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Sample records for ccr5-restricted hiv-1 envelope

  1. 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.

  2. Neutralizing antibodies decrease the envelope fluidity of HIV-1

    International Nuclear Information System (INIS)

    For successful penetration of HIV-1, the formation of a fusion pore may be required in order to accumulate critical numbers of fusion-activated gp41 with the help of fluidization of the plasma membrane and viral envelope. An increase in temperature to 40 oC after viral adsorption at 25 oC enhanced the infectivity by 1.4-fold. The enhanced infectivity was inhibited by an anti-CXCR4 peptide, T140, and anti-V3 monoclonal antibodies (0.5β and 694/98-D) by post-attachment neutralization, but not by non-neutralizing antibodies (670-30D and 246-D) specific for the C5 of gp120 and cluster I of gp41, respectively. Anti-HLA-II and an anti-HTLV-I gp46 antibody, LAT27, neutralized the molecule-carrying HIV-1C-2(MT-2). The anti-V3 antibodies suppressed the fluidity of the HIV-1C-2 envelope, whereas the non-neutralizing antibodies did not. The anti-HLA-II antibody decreased the envelope fluidity of HIV-1C-2(MT-2), but not that of HIV-1C-2. Therefore, fluidity suppression by these antibodies represents an important neutralization mechanism, in addition to inhibition of viral attachment

  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

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    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

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    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. HIV-1 Envelope Induces Memory B Cell Responses That Correlate with Plasma Antibody Levels after Envelope gp120 Protein Vaccination or HIV-1 Infection1

    OpenAIRE

    Bonsignori, Mattia; Moody, M. Anthony; Parks, Robert J.; Holl, T. Matt; Kelsoe, Garnett; Hicks, Charles B.; Vandergrift, Nathan; Tomaras, Georgia D.; Haynes, Barton F.

    2009-01-01

    Successful vaccines (i.e., tetanus and diphtheria) can induce long-lived Ab levels that are maintained by bone marrow plasma cells and plasma Ab levels do not correlate with numbers of blood memory B cells. Destruction of CD4+ T cells early in HIV-1 acute infection may result in insufficient induction of neutralizing Ab responses; thus, an HIV-1 vaccine should elicit high levels of durable Abs by long-lived plasma cells to be protective. We asked if HIV-1 envelope-specific memory responses we...

  8. 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 glycop...... results provide a proof of concept that a distally related retroviral SIV Env protein boost can increase pre-existing NAb responses against HIV-1....

  9. 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

  10. Nine Crystal Structures Determine the Substrate Envelope of the MDR HIV-1 Protease

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhigang; Wang, Yong; Brunzelle, Joseph; Kovari, Iulia A.; Kovari, Ladislau C. (WSU-MED); (NWU)

    2012-03-27

    Under drug selection pressure, emerging mutations render HIV-1 protease drug resistant, leading to the therapy failure in anti-HIV treatment. It is known that nine substrate cleavage site peptides bind to wild type (WT) HIV-1 protease in a conserved pattern. However, how the multidrug-resistant (MDR) HIV-1 protease binds to the substrate cleavage site peptides is yet to be determined. MDR769 HIV-1 protease (resistant mutations at residues 10, 36, 46, 54, 62, 63, 71, 82, 84, and 90) was selected for present study to understand the binding to its natural substrates. MDR769 HIV-1 protease was co-crystallized with nine substrate cleavage site hepta-peptides. Crystallographic studies show that MDR769 HIV-1 protease has an expanded substrate envelope with wide open flaps. Furthermore, ligand binding energy calculations indicate weaker binding in MDR769 HIV-1 protease-substrate complexes. These results help in designing the next generation of HIV-1 protease inhibitors by targeting the MDR HIV-1 protease.

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

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    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.

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

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    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.

