complex molecular epidemiologic profile with circulation of several subtypes and circulating recombinant forms (CRF); but the evolutionary and population history of those viral variants remains unknown. HIV-1 pol sequences of the most prevalent Cuban lineages (subtypes B, C and G, CRF18_cpx, CRF19_cpx, and CRFs20/23/24_BG) isolated between 1999 and 2011 were analyzed. Maximum-likelihood analyses revealed multiple introductions of subtype B (n≥66), subtype C (n≥10), subtype G (n≥8) and CRF18_cpx (n≥2) viruses in Cuba. The bulk of HIV-1 infections in this country, however, was caused by dissemination of a few founder strains probably introduced from North America/Europe (clades B(CU-I) and B(CU-II)), east Africa (clade C(CU-I)) and central Africa (clades G(CU), CRF18(CU) and CRF19(CU)), or locally generated (clades CRFs20/23/24_BG). Bayesian-coalescent analyses show that the major HIV-1 founder strains were introduced into Cuba during 1985-1995; whereas the CRFs_BG strains emerged in the second half of the 1990s. Most HIV-1 Cuban clades appear to have experienced an initial period of fast exponential spread during the 1990s and early 2000s, followed by a more recent decline in growth rate. The median initial growth rate of HIV-1 Cuban clades ranged from 0.4 year⁻¹ to 1.6 year⁻¹. Thus, the HIV-1 epidemic in Cuba has been a result of the successful introduction of a few viral strains that began to circulate at a rather late time of the AIDS pandemic, but then were rapidly disseminated through local transmission networks.

  19. Phylodynamics of the HIV-1 epidemic in Cuba.

    Directory of Open Access Journals (Sweden)

    Edson Delatorre

    Full Text Available Previous studies have shown that the HIV-1 epidemic in Cuba displayed a complex molecular epidemiologic profile with circulation of several subtypes and circulating recombinant forms (CRF; but the evolutionary and population history of those viral variants remains unknown. HIV-1 pol sequences of the most prevalent Cuban lineages (subtypes B, C and G, CRF18_cpx, CRF19_cpx, and CRFs20/23/24_BG isolated between 1999 and 2011 were analyzed. Maximum-likelihood analyses revealed multiple introductions of subtype B (n≥66, subtype C (n≥10, subtype G (n≥8 and CRF18_cpx (n≥2 viruses in Cuba. The bulk of HIV-1 infections in this country, however, was caused by dissemination of a few founder strains probably introduced from North America/Europe (clades B(CU-I and B(CU-II, east Africa (clade C(CU-I and central Africa (clades G(CU, CRF18(CU and CRF19(CU, or locally generated (clades CRFs20/23/24_BG. Bayesian-coalescent analyses show that the major HIV-1 founder strains were introduced into Cuba during 1985-1995; whereas the CRFs_BG strains emerged in the second half of the 1990s. Most HIV-1 Cuban clades appear to have experienced an initial period of fast exponential spread during the 1990s and early 2000s, followed by a more recent decline in growth rate. The median initial growth rate of HIV-1 Cuban clades ranged from 0.4 year⁻¹ to 1.6 year⁻¹. Thus, the HIV-1 epidemic in Cuba has been a result of the successful introduction of a few viral strains that began to circulate at a rather late time of the AIDS pandemic, but then were rapidly disseminated through local transmission networks.

  20. HIV-1 Continues To Replicate and Evolve in Patients with Natural Control of HIV Infection

    DEFF Research Database (Denmark)

    Mens, Helene; Kearney, Mary; Wiegand, Ann;

    2010-01-01

    Elucidating mechanisms leading to the natural control of HIV-1 infection is of great importance for vaccine design and for understanding viral pathogenesis. Rare HIV-1-infected individuals, termed HIV-1 controllers, have plasma HIV-1 RNA levels below the limit of detection by standard clinical...

  1. Impaired production of cytokines is an independent predictor of mortality in HIV-1-infected patients

    DEFF Research Database (Denmark)

    Ostrowski, Sisse R; Gerstoft, Jan; Pedersen, Bente K;

    2003-01-01

    With regard to the natural history of HIV-1 infection this study investigated whether whole-blood culture cytokine production was associated with mortality in HIV-1-infected patients.......With regard to the natural history of HIV-1 infection this study investigated whether whole-blood culture cytokine production was associated with mortality in HIV-1-infected patients....

  2. Severe anaemia is not associated with HIV-1 env gene characteristics in Malawian children

    Directory of Open Access Journals (Sweden)

    Kachala David

    2008-02-01

    Full Text Available Abstract Background Anaemia is the most common haematological complication of HIV and associated with a high morbidity and a poor prognosis. The pathogenesis of HIV-associated anaemia is poorly understood and may include a direct effect of HIV on erythropoiesis. In vitro studies have suggested that specific HIV strains, like X4 that uses the CXCR4 co-receptor present on erythroid precursors, are associated with diminished erythropoiesis. This co-receptor affinity is determined by changes in the hypervariable loop of the HIV-1 envelope genome. In a previous case-control study we observed an association between HIV and severe anaemia in Malawian children that could not be fully explained by secondary infections and micronutrient deficiencies alone. We therefore explored the possibility that alterations in the V1-V2-V3 fragment of HIV-1 were associated with severe anaemia. Methods Using peripheral blood nucleic acid isolates of HIV-infected children identified in the previous studied we assessed if variability of the V1-V2-V3 region of HIV and the occurrence of X4 strains were more common in HIV-infected children with (cases, n = 29 and without severe anaemia (controls, n = 30. For 15 cases bone marrow isolates were available to compare against peripheral blood. All children were followed for 18 months after recruitment. Results Phylogenetic analysis showed that HIV-1 subtype C was present in all but one child. All V1-V2-V3 characteristics tested: V3 charge, V1-V2 length and potential glycosylation sites, were not found to be different between cases and controls. Using a computer model (C-PSSM four children (7.8% were identified to have an X4 strain. This prevalence was not different between study groups (p = 1.00. The V3 loop characteristics for bone marrow and peripheral blood isolates in the case group were identical. None of the children identified as having an X4 strain developed a (new episode of severe anaemia during follow up. Conclusion

  3. Application of a case–control study design to investigate genotypic signatures of HIV-1 transmission

    Directory of Open Access Journals (Sweden)

    Mota Talia M

    2012-06-01

    Full Text Available Abstract Background The characterization of HIV-1 transmission strains may inform the design of an effective vaccine. Shorter variable loops with fewer predicted glycosites have been suggested as signatures enriched in envelope sequences derived during acute HIV-1 infection. Specifically, a transmission-linked lack of glycosites within the V1 and V2 loops of gp120 provides greater access to an α4β7 binding motif, which promotes the establishment of infection. Also, a histidine at position 12 in the leader sequence of Env has been described as a transmission signature that is selected against during chronic infection. The purpose of this study is to measure the association of the presence of an α4β7 binding motif, the number of N-linked glycosites, the length of the variable loops, and the prevalence of histidine at position 12 with HIV-1 transmission. A case–control study design was used to measure the prevalence of these variables between subtype B and C transmission sequences and frequency-matched randomly-selected sequences derived from chronically infected controls. Results Subtype B transmission strains had shorter V3 regions than chronic strains (p = 0.031; subtype C transmission strains had shorter V1 loops than chronic strains (p = 0.047; subtype B transmission strains had more V3 loop glycosites (p = 0.024 than chronic strains. Further investigation showed that these statistically significant results were unlikely to be biologically meaningful. Also, there was no difference observed in the prevalence of a histidine at position 12 among transmission strains and controls of either subtype. Conclusions Although a genetic bottleneck is observed after HIV-1 transmission, our results indicate that summary characteristics of Env hypothesised to be important in transmission are not divergent between transmission and chronic strains of either subtype. The success of a transmission strain to initiate infection may be a random

  4. HIV-1 subtype B: Traces of a pandemic.

    Science.gov (United States)

    Junqueira, Dennis Maletich; Almeida, Sabrina Esteves de Matos

    2016-08-01

    Human migration is a major process that shaped the origin and dissemination of HIV. Within HIV-1, subtype B (HIV-1B) is the most disseminated variant and it is assumed to be the causative agent in approximately 11% of all cases of HIV worldwide. Phylogenetic studies have revealed that HIV-1B emerged in Kinshasa (Africa) and was introduced into the Caribbean region via Haiti in or around 1966 by human migration. After localized dispersion, the virus was brought to the United States of America via homosexual/bisexual contact around 1969. Inside USA, the incidence of HIV-1B infection increased exponentially and it became established in the population, affecting not only homosexual individuals but also heterosexual individuals and injecting drug users. Soon after, the virus was disseminated and became established in other regions, including Europe, Asia, Latin America, and Australia. Recent studies suggest that, in addition to this pandemic clade, several lineages have emerged from Haiti and reached other Caribbean and Latin American countries via short-distance dissemination. Different subtype B genetic variants have also been detected in these epidemics. Four genetic variants have been described to date: subtype B', which mainly circulates in Thailand and other Asian countries; a specific variant mainly found in Trinidad and Tobago; the GPGS variant, which is primarily detected in Korea; and the GWGR variant, which is mainly detected in Brazil. This paper reviews the evolution of HIV-1B and its impact on the human population. PMID:27228177

  5. Role of semen in HIV-1 transmission: inhibitor or facilitator?

    Science.gov (United States)

    Doncel, Gustavo F; Joseph, Theresa; Thurman, Andrea R

    2011-03-01

    Sexual transmission of human immunodeficiency virus type 1 (HIV-1) accounts for 60-90% of new infections, especially in developing countries. During male-to-female transmission, the virus is typically deposited in the vagina as cell-free and cell-associated virions carried by semen. But semen is more than just a carrier for HIV-1. Evidence from in vitro and in vivo studies supports both inhibitory and enhancing effects. Intrinsic antiviral activity mediated by cationic antimicrobial peptides, cytotoxicity, and blockage of HIV-dendritic cell interactions are seminal plasma properties that inhibit HIV-1 infection. On the contrary, neutralization of vaginal acidic pH, enhanced virus-target cell attachment by seminal amyloid fibrils, opsonization by complement fragments, and electrostatic interactions are factors that facilitate HIV-1 infection. The end result, i.e., inhibition or enhancement of HIV mucosal infection, in vivo, likely depends on the summation of all these biological effects. More research is needed, especially in animal models, to dissect the role of these factors and establish their relevance in HIV-1 transmission.

  6. Characterization of HIV-1 Resistance to Tenofovir Alafenamide In Vitro.

    Science.gov (United States)

    Margot, Nicolas A; Johnson, Audun; Miller, Michael D; Callebaut, Christian

    2015-10-01

    Tenofovir alafenamide (TAF) is an investigational prodrug of the HIV-1 nucleotide reverse transcriptase (RT) inhibitor (NtRTI) tenofovir (TFV), with improved potency and drug delivery properties over the current prodrug, tenofovir disoproxil fumarate (TDF). TAF is currently in phase 3 clinical studies for the treatment of HIV-1 infection, in combination with other antiretroviral agents. Phase 1 and 2 studies have shown that TAF was associated with increased peripheral blood mononuclear cell (PBMC) drug loading and increased suppression of HIV-1 replication compared to treatment with TDF. In this study, selection of in vitro resistance to both TAF and the parent compound, TFV, led to the emergence of HIV-1 with the K65R amino acid substitution in RT with 6.5-fold-reduced susceptibility to TAF. Although TAF is more potent than TFV in vitro, the antiviral susceptibilities to TAF and TFV of a large panel of nucleoside/nucleotide RT inhibitor (NRTI)-resistant mutants were highly correlated (R(2) = 0.97), indicating that the two compounds have virtually the same resistance profile when assessed as fold change from the wild type. TAF showed full antiviral activity in PBMCs against primary HIV-1 isolates with protease inhibitor, nonnucleoside RT inhibitor (NNRTI), or integrase strand transfer inhibitor resistance but reduced activity against isolates with extensive NRTI resistance amino acid substitutions. However, the increased cell loading of TFV with TAF versus TDF observed in vivo suggests that TAF may retain activity against TDF-resistant mutant viruses. PMID:26149983

  7. HIV-1 subtype B: Traces of a pandemic.

    Science.gov (United States)

    Junqueira, Dennis Maletich; Almeida, Sabrina Esteves de Matos

    2016-08-01

    Human migration is a major process that shaped the origin and dissemination of HIV. Within HIV-1, subtype B (HIV-1B) is the most disseminated variant and it is assumed to be the causative agent in approximately 11% of all cases of HIV worldwide. Phylogenetic studies have revealed that HIV-1B emerged in Kinshasa (Africa) and was introduced into the Caribbean region via Haiti in or around 1966 by human migration. After localized dispersion, the virus was brought to the United States of America via homosexual/bisexual contact around 1969. Inside USA, the incidence of HIV-1B infection increased exponentially and it became established in the population, affecting not only homosexual individuals but also heterosexual individuals and injecting drug users. Soon after, the virus was disseminated and became established in other regions, including Europe, Asia, Latin America, and Australia. Recent studies suggest that, in addition to this pandemic clade, several lineages have emerged from Haiti and reached other Caribbean and Latin American countries via short-distance dissemination. Different subtype B genetic variants have also been detected in these epidemics. Four genetic variants have been described to date: subtype B', which mainly circulates in Thailand and other Asian countries; a specific variant mainly found in Trinidad and Tobago; the GPGS variant, which is primarily detected in Korea; and the GWGR variant, which is mainly detected in Brazil. This paper reviews the evolution of HIV-1B and its impact on the human population.

  8. Discordance between Frequency of Human Immunodeficiency Virus Type 1 (HIV-1)-Specific Gamma Interferon-Producing CD4+ T Cells and HIV-1-Specific Lymphoproliferation in HIV-1-Infected Subjects with Active Viral Replication

    OpenAIRE

    Palmer, B. E.; Boritz, E; Blyveis, N.; Wilson, C C

    2002-01-01

    One hallmark of uncontrolled, chronic human immunodeficiency virus type 1 (HIV-1) infection is the absence of strong HIV-1-specific, CD4+ T-cell-proliferative responses, yet the mechanism underlying this T helper (Th)-cell defect remains controversial. To better understand the impact of HIV-1 replication on Th-cell function, we compared the frequency of CD4+ Th-cell responses based on production of gamma interferon to lymphoproliferative responses directed against HIV-1 proteins in HIV-1-infe...

  9. Histone deacetylase inhibitors for purging HIV-1 from the latent reservoir.

    OpenAIRE

    Matalon, S.; Rasmussen, T.A.; Dinarello, C A

    2011-01-01

    A reservoir of latently infected memory CD4(+) T cells is believed to be the source of HIV-1 reemergence after discontinuation of antiretroviral therapy. HIV-1 eradication may depend on depletion of this reservoir. Integrated HIV-1 is inaccessible for expression, in part because of histone deacetylases (HDACs). One approach is to exploit the ability of HDAC inhibitors to induce HIV-1 expression from an integrated virus. With effective antiretroviral therapy, newly expressed HIV-1 is incapable...

  10. Interactions of HIV-1 proteins with their cellular partners : insights from computational methods

    OpenAIRE

    Quy, Vo Cam

    2013-01-01

    HIV-1 attacks vital cells in the human immune system. HIV-1 differs from many viruses since it is characterized by a very high genetic variability. This means that many variants of HIV-1 virus can be generated in a single infected patient in the course of one day. HIV-1 hypervariability causes drug resistance and, consequently, medical treatment failure. Targeting the interactions between proteins from HIV-1 and from Homo sapiens may represent an excellent solution for drug design because it ...

  11. HIV-1 clade C escapes broadly neutralizing autologous antibodies with N332 glycan specificity by distinct mechanisms.

    Science.gov (United States)

    Deshpande, Suprit; Patil, Shilpa; Kumar, Rajesh; Hermanus, Tandile; Murugavel, Kailapuri G; Srikrishnan, Aylur K; Solomon, Suniti; Morris, Lynn; Bhattacharya, Jayanta

    2016-01-01

    The glycan supersite centered on N332 in the V3 base of the HIV-1 envelope (Env) is a target for broadly neutralizing antibodies (bnAbs) such as PGT121 and PGT128. In this study, we examined the basis of resistance of HIV-1 clade C Envs obtained from broadly cross neutralizing (BCN) plasma of an Indian donor with N332 specificity. Pseudotyped viruses expressing autologous envs were found to be resistant to autologous BCN plasma as well as to PGT121 and PGT128 mAbs despite the majority of Envs containing an intact N332 residue. While resistance of one of the Envs to neutralization by autologous plasma antibodies with shorter V1 loop length was found to be correlated with a N332S mutation, resistance to neutralization of rest of the Envs was found to be associated with longer V1 loop length and acquisition of protective N-glycans. In summary, we show evidence of escape of circulating HIV-1 clade C in an individual from autologous BCN antibodies by three distinct mechanisms. PMID:27576440

  12. Design, Synthesis, and Biological and Structural Evaluations of Novel HIV-1 Protease Inhibitors To Combat Drug Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Parai, Maloy Kumar; Huggins, David J.; Cao, Hong; Nalam, Madhavi N.L.; Ali, Akbar; Schiffer, Celia A.; Tidor, Bruce; Rana, Tariq M. (MIT); (UMASS, MED); (Sanford-Burnham)

    2012-09-11

    A series of new HIV-1 protease inhibitors (PIs) were designed using a general strategy that combines computational structure-based design with substrate-envelope constraints. The PIs incorporate various alcohol-derived P2 carbamates with acyclic and cyclic heteroatomic functionalities into the (R)-hydroxyethylamine isostere. Most of the new PIs show potent binding affinities against wild-type HIV-1 protease and three multidrug resistant (MDR) variants. In particular, inhibitors containing the 2,2-dichloroacetamide, pyrrolidinone, imidazolidinone, and oxazolidinone moieties at P2 are the most potent with Ki values in the picomolar range. Several new PIs exhibit nanomolar antiviral potencies against patient-derived wild-type viruses from HIV-1 clades A, B, and C and two MDR variants. Crystal structure analyses of four potent inhibitors revealed that carbonyl groups of the new P2 moieties promote extensive hydrogen bond interactions with the invariant Asp29 residue of the protease. These structure-activity relationship findings can be utilized to design new PIs with enhanced enzyme inhibitory and antiviral potencies.

  13. An inhibition enzyme immunoassay, using a human monoclonal antibody (K14) reactive with gp41 of HIV-1, for the serology of HIV-1 infections.

    NARCIS (Netherlands)

    V.J.P. Teeuwsen; J.J. Schalken; G. van der Groen (Guido); R. van den Akker (Ruud); J. Goudsmit (Jaap); A.D.M.E. Osterhaus (Ab)

    1991-01-01

    textabstractAn inhibition enzyme immunoassay (IEIA), using a human monoclonal antibody (K14) reactive with gp41 of HIV-1, was evaluated for its applicability to the serology of HIV-1 infections. Using panels of serum samples from seronegative and confirmed HIV-1-seropositive individuals, it was show

  14. No evidence of association between HIV-1 and malaria in populations with low HIV-1 prevalence.

    Directory of Open Access Journals (Sweden)

    Diego F Cuadros

    Full Text Available BACKGROUND: The geographic overlap between HIV-1 and malaria has generated much interest in their potential interactions. A variety of studies have evidenced a complex HIV-malaria interaction within individuals and populations that may have dramatic effects, but the causes and implications of this co-infection at the population level are still unclear. In a previous publication, we showed that the prevalence of malaria caused by the parasite Plasmodium falciparum is associated with HIV infection in eastern sub-Saharan Africa. To complement our knowledge of the HIV-malaria co-infection, the objective of this work was to assess the relationship between malaria and HIV prevalence in the western region of sub-Saharan Africa. METHODOLOGY/PRINCIPAL FINDINGS: Population-based cross-sectional data were obtained from the HIV/AIDS Demographic and Health Surveys conducted in Burkina Faso, Ghana, Guinea, Mali, Liberia and Cameroon, and the malaria atlas project. Using generalized linear mixed models, we assessed the relationship between HIV-1 and Plasmodium falciparum parasite rate (PfPR adjusting for important socio-economic and biological cofactors. We found no evidence that individuals living in areas with stable malaria transmission (PfPR>0.46 have higher odds of being HIV-positive than individuals who live in areas with PfPR≤0.46 in western sub-Saharan Africa (estimated odds ratio 1.14, 95% confidence interval 0.86-1.50. In contrast, the results suggested that PfPR was associated with being infected with HIV in Cameroon (estimated odds ratio 1.56, 95% confidence interval 1.23-2.00. CONCLUSION/SIGNIFICANCE: Contrary to our previous research on eastern sub-Saharan Africa, this study did not identify an association between PfPR and infection with HIV in western sub-Saharan Africa, which suggests that malaria might not play an important role in the spread of HIV in populations where the HIV prevalence is low. Our work highlights the importance of

  15. Cytokine expression during syphilis infection in HIV-1-infected individuals

    DEFF Research Database (Denmark)

    Knudsen, Andreas; Benfield, Thomas; Kofoed, Kristian

    2009-01-01

    BACKGROUND: Little is known about cytokine responses to syphilis infection in HIV-1-infected individuals. METHODS: We retrospectively identified patients with HIV-1 and Treponema pallidum coinfection. Plasma samples from before, during, and after coinfection were analyzed for interleukin (IL)-2, IL...... syphilis.IL-10 and TNF-alpha levels correlated positively with plasma HIV RNA values at the time of diagnosis (r = 0.38, P = 0.023, and r = 0.64, P HIV-1 and early...... stage syphilis coinfection were associated with an increase in IL-10. IL-10 and TNF-alpha both decreased after treatment of syphilis. TNF-alpha and IL-10 correlated with low CD4 T cell counts and high plasma HIV RNA values....

  16. Sensitive non-radioactive detection of HIV-1

    DEFF Research Database (Denmark)

    Teglbjærg, Lars Stubbe; Nielsen, C; Hansen, J E

    1992-01-01

    This report describes the use of the polymerase chain reaction (PCR) for the non-radioactive detection of HIV-1 proviral genomic sequences in HIV-1 infected cells. We have developed a sensitive assay, using three different sets of nested primers and our results show that this method is superior to...... standard PCR for the detection of HIV-1 DNA. The assay described features the use of a simple and inexpensive sample preparation technique and a non-radioactive hybridization procedure for confirmation of results. To test the suitability of the assay for clinical purposes, we tested cell samples from 76...... genomic copies often are present at such low numbers that they are otherwise undetectable....

  17. Stable assembly of HIV-1 export complexes occurs cotranscriptionally

    DEFF Research Database (Denmark)

    Nawroth, Isabel; Mueller, Florian; Basyuk, Eugenia;

    2014-01-01

    The HIV-1 Rev protein mediates export of unspliced and singly spliced viral transcripts by binding to the Rev response element (RRE) and recruiting the cellular export factor CRM1. Here, we investigated the recruitment of Rev to the transcription sites of HIV-1 reporters that splice either post......- or cotranscriptionally. In both cases, we observed that Rev localized to the transcription sites of the reporters and recruited CRM1. Rev and CRM1 remained at the reporter transcription sites when cells were treated with the splicing inhibitor Spliceostatin A (SSA), showing that the proteins associate with RNA prior...... to or during early spliceosome assembly. Fluorescence recovery after photobleaching (FRAP) revealed that Rev and CRM1 have similar kinetics as the HIV-1 RNA, indicating that Rev, CRM1, and RRE-containing RNAs are released from the site of transcription in one single export complex. These results suggest...

  18. Anti - HIV-1 integrase activity of Thai Medicinal Plants

    Directory of Open Access Journals (Sweden)

    Kingkan Bunluepuech

    2009-08-01

    Full Text Available For the purpose of discovering anti-HIV-1 agents from natural sources, the aqueous and EtOH extracts of eight Thaiplants including Clerodendron indicum (whole plant, Tiliacora triandra (stem, Capparis micracantha (wood, Harrissoniaperforata (wood, Ficus glomerata (wood, Diospyros decandra (wood, Dracaena loureiri (heartwood, and Tinospora crispa (stem were screened for their inhibitory activities against HIV-1 integrase (IN using the multiplate integration assay(MIA. Of the EtOH extracts, Ficus glomerata (wood was the most potent with an IC50 value of 7.8 g/ml; whereas the water extract of Harrisonia perforata (wood was the most potent aqueous extract with an IC50 value of 2.3 g/ml. The isolation of active principles against HIV-1 IN from Ficus glomerata is now actively pursued.

  19. 2´,3´-Dialdehyde of ATP, ADP, and adenosine inhibit HIV-1 reverse transcriptase and HIV-1 replication.

    Science.gov (United States)

    Schachter, Julieta; Valadao, Ana Luiza Chaves; Aguiar, Renato Santana; Barreto-de-Souza, Victor; Rossi, Atila Duque; Arantes, Pablo Ricardo; Verli, Hugo; Quintana, Paula Gabriela; Heise, Norton; Tanuri, Amilcar; Bou-Habib, Dumith Chequer; Persechini, Pedro Muanis

    2014-01-01

    The 2´3´-dialdehyde of ATP or oxidized ATP (oATP) is a compound known for specifically making covalent bonds with the nucleotide-binding site of several ATP-binding enzymes and receptors. We investigated the effects of oATP and other oxidized purines on HIV-1 infection and we found that this compound inhibits HIV-1 and SIV infection by blocking early steps of virus replication. oATP, oxidized ADP (oADP), and oxidized Adenosine (oADO) impact the natural activity of endogenous reverse transcriptase enzyme (RT) in cell free virus particles and are able to inhibit viral replication in different cell types when added to the cell cultures either before or after infection. We used UFLC-UV to show that both oADO and oATP can be detected in the cell after being added in the extracellular medium. oATP also suppresses RT activity and replication of the HIV-1 resistant variants M184V and T215Y. We conclude that oATP, oADP and oADO display anti HIV-1 activity that is at in least in part due to inhibitory activity on HIV-1 RT.