  13. Evolutionary interactions between N-linked glycosylation sites in the HIV-1 envelope.

    Science.gov (United States)

    Poon, Art F Y; Lewis, Fraser I; Pond, Sergei L Kosakovsky; Frost, Simon D W

    2007-01-19

    The addition of asparagine (N)-linked polysaccharide chains (i.e., glycans) to the gp120 and gp41 glycoproteins of human immunodeficiency virus type 1 (HIV-1) envelope is not only required for correct protein folding, but also may provide protection against neutralizing antibodies as a "glycan shield." As a result, strong host-specific selection is frequently associated with codon positions where nonsynonymous substitutions can create or disrupt potential N-linked glycosylation sites (PNGSs). Moreover, empirical data suggest that the individual contribution of PNGSs to the neutralization sensitivity or infectivity of HIV-1 may be critically dependent on the presence or absence of other PNGSs in the envelope sequence. Here we evaluate how glycan-glycan interactions have shaped the evolution of HIV-1 envelope sequences by analyzing the distribution of PNGSs in a large-sequence alignment. Using a "covarion"-type phylogenetic model, we find that the rates at which individual PNGSs are gained or lost vary significantly over time, suggesting that the selective advantage of having a PNGS may depend on the presence or absence of other PNGSs in the sequence. Consequently, we identify specific interactions between PNGSs in the alignment using a new paired-character phylogenetic model of evolution, and a Bayesian graphical model. Despite the fundamental differences between these two methods, several interactions are jointly identified by both. Mapping these interactions onto a structural model of HIV-1 gp120 reveals that negative (exclusive) interactions occur significantly more often between colocalized glycans, while positive (inclusive) interactions are restricted to more distant glycans. Our results imply that the adaptive repertoire of alternative configurations in the HIV-1 glycan shield is limited by functional interactions between the N-linked glycans. This represents a potential vulnerability of rapidly evolving HIV-1 populations that may provide useful glycan

  14. Evolutionary interactions between N-linked glycosylation sites in the HIV-1 envelope.

    Directory of Open Access Journals (Sweden)

    Art F Y Poon

    2007-01-01

    Full Text Available The addition of asparagine (N-linked polysaccharide chains (i.e., glycans to the gp120 and gp41 glycoproteins of human immunodeficiency virus type 1 (HIV-1 envelope is not only required for correct protein folding, but also may provide protection against neutralizing antibodies as a "glycan shield." As a result, strong host-specific selection is frequently associated with codon positions where nonsynonymous substitutions can create or disrupt potential N-linked glycosylation sites (PNGSs. Moreover, empirical data suggest that the individual contribution of PNGSs to the neutralization sensitivity or infectivity of HIV-1 may be critically dependent on the presence or absence of other PNGSs in the envelope sequence. Here we evaluate how glycan-glycan interactions have shaped the evolution of HIV-1 envelope sequences by analyzing the distribution of PNGSs in a large-sequence alignment. Using a "covarion"-type phylogenetic model, we find that the rates at which individual PNGSs are gained or lost vary significantly over time, suggesting that the selective advantage of having a PNGS may depend on the presence or absence of other PNGSs in the sequence. Consequently, we identify specific interactions between PNGSs in the alignment using a new paired-character phylogenetic model of evolution, and a Bayesian graphical model. Despite the fundamental differences between these two methods, several interactions are jointly identified by both. Mapping these interactions onto a structural model of HIV-1 gp120 reveals that negative (exclusive interactions occur significantly more often between colocalized glycans, while positive (inclusive interactions are restricted to more distant glycans. Our results imply that the adaptive repertoire of alternative configurations in the HIV-1 glycan shield is limited by functional interactions between the N-linked glycans. This represents a potential vulnerability of rapidly evolving HIV-1 populations that may provide useful

  15. Targeting HIV-1 Envelope Glycoprotein Trimers to B Cells by Using APRIL Improves Antibody Responses

    OpenAIRE

    Melchers M; Bontjer I; Tong T; Chung NP; Klasse PJ; Eggink D; Montefiori DC; Gentile M; Cerutti A; Olson WC; Berkhout B; Binley JM; Moore JP; Sanders RW

    2012-01-01

    An HIV-1 vaccine remains elusive, in part because various factors limit the quantity and quality of the antibodies raised against the viral envelope glycoprotein complex (Env). We hypothesized that targeting Env vaccines directly to B cells, by fusing them to molecules that bind and activate these cells, would improve Env-specific antibody responses. Therefore, we fused trimeric Env gp140 to A PRoliferation-Inducing Ligand (APRIL), B-cell Activating Factor (BAFF), and CD40 Ligand (CD40L). The...