  20. No SEVI-mediated enhancement of rectal HIV-1 transmission of HIV-1 in two humanized mouse cohorts.

    Science.gov (United States)

    Van Dis, Erik S; Moore, Tyler C; Lavender, Kerry J; Messer, Ronald J; Keppler, Oliver T; Verheyen, Jens; Dittmer, Ulf; Hasenkrug, Kim J

    2016-01-15

    Amyloid fibrils from semen-derived peptide (SEVI) enhance HIV-1 infectivity in vitro but the ability of SEVI to mediate enhancement of HIV infection in vivo has not been tested. In this study we used immunodeficient mice reconstituted with human immune systems to test for in vivo enhancement of HIV-1 transmission. This mouse model supports mucosal transmission of HIV-1 via the intrarectal route leading to productive infection. In separate experiments with humanized mouse cohorts reconstituted with two different donor immune systems, high dose HIV-1JR-CSF that had been incubated with SEVI amyloid fibrils at physiologically relevant concentrations did not show an increased incidence of infection compared to controls. In addition, SEVI failed to enhance rectal transmission with a reduced concentration of HIV-1. Although we confirmed potent SEVI-mediated enhancement of HIV infectivity in vitro, this model showed no evidence that it plays a role in the much more complex situation of in vivo transmission. PMID:26609939

  1. Selective elimination of HIV-1-infected cells by Env-directed, HIV-1-based virus-like particles

    International Nuclear Information System (INIS)

    We recently showed that both replicating and resting cells cultivated with ganciclovir (GCV) were killed when challenged with vesicular stomatitis virus G glycoprotein pseudotyped HIV-1-based virus-like particles (VLPs) carrying the Nef7 (i.e., an HIV-1 Nef mutant incorporating in virions at high levels)/herpes simplex virus-1 thymidine kinase (HSV-TK) fusion product. On this basis, a novel anti-HIV therapeutic approach based on Nef7/TK VLPs expressing X4 or R5 HIV cell receptor complexes has been attempted. We here report that (CD4-CXCR4) and (CD4-CCR5) Nef7-based VLPs efficiently enter cells infected by X4- or R5-tropic HIV-1 strains, respectively. Importantly, the delivery of the VLP-associated Nef7/TK led to cell death upon GCV treatment. Of interest, VLPs were effective also against non-replicating, HIV-1-infected primary human monocyte-derived macrophages. HIV-targeted VLPs represent a promising candidate for the treatment of persistently HIV-1-infected cells that are part of virus reservoirs resistant to HAART therapies

  2. Anti-HIV-1 protease- and HIV-1 integrase activities of Thai medicinal plants known as Hua-Khao-Yen.

    Science.gov (United States)

    Tewtrakul, Supinya; Itharat, Arunporn; Rattanasuwan, Pranee

    2006-04-21

    Ethanolic- and water extracts from five species of Thai medicinal plants known as Hua-Khao-Yen were tested for their inhibitory effects against HIV-1 protease (HIV-PR) and HIV-1 integrase (HIV-1 IN). The result revealed that the ethanolic (EtOH) extract of Smilax corbularia exhibited anti-HIV-1 IN activity with an IC50 value of 1.9 microg/ml, followed by the water extract of Dioscorea birmanica (IC50 = 4.5 microg/ml), the EtOH extract of Dioscorea birmanica (IC50 = 4.7 microg/ml), the water extract of Smilax corbularia (IC50 = 5.4 microg/ml), the EtOH extract of Smilax glabra (IC50 = 6.7 microg/ml) and the water extract of Smilax glabra (IC50 = 8.5 microg/ml). The extracts of Pygmaeopremna herbacea and Dioscorea membranacea were apparently inactive (IC50 > 100 microg/ml). Interestingly, only the EtOH extract of Dioscorea membranacea showed appreciable activity (IC50 = 48 microg/ml) against HIV-1 PR, while the other extracts possessed mild activity. This result strongly supported the basis for the use of Smilax corbularia and Dioscorea membranacea for AIDS treatment by Thai traditional doctors. PMID:16406414

  3. Flail arm–like syndrome associated with HIV-1 infection

    Science.gov (United States)

    Nalini, A.; Desai, Anita; Mahato, Simendra Kumar

    2009-01-01

    During the last 20 years at least 23 cases of motor neuron disease have been reported in HIV-1 seropositive patients. In this report we describe the clinical picture of a young man with HIV-1 clade C infection and flail arm-like syndrome, who we were able to follow-up for a long period. We investigated and prospectively monitored a 34-year-old man with features of flail arm syndrome, who developed the weakness and wasting 1 year after being diagnosed with HIV-1 infection after a routine blood test. He presented in 2003 with progressive, symmetrical wasting and weakness of the proximal muscles of the upper limb of 2 years' duration. He had severe wasting and weakness of the shoulder and arm muscles. There were no pyramidal signs. He has been on HAART for the last 4 years and the weakness or wasting has not worsened. At the last follow-up in July 2007, the patient had the same neurological deficit and no other symptoms or signs of HIV-1 infection. MRI of the spinal cord in 2007 showed characteristic T2 hyperintense signals in the central part of the spinal cord, corresponding to the central gray matter. Thus, our patient had HIV-1 clade C infection associated with a ‘flail arm–like syndrome.’ The causal relationship between HIV-1 infection and amyotrophic lateral sclerosis (ALS)-like syndrome is still uncertain. The syndrome usually manifests as a lower motor neuron syndrome, as was seen in our young patient. It is known that treatment with antiretroviral therapy (ART) stabilizes/improves the condition. In our patient the weakness and atrophy remained stable over a period of 3.5 years after commencing HAART regimen. PMID:20142861

  4. Flail arm-like syndrome associated with HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Nalini A

    2009-01-01

    Full Text Available During the last 20 years at least 23 cases of motor neuron disease have been reported in HIV-1 seropositive patients. In this report we describe the clinical picture of a young man with HIV-1 clade C infection and flail arm-like syndrome, who we were able to follow-up for a long period. We investigated and prospectively monitored a 34-year-old man with features of flail arm syndrome, who developed the weakness and wasting 1 year after being diagnosed with HIV-1 infection after a routine blood test. He presented in 2003 with progressive, symmetrical wasting and weakness of the proximal muscles of the upper limb of 2 years′ duration. He had severe wasting and weakness of the shoulder and arm muscles. There were no pyramidal signs. He has been on HAART for the last 4 years and the weakness or wasting has not worsened. At the last follow-up in July 2007, the patient had the same neurological deficit and no other symptoms or signs of HIV-1 infection. MRI of the spinal cord in 2007 showed characteristic T2 hyperintense signals in the central part of the spinal cord, corresponding to the central gray matter. Thus, our patient had HIV-1 clade C infection associated with a ′flail arm-like syndrome.′ The causal relationship between HIV-1 infection and amyotrophic lateral sclerosis (ALS-like syndrome is still uncertain. The syndrome usually manifests as a lower motor neuron syndrome, as was seen in our young patient. It is known that treatment with antiretroviral therapy (ART stabilizes/improves the condition. In our patient the weakness and atrophy remained stable over a period of 3.5 years after commencing HAART regimen.

  5. HIV-1 induces DCIR expression in CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Alexandra A Lambert

    Full Text Available The C-type lectin receptor DCIR, which has been shown very recently to act as an attachment factor for HIV-1 in dendritic cells, is expressed predominantly on antigen-presenting cells. However, this concept was recently challenged by the discovery that DCIR can also be detected in CD4(+ T cells found in the synovial tissue from rheumatoid arthritis (RA patients. Given that RA and HIV-1 infections share common features such as a chronic inflammatory condition and polyclonal immune hyperactivation status, we hypothesized that HIV-1 could promote DCIR expression in CD4(+ T cells. We report here that HIV-1 drives DCIR expression in human primary CD4(+ T cells isolated from patients (from both aviremic/treated and viremic/treatment naive persons and cells acutely infected in vitro (seen in both virus-infected and uninfected cells. Soluble factors produced by virus-infected cells are responsible for the noticed DCIR up-regulation on uninfected cells. Infection studies with Vpr- or Nef-deleted viruses revealed that these two viral genes are not contributing to the mechanism of DCIR induction that is seen following acute infection of CD4(+ T cells with HIV-1. Moreover, we report that DCIR is linked to caspase-dependent (induced by a mitochondria-mediated generation of free radicals and -independent intrinsic apoptotic pathways (involving the death effector AIF. Finally, we demonstrate that the higher surface expression of DCIR in CD4(+ T cells is accompanied by an enhancement of virus attachment/entry, replication and transfer. This study shows for the first time that HIV-1 induces DCIR membrane expression in CD4(+ T cells, a process that might promote virus dissemination throughout the infected organism.

  6. Human cellular restriction factors that target HIV-1 replication

    OpenAIRE

    Jeang Kuan-Teh; Luban Jeremy; Strebel Klaus

    2009-01-01

    Abstract Recent findings have highlighted roles played by innate cellular factors in restricting intracellular viral replication. In this review, we discuss in brief the activities of apolipoprotein B mRNA-editing enzyme 3G (APOBEC3G), bone marrow stromal cell antigen 2 (BST-2), cyclophilin A, tripartite motif protein 5 alpha (Trim5α), and cellular microRNAs as examples of host restriction factors that target HIV-1. We point to countermeasures encoded by HIV-1 for moderating the potency of th...

  7. A novel peptide that inhibits HIV-1 entry

    Institute of Scientific and Technical Information of China (English)

    YU Yong; HUANG Xiaoxing; WANG Qiong; YANG Yaling; TIAN Po; ZHANG Wentao

    2004-01-01

    @@ The global epidemic of HIV infection, the cause of AIDS, has created an urgent need for novel classes of antiretroviral agent. Besides reverse transcriptase and protease, the viral entry process provides new anti-HIV-1 targets. A new generation of antiviral drugs intended to block HIV entry into host cells is now under develop- ment[1]. These compounds are generally referred to as fusion or entry inhibitor. Several HIV-1 entry inhibitors that target CD4-gp120 interactions, co-receptor function, and gp41-mediated membrane fusion are in different stages of clinical development[2].

  8. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus

    Science.gov (United States)

    Tully, Damien C.; Ogilvie, Colin B.; Batorsky, Rebecca E.; Bean, David J.; Power, Karen A.; Ghebremichael, Musie; Bedard, Hunter E.; Gladden, Adrianne D.; Seese, Aaron M.; Amero, Molly A.; Lane, Kimberly; McGrath, Graham; Bazner, Suzane B.; Tinsley, Jake; Lennon, Niall J.; Henn, Matthew R.; Brumme, Zabrina L.; Norris, Philip J.; Rosenberg, Eric S.; Mayer, Kenneth H.; Jessen, Heiko; Kosakovsky Pond, Sergei L.; Walker, Bruce D.; Altfeld, Marcus; Carlson, Jonathan M.; Allen, Todd M.

    2016-01-01

    Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM) exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX) transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU), we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic “signatures” within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission. PMID:27163788

  9. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus.

    Directory of Open Access Journals (Sweden)

    Damien C Tully

    2016-05-01

    Full Text Available Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU, we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission.

  10. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus.

    Science.gov (United States)

    Tully, Damien C; Ogilvie, Colin B; Batorsky, Rebecca E; Bean, David J; Power, Karen A; Ghebremichael, Musie; Bedard, Hunter E; Gladden, Adrianne D; Seese, Aaron M; Amero, Molly A; Lane, Kimberly; McGrath, Graham; Bazner, Suzane B; Tinsley, Jake; Lennon, Niall J; Henn, Matthew R; Brumme, Zabrina L; Norris, Philip J; Rosenberg, Eric S; Mayer, Kenneth H; Jessen, Heiko; Kosakovsky Pond, Sergei L; Walker, Bruce D; Altfeld, Marcus; Carlson, Jonathan M; Allen, Todd M

    2016-05-01

    Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM) exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX) transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU), we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission. PMID:27163788

  11. Strong HIV-1-Specific T Cell Responses in HIV-1-Exposed Uninfected Infants and Neonates Revealed after Regulatory T Cell Removal

    OpenAIRE

    Legrand, Fatema A.; Nixon, Douglas F.; Loo, Christopher P.; Erika Ono; Chapman, Joan M; Maristela Miyamoto; Diaz, Ricardo S.; Amélia M N Santos; Succi, Regina C. M.; Jacob Abadi; Rosenberg, Michael G.; Maria Isabel de Moraes-Pinto; Esper G Kallas

    2006-01-01

    BACKGROUND: In utero transmission of HIV-1 occurs on average in only 3%-15% of HIV-1-exposed neonates born to mothers not on antiretroviral drug therapy. Thus, despite potential exposure, the majority of infants remain uninfected. Weak HIV-1-specific T-cell responses have been detected in children exposed to HIV-1, and potentially contribute to protection against infection. We, and others, have recently shown that the removal of CD4(+) CD25(+) T-regulatory (Treg) cells can reveal strong HIV-1...

  12. Recognition of HIV-1 peptides by host CTL is related to HIV-1 similarity to human proteins.

    Directory of Open Access Journals (Sweden)

    Morgane Rolland

    Full Text Available BACKGROUND: While human immunodeficiency virus type 1 (HIV-1-specific cytotoxic T lymphocytes preferentially target specific regions of the viral proteome, HIV-1 features that contribute to immune recognition are not well understood. One hypothesis is that similarities between HIV and human proteins influence the host immune response, i.e., resemblance between viral and host peptides could preclude reactivity against certain HIV epitopes. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the extent of similarity between HIV-1 and the human proteome. Proteins from the HIV-1 B consensus sequence from 2001 were dissected into overlapping k-mers, which were then probed against a non-redundant database of the human proteome in order to identify segments of high similarity. We tested the relationship between HIV-1 similarity to host encoded peptides and immune recognition in HIV-infected individuals, and found that HIV immunogenicity could be partially modulated by the sequence similarity to the host proteome. ELISpot responses to peptides spanning the entire viral proteome evaluated in 314 individuals showed a trend indicating an inverse relationship between the similarity to the host proteome and the frequency of recognition. In addition, analysis of responses by a group of 30 HIV-infected individuals against 944 overlapping peptides representing a broad range of individual HIV-1B Nef variants, affirmed that the degree of similarity to the host was significantly lower for peptides with reactive epitopes than for those that were not recognized. CONCLUSIONS/SIGNIFICANCE: Our results suggest that antigenic motifs that are scarcely represented in human proteins might represent more immunogenic CTL targets not selected against in the host. This observation could provide guidance in the design of more effective HIV immunogens, as sequences devoid of host-like features might afford superior immune reactivity.

  13. HIV-1 infection of in vitro cultured human monocytes: early events and influence of anti HIV-1 antibodies

    DEFF Research Database (Denmark)

    Arendrup, M; Olofsson, S; Nielsen, Jens Ole;

    1994-01-01

    on this infection. Depending on the period of in vitro cultivation and the virus isolate used different patterns of susceptibility were detected. One week old monocyte/M phi s were highly susceptible to HIV-1 infection, in contrast to monocyte/M phi s cultured 4 weeks. The infection by virus isolated immediately...... to CD4 and that post binding events may be common to the infection of lymphocytes. Anti HIV-1 sera showed neutralizing activity against heterologous and even autologous escape virus. This finding, together with the observation that monocytes and M phi s are infected in vivo, suggests that protection...

  14. Effects of human SAMHD1 polymorphisms on HIV-1 susceptibility

    International Nuclear Information System (INIS)

    SAMHD1 is a human restriction factor that prevents efficient infection of macrophages, dendritic cells and resting CD4+ T cells by HIV-1. Here we explored the antiviral activity and biochemical properties of human SAMHD1 polymorphisms. Our studies focused on human SAMHD1 polymorphisms that were previously identified as evolving under positive selection for rapid amino acid replacement during primate speciation. The different human SAMHD1 polymorphisms were tested for their ability to block HIV-1, HIV-2 and equine infectious anemia virus (EIAV). All studied SAMHD1 variants block HIV-1, HIV-2 and EIAV infection when compared to wild type. We found that these variants did not lose their ability to oligomerize or to bind RNA. Furthermore, all tested variants were susceptible to degradation by Vpx, and localized to the nuclear compartment. We tested the ability of human SAMHD1 polymorphisms to decrease the dNTP cellular levels. In agreement, none of the different SAMHD1 variants lost their ability to reduce cellular levels of dNTPs. Finally, we found that none of the tested human SAMHD1 polymorphisms affected the ability of the protein to block LINE-1 retrotransposition. - Highlights: • Human SAMHD1 single-nucleotide polymorphisms block HIV-1 and HIV-2 infection. • SAMHD1 polymorphisms do not affect its ability to block LINE-1 retrotransposition. • SAMHD1 polymorphisms decrease the cellular levels of dNTPs

  15. Is the central nervous system a reservoir of HIV-1?

    Science.gov (United States)

    Gray, Lachlan R.; Roche, Michael; Flynn, Jacqueline K.; Wesselingh, Steve L.; Gorry, Paul R.; Churchill, Melissa J.

    2014-01-01

    Purpose of the review To summarize the evidence in the literature that supports the CNS as a viral reservoir for HIV-1 and to prioritise future research efforts. Recent findings HIV-1 DNA has been detected in brain tissue of patients with undetectable viral load or neurocognitive disorders, and is associated with long-lived cells such as astrocytes and microglia. In neurocognitively normal patients, HIV-1 can be found at high frequency in these cells (4% of astrocytes and 20% of macrophages). CNS cells have unique molecular mechanisms to suppress viral replication and induce latency, which include increased expression of dominant negative transcription factors and suppressive epigenetic factors. There is also evidence of continued inflammation in patients lacking a CNS viral load, suggesting the production and activity of viral neurotoxins (for example Tat). Summary Together, these findings provide evidence that the CNS can potentially act as a viral reservoir of HIV-1. However, the majority of these studies were performed in historical cohorts (absence of cART or presence of viral load) which do not reflect modern day patients (cART-treated and undetectable viral load). Future studies will need to examine patient samples with these characteristics to conclusively determine if the CNS represents a relevant and important viral reservoir. PMID:25203642

  16. A delayed HIV-1 model with virus waning term.

    Science.gov (United States)

    Li, Bing; Chen, Yuming; Lu, Xuejuan; Liu, Shengqiang

    2016-02-01

    In this paper, we propose and analyze a delayed HIV-1 model with CTL immune response and virus waning. The two discrete delays stand for the time for infected cells to produce viruses after viral entry and for the time for CD8+ T cell immune response to emerge to control viral replication. We obtain the positiveness and boundedness of solutions and find the basic reproduction number R0. If R0 1, then the system is uniformly persistent and the viral concentration maintains at some constant level. The global dynamics when R0 > 1 is complicated. We establish the local stability of the infected steady state and show that Hopf bifurcation can occur. Both analytical and numerical results indicate that if, in the initial infection stage, the effect of delays on HIV-1 infection is ignored, then the risk of HIV-1 infection (if persists) will be underestimated. Moreover, the viral load differs from that without virus waning. These results highlight the important role of delays and virus waning on HIV-1 infection. PMID:26776264

  17. Interplay between the RNA interference machinery and HIV-1

    NARCIS (Netherlands)

    N.C.T. Schopman

    2012-01-01

    Resistente infecties zijn lastig te behandelen. Nick Schopman onderzocht een verbeterde RNA-interferentie (RNAi)-gebaseerde anti-hiv-1 gentherapie. Dit kan in de toekomst leiden tot een nieuwe aanpak van de behandeling van resistente infecties. Schopman beschrijft een nieuw ontwerp van een RNAi-mole

  18. APOBEC3G inhibits elongation of HIV-1 reverse transcripts.

    Directory of Open Access Journals (Sweden)

    Kate N Bishop

    2008-12-01

    Full Text Available APOBEC3G (A3G is a host cytidine deaminase that, in the absence of Vif, restricts HIV-1 replication and reduces the amount of viral DNA that accumulates in cells. Initial studies determined that A3G induces extensive mutation of nascent HIV-1 cDNA during reverse transcription. It has been proposed that this triggers the degradation of the viral DNA, but there is now mounting evidence that this mechanism may not be correct. Here, we use a natural endogenous reverse transcriptase assay to show that, in cell-free virus particles, A3G is able to inhibit HIV-1 cDNA accumulation not only in the absence of hypermutation but also without the apparent need for any target cell factors. We find that although reverse transcription initiates in the presence of A3G, elongation of the cDNA product is impeded. These data support the model that A3G reduces HIV-1 cDNA levels by inhibiting synthesis rather than by inducing degradation.

  19. Stepping toward a Macaque Model of HIV-1 Induced AIDS

    Directory of Open Access Journals (Sweden)

    Jason T. Kimata

    2014-09-01

    Full Text Available HIV-1 exhibits a narrow host range, hindering the development of a robust animal model of pathogenesis. Past studies have demonstrated that the restricted host range of HIV-1 may be largely due to the inability of the virus to antagonize and evade effector molecules of the interferon response in other species. They have also guided the engineering of HIV-1 clones that can replicate in CD4 T-cells of Asian macaque species. However, while replication of these viruses in macaque hosts is persistent, it has been limited and without progression to AIDS. In a new study, Hatziioannou et al., demonstrate for the first time that adapted macaque-tropic HIV-1 can persistently replicate at high levels in pigtailed macaques (Macaca nemestrina, but only if CD8 T-cells are depleted at the time of inoculation. The infection causes rapid disease and recapitulates several aspects of AIDS in humans. Additionally, the virus undergoes genetic changes to further escape innate immunity in association with disease progression. Here, the importance of these findings is discussed, as they relate to pathogenesis and model development.

  20. New insights into HIV-1-primary skin disorders.

    Science.gov (United States)

    Cedeno-Laurent, Filiberto; Gómez-Flores, Minerva; Mendez, Nora; Ancer-Rodríguez, Jesús; Bryant, Joseph L; Gaspari, Anthony A; Trujillo, Jose R

    2011-01-24

    Since the first reports of AIDS, skin involvement has become a burdensome stigma for seropositive patients and a challenging task for dermatologist and infectious disease specialists due to the severe and recalcitrant nature of the conditions. Dermatologic manifestations in AIDS patients act as markers of disease progression, a fact that enhances the importance of understanding their pathogenesis.Broadly, cutaneous disorders associated with HIV type-1 infection can be classified as primary and secondary. While the pathogenesis of secondary complications, such as opportunistic infections and skin tumours, is directly correlated with a decline in the CD4+ T cell count, the origin of the certain manifestations primarily associated with the retroviral infection itself still remains under investigation.The focus of this review is to highlight the immunological phenomena that occur in the skin of HIV-1-seropositive patients, which ultimately lead to skin disorders, such as seborrhoeic dermatitis, atopic dermatitis, psoriasis and eosinophilic folliculitis. Furthermore, we compile the latest data on how shifts in the cytokines milieu, impairments of the innate immune compartment, reactions to xenobiotics and autoimmunity are causative agents in HIV-1-driven skin diseases. Additionally, we provide a thorough analysis of the small animal models currently used to study HIV-1-associated skin complications, centering on transgenic rodent models, which unfortunately, have not been able to fully unveil the role of HIV-1 genes in the pathogenesis of their primarily associated dermatological manifestations.

  1. New insights into HIV-1-primary skin disorders

    Directory of Open Access Journals (Sweden)

    Cedeno-Laurent Filiberto

    2011-01-01

    Full Text Available Abstract Since the first reports of AIDS, skin involvement has become a burdensome stigma for seropositive patients and a challenging task for dermatologist and infectious disease specialists due to the severe and recalcitrant nature of the conditions. Dermatologic manifestations in AIDS patients act as markers of disease progression, a fact that enhances the importance of understanding their pathogenesis. Broadly, cutaneous disorders associated with HIV type-1 infection can be classified as primary and secondary. While the pathogenesis of secondary complications, such as opportunistic infections and skin tumours, is directly correlated with a decline in the CD4+ T cell count, the origin of the certain manifestations primarily associated with the retroviral infection itself still remains under investigation. The focus of this review is to highlight the immunological phenomena that occur in the skin of HIV-1-seropositive patients, which ultimately lead to skin disorders, such as seborrhoeic dermatitis, atopic dermatitis, psoriasis and eosinophilic folliculitis. Furthermore, we compile the latest data on how shifts in the cytokines milieu, impairments of the innate immune compartment, reactions to xenobiotics and autoimmunity are causative agents in HIV-1-driven skin diseases. Additionally, we provide a thorough analysis of the small animal models currently used to study HIV-1-associated skin complications, centering on transgenic rodent models, which unfortunately, have not been able to fully unveil the role of HIV-1 genes in the pathogenesis of their primarily associated dermatological manifestations.

  2. Effects of human SAMHD1 polymorphisms on HIV-1 susceptibility

    Energy Technology Data Exchange (ETDEWEB)

    White, Tommy E.; Brandariz-Nuñez, Alberto; Valle-Casuso, Jose Carlos [Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, 1301 Morris Park – Price Center 501, New York, NY 10461 (United States); Knowlton, Caitlin; Kim, Baek [Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642 (United States); Sawyer, Sara L. [Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712 (United States); Diaz-Griffero, Felipe, E-mail: Felipe.Diaz-Griffero@einstein.yu.edu [Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, 1301 Morris Park – Price Center 501, New York, NY 10461 (United States)

    2014-07-15

    SAMHD1 is a human restriction factor that prevents efficient infection of macrophages, dendritic cells and resting CD4+ T cells by HIV-1. Here we explored the antiviral activity and biochemical properties of human SAMHD1 polymorphisms. Our studies focused on human SAMHD1 polymorphisms that were previously identified as evolving under positive selection for rapid amino acid replacement during primate speciation. The different human SAMHD1 polymorphisms were tested for their ability to block HIV-1, HIV-2 and equine infectious anemia virus (EIAV). All studied SAMHD1 variants block HIV-1, HIV-2 and EIAV infection when compared to wild type. We found that these variants did not lose their ability to oligomerize or to bind RNA. Furthermore, all tested variants were susceptible to degradation by Vpx, and localized to the nuclear compartment. We tested the ability of human SAMHD1 polymorphisms to decrease the dNTP cellular levels. In agreement, none of the different SAMHD1 variants lost their ability to reduce cellular levels of dNTPs. Finally, we found that none of the tested human SAMHD1 polymorphisms affected the ability of the protein to block LINE-1 retrotransposition. - Highlights: • Human SAMHD1 single-nucleotide polymorphisms block HIV-1 and HIV-2 infection. • SAMHD1 polymorphisms do not affect its ability to block LINE-1 retrotransposition. • SAMHD1 polymorphisms decrease the cellular levels of dNTPs.

  3. Differentially-Expressed Pseudogenes in HIV-1 Infection

    Directory of Open Access Journals (Sweden)

    Aditi Gupta

    2015-09-01

    Full Text Available Not all pseudogenes are transcriptionally silent as previously thought. Pseudogene transcripts, although not translated, contribute to the non-coding RNA pool of the cell that regulates the expression of other genes. Pseudogene transcripts can also directly compete with the parent gene transcripts for mRNA stability and other cell factors, modulating their expression levels. Tissue-specific and cancer-specific differential expression of these “functional” pseudogenes has been reported. To ascertain potential pseudogene:gene interactions in HIV-1 infection, we analyzed transcriptomes from infected and uninfected T-cells and found that 21 pseudogenes are differentially expressed in HIV-1 infection. This is interesting because parent genes of one-third of these differentially-expressed pseudogenes are implicated in HIV-1 life cycle, and parent genes of half of these pseudogenes are involved in different viral infections. Our bioinformatics analysis identifies candidate pseudogene:gene interactions that may be of significance in HIV-1 infection. Experimental validation of these interactions would establish that retroviruses exploit this newly-discovered layer of host gene expression regulation for their own benefit.

  4. Impact of chemotherapy for HIV-1 related lymphoma on residual viremia and cellular HIV-1 DNA in patients on suppressive antiretroviral therapy.

    Directory of Open Access Journals (Sweden)

    Anthony R Cillo

    Full Text Available The first cure of HIV-1 infection was achieved through complex, multimodal therapy including myeloablative chemotherapy, total body irradiation, anti-thymocyte globulin, and allogeneic stem cell transplantation with a CCR5 delta32 homozygous donor. The contributions of each component of this therapy to HIV-1 eradication are unclear. To assess the impact of cytotoxic chemotherapy alone on HIV-1 persistence, we longitudinally evaluated low-level plasma viremia and HIV-1 DNA in PBMC from patients in the ACTG A5001/ALLRT cohort on suppressive antiretroviral therapy (ART who underwent chemotherapy for HIV-1 related lymphoma without interrupting ART. Plasma HIV-1 RNA, total HIV-1 DNA and 2-LTR circles (2-LTRs in PBMC were measured using sensitive qPCR assays. In the 9 patients who received moderately intensive chemotherapy for HIV-1 related lymphoma with uninterrupted ART, low-level plasma HIV-1 RNA did not change significantly with chemotherapy: median HIV-1 RNA was 1 copy/mL (interquartile range: 1.0 to 20 pre-chemotherapy versus 4 copies/mL (interquartile range: 1.0 to 7.0 post-chemotherapy. HIV-1 DNA levels also did not change significantly, with median pre-chemotherapy HIV-1 DNA of 355 copies/106 CD4+ cells versus 228 copies/106 CD4+ cells post-chemotherapy. 2-LTRs were detectable in 2 of 9 patients pre-chemotherapy and in 3 of 9 patients post-chemotherapy. In summary, moderately intensive chemotherapy for HIV-1 related lymphoma in the context of continuous ART did not have a prolonged impact on HIV-1 persistence. Clinical trials registration unique identifier: NCT00001137.

  5. Characterization of Antiviral Activity of Benzamide Derivative AH0109 against HIV-1 Infection

    OpenAIRE

    Chen, Liyu; Ao, Zhujun; Jayappa, Kallesh Danappa; Kobinger, Gary; Liu, ShuiPing; Wu, Guojun; Wainberg, Mark A.; Yao, Xiaojian

    2013-01-01

    In the absence of an effective vaccine against HIV-1 infection, anti-HIV-1 strategies play a major role in disease control. However, the rapid emergence of drug resistance against all currently used anti-HIV-1 molecules necessitates the development of new antiviral molecules and/or strategies against HIV-1 infection. In this study, we have identified a benzamide derivative named AH0109 that exhibits potent anti-HIV-1 activity at an 50% effective concentration of 0.7 μM in HIV-1-susceptible CD...

  6. 作用于HIV-1 gp120小分子HIV进入抑制剂NC-2的虚拟筛选及其作用机制%Virtual screening of small molecular HIV-1 entry inhibitor NC-2 targeting gp120 and its action mechanism

    Institute of Scientific and Technical Information of China (English)

    段恒; 王玉芹; 宋德寿; 陈之朋; 裘佳寅; 陆路; 姜世勃; 刘叔文; 谭穗懿

    2013-01-01

    of 19 molecules with distinct reduction of the binding free energy after binding with gp120 were screened from 40000 molecules.Among them,NC-2 showed anti-HIV-1 activities against HIV-1 pseudotyped virus and laboratory-adapted HIV-1,and was capable of blocking HIV-1 envelope-mediated cell-cell fusion.The IC50 of NC-2 for inhibiting HIV-1ⅢB and pseudotyped HIV-1JRFL infection were 1.95±0.44 μmol/L and 10.58±0.13 μmol/L,respectively.The results of ELISA suggested that NC-2 could inhibit the binding of HIV-1 gp120 to CD4 without blocking the formation of gp41 six-helix bundle in vitro.Conclusion This computer-based virtual screening method can be used to screen HIV-1 entry inhibitors targeting gp120.Using this virtual screening approach combined with anti-viral activity screening,we obtained a potent HTW-1 entry inhibitor NC-2 with novel structure.

  7. Accuracy of the TRUGENE HIV-1 Genotyping Kit

    Science.gov (United States)

    Grant, Robert M.; Kuritzkes, Daniel R.; Johnson, Victoria A.; Mellors, John W.; Sullivan, John L.; Swanstrom, Ronald; D'Aquila, Richard T.; Van Gorder, Mark; Holodniy, Mark; Lloyd, Jr., Robert M.; Reid, Caroline; Morgan, Gillian F.; Winslow, Dean L.

    2003-01-01

    Drug resistance and poor virological responses are associated with well-characterized mutations in the viral reading frames that encode the proteins that are targeted by currently available antiretroviral drugs. An integrated system was developed that includes target gene amplification, DNA sequencing chemistry (TRUGENE HIV-1 Genotyping Kit), and hardware and interpretative software (the OpenGene DNA Sequencing System) for detection of mutations in the human immunodeficiency virus type 1 (HIV-1) protease and reverse transcriptase sequences. The integrated system incorporates reverse transcription-PCR from extracted HIV-1 RNA, a coupled amplification and sequencing step (CLIP), polyacrylamide gel electrophoresis, semiautomated analysis of data, and generation of an interpretative report. To assess the accuracy and robustness of the assay system, 270 coded plasma specimens derived from nine patients were sent to six laboratories for blinded analysis. All specimens contained HIV-1 subtype B viruses. Results of 270 independent assays were compared to “gold standard” consensus sequences of the virus populations determined by sequence analysis of 16 to 20 clones of viral DNA amplicons derived from two independent PCRs using primers not used in the kit. The accuracy of the integrated system for nucleotide base identification was 98.7%, and the accuracy for codon identification at 54 sites associated with drug resistance was 97.6%. In a separate analysis of plasma spiked with infectious molecular clones, the assay reproducibly detected all 72 different drug resistance mutations that were evaluated. There were no significant differences in accuracy between laboratories, between technologists, between kit lots, or between days. This integrated assay system for the detection of HIV-1 drug resistance mutations has a high degree of accuracy and reproducibility in several laboratories. PMID:12682149

  8. In vitro nuclear interactome of the HIV-1 Tat protein.

    LENUS (Irish Health Repository)

    Gautier, Virginie W

    2009-01-01

    BACKGROUND: One facet of the complexity underlying the biology of HIV-1 resides not only in its limited number of viral proteins, but in the extensive repertoire of cellular proteins they interact with and their higher-order assembly. HIV-1 encodes the regulatory protein Tat (86-101aa), which is essential for HIV-1 replication and primarily orchestrates HIV-1 provirus transcriptional regulation. Previous studies have demonstrated that Tat function is highly dependent on specific interactions with a range of cellular proteins. However they can only partially account for the intricate molecular mechanisms underlying the dynamics of proviral gene expression. To obtain a comprehensive nuclear interaction map of Tat in T-cells, we have designed a proteomic strategy based on affinity chromatography coupled with mass spectrometry. RESULTS: Our approach resulted in the identification of a total of 183 candidates as Tat nuclear partners, 90% of which have not been previously characterised. Subsequently we applied in silico analysis, to validate and characterise our dataset which revealed that the Tat nuclear interactome exhibits unique signature(s). First, motif composition analysis highlighted that our dataset is enriched for domains mediating protein, RNA and DNA interactions, and helicase and ATPase activities. Secondly, functional classification and network reconstruction clearly depicted Tat as a polyvalent protein adaptor and positioned Tat at the nexus of a densely interconnected interaction network involved in a range of biological processes which included gene expression regulation, RNA biogenesis, chromatin structure, chromosome organisation, DNA replication and nuclear architecture. CONCLUSION: We have completed the in vitro Tat nuclear interactome and have highlighted its modular network properties and particularly those involved in the coordination of gene expression by Tat. Ultimately, the highly specialised set of molecular interactions identified will

  9. Bioorthogonal mimetics of palmitoyl-CoA and myristoyl-CoA and their subsequent isolation by click chemistry and characterization by mass spectrometry reveal novel acylated host-proteins modified by HIV-1 infection.

    Science.gov (United States)

    Colquhoun, David R; Lyashkov, Alexey E; Ubaida Mohien, Ceereena; Aquino, Veronica N; Bullock, Brandon T; Dinglasan, Rhoel R; Agnew, Brian J; Graham, David R M

    2015-06-01

    Protein acylation plays a critical role in protein localization and function. Acylation is essential for human immunodeficiency virus 1 (HIV-1) assembly and budding of HIV-1 from the plasma membrane in lipid raft microdomains and is mediated by myristoylation of the Gag polyprotein and the copackaging of the envelope protein is facilitated by colocalization mediated by palmitoylation. Since the viral accessory protein NEF has been shown to alter the substrate specificity of myristoyl transferases, and alter cargo trafficking lipid rafts, we hypothesized that HIV-1 infection may alter protein acylation globally. To test this hypothesis, we labeled HIV-1 infected cells with biomimetics of acyl azides, which are incorporated in a manner analogous to natural acyl-Co-A. A terminal azide group allowed us to use a copper catalyzed click chemistry to conjugate the incorporated modifications to a number of substrates to carry out SDS-PAGE, fluorescence microscopy, and enrichment for LC-MS/MS. Using LC-MS/MS, we identified 103 and 174 proteins from the myristic and palmitic azide enrichments, with 27 and 45 proteins respectively that differentiated HIV-1 infected from uninfected cells. This approach has provided us with important insights into HIV-1 biology and is widely applicable to many virological systems.

  10. HIV-1 DNA vaccine with adjuvant cytokines induces specific immune responses against HIV-1 infection in mice

    Institute of Scientific and Technical Information of China (English)

    WANG Fu-xiang; SUN Yong-tao; WANG Lin-xu; LIU Juan

    2006-01-01

    @@ There is mounting evidence that the induction of strong mucosal and cell-mediated immune responses is key element to consider in constructing efficacious HIV-1 vaccine. Therapeutic vaccines that induce high levels of CTL specific to HIV are currently being developed worldwide.

  11. Antibody to gp41 MPER alters functional properties of HIV-1 Env without complete neutralization.

    Directory of Open Access Journals (Sweden)

    Arthur S Kim

    2014-07-01

    Full Text Available Human antibody 10E8 targets the conserved membrane proximal external region (MPER of envelope glycoprotein (Env subunit gp41 and neutralizes HIV-1 with exceptional potency. Remarkably, HIV-1 containing mutations that reportedly knockout 10E8 binding to linear MPER peptides are partially neutralized by 10E8, producing a local plateau in the dose response curve. Here, we found that virus partially neutralized by 10E8 becomes significantly less neutralization sensitive to various MPER antibodies and to soluble CD4 while becoming significantly more sensitive to antibodies and fusion inhibitors against the heptad repeats of gp41. Thus, 10E8 modulates sensitivity of Env to ligands both pre- and post-receptor engagement without complete neutralization. Partial neutralization by 10E8 was influenced at least in part by perturbing Env glycosylation. With unliganded Env, 10E8 bound with lower apparent affinity and lower subunit occupancy to MPER mutant compared to wild type trimers. However, 10E8 decreased functional stability of wild type Env while it had an opposite, stabilizing effect on MPER mutant Envs. Clade C isolates with natural MPER polymorphisms also showed partial neutralization by 10E8 with altered sensitivity to various gp41-targeted ligands. Our findings suggest a novel mechanism of virus neutralization by demonstrating how antibody binding to the base of a trimeric spike cross talks with adjacent subunits to modulate Env structure and function. The ability of an antibody to stabilize, destabilize, partially neutralize as well as alter neutralization sensitivity of a virion spike pre- and post-receptor engagement may have implications for immunotherapy and vaccine design.

  12. Expression, purification and crystallization of CTB-MPR, a candidate mucosal vaccine component against HIV-1

    Directory of Open Access Journals (Sweden)

    Ho-Hsien Lee

    2014-09-01

    Full Text Available CTB-MPR is a fusion protein between the B subunit of cholera toxin (CTB and the membrane-proximal region of gp41 (MPR, the transmembrane envelope protein of Human immunodeficiency virus 1 (HIV-1, and has previously been shown to induce the production of anti-HIV-1 antibodies with antiviral functions. To further improve the design of this candidate vaccine, X-ray crystallography experiments were performed to obtain structural information about this fusion protein. Several variants of CTB-MPR were designed, constructed and recombinantly expressed in Escherichia coli. The first variant contained a flexible GPGP linker between CTB and MPR, and yielded crystals that diffracted to a resolution of 2.3 Å, but only the CTB region was detected in the electron-density map. A second variant, in which the CTB was directly attached to MPR, was shown to destabilize pentamer formation. A third construct containing a polyalanine linker between CTB and MPR proved to stabilize the pentameric form of the protein during purification. The purification procedure was shown to produce a homogeneously pure and monodisperse sample for crystallization. Initial crystallization experiments led to pseudo-crystals which were ordered in only two dimensions and were disordered in the third dimension. Nanocrystals obtained using the same precipitant showed promising X-ray diffraction to 5 Å resolution in femtosecond nanocrystallography experiments at the Linac Coherent Light Source at the SLAC National Accelerator Laboratory. The results demonstrate the utility of femtosecond X-ray crystallography to enable structural analysis based on nano/microcrystals of a protein for which no macroscopic crystals ordered in three dimensions have been observed before.

  13. Structural, kinetic, and thermodynamic studies of specificity designed HIV-1 protease

    Energy Technology Data Exchange (ETDEWEB)

    Alvizo, Oscar; Mittal, Seema; Mayo, Stephen L.; Schiffer, Celia A. (CIT); (UMASS, MED)

    2012-10-23

    HIV-1 protease recognizes and cleaves more than 12 different substrates leading to viral maturation. While these substrates share no conserved motif, they are specifically selected for and cleaved by protease during viral life cycle. Drug resistant mutations evolve within the protease that compromise inhibitor binding but allow the continued recognition of all these substrates. While the substrate envelope defines a general shape for substrate recognition, successfully predicting the determinants of substrate binding specificity would provide additional insights into the mechanism of altered molecular recognition in resistant proteases. We designed a variant of HIV protease with altered specificity using positive computational design methods and validated the design using X-ray crystallography and enzyme biochemistry. The engineered variant, Pr3 (A28S/D30F/G48R), was designed to preferentially bind to one out of three of HIV protease's natural substrates; RT-RH over p2-NC and CA-p2. In kinetic assays, RT-RH binding specificity for Pr3 increased threefold compared to the wild-type (WT), which was further confirmed by isothermal titration calorimetry. Crystal structures of WT protease and the designed variant in complex with RT-RH, CA-p2, and p2-NC were determined. Structural analysis of the designed complexes revealed that one of the engineered substitutions (G48R) potentially stabilized heterogeneous flap conformations, thereby facilitating alternate modes of substrate binding. Our results demonstrate that while substrate specificity could be engineered in HIV protease, the structural pliability of protease restricted the propagation of interactions as predicted. These results offer new insights into the plasticity and structural determinants of substrate binding specificity of the HIV-1 protease.

  14. German-austrian recommendations for HIV1-therapy in pregnancy and in HIV1-exposed newborn - update 2008

    Directory of Open Access Journals (Sweden)

    Buchholz Bernd

    2009-11-01

    Full Text Available Abstract German-Austrian recommendations for HIV1-therapy in pregnancy - Update 2008 Bernd Buchholz (University Medical Centre Mannheim, Pediatric Clinic, Matthias Beichert (Mannheim, Gynecology and Obstetrics Practice, Ulrich Marcus (Robert Koch Institute, Berlin, Thomas Grubert, Andrea Gingelmaier (Gynecology Clinic of the Ludwig Maximilians University of Munich, Dr. med. Annette Haberl (HIV-Department, J. W. Goethe-University Hospital, Frankfurt, Dr. med. Brigitte Schmied (Otto-Wagner Spital, Wien. In Germany during the last years about 200-250 HIV1-infected pregnant women delivered a baby each year, a number that is currently increasing. To determine the HIV-status early in pregnancy voluntary HIV-testing of all pregnant women is recommended in Germany and Austria as part of prenatal care. In those cases, where HIV1-infection was known during pregnancy, since 1995 the rate of vertical transmission of HIV1 was reduced to 1-2%. This low transmission rate has been achieved by the combination of anti-retroviral therapy of pregnant women, caesarean section scheduled before onset of labour, anti-retroviral post exposition prophylaxis in the newborn and refraining from breast-feeding by the HIV1-infected mother. To keep pace with new results in research, approval of new anti-retroviral drugs and changes in the general treatment recommendations for HIV1-infected adults, in 1998, 2001, 2003 and 2005 an interdisciplinary consensus meeting was held. Gynaecologists, infectious disease specialists, paediatricians, pharmacologists, virologists and members of the German AIDS Hilfe (NGO were participating in this conference to update the prevention strategies. A fifth update became necessary in 2008. The updating process was started in January 2008 and was terminated in September 2008. The guidelines provide new recommendations on the indication and the starting point for HIV-therapy in pregnancies without complications, drugs and drug combinations to be

  15. Emergence of minor drug-resistant HIV-1 variants after triple antiretroviral prophylaxis for prevention of vertical HIV-1 transmission.

    Directory of Open Access Journals (Sweden)

    Andrea Hauser

    Full Text Available BACKGROUND: WHO-guidelines for prevention of mother-to-child transmission of HIV-1 in resource-limited settings recommend complex maternal antiretroviral prophylaxis comprising antenatal zidovudine (AZT, nevirapine single-dose (NVP-SD at labor onset and AZT/lamivudine (3TC during labor and one week postpartum. Data on resistance development selected by this regimen is not available. We therefore analyzed the emergence of minor drug-resistant HIV-1 variants in Tanzanian women following complex prophylaxis. METHOD: 1395 pregnant women were tested for HIV-1 at Kyela District Hospital, Tanzania. 87/202 HIV-positive women started complex prophylaxis. Blood samples were collected before start of prophylaxis, at birth and 1-2, 4-6 and 12-16 weeks postpartum. Allele-specific real-time PCR assays specific for HIV-1 subtypes A, C and D were developed and applied on samples of mothers and their vertically infected infants to quantify key resistance mutations of AZT (K70R/T215Y/T215F, NVP (K103N/Y181C and 3TC (M184V at detection limits of <1%. RESULTS: 50/87 HIV-infected women having started complex prophylaxis were eligible for the study. All women took AZT with a median duration of 53 days (IQR 39-64; all women ingested NVP-SD, 86% took 3TC. HIV-1 resistance mutations were detected in 20/50 (40% women, of which 70% displayed minority species. Variants with AZT-resistance mutations were found in 11/50 (22%, NVP-resistant variants in 9/50 (18% and 3TC-resistant variants in 4/50 women (8%. Three women harbored resistant HIV-1 against more than one drug. 49/50 infants, including the seven vertically HIV-infected were breastfed, 3/7 infants exhibited drug-resistant virus. CONCLUSION: Complex prophylaxis resulted in lower levels of NVP-selected resistance as compared to NVP-SD, but AZT-resistant HIV-1 emerged in a substantial proportion of women. Starting AZT in pregnancy week 14 instead of 28 as recommended by the current WHO-guidelines may further increase

  16. Emergence of HIV-1 drug resistance mutations among antiretroviral-naïve HIV-1-infected patients after rapid scaling up of antiretroviral therapy in Thailand

    Directory of Open Access Journals (Sweden)

    Sungkanuparph Somnuek

    2012-03-01

    Full Text Available Abstract Background After rapid scaling up of antiretroviral therapy in HIV-1-infected patients, the data of primary HIV-1 drug resistance in Thailand is still limited. This study aims to determine the prevalence and associated factors of primary HIV-1 drug resistance in Thailand. Methods A prospective observational study was conducted among antiretroviral-naïve HIV-1-infected Thai patients from 2007 to 2010. HIV-1 subtypes and mutations were assayed by sequencing a region of HIV-1 pol gene. Surveillance drug resistance mutations recommended by the World Health Organization for surveillance of transmitted HIV-1 drug resistance in 2009 were used in all analyses. Primary HIV-1 drug resistance was defined as the presence of one or more surveillance drug resistance mutations. Results Of 466 patients with a mean age of 38.8 years, 58.6% were males. Risks of HIV-1 infection included heterosexual (77.7%, homosexual (16.7%, and intravenous drug use (5.6%. Median (IQR CD4 cell count and HIV-1 RNA were 176 (42-317 cells/mm3 and 68,600 (19,515-220,330 copies/mL, respectively. HIV-1 subtypes were CRF01_AE (86.9%, B (8.6 and other recombinants (4.5%. The prevalence of primary HIV-1 drug resistance was 4.9%; most of these (73.9% had surveillance drug resistance mutations to only one class of antiretroviral drugs. The prevalence of patients with NRTI, NNRTI, and PI surveillance drug resistance mutations was 1.9%, 2.8% and 1.7%, respectively. From logistic regression analysis, there was no factor significantly associated with primary HIV-1 drug resistance. There was a trend toward higher prevalence in females [odds ratio 2.18; 95% confidence interval 0.896-5.304; p = 0.086]. Conclusions There is a significant emergence of primary HIV-1 drug resistance in Thailand after rapid scaling up of antiretroviral therapy. Although HIV-1 genotyping prior to antiretroviral therapy initiation is not routinely recommended in Thailand, our results raise concerns about the

  17. Human Ubc9 is involved in intracellular HIV-1 Env stability after trafficking out of the trans-Golgi network in a Gag dependent manner.

    Directory of Open Access Journals (Sweden)

    Christopher R Bohl

    Full Text Available The cellular E2 Sumo conjugase, Ubc9 interacts with HIV-1 Gag, and is important for the assembly of infectious HIV-1 virions. In the previous study we demonstrated that in the absence of Ubc9, a defect in virion assembly was associated with decreased levels of mature intracellular Envelope (Env that affected Env incorporation into virions and virion infectivity. We have further characterized the effect of Ubc9 knockdown on HIV Env processing and assembly. We found that gp160 stability in the endoplasmic reticulum (ER and its trafficking to the trans-Golgi network (TGN were unaffected, indicating that the decreased intracellular mature Env levels in Ubc9-depleted cells were due to a selective degradation of mature Env gp120 after cleavage from gp160 and trafficked out of the TGN. Decreased levels of Gag and mature Env were found to be associated with the plasma membrane and lipid rafts, which suggest that these viral proteins were not trafficked correctly to the assembly site. Intracellular gp120 were partially rescued when treated with a combination of lysosome inhibitors. Taken together our results suggest that in the absence of Ubc9, gp120 is preferentially degraded in the lysosomes likely before trafficking to assembly sites leading to the production of defective virions. This study provides further insight in the processing and packaging of the HIV-1 gp120 into mature HIV-1 virions.

  18. Intercompartmental Recombination of HIV-1 Contributes to env Intrahost Diversity and Modulates Viral Tropism and Sensitivity to Entry Inhibitors▿†‡

    Science.gov (United States)

    Brown, Richard J. P.; Peters, Paul J.; Caron, Catherine; Gonzalez-Perez, Maria Paz; Stones, Leanne; Ankghuambom, Chiambah; Pondei, Kemebradikumo; McClure, C. Patrick; Alemnji, George; Taylor, Stephen; Sharp, Paul M.; Clapham, Paul R.; Ball, Jonathan K.

    2011-01-01

    HIV-1 circulates within an infected host as a genetically heterogeneous viral population. Viral intrahost diversity is shaped by substitutional evolution and recombination. Although many studies have speculated that recombination could have a significant impact on viral phenotype, this has never been definitively demonstrated. We report here phylogenetic and subsequent phenotypic analyses of envelope genes obtained from HIV-1 populations present in different anatomical compartments. Assessment of env compartmentalization from immunologically discrete tissues was assessed utilizing a single genome amplification approach, minimizing in vitro-generated artifacts. Genetic compartmentalization of variants was frequently observed. In addition, multiple incidences of intercompartment recombination, presumably facilitated by low-level migration of virus or infected cells between different anatomic sites and coinfection of susceptible cells by genetically divergent strains, were identified. These analyses demonstrate that intercompartment recombination is a fundamental evolutionary mechanism that helps to shape HIV-1 env intrahost diversity in natural infection. Analysis of the phenotypic consequences of these recombination events showed that genetic compartmentalization often correlates with phenotypic compartmentalization and that intercompartment recombination results in phenotype modulation. This represents definitive proof that recombination can generate novel combinations of phenotypic traits which differ subtly from those of parental strains, an important phenomenon that may have an impact on antiviral therapy and contribute to HIV-1 persistence in vivo. PMID:21471230

  19. Progress in Research on Drug-resistance of HIV-1%HIV-1耐药性的研究进展

    Institute of Scientific and Technical Information of China (English)

    贾峥

    2011-01-01

    The drug-resistance of HIV-1 is one of the important cause for failure in treatment of AIDS in humans.The research on drug-resistance of HIV-1 is of an important significance in controlling the epidemic of drug-resistance HIV-1 strain and clinical therapy of AIDS.This paper reviews the generation, evolution and epidemic of drug-resistant strain, mechanism of drug-resistance, drug-resistant mutation, test for drug-resistance as well as novel methods for drug-resistance test of HIV-1.%HIV-1耐药株的出现是人类艾滋病(AIDS)治疗失败的重要原因之一,HIV-1耐药性的研究对于控制耐药株的流行及临床治疗真有重要意义.本文就HIV-1耐药株的产生、进化和传播,HIV-1的耐药机制及耐药性突变,HIV-1耐药性检测以及新型HIV-1耐药性检测方法等作一综述.

  20. Clinical presentation and opportunistic infections in HIV-1, HIV-2 and HIV-1/2 dual seropositive patients in Guinea-Bissau

    DEFF Research Database (Denmark)

    Sørensen, Allan; Jespersen, Sanne; Katzenstein, Terese L;

    2016-01-01

    BACKGROUND: Better understanding of HIV-2 infection is likely to affect the patient care in areas where HIV-2 is prevalent. In this study, we aimed to characterize the clinical presentations among HIV-1, HIV-2 and HIV-1/2 dual seropositive patients. METHODS: In a cross-sectional study, newly...... diagnosed HIV patients attending the HIV outpatient clinic at Hospital Nacional Simão Mendes in Guinea-Bissau were enrolled. Demographical and clinical data were collected and compared between HIV-1, HIV-2 and HIV-1/2 dual seropositive patients. RESULTS: A total of 169 patients (76% HIV-1, 17% HIV-2 and 6......% HIV 1/2) were included in the study between 21 March 2012 and 14 December 2012. HIV-1 seropositive patients were younger than HIV-2 and HIV-1/2 seropositive patients, but no difference in sex was observed. Patients with HIV-1 and HIV-1/2 had a lower baseline CD4 cell count than HIV-2 seropositive...