  16. Evolutionary Interactions between N-Linked Glycosylation Sites in the HIV-1 Envelope

    OpenAIRE

    Art F. Y. Poon; Lewis, Fraser I; Pond, Sergei L. Kosakovsky; Frost, Simon D. W.

    2007-01-01

    The addition of asparagine (N)-linked polysaccharide chains (i.e., glycans) to the gp120 and gp41 glycoproteins of human immunodeficiency virus type 1 (HIV-1) envelope is not only required for correct protein folding, but also may provide protection against neutralizing antibodies as a “glycan shield.” As a result, strong host-specific selection is frequently associated with codon positions where nonsynonymous substitutions can create or disrupt potential N-linked glycosylation sites (PNGSs)....

  17. HIV-1 subtype C envelope characteristics associated with divergent rates of chronic disease progression

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    Goulder Philip JR

    2010-11-01

    Full Text Available Abstract Background HIV-1 envelope diversity remains a significant challenge for the development of an efficacious vaccine. The evolutionary forces that shape the diversity of envelope are incompletely understood. HIV-1 subtype C envelope in particular shows significant differences and unique characteristics compared to its subtype B counterpart. Here we applied the single genome sequencing strategy of plasma derived virus from a cohort of therapy naïve chronically infected individuals in order to study diversity, divergence patterns and envelope characteristics across the entire HIV-1 subtype C gp160 in 4 slow progressors and 4 progressors over an average of 19.5 months. Results Sequence analysis indicated that intra-patient nucleotide diversity within the entire envelope was higher in slow progressors, but did not reach statistical significance (p = 0.07. However, intra-patient nucleotide diversity was significantly higher in slow progressors compared to progressors in the C2 (p = 0.0006, V3 (p = 0.01 and C3 (p = 0.005 regions. Increased amino acid length and fewer potential N-linked glycosylation sites (PNGs were observed in the V1-V4 in slow progressors compared to progressors (p = 0.009 and p = 0.02 respectively. Similarly, gp41 in the progressors was significantly longer and had fewer PNGs compared to slow progressors (p = 0.02 and p = 0.02 respectively. Positive selection hotspots mapped mainly to V1, C3, V4, C4 and gp41 in slow progressors, whereas hotspots mapped mainly to gp41 in progressors. Signature consensus sequence differences between the groups occurred mainly in gp41. Conclusions These data suggest that separate regions of envelope are under differential selective forces, and that envelope evolution differs based on disease course. Differences between slow progressors and progressors may reflect differences in immunological pressure and immune evasion mechanisms. These data also indicate that the pattern of envelope evolution

  18. Dense display of HIV-1 envelope spikes on the lambda phage scaffold does not result in the generation of improved antibody responses to HIV-1 Env

    OpenAIRE

    Mattiacio, Jonelle; Walter, Scott; Brewer, Matt; Domm, William; Friedman, Alan E.; Dewhurst, Stephen

    2011-01-01

    The generation of strong, virus-neutralizing antibody responses to the HIV-1 envelope spike (Env) is a major goal in HIV-1 vaccine research. To try to enhance the Env-specific response, we displayed oligomeric gp140 on a virus-like scaffold provided by the lambda phage capsid. To do this, an in vitro complementation system was used to “decorate” phage particles with glycosylated, mammalian cell-derived envelope oligomers. We compared the immune response to lambda phage particles displaying HI...

  19. Characterization of HIV-1 envelope gp41 genetic diversity and functional domains following perinatal transmission

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    Davis Tiffany

    2006-07-01

    Full Text Available Abstract Background HIV-1 envelope gp41 is a transmembrane protein that promotes fusion of the virus with the plasma membrane of the host cells required for virus entry. In addition, gp41 is an important target for the immune response and development of antiviral and vaccine strategies, especially when targeting the highly variable envelope gp120 has not met with resounding success. Mutations in gp41 may affect HIV-1 entry, replication, pathogenesis, and transmission. We, therefore, characterized the molecular properties of gp41, including genetic diversity, functional motifs, and evolutionary dynamics from five mother-infant pairs following perinatal transmission. Results The gp41 open reading frame (ORF was maintained with a frequency of 84.17% in five mother-infant pairs' sequences following perinatal transmission. There was a low degree of viral heterogeneity and estimates of genetic diversity in gp41 sequences. Both mother and infant gp41 sequences were under positive selection pressure, as determined by ratios of non-synonymous to synonymous substitutions. Phylogenetic analysis of 157 mother-infant gp41 sequences revealed distinct clusters for each mother-infant pair, suggesting that the epidemiologically linked mother-infant pairs were evolutionarily closer to each other as compared with epidemiologically unlinked sequences. The functional domains of gp41, including fusion peptide, heptad repeats, glycosylation sites and lentiviral lytic peptides were mostly conserved in gp41 sequences analyzed in this study. The CTL recognition epitopes and motifs recognized by fusion inhibitors were also conserved in the five mother-infant pairs. Conclusion The maintenance of an intact envelope gp41 ORF with conserved functional domains and a low degree of genetic variability as well as positive selection pressure for adaptive evolution following perinatal transmission is consistent with an indispensable role of envelope gp41 in HIV-1 replication and

  20. 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.

  1. Alteration of Methamphetamine-Induced Stereotypic Behaviour in Transgenic Mice Expressing HIV-1 Envelope Protein gp120

    OpenAIRE

    Roberts, Amanda J.; Maung, Ricky; Sejbuk, Natalia E.; Ake, Christopher; Kaul, Marcus

    2009-01-01

    The use of drugs for recreational purposes, in particular Methamphetamine, is associated with an increased risk of infection with human immunodeficiency virus (HIV)-1. HIV-1 infection in turn can lead to HIV-associated neurological disorders (HAND) that range from mild cognitive and motor impairment to HIV-associated dementia (HAD). Interestingly, post mortem brain specimens from HAD patients and transgenic (tg) mice expressing the viral envelope protein gp120 in the central nervous system di...

  2. Efficient trapping of HIV-1 envelope protein by hetero-oligomerization with an N-helix chimera

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    Silver Jonathan

    2005-08-01

    Full Text Available Abstract Background The N-heptad repeat region of the HIV-1 Transmembrane Envelope protein is a trimerization domain that forms part of a "six helix bundle" crucial to Envelope-mediated membrane fusion. N-heptad repeat peptides have been used as extracellular reagents to inhibit virus fusion. Results When expressed intracellularly with wild-type HIV-1 Envelope protein, the N-heptad repeat domain efficiently hetero-oligomerized with Envelope and trapped it in the endoplasmic reticulum or early Golgi, as indicated by lack of transport to the cell surface, absent proteolytic processing, and aberrant glycosylation. Conclusion Post-translational processing of HIV Envelope is very sensitive to an agent that binds to the N-heptad repeat during synthesis, suggesting that it might be possible to modify drugs that bind to this region to have transport-blocking properties.

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

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    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.

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

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    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.

  5. Recombination Enhances HIV-1 Envelope Diversity by Facilitating the Survival of Latent Genomic Fragments in the Plasma Virus Population.

    Science.gov (United States)

    Immonen, Taina T; Conway, Jessica M; Romero-Severson, Ethan O; Perelson, Alan S; Leitner, Thomas

    2015-12-01

    HIV-1 is subject to immune pressure exerted by the host, giving variants that escape the immune response an advantage. Virus released from activated latent cells competes against variants that have continually evolved and adapted to host immune pressure. Nevertheless, there is increasing evidence that virus displaying a signal of latency survives in patient plasma despite having reduced fitness due to long-term immune memory. We investigated the survival of virus with latent envelope genomic fragments by simulating within-host HIV-1 sequence evolution and the cycling of viral lineages in and out of the latent reservoir. Our model incorporates a detailed mutation process including nucleotide substitution, recombination, latent reservoir dynamics, diversifying selection pressure driven by the immune response, and purifying selection pressure asserted by deleterious mutations. We evaluated the ability of our model to capture sequence evolution in vivo by comparing our simulated sequences to HIV-1 envelope sequence data from 16 HIV-infected untreated patients. Empirical sequence divergence and diversity measures were qualitatively and quantitatively similar to those of our simulated HIV-1 populations, suggesting that our model invokes realistic trends of HIV-1 genetic evolution. Moreover, reconstructed phylogenies of simulated and patient HIV-1 populations showed similar topological structures. Our simulation results suggest that recombination is a key mechanism facilitating the persistence of virus with latent envelope genomic fragments in the productively infected cell population. Recombination increased the survival probability of latent virus forms approximately 13-fold. Prevalence of virus with latent fragments in productively infected cells was observed in only 2% of simulations when we ignored recombination, while the proportion increased to 27% of simulations when we allowed recombination. We also found that the selection pressures exerted by different fitness