  1. Contrasting roles for TLR ligands in HIV-1 pathogenesis.

    Directory of Open Access Journals (Sweden)

    Beda Brichacek

    Full Text Available The first line of a host's response to various pathogens is triggered by their engagement of cellular pattern recognition receptors (PRRs. Binding of microbial ligands to these receptors leads to the induction of a variety of cellular factors that alter intracellular and extracellular environment and interfere directly or indirectly with the life cycle of the triggering pathogen. Such changes may also affect any coinfecting microbe. Using ligands to Toll-like receptors (TLRs 5 and 9, we examined their effect on human immunodeficiency virus (HIV-1 replication in lymphoid tissue ex vivo. We found marked differences in the outcomes of such treatment. While flagellin (TLR5 agonist treatment enhanced replication of CC chemokine receptor 5 (CCR 5-tropic and CXC chemokine receptor 4 (CXCR4-tropic HIV-1, treatment with oligodeoxynucleotide (ODN M362 (TLR9 agonist suppressed both viral variants. The differential effects of these TLR ligands on HIV-1 replication correlated with changes in production of CC chemokines CCL3, CCL4, CCL5, and of CXC chemokines CXCL10, and CXCL12 in the ligand-treated HIV-1-infected tissues. The nature and/or magnitude of these changes were dependent on the ligand as well as on the HIV-1 viral strain. Moreover, the tested ligands differed in their ability to induce cellular activation as evaluated by the expression of the cluster of differentiation markers (CD 25, CD38, CD39, CD69, CD154, and human leukocyte antigen D related (HLA-DR as well as of a cell proliferation marker, Ki67, and of CCR5. No significant effect of the ligand treatment was observed on apoptosis and cell death/loss in the treated lymphoid tissue ex vivo. Our results suggest that binding of microbial ligands to TLRs is one of the mechanisms that mediate interactions between coinfected microbes and HIV-1 in human tissues. Thus, the engagement of appropriate TLRs by microbial molecules or their mimetic might become a new strategy for HIV therapy or prevention.

  2. Characteristics of HIV-1 serodiscordant couples enrolled in a clinical trial of antiretroviral pre-exposure prophylaxis for HIV-1 prevention.

    Directory of Open Access Journals (Sweden)

    Andrew Mujugira

    Full Text Available Stable heterosexual HIV-1 serodiscordant couples in Africa have high HIV-1 transmission rates and are a critical population for evaluation of new HIV-1 prevention strategies. The Partners PrEP Study is a randomized, double-blind, placebo-controlled trial of tenofovir and emtricitabine-tenofovir pre-exposure prophylaxis to decrease HIV-1 acquisition within heterosexual HIV-1 serodiscordant couples. We describe the trial design and characteristics of the study cohort.HIV-1 serodiscordant couples, in which the HIV-1 infected partner did not meet national guidelines for initiation of antiretroviral therapy, were enrolled at 9 research sites in Kenya and Uganda. The HIV-1 susceptible partner was randomized to daily oral tenofovir, emtricitabine-tenofovir, or matching placebo with monthly follow-up for 24-36 months.From July 2008 to November 2010, 7920 HIV-1 serodiscordant couples were screened and 4758 enrolled. For 62% (2966/4758 of enrolled couples, the HIV-1 susceptible partner was male. Median age was 33 years for HIV-1 susceptible and HIV-1 infected partners [IQR (28-40 and (26-39 respectively]. Most couples (98% were married, with a median duration of partnership of 7.0 years (IQR 3.0-14.0 and recent knowledge of their serodiscordant status [median 0.4 years (IQR 0.1-2.0]. During the month prior to enrollment, couples reported a median of 4 sex acts (IQR 2-8; 27% reported unprotected sex and 14% of male and 1% of female HIV-1 susceptible partners reported sex with outside partners. Among HIV-1 infected partners, the median plasma HIV-1 level was 3.94 log(10 copies/mL (IQR 3.31-4.53 and median CD4 count was 496 cells/µL (IQR 375-662; the majority (64% had WHO stage 1 HIV-1 disease.Couples at high risk of HIV-1 transmission were rapidly recruited into the Partners PrEP Study, the largest efficacy trial of oral PrEP. (ClinicalTrials.gov NCT00557245.

  3. A Haplotype Block Model for Fine Mapping of Quantitative Trait Loci Regulating HIV-1 Pathogenesis

    OpenAIRE

    Zhu, Yun; Hou, Wei; Wu, Rongling

    2003-01-01

    The dynamic change of human immunodeficiency virus type-1 (HIV-1) particles that cause AIDS displays considerable variation from patients to patients. It is likely that such variation in HIV-1 pathogenesis is correlated with the genetic architecture of hosts. Traditional genetic analysis of HIV-1 infection is based on various biochemical approaches, but it has been little successful because HIV-1 dynamics, as a complex trait, is under polygenic control and sensitive to environmental changes. ...

  4. Predictors of impaired HDL function in HIV-1 infected compared to uninfected individuals

    OpenAIRE

    Kelesidis, Theodoros

    2016-01-01

    Objective: HDL function rather than absolute level may be a more accurate indicator for cardiovascular disease (CVD) but it is unclear what drives HDL dysfunction in HIV-1 infection. The objective of this study is to identify factors that may contribute to HDL dysfunction in chronic HIV-1 infection. Design: Retrospective study of HIV-1 infected males with low overall CVD risk and healthy males with no known CVD risk matched by race to the HIV-1 infected participants. Methods: We related para...

  5. Maternal HIV-1 envelope–specific antibody responses and reduced risk of perinatal transmission

    OpenAIRE

    Permar, Sallie R.; Fong, Youyi; Vandergrift, Nathan; Fouda, Genevieve G.; Gilbert, Peter; Parks, Robert; Jaeger, Frederick H.; Pollara, Justin; Martelli, Amanda; Liebl, Brooke E.; Lloyd, Krissey; Yates, Nicole L.; Overman, R. Glenn; Shen, Xiaoying; Whitaker, Kaylan

    2015-01-01

    Despite the wide availability of antiretroviral drugs, more than 250,000 infants are vertically infected with HIV-1 annually, emphasizing the need for additional interventions to eliminate pediatric HIV-1 infections. Here, we aimed to define humoral immune correlates of risk of mother-to-child transmission (MTCT) of HIV-1, including responses associated with protection in the RV144 vaccine trial. Eighty-three untreated, HIV-1–transmitting mothers and 165 propensity score–mat...

  6. SAMHD1: a new insight into HIV-1 restriction in myeloid cells

    OpenAIRE

    Wu Li; St Gelais Corine

    2011-01-01

    Abstract Human myeloid-lineage cells are refractory to HIV-1 infection. The Vpx proteins from HIV-2 and sooty mangabey SIV render these cells permissive to HIV-1 infection through proteasomal degradation of a putative restriction factor. Two recent studies discovered the cellular protein SAMHD1 to be this restriction factor, demonstrating that Vpx induces proteasomal degradation of SAMHD1 and enhances HIV-1 infection in myeloid-lineage cells. SAMHD1 functions as a myeloid-cell-specific HIV-1 ...

  7. Neurobehavioral Alterations in HIV-1 Transgenic Rats: Evidence for Dopaminergic Dysfunction

    OpenAIRE

    Moran, L. M.; Booze, R.M.; Webb, K. M.; Mactutus, C. F.

    2012-01-01

    Clinical studies have provided evidence that the progression of HIV-1-associated neurocognitive disorders (HAND) involves alterations in dopamine (DA) systems. Drugs of abuse that act on the brain DA system, such as cocaine (Coc), may exacerbate HIV-1 infection and consequent behavioral and neurological manifestations. In the present study, we used the HIV-1 transgenic (Tg) rat, which constitutively expresses 7 of the 9 HIV-1 genes, to assess potential DA system alterations in three behaviora...

  8. Indeterminate rapid HIV-1 test results among antenatal and postnatal mothers

    OpenAIRE

    Matemo, D; Kinuthia, J.; John, F; Chung, M.; Farquhar, C; John-Stewart, G; Kiarie, J.

    2009-01-01

    The sensitivity and specificity of rapid HIV-1 tests may be altered during pregnancy and postpartum. We conducted a study to determine the prevalence and correlates of false-positive Abbott Determine™ and false-negative Uni-Gold™ rapid HIV-1 test results among antenatal and postnatal mothers attending a primary care clinic in Nairobi, Kenya. Mothers were tested for HIV-1 using Abbott Determine™ and non-reactive results were considered HIV-1 antibody negative. Reactive samples by Determine wer...

  9. Antigen Gene Cloning and Expression of HIV-1 Toward AIDS Vaccine Design Ⅱ. Subtype Classification and Quasi-species Identification of HIV-1

    Institute of Scientific and Technical Information of China (English)

    ZENG Qingping (曾庆平); YANG Ruiyi (杨瑞仪); FENG Liling (冯丽玲); CHEN Zhuhua (陈竹华); ZENG Changhong (曾常红)

    2002-01-01

    Objectives: To analyze subtypes and quasi-species of isolatedviruses from HIV-1 infected individuals among the populationof Guangdong Province, for understanding the molecularepidemioiogical dynamics of local HIV-1 isolates, thus laying afoundation for designing a candidate AIDS vaccine.Methods: By hetero-duplex mobility assay (HMA) andsingle strand conformation poly- morphism (SSCP) analysison amplicons from single-primed polymerase chain reaction(SP-PCR), subtypes and quasi-species of tested HIV-1 isolateswere elucidated, and amplicons were sequenced forconfirmation.Results: Specific amplicons from different subtypes andquasi-species of HIV-1 could be discernible by HMA andSSCP analysis.Conclusion: HIV-1 isolates from different patients might beeither a different subtype or an identical subtype, and HIV-1isolates from an individual were present in a population ofquasi-species.

  10. Production and characterization of human anti-V3 monoclonal antibodies from the cells of HIV-1 infected Indian donors

    Directory of Open Access Journals (Sweden)

    Andrabi Raiees

    2012-09-01

    Full Text Available Abstract Background Analysis of human monoclonal antibodies (mAbs developed from HIV-1 infected donors have enormously contributed to the identification of neutralization sensitive epitopes on the HIV-1 envelope glycoprotein. The third variable region (V3 is a crucial target on gp120, primarily due to its involvement in co-receptor (CXCR4 or CCR5 binding and presence of epitopes recognized by broadly neutralizing antibodies. Methods Thirty-three HIV-1 seropositive drug naive patients (18 males and 15 females within the age range of 20–57 years (median = 33 years were recruited in this study for mAb production. The mAbs were selected from EBV transformed cultures with conformationally constrained Cholera-toxin-B containing V3C (V3C-CTB fusion protein. We tested the mAbs for their binding with HIV-1 derived proteins and peptides by ELISA and for neutralization against HIV-1 viruses by TZM-bl assays. Results We isolated three anti-V3 mAbs, 277, 903 and 904 from the cells of different individuals. The ELISA binding revealed a subtype-C and subtype-A specific binding of antibody 277 and 903 while mAb 904 exhibited cross reactivity also with subtype-B V3. Epitope mapping of mAbs with overlapping V3 peptides showed exclusive binding to V3 crown. The antibodies displayed high and low neutralizing activity against 2/5 tier 1 and 1/6 tier 2 viruses respectively. Overall, we observed a resistance of the tier 2 viruses to neutralization by the anti-V3 mAbs, despite the exposure of the epitopes recognized by these antibodies on two representative native viruses (Du156.12 and JRFL, suggesting that the affinity of mAb might equally be crucial for neutralization, as the epitope recognition. Conclusions Our study suggests that the anti-V3 antibodies derived from subtype-C infected Indian patients display neutralization potential against tier 1 viruses while such activity may be limited against more resistant tier 2 viruses. Defining the fine epitope

  11. Histone deacetylase inhibitors for purging HIV-1 from the latent reservoir.

    NARCIS (Netherlands)

    Matalon, S.; Rasmussen, T.A.; Dinarello, C.A.

    2011-01-01

    A reservoir of latently infected memory CD4(+) T cells is believed to be the source of HIV-1 reemergence after discontinuation of antiretroviral therapy. HIV-1 eradication may depend on depletion of this reservoir. Integrated HIV-1 is inaccessible for expression, in part because of histone deacetyla

  12. Neutralizing antibodies in slowly progressing HIV-1 infection

    DEFF Research Database (Denmark)

    Schønning, Kristian; Nielsen, C; Iversen, Johan;

    1995-01-01

    Ten asymptomatic individuals who had experienced only limited CD4+ cell loss after prolonged infection with HIV-1 were studied. These individuals had a mean CD4+ cell count of 674 x 10(6) cells/L and a mean duration of infection of 8.5 years. Also included were 10 asymptomatic HIV-1-infected...... with SPI generally neutralized the contemporaneous isolate, whereas serum from individuals with RPI did not [geometric mean antibody titer (GMT), 45 vs. 3; p = 0.0047]. There was no difference in neutralizing ability against HIVMN (GMT,2,593 vs. 2,263; p = 0.74) and only a small difference against HIVIIIB...... (GMT, 115 vs. 50; p = 0.075). Our results indicate that individuals with SPI are characterized by an ability to neutralize their own HIV strain.(ABSTRACT TRUNCATED AT 250 WORDS)...

  13. Analysis of dinucleotide signatures in HIV-1 subtype B genomes

    Indian Academy of Sciences (India)

    Aridaman Pandit; Jyothirmayi Vadlamudi; Somdatta Sinha

    2013-12-01

    Dinucleotide usage is known to vary in the genomes of organisms. The dinucleotide usage profiles or genome signatures are similar for sequence samples taken from the same genome, but are different for taxonomically distant species. This concept of genome signatures has been used to study several organisms including viruses, to elucidate the signatures of evolutionary processes at the genome level. Genome signatures assume greater importance in the case of host–pathogen interactions, where molecular interactions between the two species take place continuously, and can influence their genomic composition. In this study, analyses of whole genome sequences of the HIV-1 subtype B, a retrovirus that caused global pandemic of AIDS, have been carried out to analyse the variation in genome signatures of the virus from 1983 to 2007.We show statistically significant temporal variations in some dinucleotide patterns highlighting the selective evolution of the dinucleotide profiles of HIV-1 subtype B, possibly a consequence of host specific selection.

  14. Construction of HIV-1 Virus-like Particle Vaccine

    Institute of Scientific and Technical Information of China (English)

    ZHAO Dong-hai; ZHANG Xi-zhen; YU Xiang-hui; KONG Wei

    2008-01-01

    The virus-like particle(VLPs) vaccine is an ideal HIV-1 vaccine,which can simultaneously induce a neutralizing antibody reaction and ceil-mediated immunity effectively.In this study,two kinds of plasmids have been used,one can express the HIV-1 main structure proteins,Gagpol and Env,and the other contains an antibiotic gene.The two kinds of plasmids have been cotransfected into 293 cells.A stable cell line that can express Gagpol and Env proteins efficiently and lastingly has been screened.It has been confirmed that Gagpol and Env proteins in the cell culture supernatant can be self-assembled into virus-like particles.The authors have detected the secretion of VLPs in the cell medium,defined the peak of the secretion,and followed and monitored the stability of expression.

  15. Anti-HIV-1 Activities of 4 Telomerase Restrictors

    Institute of Scientific and Technical Information of China (English)

    YU Xin; WANG Jinghui; de Giuli Morghen; Radaelli A; Zanotto C; Beggio P

    2007-01-01

    MTT Cell Proliferation Assay was used to optimize the concentration of Telomerase Restrictors(TRs) with minimum toxicity to the selected cells. FACSort flow cytometer and Innotest P24 HIV(Human immunodeficiency Virus) antigen mAb ELISA Kit were used to investigate the anti-HIV-1 activities of TRs. The results showed that TRs had low cytotoxicity to the PBMC (Peripheral Blood mononuclear cells) and CEM/GFP if the concentration of TRs was at 50 μmol/L or below, and the supernatant from PBMC pretreated with SHIV and TR1-001 /TR1-002 could not infect the PBMC, while can infect the C8166 with reduced infectivity, which suggested that the TRs may be one of the novel resources for screening anti-HIV-1 agents.

  16. Attenuation of multiple Nef functions in HIV-1 elite controllers

    Directory of Open Access Journals (Sweden)

    Mwimanzi Philip

    2013-01-01

    Full Text Available Abstract Background Impaired HIV-1 Gag, Pol, and Env function has been described in elite controllers (EC who spontaneously suppress plasma viremia to Results In general, EC Nef clones were functional; however, all five activities were significantly lower in EC compared to CP. Nef clones from HLA-B*57-expressing EC exhibited poorer CD4 down-regulation function compared to those from non-B*57 EC, and the number of EC-specific B*57-associated Nef polymorphisms correlated inversely with 4 of 5 Nef functions in these individuals. Conclusion Results indicate that decreased HIV-1 Nef function, due in part to host immune selection pressures, may be a hallmark of the EC phenotype.

  17. Progress and Perspectives on HIV-1 microbicide development.

    Science.gov (United States)

    Alexandre, Kabamba B; Mufhandu, Hazel T; London, Grace M; Chakauya, E; Khati, M

    2016-10-01

    The majority of HIV-1 infections occur via sexual intercourse. Women are the most affected by the epidemic, particularly in developing countries, due to their socio-economic dependence on men and the fact that they are often victims of gender based sexual violence. Despite significant efforts that resulted in the reduction of infection rates in some countries, there is still need for effective prevention methods against the virus. One of these methods for preventing sexual transmission in women is the use of microbicides. In this review we provide a summary of the progress made toward the discovery of affordable and effective HIV-1 microbicides and suggest future directions. We show that there is a wide range of compounds that have been proposed as potential microbicides. Although most of them have so far failed to show protection in humans, there are many promising ones currently in pre-clinical studies and in clinical trials. PMID:27429040

  18. Detection of Acute HIV-1 Infection by RT-LAMP.

    Directory of Open Access Journals (Sweden)

    Donna L Rudolph

    Full Text Available A rapid, cost-effective diagnostic test for the detection of acute HIV-1 infection is highly desired. Isothermal amplification techniques, such as reverse-transcription loop-mediated isothermal amplification (RT-LAMP, exhibit characteristics that are ideal for the development of a rapid nucleic acid amplification test (NAAT because they are quick, easy to perform and do not require complex, dedicated equipment and laboratory space. In this study, we assessed the ability of the HIV-1 RT-LAMP assay to detect acute HIV infection as compared to a representative rapid antibody test and several FDA-approved laboratory-based assays. The HIV-1 RT-LAMP assay detected seroconverting individuals one to three weeks earlier than a rapid HIV antibody test and up to two weeks earlier than a lab-based antigen/antibody (Ag/Ab combo enzyme immunoassay (EIA. RT-LAMP was not as sensitive as a lab-based qualitative RNA assay, which could be attributed to the significantly smaller nucleic acid input volume. To our knowledge, this is the first demonstration of detecting acute HIV infection using the RT-LAMP assay. The availability of a rapid NAAT, such as the HIV-1 RT-LAMP assay, at the point of care (POC or in laboratories that do not have access to large platform NAAT could increase the percentage of individuals who receive an acute HIV infection status or confirmation of their HIV status, while immediately linking them to counseling and medical care. In addition, early knowledge of HIV status could lead to reduced high-risk behavior at a time when individuals are at a higher risk for transmitting the virus.

  19. HIV-1 Integrase Inhibitor Resistance and Its Clinical Implications

    OpenAIRE

    Blanco, Jose-Luis; Varghese, Vici; Rhee, Soo-Yon; Gatell, Jose M.; Shafer, Robert W.

    2011-01-01

    With the approval in 2007 of the first integrase inhibitor (INI), raltegravir, clinicians became better able to suppress virus replication in patients infected with human immunodeficiency virus type 1 (HIV-1) who were harboring many of the most highly drug-resistant viruses. Raltegravir also provided clinicians with additional options for first-line therapy and for the simplification of regimens in patients with stable virological suppression. Two additional INIs in advanced clinical developm...

  20. Hydrophobic core flexibility modulates enzyme activity in HIV-1 protease

    OpenAIRE

    Mittal, Seema; Cai, Yufeng; Nalam, Madhavi N.; Bolon, Daniel N. A.; Schiffer, Celia A.

    2012-01-01

    Human immunodeficiency virus Type-1 (HIV-1) protease is crucial for viral maturation and infectivity. Studies of protease dynamics suggest that the rearrangement of the hydrophobic core is essential for enzyme activity. Many mutations in the hydrophobic core are also associated with drug resistance and may modulate the core flexibility. To test the role of flexibility in protease activity, pairs of cysteines were introduced at the interfaces of flexible regions remote from the active site. Di...

  1. HIV-1 tuberculosis-associated immune reconstitution inflammatory syndrome

    OpenAIRE

    Lai, Rachel P. J.; Meintjes, Graeme; Wilkinson, Robert J.

    2015-01-01

    Patients co-infected with HIV-1 and tuberculosis (TB) are at risk of developing TB-associated immune reconstitution inflammatory syndrome (TB-IRIS) following commencement of antiretroviral therapy (ART). TB-IRIS is characterized by transient but severe localized or systemic inflammatory reactions against Mycobacterium tuberculosis antigens. Here, we review the risk factors and clinical management of TB-IRIS, as well as the roles played by different aspects of the immune response in contributi...

  2. Digoxin Suppresses HIV-1 Replication by Altering Viral RNA Processing

    OpenAIRE

    Wong, Raymond W; Ahalya Balachandran; Ostrowski, Mario A.; Alan Cochrane

    2013-01-01

    Author Summary Antiretroviral therapies (ART) for HIV/AIDS are successful in slowing disease progression by inhibiting viral proteins. However, the ability of HIV to adapt to ARTs has given rise to drug-resistant virus strains that now represent ≥16% of newly infected people. This development calls for the generation of new treatment strategies. Since HIV is dependent upon RNA processing under control of the host, we searched for compounds/drugs that inhibit HIV-1 replication at this step. We...

  3. DETERMINANTS OF THE HIV-1 CORE ASSEMBLY PATHWAY

    OpenAIRE

    López, Claudia S.; Eccles, Jacob D.; Still, Amelia; Sloan, Rachel E.; Barklis, Robin Lid; Tsagli, Seyram M.; Barklis, Eric

    2011-01-01

    Based on structural information, we have analyzed the mechanism of mature HIV-1 core assembly and the contributions of structural elements to the assembly process. Through the use of several in vitro assembly assay systems, we have examined details of how capsid (CA) protein helix 1, β-hairpin and cyclophilin loop elements impact assembly-dependent protein interactions, and we present evidence for a contribution of CA helix 6 to the mature assembly-competent conformation of CA. Additional exp...

  4. Copy number variation of KIR genes influences HIV-1 control.

    Directory of Open Access Journals (Sweden)

    Kimberly Pelak

    2011-11-01

    Full Text Available A genome-wide screen for large structural variants showed that a copy number variant (CNV in the region encoding killer cell immunoglobulin-like receptors (KIR associates with HIV-1 control as measured by plasma viral load at set point in individuals of European ancestry. This CNV encompasses the KIR3DL1-KIR3DS1 locus, encoding receptors that interact with specific HLA-Bw4 molecules to regulate the activation of lymphocyte subsets including natural killer (NK cells. We quantified the number of copies of KIR3DS1 and KIR3DL1 in a large HIV-1 positive cohort, and showed that an increase in KIR3DS1 count associates with a lower viral set point if its putative ligand is present (p = 0.00028, as does an increase in KIR3DL1 count in the presence of KIR3DS1 and appropriate ligands for both receptors (p = 0.0015. We further provide functional data that demonstrate that NK cells from individuals with multiple copies of KIR3DL1, in the presence of KIR3DS1 and the appropriate ligands, inhibit HIV-1 replication more robustly, and associated with a significant expansion in the frequency of KIR3DS1+, but not KIR3DL1+, NK cells in their peripheral blood. Our results suggest that the relative amounts of these activating and inhibitory KIR play a role in regulating the peripheral expansion of highly antiviral KIR3DS1+ NK cells, which may determine differences in HIV-1 control following infection.

  5. Neuroimaging studies of the aging HIV-1-infected brain

    OpenAIRE

    Holt, John L.; Kraft-Terry, Stephanie D.; Chang, Linda

    2012-01-01

    Highly active antiretroviral therapy (HAART) has increased life expectancy among HIV-infected individuals, and by 2015, at least half of all HIV-infected individuals will be over 50 years of age. Neurodegenerative processes associated with aging may be facilitated by HIV-1 infection, resulting in premature brain aging. This review will highlight brain abnormalities in HIV patients in the setting of aging, focusing on recent neuroimaging studies of the structural, physiological, functional and...

  6. HIV-1 binding and neutralizing antibodies of injecting drug users

    Directory of Open Access Journals (Sweden)

    E.P. Ouverney

    2005-09-01

    Full Text Available Previous studies have demonstrated a stronger seroreactivity against some synthetic peptides responsible for inducing neutralizing antibodies in injecting drug users (IDU compared to that of individuals sexually infected with HIV-1 (S, but the effectiveness in terms of the neutralizing ability of these antibodies has not been evaluated. Our objective was to study the humoral immune response of IDU by determining the specificity of their antibodies and the presence of neutralizing antibodies. The neutralization capacity against the HIV-1 isolate MN (genotype B, the primary HIV-1 isolate 95BRRJ021 (genotype F, and the seroreactivity with peptides known to induce neutralizing antibodies, from the V2 and V3 loops of different HIV-1 subtypes, were analyzed. Seroreactivity indicates that IDU plasma are more likely to recognize a broader range of peptides than S plasma, with significantly higher titers, especially of V3 peptides. Similar neutralization frequencies of the MN isolate were observed in plasma of the IDU (16/47 and S (20/60 groups in the 1:10 dilution. The neutralization of the 95BRRJ021 isolate was more frequently observed for plasma from the S group (15/23 than from the IDU group (15/47, P = 0.0108. No correlation between neutralization and seroreactivity with the peptides tested was observed. These results suggest that an important factor responsible for the extensive and broad humoral immune response observed in IDU is their infection route. There was very little difference in neutralizing antibody response between the IDU and S groups despite their differences in seroreactivity and health status.

  7. HIV-1 Vpr: A Novel Role in Regulating RNA Splicing

    OpenAIRE

    Zhang, Xianfeng; Aida, Yoko

    2009-01-01

    Pre-mRNA splicing is a critical step in gene expression for metazoans. Several viral proteins regulate the splicing of pre-mRNAs through complex interactions between the virus and the host cell RNA splicing machinery. Here, we focus on a novel function of HIV-1 Vpr, that selectively inhibit cellular and viral pre-mRNA splicing, via interactions with components of functional spliceosomal complexes. This review discusses our current knowledge of how RNA splicing regulation is accomplished by Vp...