  6. Prediction of exposed domains of envelope glycoprotein in Indian HIV-1 isolates and experimental confirmation of their immunogenicity in humans

    Directory of Open Access Journals (Sweden)

    Mohabatkar H.

    2004-01-01

    Full Text Available We describe the impact of subtype differences on the seroreactivity of linear antigenic epitopes in envelope glycoprotein of HIV-1 isolates from different geographical locations. By computer analysis, we predicted potential antigenic sites of envelope glycoprotein (gp120 and gp4l of this virus. For this purpose, after fetching sequences of proteins of interest from data banks, values of hydrophilicity, flexibility, accessibility, inverted hydrophobicity, and secondary structure were considered. We identified several potential antigenic epitopes in a B subtype strain of envelope glycoprotein of HIV-1 (IIIB. Solid- phase peptide synthesis methods of Merrifield and Fmoc chemistry were used for synthesizing peptides. These synthetic peptides corresponded mainly to the C2, V3 and CD4 binding sites of gp120 and some parts of the ectodomain of gp41. The reactivity of these peptides was tested by ELISA against different HIV-1-positive sera from different locations in India. For two of these predicted epitopes, the corresponding Indian consensus sequences (LAIERYLKQQLLGWG and DIIGDIRQAHCNISEDKWNET (subtype C were also synthesized and their reactivity was tested by ELISA. These peptides also distinguished HIV-1-positive sera of Indians with C subtype infections from sera from HIV-negative subjects.

  7. 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.

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

    International Nuclear Information System (INIS)

    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.

  9. 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.

  10. 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

  11. The immunosuppressive domain of the transmembrane envelope protein gp41 of HIV-1 binds to human monocytes and B cells.

    Science.gov (United States)

    Mühle, Michael; Kroniger, Tobias; Hoffmann, Kerstin; Denner, Joachim

    2016-06-01

    The induction of the acquired immunodeficiency syndrome by the human immunodeficiency virus-1 (HIV-1) is a complex process which is not yet understood in full detail. Still open is the question whether the highly conserved so-called immunosuppressive (Isu) domain in the transmembrane envelope (TM) protein gp41 of HIV-1 is actively participating in immunopathogenesis. Inactivated virus particles, recombinant gp41 and peptides corresponding to the Isu domain have been reported to inhibit lymphocyte proliferation, as well as to alter cytokine release and gene expression. Here we demonstrate, using fluorescence-activated cell sorting and competition experiments, that homopolymers of the Isu peptide of HIV-1 are binding specifically to human peripheral blood mononuclear cells, mainly to monocytes and B cells. These data suggest that a putative receptor might be involved in the immunomodulatory effects observed previously. PMID:26754765

  12. 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...

  13. 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

  14. 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

  15. Nucleic acids encoding mosaic clade M human immunodeficiency virus type 1 (HIV-1) envelope immunogens

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette T; Fischer, William; Liao, Hua-Xin; Haynes, Barton F; Letvin, Norman; Hahn, Beatrice H

    2015-04-21

    The present invention relates to nucleic acids encoding mosaic clade M HIV-1 Env polypeptides and to compositions and vectors comprising same. The nucleic acids of the invention are suitable for use in inducing an immune response to HIV-1 in a human.