  8. Structural Analysis of Human and Macaque Monoclonal Antibodies 2909 and 2.5B: Implications for the Configuration of the Quaternary Neutralizing Epitope of HIV-1 gp120

    Energy Technology Data Exchange (ETDEWEB)

    B Spurrier; J Sampson; M Totrov; H Li; T ONeal; C Williams; J Robinson; M Gorny; S Zolla-Pazner; X Kong

    2011-12-31

    The quaternary neutralizing epitope (QNE) of HIV-1 gp120 is preferentially expressed on the trimeric envelope spikes of intact HIV virions, and QNE-specific monoclonal antibodies (mAbs) potently neutralize HIV-1. Here, we present the crystal structures of the Fabs of human mAb 2909 and macaque mAb 2.5B. Both mAbs have long beta hairpin CDR H3 regions >20 {angstrom} in length that are each situated at the center of their respective antigen-binding sites. Computational analysis showed that the paratopes include the whole CDR H3, while additional CDR residues form shallow binding pockets. Structural modeling suggests a way to understand the configuration of QNEs and the antigen-antibody interaction for QNE mAbs. Our data will be useful in designing immunogens that may elicit potent neutralizing QNE Abs.

  9. Mother-to-Child HIV-1 Transmission Events Are Differentially Impacted by Breast Milk and Its Components from HIV-1-Infected Women.

    Directory of Open Access Journals (Sweden)

    Ruizhong Shen

    Full Text Available Breast milk is a vehicle of infection and source of protection in post-natal mother-to-child HIV-1 transmission (MTCT. Understanding the mechanism by which breast milk limits vertical transmission will provide critical insight into the design of preventive and therapeutic approaches to interrupt HIV-1 mucosal transmission. However, characterization of the inhibitory activity of breast milk in human intestinal mucosa, the portal of entry in postnatal MTCT, has been constrained by the limited availability of primary mucosal target cells and tissues to recapitulate mucosal transmission ex vivo. Here, we characterized the impact of skimmed breast milk, breast milk antibodies (Igs and non-Ig components from HIV-1-infected Ugandan women on the major events of HIV-1 mucosal transmission using primary human intestinal cells and tissues. HIV-1-specific IgG antibodies and non-Ig components in breast milk inhibited the uptake of Ugandan HIV-1 isolates by primary human intestinal epithelial cells, viral replication in and transport of HIV-1- bearing dendritic cells through the human intestinal mucosa. Breast milk HIV-1-specific IgG and IgA, as well as innate factors, blocked the uptake and transport of HIV-1 through intestinal mucosa. Thus, breast milk components have distinct and complementary effects in reducing HIV-1 uptake, transport through and replication in the intestinal mucosa and, therefore, likely contribute to preventing postnatal HIV-1 transmission. Our data suggests that a successful preventive or therapeutic approach would require multiple immune factors acting at multiple steps in the HIV-1 mucosal transmission process.

  10. Rapid Antiretroviral Therapy Initiation for Women in an HIV-1 Prevention Clinical Trial Experiencing Primary HIV-1 Infection during Pregnancy or Breastfeeding.

    Directory of Open Access Journals (Sweden)

    Susan Morrison

    Full Text Available During an HIV-1 prevention clinical trial in East Africa, we observed 16 cases of primary HIV-1 infection in women coincident with pregnancy or breastfeeding. Nine of eleven pregnant women initiated rapid combination antiretroviral therapy (ART, despite having CD4 counts exceeding national criteria for ART initiation; breastfeeding women initiated ART or replacement feeding. Rapid ART initiation during primary HIV-1 infection during pregnancy and breastfeeding is feasible in this setting.

  11. Rapid Antiretroviral Therapy Initiation for Women in an HIV-1 Prevention Clinical Trial Experiencing Primary HIV-1 Infection during Pregnancy or Breastfeeding

    OpenAIRE

    Susan Morrison; Grace John-Stewart; John J Egessa; Sezi Mubezi; Sylvia Kusemererwa; Dennis K Bii; Nulu Bulya; Francis Mugume; Campbell, James D.; Jonathan Wangisi; Bukusi, Elizabeth A.; Connie Celum; Baeten, Jared M.

    2015-01-01

    During an HIV-1 prevention clinical trial in East Africa, we observed 16 cases of primary HIV-1 infection in women coincident with pregnancy or breastfeeding. Nine of eleven pregnant women initiated rapid combination antiretroviral therapy (ART), despite having CD4 counts exceeding national criteria for ART initiation; breastfeeding women initiated ART or replacement feeding. Rapid ART initiation during primary HIV-1 infection during pregnancy and breastfeeding is feasible in this setting.

  12. β-catenin/TCF-4 signaling regulates susceptibility of macrophages and resistance of monocytes to HIV-1 productive infection

    OpenAIRE

    Aljawai, Yosra; Richards, Maureen H.; Seaton, Melanie S.; Narasipura, Srinivas D.; Al-Harthi, Lena

    2014-01-01

    Cells of the monocyte/macrophage lineage are an important target for HIV-1 infection. They are often at anatomical sites linked to HIV-1 transmission and are an important vehicle for disseminating HIV-1 throughout the body, including the central nervous system. Monocytes do not support extensive productive HIV-1 replication, but they become more susceptible to HIV-1 infection as they differentiate into macrophages. The mechanisms guiding susceptibility of HIV-1 replication in monocytes versus...

  13. Combinatorial RNAi against HIV-1 using extended short hairpin RNAs.

    Science.gov (United States)

    Liu, Ying Poi; von Eije, Karin Jasmijn; Schopman, Nick C T; Westerink, Jan-Tinus; ter Brake, Olivier; Haasnoot, Joost; Berkhout, Ben

    2009-10-01

    RNA interference (RNAi) is a widely used gene suppression tool that holds great promise as a novel antiviral approach. However, for error-prone viruses including human immunodeficiency virus type 1(HIV-1), a combinatorial approach against multiple conserved sequences is required to prevent the emergence of RNAi-resistant escape viruses. Previously, we constructed extended short hairpin RNAs (e-shRNAs) that encode two potent small interfering RNAs (siRNAs) (e2-shRNAs). We showed that a minimal hairpin stem length of 43 base pairs (bp) is needed to obtain two functional siRNAs. In this study, we elaborated on the e2-shRNA design to make e-shRNAs encoding three or four antiviral siRNAs. We demonstrate that siRNA production and the antiviral effect is optimal for e3-shRNA of 66 bp. Further extension of the hairpin stem results in a loss of RNAi activity. The same was observed for long hairpin RNAs (lhRNAs) that target consecutive HIV-1 sequences. Importantly, we show that HIV-1 replication is durably inhibited in T cells stably transduced with a lentiviral vector containing the e3-shRNA expression cassette. These results show that e-shRNAs can be used as a combinatorial RNAi approach to target error-prone viruses. PMID:19672247

  14. Copy number variation of KIR genes influences HIV-1 control

    DEFF Research Database (Denmark)

    Pelak, Kimberly; Need, Anna C; Fellay, Jacques;

    2011-01-01

    A genome-wide screen for large structural variants showed that a copy number variant (CNV) in the region encoding killer cell immunoglobulin-like receptors (KIR) associates with HIV-1 control as measured by plasma viral load at set point in individuals of European ancestry. This CNV encompasses...... the KIR3DL1-KIR3DS1 locus, encoding receptors that interact with specific HLA-Bw4 molecules to regulate the activation of lymphocyte subsets including natural killer (NK) cells. We quantified the number of copies of KIR3DS1 and KIR3DL1 in a large HIV-1 positive cohort, and showed that an increase in KIR3...... individuals with multiple copies of KIR3DL1, in the presence of KIR3DS1 and the appropriate ligands, inhibit HIV-1 replication more robustly, and associated with a significant expansion in the frequency of KIR3DS1+, but not KIR3DL1+, NK cells in their peripheral blood. Our results suggest that the relative...

  15. Positron emission tomography in patients suffering from HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Sathekge, Mike [University Hospital of Pretoria, Department of Nuclear Medicine, Pretoria (South Africa); Goethals, Ingeborg; Wiele, Christophe van de [University Hospital Ghent, Department of Nuclear Medicine, Ghent (Belgium); Maes, Alex [AZ Groening, Department of Nuclear Medicine, Kortrijk (Belgium)

    2009-07-15

    This paper reviews currently available PET studies performed either to improve our understanding of the pathogenesis of HIV-1 infection or to assess the value of PET imaging in the clinical decision making of patients infected with HIV-1 presenting with AIDS-related opportunistic infections and malignancies. FDG PET has shown that HIV-1 infection progresses by distinct anatomical steps, with involvement of the upper torso preceding involvement of the lower part of the torso, and that the degree of FDG uptake relates to viral load. The former finding suggests that lymphoid tissues are engaged in a predictable sequence and that diffusible mediators of activation might be important targets for vaccine or therapeutic intervention strategies. In lipodystrophic HIV-infected patients, limited available data support the hypothesis that stavudine-related lipodystrophy is associated with increased glucose uptake by adipose tissue as a result of the metabolic stress of adipose tissue in response to highly active antiretroviral treatment (HAART). Finally, in early AIDS-related dementia complex (ADC), striatal hypermetabolism is observed, whereas progressive ADC is characterized by a decrease in subcortical and cortical metabolism. In the clinical setting, PET has been shown to allow the differentiation of AIDS-related opportunistic infections and malignancies, and to allow monitoring of side effects of HAART. However, in patients suffering from HIV infection and presenting with extracerebral lymphoma or other human malignancies, knowledge of viraemia is essential when interpreting FDG PET imaging. (orig.)

  16. Oligodendrocyte Injury and Pathogenesis of HIV-1-Associated Neurocognitive Disorders.

    Science.gov (United States)

    Liu, Han; Xu, Enquan; Liu, Jianuo; Xiong, Huangui

    2016-01-01

    Oligodendrocytes wrap neuronal axons to form myelin, an insulating sheath which is essential for nervous impulse conduction along axons. Axonal myelination is highly regulated by neuronal and astrocytic signals and the maintenance of myelin sheaths is a very complex process. Oligodendrocyte damage can cause axonal demyelination and neuronal injury, leading to neurological disorders. Demyelination in the cerebrum may produce cognitive impairment in a variety of neurological disorders, including human immunodeficiency virus type one (HIV-1)-associated neurocognitive disorders (HAND). Although the combined antiretroviral therapy has markedly reduced the incidence of HIV-1-associated dementia, a severe form of HAND, milder forms of HAND remain prevalent even when the peripheral viral load is well controlled. HAND manifests as a subcortical dementia with damage in the brain white matter (e.g., corpus callosum), which consists of myelinated axonal fibers. How HIV-1 brain infection causes myelin injury and resultant white matter damage is an interesting area of current HIV research. In this review, we tentatively address recent progress on oligodendrocyte dysregulation and HAND pathogenesis. PMID:27455335

  17. Targeting dendritic cells for improved HIV-1 vaccines.

    Science.gov (United States)

    Smed-Sörensen, Anna; Loré, Karin

    2013-01-01

    As dendritic cells (DCs) have the unique capacity to activate antigen-naive T cells they likely play a critical role in eliciting immune responses to vaccines. DCs are therefore being explored as attractive targets for vaccines, but understanding the interaction of DCs and clinically relevant vaccine antigens and adjuvants is a prerequisite. The HIV-1/AIDS epidemic continues to be a significant health problem, and despite intense research efforts over the past 30 years a protective vaccine has not yet been developed. A common challenge in vaccine design is to find a vaccine formulation that best shapes the immune response to protect against and/or control the given pathogen. Here, we discuss the importance of understanding the diversity, anatomical location and function of different human DC subsets in order to identify the optimal target cells for an HIV-1 vaccine. We review human DC interactions with some of the HIV-1 vaccine antigen delivery vehicles and adjuvants currently utilized in preclinical and clinical studies. Specifically, the effects of distinctly different vaccine adjuvants in terms of activation of DCs and improving DC function and vaccine efficacy are discussed. The susceptibility and responses of DCs to recombinant adenovirus vectors are reviewed, as well as the strategy of directly targeting DCs by using DC marker-specific monoclonal antibodies coupled to an antigen. PMID:22975879

  18. Positron emission tomography in patients suffering from HIV-1 infection

    International Nuclear Information System (INIS)

    This paper reviews currently available PET studies performed either to improve our understanding of the pathogenesis of HIV-1 infection or to assess the value of PET imaging in the clinical decision making of patients infected with HIV-1 presenting with AIDS-related opportunistic infections and malignancies. FDG PET has shown that HIV-1 infection progresses by distinct anatomical steps, with involvement of the upper torso preceding involvement of the lower part of the torso, and that the degree of FDG uptake relates to viral load. The former finding suggests that lymphoid tissues are engaged in a predictable sequence and that diffusible mediators of activation might be important targets for vaccine or therapeutic intervention strategies. In lipodystrophic HIV-infected patients, limited available data support the hypothesis that stavudine-related lipodystrophy is associated with increased glucose uptake by adipose tissue as a result of the metabolic stress of adipose tissue in response to highly active antiretroviral treatment (HAART). Finally, in early AIDS-related dementia complex (ADC), striatal hypermetabolism is observed, whereas progressive ADC is characterized by a decrease in subcortical and cortical metabolism. In the clinical setting, PET has been shown to allow the differentiation of AIDS-related opportunistic infections and malignancies, and to allow monitoring of side effects of HAART. However, in patients suffering from HIV infection and presenting with extracerebral lymphoma or other human malignancies, knowledge of viraemia is essential when interpreting FDG PET imaging. (orig.)

  19. TRIM5 and the Regulation of HIV-1 Infectivity

    Directory of Open Access Journals (Sweden)

    Jeremy Luban

    2012-01-01

    Full Text Available The past ten years have seen an explosion of information concerning host restriction factors that inhibit the replication of HIV-1 and other retroviruses. Among these factors is TRIM5, an innate immune signaling molecule that recognizes the capsid lattice as soon as the retrovirion core is released into the cytoplasm of otherwise susceptible target cells. Recognition of the capsid lattice has several consequences that include multimerization of TRIM5 into a complementary lattice, premature uncoating of the virion core, and activation of TRIM5 E3 ubiquitin ligase activity. Unattached, K63-linked ubiquitin chains are generated that activate the TAK1 kinase complex and downstream inflammatory mediators. Polymorphisms in the capsid recognition domain of TRIM5 explain the observed species-specific differences among orthologues and the relatively weak anti-HIV-1 activity of human TRIM5. Better understanding of the complex interaction between TRIM5 and the retrovirus capsid lattice may someday lead to exploitation of this interaction for the development of potent HIV-1 inhibitors.

  20. Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells.

    Directory of Open Access Journals (Sweden)

    Wilfried Posch

    2015-06-01

    Full Text Available DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection.

  1. Flap Conformations in HIV-1 Protease are Altered by Mutations

    Science.gov (United States)

    Fanucci, Gail; Blackburn, Mandy; Veloro, Angelo; Galiano, Luis; Fangu, Ding; Simmerling, Carlos

    2009-03-01

    HIV-1 protease (PR) is an enzyme that is a major drug target in the treatment of AIDS. Although the structure and function of HIV-1 PR have been studied for over 20 years, questions remain regarding the conformations and dynamics of the β-hairpin turns (flaps) that cover the active site cavity. Distance measurements with pulsed EPR spectroscopy of spin labeled constructs of HIV-1 PR have been used to characterize the flap conformations in the apo and inhibitor bound states. From the most probably distances and the breadth of the distance distribution profiles from analysis of the EPR data, insights regarding the flap conformations and flexibility are gained. The EPR results clearly show how drug pressure selected mutations alter the average conformation of the flaps and the degree of opening of the flaps. Molecular dynamics simulations successfully regenerate the experimentally determined distance distribution profiles, and more importantly, provide structural models for full interpretation of the EPR results. By combining experiment and theory to understand the role that altered flap flexibility/conformations play in the mechanism of drug resistance, key insights are gained toward the rational development of new inhibitors of this important enzyme.

  2. Characterization of the virus-cell interactions by HIV-1 subtype C variants from an antiretroviral therapy-naïve subject with baseline resistance to the CCR5 inhibitor maraviroc

    DEFF Research Database (Denmark)

    Jakobsen, Martin Roelsgaard

    The CCR5 inhibitor maraviroc (MVC) exerts its antiviral activity by binding to- and altering the conformation of the CCR5 extracellular loops such that HIV-1 gp120 no longer recognizes CCR5. Viruses that have become resistant to MVC through long-term in vitro culture, or from treatment failure...... in vivo, can use the MVCbound form of CCR5 for HIV-1 entry via adaptive alterations in gp120. Partial baseline resistance to another CCR5 inhibitor through this mechanism, AD101, has been noted recently in one subject (1). Here, we identified and characterized envelope (Env) clones with baseline...... related abstract by Jakobsen et al., “Preferential CCR5-usage by R5X4 subtype C HIV-1 imparts sensitivity to maraviroc and tempers disease progression”), nine subjects persistently harboured CCR5-using (R5) Envs to late stages of infection. Virus inhibition assays in NP2-CD4/CCR5 cells using Env...

  3. German-austrian recommendations for HIV1-therapy in pregnancy and in HIV1-exposed newborn - update 2008

    OpenAIRE

    Buchholz Bernd; Beichert Matthias; Marcus Ulrich; Grubert Thomas; Gingelmaier Andrea; Haberl Annette; Schmied Brigitte

    2009-01-01

    Abstract German-Austrian recommendations for HIV1-therapy in pregnancy - Update 2008 Bernd Buchholz (University Medical Centre Mannheim, Pediatric Clinic), Matthias Beichert (Mannheim, Gynecology and Obstetrics Practice), Ulrich Marcus (Robert Koch Institute, Berlin), Thomas Grubert, Andrea Gingelmaier (Gynecology Clinic of the Ludwig Maximilians University of Munich), Dr. med. Annette Haberl (HIV-Department, J. W. Goethe-University Hospital, Frankfurt), Dr. med. Brigitte Schmied (Otto-Wagner...

  4. Focus on Chirality of HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors

    Directory of Open Access Journals (Sweden)

    Valeria Famiglini

    2016-02-01

    Full Text Available Chiral HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs are of great interest since one enantiomer is often more potent than the corresponding counterpart against the HIV-1 wild type (WT and the HIV-1 drug resistant mutant strains. This review exemplifies the various studies made to investigate the effect of chirality on the antiretroviral activity of top HIV-1 NNRTI compounds, such as nevirapine (NVP, efavirenz (EFV, alkynyl- and alkenylquinazolinone DuPont compounds (DPC, diarylpyrimidine (DAPY, dihydroalkyloxybenzyloxopyrimidine (DABO, phenethylthiazolylthiourea (PETT, indolylarylsulfone (IAS, arylphosphoindole (API and trifluoromethylated indole (TFMI The chiral separation, the enantiosynthesis, along with the biological properties of these HIV-1 NNRTIs, are discussed.

  5. HIV-1 transmission during early antiretroviral therapy: evaluation of two HIV-1 transmission events in the HPTN 052 prevention study.

    Directory of Open Access Journals (Sweden)

    Li-Hua Ping

    Full Text Available In the HPTN 052 study, transmission between HIV-discordant couples was reduced by 96% when the HIV-infected partner received suppressive antiretroviral therapy (ART. We examined two transmission events where the newly infected partner was diagnosed after the HIV-infected partner (index initiated therapy. We evaluated the sequence complexity of the viral populations and antibody reactivity in the newly infected partner to estimate the dates of transmission to the newly infected partners. In both cases, transmission most likely occurred significantly before HIV-1 diagnosis of the newly infected partner, and either just before the initiation of therapy or before viral replication was adequately suppressed by therapy of the index. This study further strengthens the conclusion about the efficacy of blocking transmission by treating the infected partner of discordant couples. However, this study does not rule out the potential for HIV-1 transmission to occur shortly after initiation of ART, and this should be recognized when antiretroviral therapy is used for HIV-1 prevention.

  6. HIV-1潜伏感染及功能性治愈%HIV-1 Latency and Functional Cure

    Institute of Scientific and Technical Information of China (English)

    杨福春; 李川; 王建华

    2015-01-01

    尽管高效抗反转录病毒治疗(HAART)可有效控制艾滋病(AIDS)病人体内的艾滋病病毒1型(HIV-1)的复制,但却无法根除潜伏感染的病毒,这成为当前艾滋病治疗的主要难点之一.研究HIV-1在宿主细胞内建立和维持潜伏的分子细胞学机制,有助于发现新的抗病毒靶点和发展新的抗病毒治疗策略.近年来对HIV感染者/AIDS病人提出功能性治愈策略,相关的免疫或基因治疗手段被相继提出,部分策略已处于临床试验阶段.该文对HIV-1潜伏感染机制和功能性治愈相关研究进展进行简要综述.

  7. Single peptide and anti-idiotype based immunizations can broaden the antibody response against the variable V3 domain of HIV-1 in mice.

    Science.gov (United States)

    Boudet, F; Keller, H; Kieny, M P; Thèze, J

    1995-05-01

    The third variable (V3) domain of the human immunodeficiency virus type 1 (HIV-1) external envelope glycoprotein gp120 is a major target of neutralizing antibodies in infected persons and in experimental immunized animals. Given the high degree of sequence variability of V3, the humoral response toward this region is very type-specific. In the present study, we evaluated the potential of a single peptide and an anti-idiotypic antibody to broaden the anti-V3 antibody specificity in BALB/c mice. We show that a synthetic peptide derived from the V3 determinant of HIV-1 MN isolate (V3MN), when used as an immunogen, was able to induce an antibody response to multiple (up to six) HIV-1 strains. The extent of this cross-reactivity, which tended to enlarge as the injections increased, appeared to be inversely correlated with the binding affinity to V3MN peptide. These data thus present evidence that, despite its great sequence heterogeneity, the V3 loop encompasses conserved amino-acid positions and/or stretches which may be less immunogenic than their variable counterparts. We additionally demonstrate that a rabbit anti-idiotype (Ab2), recognizing a binding site related idiotype on a V3-specific mouse monoclonal antibody (Ab1), could mount a broadened humoral response (Ab3) in mice. Unlike nominal antibody Ab1 which strictly reacted with the European HIV-1 LAI isolate, elicited Ab3 recognized the two divergent HIV-1 strains SF2 and 1286, originating respectively from North America and Central Africa, in addition to LAI. The reasons accounting for this Ab2-induced enlargement of the V3 antibody response are discussed. Our findings suggest that single peptide and anti-idiotype based immunizations may provide viable approaches to overcome, at least in part, HIV epitope variability. PMID:7783749

  8. Down-regulation of HIV-1 Infection by Inhibition of the MAPK Signaling Pathway

    Institute of Scientific and Technical Information of China (English)

    Jian Gong; Xi-hui Shen; Chao Chen; Hui Qiu; Rong-ge Yang

    2011-01-01

    The human immunodeficiency virus type 1(HIV-1)can interact with and exploit the host cellular machinery to replicate and propagate itself.Numerous studies have shown that the Mitogen-activated protein kinase(MAPK)signal pathway can positively regulate the replication of HIV-1,but exactly how each MAPK pathway affects HIV-1 infection and replication is not understood.In this study,we used the Extracellular signal-regulated kinase(ERK)pathway inhibitor,PD98059,the Jun N-terminal kinase(JNK)pathway inhibitor,SP600125,and the p38 pathway inhibitor,SB203580,to investigate the roles of these pathways in HIV-1replication.We found that application of PD98059 results in a strong VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus and HIV-1NL4-3 virus inhibition activity.In addition,SB203580 and SP600125 also elicited marked VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus inhibition activity but no HIV-1NL4-3 virus inhibition activity.We also found that SB203580 and SP600125 can enhance the HIV-1 inhibition activity of PD98059when cells were treated with all three MAPK pathway inhibitors in combination.Finally,we show that HIV-1virus inhibition activity of the MAPK pathway inhibitors was the result of the negative regulation of HIV-1 LTR promoter activity.

  9. Sargassum fusiforme fraction is a potent and specific inhibitor of HIV-1 fusion and reverse transcriptase

    Directory of Open Access Journals (Sweden)

    Thornber Carol

    2008-01-01

    Full Text Available Abstract Sargassum fusiforme (Harvey Setchell has been shown to be a highly effective inhibitor of HIV-1 infection. To identify its mechanism of action, we performed bioactivity-guided fractionation on Sargassum fusiforme mixture. Here, we report isolation of a bioactive fraction SP4-2 (S. fusiforme, which at 8 μg/ml inhibited HIV-1 infection by 86.9%, with IC50 value of 3.7 μg. That represents 230-fold enhancement of antiretroviral potency as compared to the whole extract. Inhibition was mediated against both CXCR4 (X4 and CCR5 (R5 tropic HIV-1. Specifically, 10 μg/ml SP4-2 blocked HIV-1 fusion and entry by 53%. This effect was reversed by interaction of SP4-2 with sCD4, suggesting that S. fusiforme inhibits HIV-1 infection by blocking CD4 receptor, which also explained observed inhibition of both X4 and R5-tropic HIV-1. SP4-2 also inhibited HIV-1 replication after virus entry, by directly inhibiting HIV-1 reverse transcriptase (RT in a dose dependent manner by up to 79%. We conclude that the SP4-2 fraction contains at least two distinct and biologically active molecules, one that inhibits HIV-1 fusion by interacting with CD4 receptor, and another that directly inhibits HIV-1 RT. We propose that S. fusiforme is a lead candidate for anti-HIV-1 drug development.

  10. In vivo functions of CPSF6 for HIV-1 as revealed by HIV-1 capsid evolution in HLA-B27-positive subjects.

    Directory of Open Access Journals (Sweden)

    Matthew S Henning

    2014-01-01

    Full Text Available The host protein CPSF6 possesses a domain that can interact with the HIV-1 capsid (CA protein. CPSF6 has been implicated in regulating HIV-1 nuclear entry. However, its functional significance for HIV-1 replication has yet to be firmly established. Here we provide evidence for two divergent functions of CPSF6 for HIV-1 replication in vivo. We demonstrate that endogenous CPSF6 exerts an inhibitory effect on naturally occurring HIV-1 variants in individuals carrying the HLA-B27 allele. Conversely, we find a strong selective pressure in these individuals to preserve CPSF6 binding, while escaping from the restrictive activity by CPSF6. This active maintenance of CPSF6 binding during HIV-1 CA evolution in vivo contrasts with the in vitro viral evolution, which can reduce CPSF6 binding to evade from CPSF6-mediated restriction. Thus, these observations argue for a beneficial role of CPSF6 for HIV-1 in vivo. CPSF6-mediated restriction renders HIV-1 less dependent or independent from TNPO3, RanBP2 and Nup153, host factors implicated in HIV-1 nuclear entry. However, viral evolution that maintains CPSF6 binding in HLA-B27+ subjects invariably restores the ability to utilize these host factors, which may be the major selective pressure for CPSF6 binding in vivo. Our study uncovers two opposing CA-dependent functions of CPSF6 in HIV-1 replication in vivo; however, the benefit for binding CPSF6 appears to outweigh the cost, providing support for a vital function of CPSF6 during HIV-1 replication in vivo.

  11. Viral escape from HIV-1 neutralizing antibodies drives increased plasma neutralization breadth through sequential recognition of multiple epitopes and immunotypes.

    Directory of Open Access Journals (Sweden)

    Constantinos Kurt Wibmer

    2013-10-01

    Full Text Available Identifying the targets of broadly neutralizing antibodies to HIV-1 and understanding how these antibodies develop remain important goals in the quest to rationally develop an HIV-1 vaccine. We previously identified a participant in the CAPRISA Acute Infection Cohort (CAP257 whose plasma neutralized 84% of heterologous viruses. In this study we showed that breadth in CAP257 was largely due to the sequential, transient appearance of three distinct broadly neutralizing antibody specificities spanning the first 4.5 years of infection. The first specificity targeted an epitope in the V2 region of gp120 that was also recognized by strain-specific antibodies 7 weeks earlier. Specificity for the autologous virus was determined largely by a rare N167 antigenic variant of V2, with viral escape to the more common D167 immunotype coinciding with the development of the first wave of broadly neutralizing antibodies. Escape from these broadly neutralizing V2 antibodies through deletion of the glycan at N160 was associated with exposure of an epitope in the CD4 binding site that became the target for a second wave of broadly neutralizing antibodies. Neutralization by these CD4 binding site antibodies was almost entirely dependent on the glycan at position N276. Early viral escape mutations in the CD4 binding site drove an increase in wave two neutralization breadth, as this second wave of heterologous neutralization matured to recognize multiple immunotypes within this site. The third wave targeted a quaternary epitope that did not overlap any of the four known sites of vulnerability on the HIV-1 envelope and remains undefined. Altogether this study showed that the human immune system is capable of generating multiple broadly neutralizing antibodies in response to a constantly evolving viral population that exposes new targets as a consequence of escape from earlier neutralizing antibodies.

  12. Decreased HIV diversity after allogeneic stem cell transplantation of an HIV-1 infected patient: a case report

    Directory of Open Access Journals (Sweden)

    Thielen Alexander

    2010-03-01

    Full Text Available Abstract The human immunodeficiency virus type 1 (HIV-1 coreceptor use and viral evolution were analyzed in blood samples from an HIV-1 infected patient undergoing allogeneic stem cell transplantation (SCT. Coreceptor use was predicted in silico from sequence data obtained from the third variable loop region of the viral envelope gene with two software tools. Viral diversity and evolution was evaluated on the same samples by Bayesian inference and maximum likelihood methods. In addition, phenotypic analysis was done by comparison of viral growth in peripheral blood mononuclear cells and in a CCR5 (R5-deficient T-cell line which was controlled by a reporter assay confirming viral tropism. In silico coreceptor predictions did not match experimental determinations that showed a consistent R5 tropism. Anti-HIV directed antibodies could be detected before and after the SCT. These preexisting antibodies did not prevent viral rebound after the interruption of antiretroviral therapy during the SCT. Eventually, transplantation and readministration of anti-retroviral drugs lead to sustained increase in CD4 counts and decreased viral load to undetectable levels. Unexpectedly, viral diversity decreased after successful SCT. Our data evidence that only R5-tropic virus was found in the patient before and after transplantation. Therefore, blocking CCR5 receptor during stem cell transplantation might have had beneficial effects and this might apply to more patients undergoing allogeneic stem cell transplantation. Furthermore, we revealed a scenario of HIV-1 dynamic different from the commonly described ones. Analysis of viral evolution shows the decrease of viral diversity even during episodes with bursts in viral load.

  13. Biophysical Characterization of a Vaccine Candidate against HIV-1: The Transmembrane and Membrane Proximal Domains of HIV-1 gp41 as a Maltose Binding Protein Fusion.

    Directory of Open Access Journals (Sweden)

    Zhen Gong

    Full Text Available The membrane proximal region (MPR, residues 649-683 and transmembrane domain (TMD, residues 684-705 of the gp41 subunit of HIV-1's envelope protein are highly conserved and are important in viral mucosal transmission, virus attachment and membrane fusion with target cells. Several structures of the trimeric membrane proximal external region (residues 662-683 of MPR have been reported at the atomic level; however, the atomic structure of the TMD still remains unknown. To elucidate the structure of both MPR and TMD, we expressed the region spanning both domains, MPR-TM (residues 649-705, in Escherichia coli as a fusion protein with maltose binding protein (MBP. MPR-TM was initially fused to the C-terminus of MBP via a 42 aa-long linker containing a TEV protease recognition site (MBP-linker-MPR-TM. Biophysical characterization indicated that the purified MBP-linker-MPR-TM protein was a monodisperse and stable candidate for crystallization. However, crystals of the MBP-linker-MPR-TM protein could not be obtained in extensive crystallization screens. It is possible that the 42 residue-long linker between MBP and MPR-TM was interfering with crystal formation. To test this hypothesis, the 42 residue-long linker was replaced with three alanine residues. The fusion protein, MBP-AAA-MPR-TM, was similarly purified and characterized. Significantly, both the MBP-linker-MPR-TM and MBP-AAA-MPR-TM proteins strongly interacted with broadly neutralizing monoclonal antibodies 2F5 and 4E10. With epitopes accessible to the broadly neutralizing antibodies, these MBP/MPR-TM recombinant proteins may be in immunologically relevant conformations that mimic a pre-hairpin intermediate of gp41.

  14. Antibodies to a conformational epitope on gp41 neutralize HIV-1 by destabilizing the Env spike

    Science.gov (United States)

    Lee, Jeong Hyun; Leaman, Daniel P.; Kim, Arthur S.; Torrents de La Peña, Alba; Sliepen, Kwinten; Yasmeen, Anila; Derking, Ronald; Ramos, Alejandra; de Taeye, Steven W.; Ozorowski, Gabriel; Klein, Florian; Burton, Dennis R.; Nussenzweig, Michel C.; Poignard, Pascal; Moore, John P.; Klasse, Per Johan; Sanders, Rogier W.; Zwick, Michael B.; Wilson, Ian A.; Ward, Andrew B.

    2015-09-01

    The recent identification of three broadly neutralizing antibodies (bnAbs) against gp120-gp41 interface epitopes has expanded the targetable surface on the HIV-1 envelope glycoprotein (Env) trimer. By using biochemical, biophysical and computational methods, we map the previously unknown trimer epitopes of two related antibodies, 3BC315 and 3BC176. A cryo-EM reconstruction of a soluble Env trimer bound to 3BC315 Fab at 9.3 Å resolution reveals that the antibody binds between two gp41 protomers, and neutralizes the virus by accelerating trimer decay. In contrast, bnAb 35O22 binding to a partially overlapping quaternary epitope at the gp120-gp41 interface does not induce decay. A conserved gp41-proximal glycan at N88 was also shown to play a role in the binding kinetics of 3BC176 and 3BC315. Finally, our data suggest that the dynamic structure of the Env trimer influences exposure of bnAb epitopes.

  15. The gp41659 - 671 HIV-1 antibody epitope: a structurally challenging small peptide

    Science.gov (United States)

    Zhang, Yuan; Sagui, Celeste

    2014-03-01

    We present the results of extensive Molecular Dynamics (MD) simulations of the tridecapeptide corresponding to residues 659-671 of the envelope glycoprotein gp41 of HIV-1, which spans the 2F5 monoclonal antibody epitope ELDKWA. The most recent AMBER force fields ff99SB and ff12SB in both implicit and explicit solvents have been used for a cumulative time longer than 7.2 μs . We have analyzed the conformational ensembles of the peptide both with and without applied tensile restraints, and found that: (1) The amount of helical populations is important in aqueous solution, but this structure forms part of a flexible conformational ensemble with a rugged free energy landscape with shallow minima, which agrees well with the bulk of the experimental observations; (2) our results are more consistent with the experimental results than those from previous simulations; (3) under uniaxial tension, the disordered peptide first becomes fully helical before melting into turns, loops and 310-helices.

  16. HIV-1 RNAs are Not Part of the Argonaute 2 Associated RNA Interference Pathway in Macrophages.

    Directory of Open Access Journals (Sweden)

    Valentina Vongrad

    Full Text Available MiRNAs and other small noncoding RNAs (sncRNAs are key players in post-transcriptional gene regulation. HIV-1 derived small noncoding RNAs (sncRNAs have been described in HIV-1 infected cells, but their biological functions still remain to be elucidated. Here, we approached the question whether viral sncRNAs may play a role in the RNA interference (RNAi pathway or whether viral mRNAs are targeted by cellular miRNAs in human monocyte derived macrophages (MDM.The incorporation of viral sncRNAs and/or their target RNAs into RNA-induced silencing complex was investigated using photoactivatable ribonucleoside-induced cross-linking and immunoprecipitation (PAR-CLIP as well as high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation (HITS-CLIP, which capture Argonaute2-bound miRNAs and their target RNAs. HIV-1 infected monocyte-derived macrophages (MDM were chosen as target cells, as they have previously been shown to express HIV-1 sncRNAs. In addition, we applied small RNA deep sequencing to study differential cellular miRNA expression in HIV-1 infected versus non-infected MDMs.PAR-CLIP and HITS-CLIP data demonstrated the absence of HIV-1 RNAs in Ago2-RISC, although the presence of a multitude of HIV-1 sncRNAs in HIV-1 infected MDMs was confirmed by small RNA sequencing. Small RNA sequencing revealed that 1.4% of all sncRNAs were of HIV-1 origin. However, neither HIV-1 derived sncRNAs nor putative HIV-1 target sequences incorporated into Ago2-RISC were identified suggesting that HIV-1 sncRNAs are not involved in the canonical RNAi pathway nor is HIV-1 targeted by this pathway in HIV-1 infected macrophages.

  17. Broad and potent HIV-1 neutralization by a human antibody that binds the gp41-gp120 interface

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jinghe; Kang, Byong H.; Pancera, Marie; Lee, Jeong Hyun; Tong, Tommy; Feng, Yu; Imamichi, Hiromi; Georgiev, Ivelin S.; Chuang, Gwo-Yu; Druz, Aliaksandr; Doria-Rose, Nicole A.; Laub, Leo; Sliepen, Kwinten; van Gils, Marit J.; de la Peña, Alba Torrents; Derking, Ronald; Klasse, Per-Johan; Migueles, Stephen A.; Bailer, Robert T.; Alam, Munir; Pugach, Pavel; Haynes, Barton F.; Wyatt, Richard T.; Sanders, Rogier W.; Binley, James M.; Ward, Andrew B.; Mascola, John R.; Kwong, Peter D.; Connors, Mark [NIH

    2015-10-15

    The isolation of human monoclonal antibodies is providing important insights into the specificities that underlie broad neutralization of HIV-1 (reviewed in ref. 1). Here we report a broad and extremely potent HIV-specific monoclonal antibody, termed 35O22, which binds a novel HIV-1 envelope glycoprotein (Env) epitope. 35O22 neutralized 62% of 181 pseudoviruses with a half-maximum inhibitory concentration (IC50) <50 μg ml-1. The median IC50 of neutralized viruses was 0.033 μg ml-1, among the most potent thus far described. 35O22 did not bind monomeric forms of Env tested, but did bind the trimeric BG505 SOSIP.664. Mutagenesis and a reconstruction by negative-stain electron microscopy of the Fab in complex with trimer revealed that it bound to a conserved epitope, which stretched across gp120 and gp41. The specificity of 35O22 represents a novel site of vulnerability on HIV Env, which serum analysis indicates to be commonly elicited by natural infection. Binding to this new site of vulnerability may thus be an important complement to current monoclonal-antibody-based approaches to immunotherapies, prophylaxis and vaccine design.

  18. Broad and potent HIV-1 neutralization by a human antibody that binds the gp41-120 interface

    Science.gov (United States)

    Huang, Jinghe; Kang, Byong H.; Pancera, Marie; Lee, Jeong Hyun; Tong, Tommy; Feng, Yu; Georgiev, Ivelin S.; Chuang, Gwo-Yu; Druz, Aliaksandr; Doria-Rose, Nicole A.; Laub, Leo; Sliepen, Kwinten; van Gils, Marit J.; de la Peña, Alba Torrents; Derking, Ronald; Klasse, Per-Johan; Migueles, Stephen A.; Bailer, Robert T.; Alam, Munir; Pugach, Pavel; Haynes, Barton F.; Wyatt, Richard T.; Sanders, Rogier W.; Binley, James M.; Ward, Andrew B.; Mascola, John R.; Kwong, Peter D.; Connors, Mark

    2014-01-01

    The isolation of human monoclonal antibodies (mAbs) is providing important insights regarding the specificities that underlie broad neutralization of HIV-1 (reviewed in1). Here we report a broad and extremely potent HIV-specific mAb, termed 35O22, which binds novel HIV-1 envelope glycoprotein (Env) epitope. 35O22 neutralized 62% of 181 pseudoviruses with an IC50<50 μg/ml. The median IC50 of neutralized viruses was 0.033 μg/ml, among the most potent thus far described. 35O22 did not bind monomeric forms of Env tested, but did bind the trimeric BG505 SOSIP.664. Mutagenesis and a reconstruction by negative-stain electron microscopy of the Fab in complex with trimer revealed it to bind a conserved epitope, which stretched across gp120 and gp41. The specificity of 35O22 represents a novel site of vulnerability on HIV Env, which serum analysis indicates to be commonly elicited by natural infection. Binding to this new site of vulnerability may thus be an important complement to current mAb-based approaches to immunotherapies, prophylaxis, and vaccine design. PMID:25186731

  19. Broad and potent HIV-1 neutralization by a human antibody that binds the gp41-gp120 interface.

    Science.gov (United States)

    Huang, Jinghe; Kang, Byong H; Pancera, Marie; Lee, Jeong Hyun; Tong, Tommy; Feng, Yu; Imamichi, Hiromi; Georgiev, Ivelin S; Chuang, Gwo-Yu; Druz, Aliaksandr; Doria-Rose, Nicole A; Laub, Leo; Sliepen, Kwinten; van Gils, Marit J; de la Peña, Alba Torrents; Derking, Ronald; Klasse, Per-Johan; Migueles, Stephen A; Bailer, Robert T; Alam, Munir; Pugach, Pavel; Haynes, Barton F; Wyatt, Richard T; Sanders, Rogier W; Binley, James M; Ward, Andrew B; Mascola, John R; Kwong, Peter D; Connors, Mark

    2014-11-01

    The isolation of human monoclonal antibodies is providing important insights into the specificities that underlie broad neutralization of HIV-1 (reviewed in ref. 1). Here we report a broad and extremely potent HIV-specific monoclonal antibody, termed 35O22, which binds a novel HIV-1 envelope glycoprotein (Env) epitope. 35O22 neutralized 62% of 181 pseudoviruses with a half-maximum inhibitory concentration (IC50) <50 μg ml(-1). The median IC50 of neutralized viruses was 0.033 μg ml(-1), among the most potent thus far described. 35O22 did not bind monomeric forms of Env tested, but did bind the trimeric BG505 SOSIP.664. Mutagenesis and a reconstruction by negative-stain electron microscopy of the Fab in complex with trimer revealed that it bound to a conserved epitope, which stretched across gp120 and gp41. The specificity of 35O22 represents a novel site of vulnerability on HIV Env, which serum analysis indicates to be commonly elicited by natural infection. Binding to this new site of vulnerability may thus be an important complement to current monoclonal-antibody-based approaches to immunotherapies, prophylaxis and vaccine design. PMID:25186731

  20. Predefined GPGRAFY-Epitope-Specific Monoclonal Antibodies with Different Activities for Recognizing Native HIV-1 gp120

    Institute of Scientific and Technical Information of China (English)

    蓝灿辉; 田海军; 陈应华

    2004-01-01

    A seven-amino acid epitope GPGRAFY at the tip of the V3 loop in HIV-1 gp120 is the principal neutralizing epitope,and a subset of anti-V3 antibodies specific for this epitope shows a broad range of neutralizing activity.GPGRAFY-epitope-specific neutralizing antibodies were produced using predefined GPGRAFY-epitope-specific peptides instead of a natural or recombinant gp120 bearing this epitope.All six monoclonal antibodies (mAbs) could recognize the GPGRAFY-epitope on peptides and two of the antibodies,9D8 and 2D7,could recognize recombinant gp120 in enzymelinked immunosorkentassy (ELISA) assays.In the flow cytometry analysis,the mAbs 9D8 and 2D7 could bind to HIV-Env+ CHO-WT cells and the specific bindings could be inhibited by the GPGRAFY-epitope peptide,which suggests that these two mAbs could recognize the native envelope protein gp120 expressed on the cell membrane.However,in syncytium assays,none of the mAbs was capable of inhibiting HIV-Env-mediated cell membrane fusion.The different activities for recognizing native HIV-1 gp120 might be associated with different antibody affinities against the epitopes.The development of conformational mimics of the neutralization epitope in the gp120 V3 loop could elicit neutralizing mAbs with high affinity.

  1. Modeling HIV-1 Induced Neuroinflammation in Mice: Role of Platelets in Mediating Blood-Brain Barrier Dysfunction.

    Science.gov (United States)

    Jones, Letitia D; Jackson, Joseph W; Maggirwar, Sanjay B

    2016-01-01

    The number of HIV-1 positive individuals developing some form of HIV-associated neurocognitive disorder (HAND) is increasing. In these individuals, the integrity of the blood-brain barrier (BBB) is compromised due to an increase in exposure to pro-inflammatory mediators, viral proteins, and virus released from infected cells. It has been shown that soluble CD40L (sCD40L) is released upon platelet activation and is an important mediator of the pathogenesis of HAND but the underlying mechanisms are unclear, emphasizing the need of an effective animal model. Here, we have utilized a novel animal model in which wild-type (WT) mice were infected with EcoHIV; a derivative of HIV-1 that contains a substitution of envelope protein gp120 with that of gp80 derived from murine leukemia virus-1 (MuLV-1). As early as two-weeks post-infection, EcoHIV led to increased permeability of the BBB associated with decreased expression of tight junction protein claudin-5, in CD40L and platelet activation-dependent manner. Treatment with an antiplatelet drug, eptifibatide, in EcoHIV-infected mice normalized BBB function, sCD40L release and platelet activity, thus implicating platelet activation and platelet-derived CD40L in virally induced BBB dysfunction. Our results also validate and underscore the importance of EcoHIV infection mouse model as a tool to explore therapeutic targets for HAND.

  2. Modeling HIV-1 Induced Neuroinflammation in Mice: Role of Platelets in Mediating Blood-Brain Barrier Dysfunction.

    Directory of Open Access Journals (Sweden)

    Letitia D Jones

    Full Text Available The number of HIV-1 positive individuals developing some form of HIV-associated neurocognitive disorder (HAND is increasing. In these individuals, the integrity of the blood-brain barrier (BBB is compromised due to an increase in exposure to pro-inflammatory mediators, viral proteins, and virus released from infected cells. It has been shown that soluble CD40L (sCD40L is released upon platelet activation and is an important mediator of the pathogenesis of HAND but the underlying mechanisms are unclear, emphasizing the need of an effective animal model. Here, we have utilized a novel animal model in which wild-type (WT mice were infected with EcoHIV; a derivative of HIV-1 that contains a substitution of envelope protein gp120 with that of gp80 derived from murine leukemia virus-1 (MuLV-1. As early as two-weeks post-infection, EcoHIV led to increased permeability of the BBB associated with decreased expression of tight junction protein claudin-5, in CD40L and platelet activation-dependent manner. Treatment with an antiplatelet drug, eptifibatide, in EcoHIV-infected mice normalized BBB function, sCD40L release and platelet activity, thus implicating platelet activation and platelet-derived CD40L in virally induced BBB dysfunction. Our results also validate and underscore the importance of EcoHIV infection mouse model as a tool to explore therapeutic targets for HAND.

  3. Computer-based design of novel HIV-1 entry inhibitors: neomycin conjugated to arginine peptides at two specific sites.

    Science.gov (United States)

    Berchanski, Alexander; Lapidot, Aviva

    2009-03-01

    Aminoglycoside-arginine conjugates (AAC and APAC) are multi-target inhibitors of human immunodeficiency virus type-1 (HIV-1). Here, we predict new conjugates of neomycin with two arginine peptide chains binding at specific sites on neomycin [poly-arginine-neomycin-poly-arginine (PA-Neo-PA)]. The rationale for the design of such compounds is to separate two short arginine peptides with neomycin, which may extend the binding region of the CXC chemokine receptor type 4 (CXCR4). We used homology models of CXCR4 and unliganded envelope glycoprotein 120 (HIV-1(IIIB) gp120) and docked PA-Neo-PAs and APACs to these using a multistep docking procedure. The results indicate that PA-Neo-PAs spread over two negatively charged patches of CXCR4. PA-Neo-PA-CXCR4 complexes are energetically more favorable than AACs/APAC-CXCR4 complexes. Notably, our CXCR4 model and docking procedure can be applied to predict new compounds that are either inhibitors of gp120-CXCR4 binding without affecting stromal cell-derived factor 1 alpha (SDF-1 alpha) chemotaxis activity, or inhibitors of SDF-1 alpha-CXCR4 binding resulting in an anti-metastasis effect. We also predict that PA-Neo-PAs and APACs can interfere with CD4-gp120 binding in unliganded conformation.

  4. Structure of HIV-1 gp120 V1/V2 domain with broadly neutralizing antibody PG9

    Energy Technology Data Exchange (ETDEWEB)

    McLellan, Jason S.; Pancera, Marie; Carrico, Chris; Gorman, Jason; Julien, Jean-Philippe; Khayat, Reza; Louder, Robert; Pejchal, Robert; Sastry, Mallika; Dai, Kaifan; O’Dell, Sijy; Patel, Nikita; Shahzad-ul-Hussan, Syed; Yang, Yongping; Zhang, Baoshan; Zhou, Tongqing; Zhu, Jiang; Boyington, Jeffrey C.; Chuang, Gwo-Yu; Diwanji, Devan; Georgiev, Ivelin; Kwon, Young Do; Lee, Doyung; Louder, Mark K.; Moquin, Stephanie; Schmidt, Stephen D.; Yang, Zhi-Yong; Bonsignori, Mattia; Crump, John A.; Kapiga, Saidi H.; Sam, Noel E.; Haynes, Barton F.; Burton, Dennis R.; Koff, Wayne C.; Walker, Laura M.; Phogat, Sanjay; Wyatt, Richard; Orwenyo, Jared; Wang, Lai-Xi; Arthos, James; Bewley, Carole A.; Mascola, John R.; Nabel, Gary J.; Schief, William R.; Ward, Andrew B.; Wilson, Ian A.; Kwong, Peter D. (UWASH); (NIH); (Scripps); (Duke); (IAVI); (Maryland-MED)

    2012-12-13

    Variable regions 1 and 2 (V1/V2) of human immunodeficiency virus-1 (HIV-1) gp120 envelope glycoprotein are critical for viral evasion of antibody neutralization, and are themselves protected by extraordinary sequence diversity and N-linked glycosylation. Human antibodies such as PG9 nonetheless engage V1/V2 and neutralize 80% of HIV-1 isolates. Here we report the structure of V1/V2 in complex with PG9. V1/V2 forms a four-stranded {beta}-sheet domain, in which sequence diversity and glycosylation are largely segregated to strand-connecting loops. PG9 recognition involves electrostatic, sequence-independent and glycan interactions: the latter account for over half the interactive surface but are of sufficiently weak affinity to avoid autoreactivity. The structures of V1/V2-directed antibodies CH04 and PGT145 indicate that they share a common mode of glycan penetration by extended anionic loops. In addition to structurally defining V1/V2, the results thus identify a paradigm of antibody recognition for highly glycosylated antigens, which - with PG9 - involves a site of vulnerability comprising just two glycans and a strand.

  5. Optimization of the Solubility of HIV-1-Neutralizing Antibody 10E8 through Somatic Variation and Structure-Based Design

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Young D.; Georgiev, Ivelin S.; Ofek, Gilad; Zhang, Baoshan; Asokan, Mangaiarkarasi; Bailer, Robert T.; Bao, Amy; Caruso, William; Chen, Xuejun; Choe, Misook; Druz, Aliaksandr; Ko, Sung-Youl; Louder, Mark K.; McKee, Krisha; O' Dell, Sijy; Pegu, Amarendra; Rudicell, Rebecca S.; Shi, Wei; Wang, Keyun; Yang, Yongping; Alger, Mandy; Bender, Michael F.; Carlton, Kevin; Cooper, Jonathan W.; Blinn, Julie; Eudailey, Joshua; Lloyd, Krissey; Parks, Robert; Alam, S. Munir; Haynes, Barton F.; Padte, Neal N.; Yu, Jian; Ho, David D.; Huang, Jinghe; Connors, Mark; Schwartz, Richard M.; Mascola, John R.; Kwong, Peter D.; Sundquist, W. I.

    2016-04-06

    ABSTRACT

    Extraordinary antibodies capable of near pan-neutralization of HIV-1 have been identified. One of the broadest is antibody 10E8, which recognizes the membrane-proximal external region (MPER) of the HIV-1 envelope and neutralizes >95% of circulating HIV-1 strains. If delivered passively, 10E8 might serve to prevent or treat HIV-1 infection. Antibody 10E8, however, is markedly less soluble than other antibodies. Here, we describe the use of both structural biology and somatic variation to develop optimized versions of 10E8 with increased solubility. From the structure of 10E8, we identified a prominent hydrophobic patch; reversion of four hydrophobic residues in this patch to their hydrophilic germ line counterparts resulted in an ~10-fold decrease in turbidity. We also used somatic variants of 10E8, identified previously by next-generation sequencing, to optimize heavy and light chains; this process yielded several improved variants. Of these, variant 10E8v4 with 26 changes versus the parent 10E8 was the most soluble, with a paratope we showed crystallographically to be virtually identical to that of 10E8, a potency on a panel of 200 HIV-1 isolates also similar to that of 10E8, and a half-life in rhesus macaques of ~10 days. An anomaly in 10E8v4 size exclusion chromatography that appeared to be related to conformational isomerization was resolved by engineering an interchain disulfide. Thus, by combining a structure-based approach with natural variation in potency and solubility from the 10E8 lineage, we successfully created variants of 10E8 which retained the potency and extraordinary neutralization breadth of the parent 10E8 but with substantially increased solubility.