  16. Role of protein disulfide isomerase and other thiol-reactive proteins in HIV-1 envelope protein-mediated fusion

    International Nuclear Information System (INIS)

    Cell-surface protein disulfide isomerase (PDI) has been proposed to promote disulfide bond rearrangements in HIV-1 envelope protein (Env) that accompany Env-mediated fusion. We evaluated the role of PDI in ways that have not been previously tested by downregulating PDI with siRNA and by overexpressing wild-type or variant forms of PDI in transiently and stably transfected cells. These manipulations, as well as treatment with anti-PDI antibodies, had only small effects on infection or cell fusion mediated by NL4-3 or AD8 strains of HIV-1. However, the cell-surface thiol-reactive reagent 5, 5'-dithiobis(2-nitrobenzoic acid) (DTNB) had a much stronger inhibitory effect in our system, suggesting that cell-surface thiol-containing molecules other than PDI, acting alone or in concert, have a greater effect than PDI on HIV-1 Env-mediated fusion. We evaluated one such candidate, thioredoxin, a PDI family member reported to reduce a labile disulfide bond in CD4. We found that the ability of thioredoxin to reduce the disulfide bond in CD4 is enhanced in the presence of HIV-1 Env gp120 and that thioredoxin also reduces disulfide bonds in gp120 directly in the absence of CD4. We discuss the implications of these observations for identification of molecules involved in disulfide rearrangements in Env during fusion

  17. 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.

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

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    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

  19. Cellulose acetate phthalate, a common pharmaceutical excipient, inactivates HIV-1 and blocks the coreceptor binding site on the virus envelope glycoprotein gp120

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    Li Yun-Yao

    2001-09-01

    Full Text Available Abstract Background Cellulose acetate phthalate (CAP, a pharmaceutical excipient used for enteric film coating of capsules and tablets, was shown to inhibit infection by the human immunodeficiency virus type 1 (HIV-1 and several herpesviruses. CAP formulations inactivated HIV-1, herpesvirus types 1 (HSV-1 and 2 (HSV-2 and the major nonviral sexually transmitted disease (STD pathogens and were effective in animal models for vaginal infection by HSV-2 and simian immunodeficiency virus. Methods Enzyme-linked immunoassays and flow cytometry were used to demonstrate CAP binding to HIV-1 and to define the binding site on the virus envelope. Results 1 CAP binds to HIV-1 virus particles and to the envelope glycoprotein gp120; 2 this leads to blockade of the gp120 V3 loop and other gp120 sites resulting in diminished reactivity with HIV-1 coreceptors CXCR4 and CCR5; 3 CAP binding to HIV-1 virions impairs their infectivity; 4 these findings apply to both HIV-1 IIIB, an X4 virus, and HIV-1 BaL, an R5 virus. Conclusions These results provide support for consideration of CAP as a topical microbicide of choice for prevention of STDs, including HIV-1 infection.

  20. 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 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...

  1. Effect of trimerization motifs on quaternary structure, antigenicity, and immunogenicity of a noncleavable HIV-1 gp140 envelope glycoprotein

    International Nuclear Information System (INIS)

    The external domains of the HIV-1 envelope glycoprotein (gp120 and the gp41 ectodomain, collectively known as gp140) contain all known viral neutralization epitopes. Various strategies have been used to create soluble trimers of the envelope to mimic the structure of the native viral protein, including mutation of the gp120-gp41 cleavage site, introduction of disulfide bonds, and fusion to heterologous trimerization motifs. We compared the effects on quaternary structure, antigenicity, and immunogenicity of three such motifs: T4 fibritin, a GCN4 variant, and the Escherichia coli aspartate transcarbamoylase catalytic subunit. Fusion of each motif to the C-terminus of a noncleavable JRCSF gp140(-) envelope protein led to enhanced trimerization but had limited effects on the antigenic profile and CD4-binding ability of the trimers. Immunization of rabbits provided no evidence that the trimerized gp140(-) constructs induced significantly improved neutralizing antibodies to several HIV-1 pseudoviruses, compared to gp140 lacking a trimerization motif. However, modest differences in both binding specificity and neutralizing antibody responses were observed among the various immunogens.

  2. Computer-aided design of novel HIV-1 entry inhibitors blocking the virus envelope gp120 V3 loop

    Directory of Open Access Journals (Sweden)

    Tuzikov A. V.