    IMPORTANCE Antibody 10E8 could be used to prevent HIV-1 infection, if manufactured and delivered economically. It suffers, however, from issues of solubility, which impede manufacturing. We hypothesized that the physical characteristic of 10E8 could be

  6. Neutralizing Antibody Response and Antibody-Dependent Cellular Cytotoxicity in HIV-1-Infected Individuals from Guinea-Bissau and Denmark

    DEFF Research Database (Denmark)

    Borggren, Marie; Jensen, Sanne Skov; Heyndrickx, Leo;

    2016-01-01

    The development of therapeutic and prophylactic HIV vaccines for African countries is urgently needed, but the question of what immunogens to use needs to be answered. One approach is to include HIV envelope immunogens derived from HIV-positive individuals from a geographically concentrated...... epidemic with more limited viral genetic diversity for a region-based vaccine. To address if there is a basis for a regional selected antibody vaccine, we have screened two regionally separate cohorts from Guinea-Bissau and Denmark for neutralizing antibody activity and antibody-dependent cellular...... cytotoxicity (ADCC) against local and nonlocal circulating HIV-1 strains. The neutralizing activity did not demonstrate higher potential against local circulating strains according to geography and subtype determination, but the plasma from Danish individuals demonstrated significantly higher inhibitory...

  7. Envelopes of Commutative Rings

    Institute of Scientific and Technical Information of China (English)

    Rafael PARRA; Manuel SAOR(I)N

    2012-01-01

    Given a significative class F of commutative rings,we study the precise conditions under which a commutative ring R has an F-envelope.A full answer is obtained when.F is the class of fields,semisimple commutative rings or integral domains.When F is the class of Noetherian rings,we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic.The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope,which we conjecture is the empty class.

  8. Generation of HIV-1 and Internal Control Transcripts as Standards for an In-House Quantitative Competitive RT-PCR Assay to Determine HIV-1 Viral Load

    Directory of Open Access Journals (Sweden)

    Anny Armas Cayarga

    2011-01-01

    Full Text Available Human immunodeficiency virus type-1 (HIV-1 viral load is useful for monitoring disease progression in HIV-infected individuals. We generated RNA standards of HIV-1 and internal control (IC by in vitro transcription and evaluated its performance in a quantitative reverse transcription polymerase chain reaction (qRT-PCR assay. HIV-1 and IC standards were obtained at high RNA concentrations, without DNA contamination. When these transcripts were included as standards in a qRT-PCR assay, it was obtained a good accuracy (±0.5 log10 unit of the expected results in the quantification of the HIV-1 RNA international standard and controls. The lower limit detection achieved using these standards was 511.0 IU/mL. A high correlation (=0.925 was obtained between the in-house qRT-PCR assay and the NucliSens easyQ HIV-1 test (bioMerieux for HIV-1 RNA quantitation with clinical samples (=14. HIV-1 and IC RNA transcripts, generated in this study, proved to be useful as standards in an in-house qRT-PCR assay for determination of HIV-1 viral load.

  9. Cocaine enhances HIV-1-induced CD4(+) T-cell apoptosis: implications in disease progression in cocaine-abusing HIV-1 patients.

    Science.gov (United States)

    Pandhare, Jui; Addai, Amma B; Mantri, Chinmay K; Hager, Cynthia; Smith, Rita M; Barnett, Louis; Villalta, Fernando; Kalams, Spyros A; Dash, Chandravanu

    2014-04-01

    Substance abuse is a major barrier in eradication of the HIV epidemic because it serves as a powerful cofactor for viral transmission, disease progression, and AIDS-related mortality. Cocaine, one of the commonly abused drugs among HIV-1 patients, has been suggested to accelerate HIV disease progression. However, the underlying mechanism remains largely unknown. Therefore, we tested whether cocaine augments HIV-1-associated CD4(+) T-cell decline, a predictor of HIV disease progression. We examined apoptosis of resting CD4(+) T cells from HIV-1-negative and HIV-1-positive donors in our study, because decline of uninfected cells plays a major role in HIV-1 disease progression. Treatment of resting CD4(+) T cells with cocaine (up to 100 μmol/L concentrations) did not induce apoptosis, but 200 to 1000 μmol/L cocaine induced apoptosis in a dose-dependent manner. Notably, treatment of CD4(+) T cells isolated from healthy donors with both HIV-1 virions and cocaine significantly increased apoptosis compared with the apoptosis induced by cocaine or virions alone. Most important, our biochemical data suggest that cocaine induces CD4(+) T-cell apoptosis by increasing intracellular reactive oxygen species levels and inducing mitochondrial depolarization. Collectively, our results provide evidence of a synergy between cocaine and HIV-1 on CD4(+) T-cell apoptosis that may, in part, explain the accelerated disease observed in HIV-1-infected drug abusers. PMID:24486327

  10. Rare HIV-1 Subtype J Genomes and a New H/U/CRF02_AG Recombinant Genome Suggests an Ancient Origin of HIV-1 in Angola.

    Science.gov (United States)

    Bártolo, Inês; Calado, Rita; Borrego, Pedro; Leitner, Thomas; Taveira, Nuno

    2016-08-01

    Angola has an extremely diverse HIV-1 epidemic fueled in part by the frequent interchange of people with the Democratic Republic of Congo (DRC) and Republic of Congo (RC). Characterization of HIV-1 strains circulating in Angola should help to better understand the origin of HIV-1 subtypes and recombinant forms and their transmission dynamics. In this study we characterize the first near full-length HIV-1 genomic sequences from HIV-1 infected individuals from Angola. Samples were obtained in 1993 from three HIV-1 infected patients living in Cabinda, Angola. Near full-length genomic sequences were obtained from virus isolates. Maximum likelihood phylogenetic tree inference and analyses of potential recombination patterns were performed to evaluate the sequence classifications and origins. Phylogenetic and recombination analyses revealed that one virus was a pure subtype J, another mostly subtype J with a small uncertain region, and the final virus was classified as a H/U/CRF02_AG recombinant. Consistent with their epidemiological data, the subtype J sequences were more closely related to each other than to other J sequences previously published. Based on the env gene, taxa from Angola occur throughout the global subtype J phylogeny. HIV-1 subtypes J and H are present in Angola at low levels since at least 1993. Low transmission efficiency and/or high recombination potential may explain their limited epidemic success in Angola and worldwide. The high diversity of rare subtypes in Angola suggests that Angola was part of the early establishment of the HIV-1 pandemic.

  11. HIV-1 clade B pol evolution following primary infection.

    Directory of Open Access Journals (Sweden)

    George K Hightower

    Full Text Available OBJECTIVE: Characterize intra-individual HIV-1 subtype B pol evolution in antiretroviral naive individuals. DESIGN: Longitudinal cohort study of individuals enrolled during primary infection. METHODS: Eligible individuals were antiretroviral naïve participants enrolled in the cohort from December 1997-December 2005 and having at least two blood samples available with the first one collected within a year of their estimated date of infection. Population-based pol sequences were generated from collected blood samples and analyzed for genetic divergence over time in respect to dual infection status, HLA, CD4 count and viral load. RESULTS: 93 participants were observed for a median of 1.8 years (Mean = 2.2 years, SD =1.9 years. All participants classified as mono-infected had less than 0.7% divergence between any two of their pol sequences using the Tamura-Nei model (TN93, while individuals with dual infection had up to 7.0% divergence. The global substitution rates (substitutions/nucleotide/year for mono and dually infected individuals were significantly different (p<0.001; however, substitution rates were not associated with HLA haplotype, CD4 or viral load. CONCLUSIONS: Even after a maximum of almost 9 years of follow-up, all mono-infected participants had less than 1% divergence between baseline and longitudinal sequences, while participants with dual infection had 10 times greater divergence. These data support the use of HIV-1 pol sequence data to evaluate transmission events, networks and HIV-1 dual infection.

  12. Predicting Bevirimat resistance of HIV-1 from genotype

    Directory of Open Access Journals (Sweden)

    Hoffmann Daniel

    2010-01-01

    Full Text Available Abstract Background Maturation inhibitors are a new class of antiretroviral drugs. Bevirimat (BVM was the first substance in this class of inhibitors entering clinical trials. While the inhibitory function of BVM is well established, the molecular mechanisms of action and resistance are not well understood. It is known that mutations in the regions CS p24/p2 and p2 can cause phenotypic resistance to BVM. We have investigated a set of p24/p2 sequences of HIV-1 of known phenotypic resistance to BVM to test whether BVM resistance can be predicted from sequence, and to identify possible molecular mechanisms of BVM resistance in HIV-1. Results We used artificial neural networks and random forests with different descriptors for the prediction of BVM resistance. Random forests with hydrophobicity as descriptor performed best and classified the sequences with an area under the Receiver Operating Characteristics (ROC curve of 0.93 ± 0.001. For the collected data we find that p2 sequence positions 369 to 376 have the highest impact on resistance, with positions 370 and 372 being particularly important. These findings are in partial agreement with other recent studies. Apart from the complex machine learning models we derived a number of simple rules that predict BVM resistance from sequence with surprising accuracy. According to computational predictions based on the data set used, cleavage sites are usually not shifted by resistance mutations. However, we found that resistance mutations could shorten and weaken the α-helix in p2, which hints at a possible resistance mechanism. Conclusions We found that BVM resistance of HIV-1 can be predicted well from the sequence of the p2 peptide, which may prove useful for personalized therapy if maturation inhibitors reach clinical practice. Results of secondary structure analysis are compatible with a possible route to BVM resistance in which mutations weaken a six-helix bundle discovered in recent experiments

  13. Docking study of HIV-1 reverse transcriptase with phytochemicals.

    Science.gov (United States)

    Seal, Abhik; Aykkal, Riju; Babu, Rosana O; Ghosh, Mriganka

    2011-02-15

    Natural products are important sources of drug discovery. In this context groups of different set of phytochemicals were taken and docked into the different cavities of the Reverse transcriptase (PDB ID: 1REV) of Human immunodeficiency virus (HIV) and results were discussed. Natural compounds such as Curcumin, Geranin, Gallotannin, Tiliroside, Kaempferol-3-o-glucoside and Trachelogenin were found to very effective according to its binding energy and ligand efficiency score. Those compounds also were found to have no adverse effect as carcinogenicity and mutagenicity and favorable drug likeness score. Hence, considering the facts those compounds could use effectively for HIV-1 drug discovery.

  14. GACPAT HIV 1 + 2: a simple, inexpensive assay to screen for, and discriminate between, anti-HIV 1 and anti-HIV 2.

    Science.gov (United States)

    Parry, J V; Connell, J A; Reinbott, P; Garcia, A B; Avillez, F; Mortimer, P P

    1995-01-01

    A simple and cheap assay suitable for screening for anti-HIV 1 and anti-HIV 2 and discriminating between them was evaluated. In it specimens are incubated in U-bottomed microplate wells coated with anti-human IgG for 30 min at room temperature. After washing, 100 microliters of a 1 in 50 dilution of HIV 1-coated gelatin particles (Serodia-HIV 1/2, Fujirebio) are added. Settling patterns are read on the second day: A positive reaction is indicated by adherence of the particles and a negative by a button. The HIV 1 particles are then washed away and HIV 2 particles added. Anti-HIV 2 reaction patterns are read on the third day. To assess the performance of the modified "GACPAT HIV 1 + 2" assay a panel of 1,621 serum/plasma specimens was used. It comprised validated anti-HIV 1 positive (n = 220), anti-HIV 2 positive (n = 214), dual anti-HIV 1/anti-HIV 2 positive (n = 11), and anti-HIV negative (n = 1,176) serum/plasma specimens. All 434 specimens that contained anti-HIV 1 or anti-HIV 2 reacted positively with the homologous particles. The 11 dually positive specimens reacted positively with both HIV 1 and HIV 2 particles. Five (2.3%) anti-HIV 1 and five (2.3%) anti-HIV 2 positive specimens gave positive reactions with both particle types, but none of the five cross-reactive anti-HIV 2 specimens were dually reactive when the order of particle addition was reversed.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Design and pre-clinical evaluation of a universal HIV-1 vaccine.

    Directory of Open Access Journals (Sweden)

    Sven Létourneau

    Full Text Available BACKGROUND: One of the big roadblocks in development of HIV-1/AIDS vaccines is the enormous diversity of HIV-1, which could limit the value of any HIV-1 vaccine candidate currently under test. METHODOLOGY AND FINDINGS: To address the HIV-1 variation, we designed a novel T cell immunogen, designated HIV(CONSV, by assembling the 14 most conserved regions of the HIV-1 proteome into one chimaeric protein. Each segment is a consensus sequence from one of the four major HIV-1 clades A, B, C and D, which alternate to ensure equal clade coverage. The gene coding for the HIV(CONSV protein was inserted into the three most studied vaccine vectors, plasmid DNA, human adenovirus serotype 5 and modified vaccine virus Ankara (MVA, and induced HIV-1-specific T cell responses in mice. We also demonstrated that these conserved regions prime CD8(+ and CD4(+ T cell to highly conserved epitopes in humans and that these epitopes, although usually subdominant, generate memory T cells in patients during natural HIV-1 infection. SIGNIFICANCE: Therefore, this vaccine approach provides an attractive and testable alternative for overcoming the HIV-1 variability, while focusing T cell responses on regions of the virus that are less likely to mutate and escape. Furthermore, this approach has merit in the simplicity of design and delivery, requiring only a single immunogen to provide extensive coverage of global HIV-1 population diversity.

  16. Higher Desolvation Energy Reduces Molecular Recognition in Multi-Drug Resistant HIV-1 Protease

    Directory of Open Access Journals (Sweden)

    Ladislau C. Kovari

    2012-05-01

    Full Text Available Designing HIV-1 protease inhibitors that overcome drug-resistance is still a challenging task. In this study, four clinical isolates of multi-drug resistant HIV-1 proteases that exhibit resistance to all the US FDA-approved HIV-1 protease inhibitors and also reduce the substrate recognition ability were examined. A multi-drug resistant HIV-1 protease isolate, MDR 769, was co-crystallized with the p2/NC substrate and the mutated CA/p2 substrate, CA/p2 P1’F. Both substrates display different levels of molecular recognition by the wild-type and multi-drug resistant HIV-1 protease. From the crystal structures, only limited differences can be identified between the wild-type and multi-drug resistant protease. Therefore, a wild-type HIV-1 protease and four multi-drug resistant HIV-1 proteases in complex with the two peptides were modeled based on the crystal structures and examined during a 10 ns-molecular dynamics simulation. The simulation results reveal that the multi-drug resistant HIV-1 proteases require higher desolvation energy to form complexes with the peptides. This result suggests that the desolvation of the HIV-1 protease active site is an important step of protease-ligand complex formation as well as drug resistance. Therefore, desolvation energy could be considered as a parameter in the evaluation of future HIV-1 protease inhibitor candidates.

  17. Why do HIV-1 and HIV-2 use different pathways to develop AZT resistance?

    Directory of Open Access Journals (Sweden)

    2006-02-01

    Full Text Available The human immunodeficiency virus type 1 (HIV-1 develops resistance to all available drugs, including the nucleoside analog reverse transcriptase inhibitors (NRTIs such as AZT. ATP-mediated excision underlies the most common form of HIV-1 resistance to AZT. However, clinical data suggest that when HIV-2 is challenged with AZT, it usually accumulates resistance mutations that cause AZT resistance by reduced incorporation of AZTTP rather than selective excision of AZTMP. We compared the properties of HIV-1 and HIV-2 reverse transcriptase (RT in vitro. Although both RTs have similar levels of polymerase activity, HIV-1 RT more readily incorporates, and is more susceptible to, inhibition by AZTTP than is HIV-2 RT. Differences in the region around the polymerase active site could explain why HIV-2 RT incorporates AZTTP less efficiently than HIV-1 RT. HIV-1 RT is markedly more efficient at carrying out the excision reaction with ATP as the pyrophosphate donor than is HIV-2 RT. This suggests that HIV-1 RT has a better nascent ATP binding site than HIV-2 RT, making it easier for HIV-1 RT to develop a more effective ATP binding site by mutation. A comparison of HIV-1 and HIV-2 RT shows that there are numerous differences in the putative ATP binding sites that could explain why HIV-1 RT binds ATP more effectively. HIV-1 RT incorporates AZTTP more efficiently than does HIV-2 RT. However, HIV-1 RT is more efficient at ATP-mediated excision of AZTMP than is HIV-2 RT. Mutations in HIV-1 RT conferring AZT resistance tend to increase the efficiency of the ATP-mediated excision pathway, while mutations in HIV-2 RT conferring AZT resistance tend to increase the level of AZTTP exclusion from the polymerase active site. Thus, each RT usually chooses the pathway best suited to extend the properties of the respective wild-type enzymes.

  18. Dendritic cells are less susceptible to human immunodeficiency virus type 2 (HIV-2) infection than to HIV-1 infection

    NARCIS (Netherlands)

    M.G. Duvall (Melody); K. Loré (Karin); H. Blaak (Hetty); D.A. Ambrozak (David); W.C. Adams (William); K. Santos (Kathlyn); C. Geldmacher (Christof); J.R. Mascola (John); A.J. McMichael (Andrew); A. Jaye (Assan); H. Whittle; S.L. Rowland-Jones (Sarah); R.A. Koup (Richard)

    2007-01-01

    textabstractHuman immunodeficiency virus type 1 (HIV-1) infection of dendritic cells (DCs) has been documented in vivo and may be an important contributor to HIV-1 transmission and pathogenesis. HIV-1-specific CD4+T cells respond to HIV antigens presented by HIV-1-infected DCs and in this process be

  19. Identification of Env-specific Monoclonal Antibodies from Chinese HIV-1 Infected Person by B cell Activation and RT-PCR Cloning%利用B细胞培养和RT-PCR技术从我国HIV-1感染者中筛选膜蛋白特异性单克隆抗体的初步研究

    Institute of Scientific and Technical Information of China (English)

    汪慧敏; 管永军; 曾毅; 徐柯; 余双庆; 丁林林; 罗海艳; Robin Flinko; George K lewis; 冯霞; 邵继荣

    2012-01-01

    RNA,从中扩增抗体重链和轻链基因并克隆到表达载体中,再用携带重链基因的质粒和携带轻链基因的质粒共转染293T细胞,获得HIV-1特异性人单克隆抗体,进行抗体特性的鉴定.结果从1例HIV-1感染者的记忆性B细胞中筛选出了4株HIV-1包膜糖蛋白(Envelope glycoprotein,Env)特异性人单克隆抗体,其中2株具有较好的抗体依赖细胞介导的细胞毒作用活性,另有1株对HIV-1假病毒有较弱的中和活性.说明我们成功地引进了利用B细胞培养和RT-PCR技术从人体淋巴细胞中筛选特异性抗体基因的人单克隆抗体技术平台.用该技术可以成功获得HIV-1 Env特异性单克隆抗体,为将来从能产生高滴度广谱中和抗体的感染者体内筛选广谱中和抗体打下了基础.

  20. Association of Neutralization Sensitivity of HIV- 1 Primary Isolates With Biological Properties of Isolates From HIV-1 Infected Chinese Individuals

    Institute of Scientific and Technical Information of China (English)

    FA-XIN HEI; HAI-LI TANG; KUN-XUE HONG; JIAN-PING CHEN; HONG PENG; LIN YUAN; JIANG-QING XU; YI-MING SHAO

    2005-01-01

    Objective Although HIV-1 infection is prevalent in many regions in China, it remains largely unknown on the biological characteristics of dominant circulating isolates. This study was designed to isolate the circulating viral strains from different prevalent regions and to characterize their biological properties and neutralization sensitivity. Methods Primary viruses were isolated from fresh PBMCs using the traditional co-culture method and their capacity of inducing syncytium was tested in MT-2 cells. Meanwhile, their coreceptor usage was determined with two cell lines: Magi and GHOST (3) stably expressing CD4 and the chemokine receptor CCR5 or CXCR4. Furthermore, the sensitivity of these viruses to neutralization by HIV-1-infected patients' plasma which were highly active to neutralize SF33 strain, was quantified in GHOST cell-based neutralization assay. Results Six primary viral strains were isolated from 4 separated regions. Isolates LTG0213,LTG0214 and XVS032691 induced syncytia in MT-2 cells, and used CXCR4 as coreceptor. Isolates XJN0021, XJN0091, or SHXDC0041 did not induce syncytia, and used CCR5 as coreceptor. Overall neutralization sensitivity differed among four representative strains: HIV-1 XVS032691>LTG0214>XJN0091≈SHXDC0041. Conclusion The neutralization sensitivity of HIV isolates is linked with the phenotype of isolates, in which syncytium-inducing (SI) or CXCR4-tropic (X4) viruses are more easily neutralized than non-syncytium-inducing (NSI) or CCR5-tropic (R5) viruses. The genetic subtypes based on the phylogeny of env sequences are not classical neutralization serotypes.

  1. Development of an HIV-1 Subtype Panel in China: Isolation and Characterization of 30 HIV-1 Primary Strains Circulating in China.

    Directory of Open Access Journals (Sweden)

    Jingwan Han

    Full Text Available The complex epidemic and significant diversity of HIV-1 strains in China pose serious challenges for surveillance and diagnostic assays, vaccine development and clinical management. There is a lack of HIV-1 isolates in current canonical HIV-1 subtype panels that can represent HIV-1 diversity in China; an HIV-1 subtype panel for China is urgently needed.Blood samples were collected from HIV-1 infected patients participating in the drug-resistance surveillance program in China. The samples were isolated, cultured and stored as neat culture supernatant. The HIV-1 isolates were fully characterized. The panel was used to compare 2 viral load assays and 2 p24 assays as the examples of how this panel could be used.An HIV-1 subtype panel for China composed of 30 HIV-1 primary strains of four subtypes (B [including Thai-B], CRF01_AE, CRF07_BC and G was established. The samples were isolated and cultured to a high-titer (10(6-10(9 copies/ml/high-volume (40 ml. The HIV-1 isolates were fully characterized by the final viral load, p24 concentration, gag-pol and envC2V3 sequencing, co-receptor prediction, determination of the four amino acids at the tip of the env V3-loop, glycosylation sites in the V3 loop and the drug-resistance mutations. The comparison of two p24 assays and two viral load assays on the isolates illustrated how this panel may be used for the evaluation of diagnostic assay performance. The Pearson value between p24 assays were 0.938. The viral load results showed excellent concordance and agreement for samples of Thai-B, but lower correlations for samples of CRF01_AE.The current panel of 30 HIV-1 isolates served as a basis for the development of a comprehensive panel of fully characterized viral isolates, which could reflect the current dynamic and complex HIV-1 epidemic in China. This panel will be available to support HIV-1 research, assay evaluation, vaccine and drug development.

  2. A novel strategy for efficient production of anti-V3 human scFvs against HIV-1 clade C

    Directory of Open Access Journals (Sweden)

    Kumar Rajesh

    2012-11-01

    Full Text Available Abstract Background Production of human monoclonal antibodies that exhibit broadly neutralizing activity is needed for preventing HIV-1 infection, however only a few such antibodies have been generated till date. Isolation of antibodies by the hybridoma technology is a cumbersome process with fewer yields. Further, the loss of unstable or slowly growing clones which may have unique binding specificities often occurs during cloning and propagation and the strongly positive clones are often lost. This has been avoided by the process described in this paper, wherein, by combining the strategy of EBV transformation and recombinant DNA technology, we constructed human single chain variable fragments (scFvs against the third variable region (V3 of the clade C HIV-1 envelope. Results An antigen specific phage library of 7000 clones was constructed from the enriched V3- positive antibody secreting EBV transformed cells. By ligation of the digested scFv DNA into phagemid vector and bio panning against the HIV-1 consensus C and B V3 peptides followed by random selection of 40 clones, we identified 15 clones that showed V3 reactivity in phage ELISA. DNA fingerprinting analysis and sequencing showed that 13 out of the 15 clones were distinct. Expression of the positive clones was tested by SDS-PAGE and Western blot. All the 13 anti-V3 scFvs showed cross-reactivity against both the clade C and B V3 peptides and did not show any reactivity against other unrelated peptides in ELISA. Preliminary neutralization assays indicated varying degrees of neutralization of clade C and B viruses. EBV transformation, followed by antigen selection of lines to identify specific binders, enabled the selection of phage from un-cloned lines for scFv generation, thus avoiding the problems of hybridoma technology. Moreover, as the clones were pretested for antigen binding, a comparatively small library sufficed for the selection of a considerable number of unique antigen binding

  3. Copy number variation of KIR genes influences HIV-1 control

    DEFF Research Database (Denmark)

    Pelak, Kimberly; Need, Anna C; Fellay, Jacques;

    2011-01-01

    A genome-wide screen for large structural variants showed that a copy number variant (CNV) in the region encoding killer cell immunoglobulin-like receptors (KIR) associates with HIV-1 control as measured by plasma viral load at set point in individuals of European ancestry. This CNV encompasses...... the KIR3DL1-KIR3DS1 locus, encoding receptors that interact with specific HLA-Bw4 molecules to regulate the activation of lymphocyte subsets including natural killer (NK) cells. We quantified the number of copies of KIR3DS1 and KIR3DL1 in a large HIV-1 positive cohort, and showed that an increase in KIR3......DS1 count associates with a lower viral set point if its putative ligand is present (p = 0.00028), as does an increase in KIR3DL1 count in the presence of KIR3DS1 and appropriate ligands for both receptors (p = 0.0015). We further provide functional data that demonstrate that NK cells from...

  4. Hydrophobic Core Flexibility Modulates Enzyme Activity in HIV-1 Protease

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Seema; Cai, Yufeng; Nalam, Madhavi N.L.; Bolon, Daniel N.A.; Schiffer, Celia A. (UMASS, MED)

    2012-09-11

    Human immunodeficiency virus Type-1 (HIV-1) protease is crucial for viral maturation and infectivity. Studies of protease dynamics suggest that the rearrangement of the hydrophobic core is essential for enzyme activity. Many mutations in the hydrophobic core are also associated with drug resistance and may modulate the core flexibility. To test the role of flexibility in protease activity, pairs of cysteines were introduced at the interfaces of flexible regions remote from the active site. Disulfide bond formation was confirmed by crystal structures and by alkylation of free cysteines and mass spectrometry. Oxidized and reduced crystal structures of these variants show the overall structure of the protease is retained. However, cross-linking the cysteines led to drastic loss in enzyme activity, which was regained upon reducing the disulfide cross-links. Molecular dynamics simulations showed that altered dynamics propagated throughout the enzyme from the engineered disulfide. Thus, altered flexibility within the hydrophobic core can modulate HIV-1 protease activity, supporting the hypothesis that drug resistant mutations distal from the active site can alter the balance between substrate turnover and inhibitor binding by modulating enzyme activity.

  5. Large-scale functional purification of recombinant HIV-1 capsid.

    Directory of Open Access Journals (Sweden)

    Magdeleine Hung

    Full Text Available During human immunodeficiency virus type-1 (HIV-1 virion maturation, capsid proteins undergo a major rearrangement to form a conical core that protects the viral nucleoprotein complexes. Mutations in the capsid sequence that alter the stability of the capsid core are deleterious to viral infectivity and replication. Recently, capsid assembly has become an attractive target for the development of a new generation of anti-retroviral agents. Drug screening efforts and subsequent structural and mechanistic studies require gram quantities of active, homogeneous and pure protein. Conventional means of laboratory purification of Escherichia coli expressed recombinant capsid protein rely on column chromatography steps that are not amenable to large-scale production. Here we present a function-based purification of wild-type and quadruple mutant capsid proteins, which relies on the inherent propensity of capsid protein to polymerize and depolymerize. This method does not require the packing of sizable chromatography columns and can generate double-digit gram quantities of functionally and biochemically well-behaved proteins with greater than 98% purity. We have used the purified capsid protein to characterize two known assembly inhibitors in our in-house developed polymerization assay and to measure their binding affinities. Our capsid purification procedure provides a robust method for purifying large quantities of a key protein in the HIV-1 life cycle, facilitating identification of the next generation anti-HIV agents.

  6. Pentosan polysulfate as an inhibitor of extracellular HIV-1 Tat.

    Science.gov (United States)

    Rusnati, M; Urbinati, C; Caputo, A; Possati, L; Lortat-Jacob, H; Giacca, M; Ribatti, D; Presta, M

    2001-06-22

    HIV-1 Tat protein, released from HIV-infected cells, may act as a pleiotropic heparin-binding growth factor. From this observation, extracellular Tat has been implicated in the pathogenesis of AIDS and of AIDS-associated pathologies. Here we demonstrate that the heparin analog pentosan polysulfate (PPS) inhibits the interaction of glutathione S-transferase (GST)-Tat protein with heparin immobilized to a BIAcore sensor chip. Competition experiments showed that Tat-PPS interaction occurs with high affinity (K(d) = 9.0 nm). Also, GST.Tat prevents the binding of [(3)H]heparin to GST.Tat immobilized to glutathione-agarose beads. In vitro, PPS inhibits GST.Tat internalization and, consequently, HIV-1 long terminal repeat transactivation in HL3T1 cells. Also, PPS inhibits cell surface interaction and mitogenic activity of GST.Tat in murine adenocarcinoma T53 Tat-less cells. In all assays, PPS exerts its Tat antagonist activity with an ID(50) equal to approximately 1.0 nm. In vivo, PPS inhibits the neovascularization induced by GST.Tat or by Tat-overexpressing T53 cells in the chick embryo chorioallantoic membrane. In conclusion, PPS binds Tat protein and inhibits its cell surface interaction, internalization, and biological activity in vitro and in vivo. PPS may represent a prototypic molecule for the development of novel Tat antagonists with therapeutic implications in AIDS and AIDS-associated pathologies, including Kaposi's sarcoma.

  7. The cell biology of HIV-1 and other retroviruses

    Directory of Open Access Journals (Sweden)

    Mouland Andrew J

    2006-11-01

    Full Text Available Abstract In recognition of the growing influence of cell biology in retrovirus research, we recently organized a Summer conference sponsored by the American Society for Cell Biology (ASCB on the Cell Biology of HIV-1 and other Retroviruses (July 20–23, 2006, Emory University, Atlanta, Georgia. The meeting brought together a number of leading investigators interested in the interplay between cell biology and retrovirology with an emphasis on presentation of new and unpublished data. The conference was arranged from early to late events in the virus replication cycle, with sessions on viral fusion, entry, and transmission; post-entry restrictions to retroviral infection; nuclear import and integration; gene expression/regulation of retroviral Gag and genomic RNA; and assembly/release. In this review, we will attempt to touch briefly on some of the highlights of the conference, and will emphasize themes and trends that emerged at the meeting. Meeting report The conference began with a keynote address from W. Sundquist on the biochemistry of HIV-1 budding. This presentation will be described in the section on Assembly and Release of Retroviruses.

  8. Mechanism of Inhibition to HIV-1 by Mycoplasma Fermentans

    Institute of Scientific and Technical Information of China (English)

    尚红; 姜拥军; 王琪; 王亚男; 张子宁

    2003-01-01

    To explore the mechanism of the inhibition of HIV-1 by Mycoplasma fermerttans, culture supernatants and thallodic proteins from M.fermerttans PG18 were prepared and the protein components of the supernatants were purified withhigh performance liquid chromatography (HPLC). The inhibitory activities to reverse transcriptase (RT) and the nuclease activities were detected; the influence of M.fermerttans on IL-10 secretion by both normal and H1V-1 infected human PBMC were determined, and the inhibitory effect of rhIL-10 on H1V-1 replication was detected with EI,ISA method. The results showed that the purified proteins with a molecular weight of 67-100 kDa or 10-25 kDa showed a 36% or 34% in hibitory ac-tivity to RT and partial nuclease activity. The thallodic protein could induce both normal and H1V-1 infected PBMC to secret IL-10 remarkably, and to the latter, this effect was more apparent. While rhIL-10 could inhibit replication of H1V-1 in PB-MC in vitro in a dose-dependant manner. It concludes that the inhibitory effect of the M.fermentans PG18 culture supernatants on RT and the promoting effect of PG18 thallodic protein on IL-10 secretion in PBMC explain the mechanisms of inhibition to HIV-1 by M.fermentans PG18.

  9. Tetherin restricts productive HIV-1 cell-to-cell transmission.

    Directory of Open Access Journals (Sweden)

    Nicoletta Casartelli

    Full Text Available The IFN-inducible antiviral protein tetherin (or BST-2/CD317/HM1.24 impairs release of mature HIV-1 particles from infected cells. HIV-1 Vpu antagonizes the effect of tetherin. The fate of virions trapped at the cell surface remains poorly understood. Here, we asked whether tetherin impairs HIV cell-to-cell transmission, a major means of viral spread. Tetherin-positive or -negative cells, infected with wild-type or DeltaVpu HIV, were used as donor cells and cocultivated with target lymphocytes. We show that tetherin inhibits productive cell-to-cell transmission of DeltaVpu to targets and impairs that of WT HIV. Tetherin accumulates with Gag at the contact zone between infected and target cells, but does not prevent the formation of virological synapses. In the presence of tetherin, viruses are then mostly transferred to targets as abnormally large patches. These viral aggregates do not efficiently promote infection after transfer, because they accumulate at the surface of target cells and are impaired in their fusion capacities. Tetherin, by imprinting virions in donor cells, is the first example of a surface restriction factor limiting viral cell-to-cell spread.

  10. Iron status in HIV-1 infection: implications in disease pathology

    Directory of Open Access Journals (Sweden)

    Banjoko S Olatunbosun

    2012-12-01

    Full Text Available Abstract Background There had been conflicting reports with levels of markers of iron metabolism in HIV infection. This study was therefore aimed at investigating iron status and its possible mediation of severity of HIV- 1 infection and pathogenesis. Method Eighty (80 anti-retroviral naive HIV-1 positive and 50 sero-negative controls were recruited for the study. Concentrations of serum total iron, transferrin, total iron binding capacity (TIBC, CD4+ T -lymphocytes, vitamin C, zinc, selenium and transferrin saturation were estimated. Results The mean CD4+ T-lymphocyte cell counts, serum iron, TIBC, transferrin saturation for the tests and controls were 319 ± 22, 952 ± 57 cells/μl (P 4+ T-lymphocyte cell count had a positive correlation with levels of vitamin C (r = 0.497, P Conclusion It could be inferred that derangement in iron metabolism, in addition to oxidative stress, might have contributed to the depletion of CD4+ T cell population in our subjects and this may result in poor prognosis of the disease.

  11. Effects of HIV-1 on Cognition in Humanized NSG Mice

    Science.gov (United States)

    Akhter, Sidra Pervez

    Host species specificity of human immunodeficiency virus (HIV) creates a challenge to study the pathology, diagnostic tools, and therapeutic agents. The closely related simian immunodeficiency virus and studies of neurocognitive impairments on transgenic animals expressing partial viral genome have significant limitations. The humanized mice model provides a small animal system in which a human immune system can be engrafted and immunopathobiology of HIV-1 infection can be studied. However, features of HIV-associated neurocognitive disorders (HAND) were not evaluated in this model. Open field activity test was selected to characterize behavior of original strain NOD/scid-IL-2Rgammac null (NSG) mice, effects of engraftment of human CD34+ hematopoietic stem cells (HSCs) and functional human immune system (huNSG), and finally, investigate the behavior changes induced by chronic HIV-1 infection. Long-term infected HuNSG mice showed the loss of working memory and increased anxiety in the open field. Additionally, these animals were utilized for evaluation of central nervous system metabolic and structural changes. Detected behavioral abnormalities are correlated with obtained neuroimaging and histological abnormalities published.

  12. Developing a dynamic pharmacophore model for HIV-1 integrase.

    Science.gov (United States)

    Carlson, H A; Masukawa, K M; Rubins, K; Bushman, F D; Jorgensen, W L; Lins, R D; Briggs, J M; McCammon, J A

    2000-06-01

    We present the first receptor-based pharmacophore model for HIV-1 integrase. The development of "dynamic" pharmacophore models is a new method that accounts for the inherent flexibility of the active site and aims to reduce the entropic penalties associated with binding a ligand. Furthermore, this new drug discovery method overcomes the limitation of an incomplete crystal structure of the target protein. A molecular dynamics (MD) simulation describes the flexibility of the uncomplexed protein. Many conformational models of the protein are saved from the MD simulations and used in a series of multi-unit search for interacting conformers (MUSIC) simulations. MUSIC is a multiple-copy minimization method, available in the BOSS program; it is used to determine binding regions for probe molecules containing functional groups that complement the active site. All protein conformations from the MD are overlaid, and conserved binding regions for the probe molecules are identified. Those conserved binding regions define the dynamic pharmacophore model. Here, the dynamic model is compared to known inhibitors of the integrase as well as a three-point, ligand-based pharmacophore model from the literature. Also, a "static" pharmacophore model was determined in the standard fashion, using a single crystal structure. Inhibitors thought to bind in the active site of HIV-1 integrase fit the dynamic model but not the static model. Finally, we have identified a set of compounds from the Available Chemicals Directory that fit the dynamic pharmacophore model, and experimental testing of the compounds has confirmed several new inhibitors. PMID:10841789

  13. HIV-1 Tat interacts with LIS1 protein

    Directory of Open Access Journals (Sweden)

    Turner Willie

    2005-02-01

    Full Text Available Abstract Background HIV-1 Tat activates transcription of HIV-1 viral genes by inducing phosphorylation of the C-terminal domain (CTD of RNA polymerase II (RNAPII. Tat can also disturb cellular metabolism by inhibiting proliferation of antigen-specific T lymphocytes and by inducing cellular apoptosis. Tat-induced apoptosis of T-cells is attributed, in part, to the distortion of microtubules polymerization. LIS1 is a microtubule-associated protein that facilitates microtubule polymerization. Results We identified here LIS1 as a Tat-interacting protein during extensive biochemical fractionation of T-cell extracts. We found several proteins to co-purify with a Tat-associated RNAPII CTD kinase activity including LIS1, CDK7, cyclin H, and MAT1. Tat interacted with LIS1 but not with CDK7, cyclin H or MAT1 in vitro. LIS1 also co-immunoprecipitated with Tat expressed in HeLa cells. Further, LIS1 interacted with Tat in a yeast two-hybrid system. Conclusion Our results indicate that Tat interacts with LIS1 in vitro and in vivo and that this interaction might contribute to the effect of Tat on microtubule formation.

  14. Intra-spike crosslinking overcomes antibody evasion by HIV-1.

    Science.gov (United States)

    Galimidi, Rachel P; Klein, Joshua S; Politzer, Maria S; Bai, Shiyu; Seaman, Michael S; Nussenzweig, Michel C; West, Anthony P; Bjorkman, Pamela J

    2015-01-29

    Antibodies developed during HIV-1 infection lose efficacy as the viral spike mutates. We postulated that anti-HIV-1 antibodies primarily bind monovalently because HIV's low spike density impedes bivalent binding through inter-spike crosslinking, and the spike structure prohibits bivalent binding through intra-spike crosslinking. Monovalent binding reduces avidity and potency, thus expanding the range of mutations permitting antibody evasion. To test this idea, we engineered antibody-based molecules capable of bivalent binding through intra-spike crosslinking. We used DNA as a "molecular ruler" to measure intra-epitope distances on virion-bound spikes and construct intra-spike crosslinking molecules. Optimal bivalent reagents exhibited up to 2.5 orders of magnitude increased potency (>100-fold average increases across virus panels) and identified conformational states of virion-bound spikes. The demonstration that intra-spike crosslinking lowers the concentration of antibodies required for neutralization supports the hypothesis that low spike densities facilitate antibody evasion and the use of molecules capable of intra-spike crosslinking for therapy or passive protection. PMID:25635457

  15. The evolutionary rate dynamically tracks changes in HIV-1 epidemics

    Energy Technology Data Exchange (ETDEWEB)

    Maljkovic-berry, Irina [Los Alamos National Laboratory; Athreya, Gayathri [Los Alamos National Laboratory; Daniels, Marcus [Los Alamos National Laboratory; Bruno, William [Los Alamos National Laboratory; Korber, Bette [Los Alamos National Laboratory; Kuiken, Carla [Los Alamos National Laboratory; Ribeiro, Ruy M [Los Alamos National Laboratory

    2009-01-01

    Large-sequence datasets provide an opportunity to investigate the dynamics of pathogen epidemics. Thus, a fast method to estimate the evolutionary rate from large and numerous phylogenetic trees becomes necessary. Based on minimizing tip height variances, we optimize the root in a given phylogenetic tree to estimate the most homogenous evolutionary rate between samples from at least two different time points. Simulations showed that the method had no bias in the estimation of evolutionary rates and that it was robust to tree rooting and topological errors. We show that the evolutionary rates of HIV-1 subtype B and C epidemics have changed over time, with the rate of evolution inversely correlated to the rate of virus spread. For subtype B, the evolutionary rate slowed down and tracked the start of the HAART era in 1996. Subtype C in Ethiopia showed an increase in the evolutionary rate when the prevalence increase markedly slowed down in 1995. Thus, we show that the evolutionary rate of HIV-1 on the population level dynamically tracks epidemic events.

  16. Exploring the complexity of the HIV-1 fitness landscape.

    Directory of Open Access Journals (Sweden)

    Roger D Kouyos

    Full Text Available Although fitness landscapes are central to evolutionary theory, so far no biologically realistic examples for large-scale fitness landscapes have been described. Most currently available biological examples are restricted to very few loci or alleles and therefore do not capture the high dimensionality characteristic of real fitness landscapes. Here we analyze large-scale fitness landscapes that are based on predictive models for in vitro replicative fitness of HIV-1. We find that these landscapes are characterized by large correlation lengths, considerable neutrality, and high ruggedness and that these properties depend only weakly on whether fitness is measured in the absence or presence of different antiretrovirals. Accordingly, adaptive processes on these landscapes depend sensitively on the initial conditions. While the relative extent to which mutations affect fitness on their own (main effects or in combination with other mutations (epistasis is a strong determinant of these properties, the fitness landscape of HIV-1 is considerably less rugged, less neutral, and more correlated than expected from the distribution of main effects and epistatic interactions alone. Overall this study confirms theoretical conjectures about the complexity of biological fitness landscapes and the importance of the high dimensionality of the genetic space in which adaptation takes place.

  17. Immunological responses to envelope glycoprotein 120 from subtypes of human immunodeficiency virus type 1.

    Science.gov (United States)

    Gilljam, G; Svensson, A; Ekström, A; Wahren, B

    1999-07-01

    The outer envelope glycoprotein (gp120) from subtypes A-E of HIV-1 was purified using a specific high mannose-binding lectin, Galanthus nivalis agglutinin. All isolates were grown in peripheral blood lymphocyte cells in order to avoid selection in cell lines. A comparison of the reactivities of the envelope proteins was made using sera from patients infected with the different subtypes. In this study, the B and C subtype envelope glycoproteins showed the strongest immunological reactivity, when reacted with sera from patients infected with the same subtype of virus. On the other hand, sera of patients infected with subtype A or C virus had the strongest and broadest reactivities, to envelope glycoproteins of many subtypes. The purified gp120 proteins from all five subtypes stimulated mononuclear cells from HIV-1 (subtype B)-infected patients, indicating conserved T cell-activating epitopes. The immunological reactivities indicate that strong antigenicity does not always predict the broadest immunogenicity of an envelope glycoprotein. Glycoprotein 120 from foreign subtypes may serve to induce strong cross-reactive immune responses.

  18. HIV-1 Protease, Reverse Transcriptase, and Integrase Variation

    Science.gov (United States)

    Sankaran, Kris; Varghese, Vici; Winters, Mark A.; Hurt, Christopher B.; Eron, Joseph J.; Parkin, Neil; Holmes, Susan P.; Holodniy, Mark; Shafer, Robert W.

    2016-01-01

    ABSTRACT HIV-1 protease (PR), reverse transcriptase (RT), and integrase (IN) variability presents a challenge to laboratories performing genotypic resistance testing. This challenge will grow with increased sequencing of samples enriched for proviral DNA such as dried blood spots and increased use of next-generation sequencing (NGS) to detect low-abundance HIV-1 variants. We analyzed PR and RT sequences from >100,000 individuals and IN sequences from >10,000 individuals to characterize variation at each amino acid position, identify mutations indicating APOBEC-mediated G-to-A editing, and identify mutations resulting from selective drug pressure. Forty-seven percent of PR, 37% of RT, and 34% of IN positions had one or more amino acid variants with a prevalence of ≥1%. Seventy percent of PR, 60% of RT, and 60% of IN positions had one or more variants with a prevalence of ≥0.1%. Overall 201 PR, 636 RT, and 346 IN variants had a prevalence of ≥0.1%. The median intersubtype prevalence ratios were 2.9-, 2.1-, and 1.9-fold for these PR, RT, and IN variants, respectively. Only 5.0% of PR, 3.7% of RT, and 2.0% of IN variants had a median intersubtype prevalence ratio of ≥10-fold. Variants at lower prevalences were more likely to differ biochemically and to be part of an electrophoretic mixture compared to high-prevalence variants. There were 209 mutations indicative of APOBEC-mediated G-to-A editing and 326 mutations nonpolymorphic treatment selected. Identification of viruses with a high number of APOBEC-associated mutations will facilitate the quality control of dried blood spot sequencing. Identifying sequences with a high proportion of rare mutations will facilitate the quality control of NGS. IMPORTANCE Most antiretroviral drugs target three HIV-1 proteins: PR, RT, and IN. These proteins are highly variable: many different amino acids can be present at the same position in viruses from different individuals. Some of the amino acid variants cause drug

  19. Tat RNA silencing suppressor activity contributes to perturbation of lymphocyte miRNA by HIV-1

    Directory of Open Access Journals (Sweden)

    Yu Lianbo

    2011-05-01

    Full Text Available Abstract Background MicroRNA (miRNA-mediated RNA silencing is integral to virtually every cellular process including cell cycle progression and response to virus infection. The interplay between RNA silencing and HIV-1 is multifaceted, and accumulating evidence posits a strike-counterstrike interface that alters the cellular environment to favor virus replication. For instance, miRNA-mediated RNA silencing of HIV-1 translation is antagonized by HIV-1 Tat RNA silencing suppressor activity. The activity of HIV-1 accessory proteins Vpr/Vif delays cell cycle progression, which is a process prominently modulated by miRNA. The expression profile of cellular miRNA is altered by HIV-1 infection in both cultured cells and clinical samples. The open question stands of what, if any, is the contribution of Tat RNA silencing suppressor activity or Vpr/Vif activity to the perturbation of cellular miRNA by HIV-1. Results Herein, we compared the perturbation of miRNA expression profiles of lymphocytes infected with HIV-1NL4-3 or derivative strains that are deficient in Tat RNA silencing suppressor activity (Tat K51A substitution or ablated of the vpr/vif open reading frames. Microarrays recapitulated the perturbation of the cellular miRNA profile by HIV-1 infection. The miRNA expression trends overlapped ~50% with published microarray results on clinical samples from HIV-1 infected patients. Moreover, the number of miRNA perturbed by HIV-1 was largely similar despite ablation of Tat RSS activity and Vpr/Vif; however, the Tat RSS mutation lessened HIV-1 downregulation of twenty-two miRNAs. Conclusions Our study identified miRNA expression changes attributable to Tat RSS activity in HIV-1NL4-3. The results accomplish a necessary step in the process to understand the interface of HIV-1 with host RNA silencing activity. The overlap in miRNA expression trends observed between HIV-1 infected CEMx174 lymphocytes and primary cells supports the utility of cultured

  20. In silico prediction of mutant HIV-1 proteases cleaving a target sequence

    CERN Document Server

    Jensen, Jan H; Winther, Jakob R; De Vico, Luca

    2014-01-01

    HIV-1 protease represents an appealing system for directed enzyme re-design, since it has various different endogenous targets, a relatively simple structure and it is well studied. Recently Chaudhury and Gray (Structure (2009) 17: 1636 -- 1648) published a computational algorithm to discern the specificity determining residues of HIV-1 protease. In this paper we present two computational tools aimed at re-designing HIV-1 protease, derived from the algorithm of Chaudhuri and Gray. First, we present an energy-only based methodology to discriminate cleavable and non cleavable peptides for HIV-1 proteases, both wild type and mutant. Secondly, we show an algorithm we developed to predict mutant HIV-1 proteases capable of cleaving a new target substrate peptide, different from the natural targets of HIV-1 protease. The obtained in silico mutant enzymes were analyzed in terms of cleavability and specificity towards the target peptide using the energy-only methodology. We found two mutant proteases as best candidate...

  1. HLA alleles associated with slow progression to AIDS truly prefer to present HIV-1 p24

    DEFF Research Database (Denmark)

    Borghans, José A M; Mølgaard, Anne; de Boer, Rob J;

    2007-01-01

    BACKGROUND: The mechanism behind the association between human leukocyte antigen (HLA) molecules and the rate of HIV-1 disease progression is still poorly understood. Recent data suggest that "protective" HLA molecules, i.e. those associated with a low HIV-1 viral load and relatively slow disease...... effect, we predicted HIV-1 epitopes from the whole genome of HIV-1, and found that protective HLA alleles have a true preference for the p24 Gag protein, while non-protective HLA alleles preferentially target HIV-1 Nef. In line with this, we found a significant negative correlation between the predicted...... affinity of the best-binding p24 epitopes and the relative hazard of HIV-1 disease progression for a large number of HLA molecules. When the epitopes targeted by protective HLA alleles were mapped to the known p24 structure, we found that mutations in these epitopes are likely to disturb the p24 dimer...

  2. HLA Alleles Associated with Slow Progression to AIDS Truly Prefer to Present HIV-1 p24

    DEFF Research Database (Denmark)

    Borghans, J. A.; Molgaard, A.; Boer, R. J. de;

    2007-01-01

    BACKGROUND: The mechanism behind the association between human leukocyte antigen (HLA) molecules and the rate of HIV-1 disease progression is still poorly understood. Recent data suggest that "protective" HLA molecules, i.e. those associated with a low HIV-1 viral load and relatively slow disease...... and effect, we predicted HIV-1 epitopes from the whole genome of HIV-1, and found that protective HLA alleles have a true preference for the p24 Gag protein, while non-protective HLA alleles preferentially target HIV-1 Nef. In line with this, we found a significant negative correlation between the predicted...... affinity of the best-binding p24 epitopes and the relative hazard of HIV-1 disease progression for a large number of HLA molecules. When the epitopes targeted by protective HLA alleles were mapped to the known p24 structure, we found that mutations in these epitopes are likely to disturb the p24 dimer...

  3. ESCRT-III CHMP2A and CHMP3 form variable helical polymers in vitro and act synergistically during HIV-1 budding.

    Science.gov (United States)

    Effantin, Grégory; Dordor, Aurélien; Sandrin, Virginie; Martinelli, Nicolas; Sundquist, Wesley I; Schoehn, Guy; Weissenhorn, Winfried

    2013-02-01

    The endosomal sorting complex required for transport-III (ESCRT-III) proteins are essential for budding of some enveloped viruses, for the formation of intraluminal vesicles at the endosome and for the abscission step of cytokinesis. ESCRT-III proteins form polymers that constrict membrane tubes, leading to fission. We have used electron cryomicroscopy to determine the molecular organization of pleiomorphic ESCRT-III CHMP2A-CHMP3 polymers. The three-dimensional reconstruction at 22 Å resolution reveals a helical organization of filaments of CHMP molecules organized in a head-to-tail fashion. Protease susceptibility experiments indicate that polymerization is achieved via conformational changes that increase the protomer stability. Combinatorial siRNA knockdown experiments indicate that CHMP3 contributes synergistically to HIV-1 budding, and the CHMP3 contribution is ~ 10-fold more pronounced in concert with CHMP2A than with CHMP2B. This is consistent with surface plasmon resonance affinity measurements that suggest sequential CHMP4B-CHMP3-CHMP2A recruitment while showing that both CHMP2A and CHMP2B interact with CHMP4B, in agreement with their redundant functions in HIV-1 budding. Our data thus indicate that the CHMP2A-CHMP3 polymer observed in vitro contributes to HIV-1 budding by assembling on CHMP4B polymers. PMID:23051622

  4. Remodeling of the Host Cell Plasma Membrane by HIV-1 Nef and Vpu: A Strategy to Ensure Viral Fitness and Persistence

    Directory of Open Access Journals (Sweden)

    Scott M. Sugden

    2016-03-01

    Full Text Available The plasma membrane protects the cell from its surroundings and regulates cellular communication, homing, and metabolism. Not surprisingly, the composition of this membrane is highly controlled through the vesicular trafficking of proteins to and from the cell surface. As intracellular pathogens, most viruses exploit the host plasma membrane to promote viral replication while avoiding immune detection. This is particularly true for the enveloped human immunodeficiency virus (HIV, which assembles and obtains its lipid shell directly at the plasma membrane. HIV-1 encodes two proteins, negative factor (Nef and viral protein U (Vpu, which function primarily by altering the quantity and localization of cell surface molecules to increase virus fitness despite host antiviral immune responses. These proteins are expressed at different stages in the HIV-1 life cycle and employ a variety of mechanisms to target both unique and redundant surface proteins, including the viral receptor CD4, host restriction factors, immunoreceptors, homing molecules, tetraspanins and membrane transporters. In this review, we discuss recent progress in the study of the Nef and Vpu targeting of host membrane proteins with an emphasis on how remodeling of the cell membrane allows HIV-1 to avoid host antiviral immune responses leading to the establishment of systemic and persistent infection.

  5. Lack of integrase inhibitors associated resistance mutations among HIV-<