    2012-12-01

    Full Text Available Aim. The object of this study was to implement computer-aided design of the water-soluble analog of glycolipid β -galactosylceramide (β-GalCer, which presents a potential HIV-1 entry inhibitor, by the analysis of intermolecular interactions of β-GalCer with the central region of the virus envelope gp120 V3 loop followed by synthesis of this glycolipid derivative and testing for antiviral activity. Methods. To reach the object of view, computer modeling procedures, such as quantum chemical calculations, molecular docking, molecular dynamics and free energy simulations, were involved in the studies in conjunction with chemical synthesis and anti-HIV-1 assay methods. Results. As a result, the high probability of exhibiting of antiviral activity was predicted for the designed β-GalCer analog. The data of molecular modeling were confirmed by those of primary medical trials of the synthesized compound. Conclusions. In the light of the findings obtained, the designed analog of β-GalCer may be considered as the basic structure for simulation of its more potent structural forms and for posterior selection of drug candidates most promising for synthesis and anti-HIV-1 assays.

  3. 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...

  4. 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

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

    Science.gov (United States)

    Saha, Kunal; Yan, Hui; Nelson, Julie A E; Zerhouni-Layachi, Bouchra

    2005-06-20

    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. PMID:15914218

  6. 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.

  7. 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

  8. Assembly, structure, and antigenic properties of virus-like particles rich in HIV-1 envelope gp120

    International Nuclear Information System (INIS)

    In order to improve the immunogenicity of HIV-1 envelope glycoproteins, we have fused gp120 to a carrier protein, hepatitis B surface antigen (HBsAg), which is capable of spontaneous assembly into virus-like particles. The HBsAg-gp120 hybrid proteins assembled efficiently into 20-30 nm particles. The particles resemble native HBsAg particles in size and density, consistent with a lipid composition of about 25% and a gp120 content of about 100 per particle. Particulate gp120 folds in its native conformation and is biologically active, as shown by high affinity binding of CD4. The particles express conformational determinants targeted by a panel of broadly cross-reactive neutralizing antibodies, and they show tight packing of gp120. Because the particles are lipoprotein micelles, an array of gp120 on their surface closely mimics gp120 on the surface of HIV-1 virions. These gp120-rich particles can enhance the quality, as well as quantity, of antibodies elicited by a gp120 vaccine

  9. Cross-Reactive Human IgM-Derived Monoclonal Antibodies that Bind to HIV-1 Envelope Glycoproteins.

    Science.gov (United States)

    Chen, Weizao; Zhu, Zhongyu; Liao, Huaxin; Quinnan, Gerald V; Broder, Christopher C; Haynes, Barton F; Dimitrov, Dimiter S

    2010-02-01

    Elicitation of antibodies with potent and broad neutralizing activity against HIV by immunization remains a challenge. Several monoclonal antibodies (mAbs) isolated from humans with HIV-1 infection exhibit such activity but vaccine immunogens based on structures containing their epitopes have not been successful for their elicitation. All known broadly neutralizing mAbs (bnmAbs) are immunoglobulin (Ig) Gs (IgGs) and highly somatically hypermutated which could impede their elicitation. Ig Ms (IgMs) are on average significantly less divergent from germline antibodies and are relevant for the development of vaccine immunogens but are underexplored compared to IgGs. Here we describe the identification and characterization of several human IgM-derived mAbs against HIV-1 which were selected from a large phage-displayed naive human antibody library constructed from blood, lymph nodes and spleens of 59 healthy donors. These antibodies bound with high affinity to recombinant envelope glycoproteins (gp140s, Envs) of HIV-1 isolates from different clades. They enhanced or did not neutralize infection by some of the HIV-1 primary isolates using CCR5 as a coreceptor but neutralized all CXCR4 isolates tested although weakly. One of these antibodies with relatively low degree of somatic hypermutation was more extensively characterized. It bound to a highly conserved region partially overlapping with the coreceptor binding site and close to but not overlapping with the CD4 binding site. These results suggest the existence of conserved structures that could direct the immune response to non-neutralizing or even enhancing antibodies which may represent a strategy used by the virus to escape neutralizing immune responses. Further studies will show whether such a strategy plays a role in HIV infection of humans, how important that role could be, and what the mechanisms of infection enhancement are. The newly identified mAbs could be used as reagents to further characterize conserved

  10. Cross-Reactive Human IgM-Derived Monoclonal Antibodies that Bind to HIV-1 Envelope Glycoproteins

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    Barton F. Haynes

    2010-02-01

    Full Text Available Elicitation of antibodies with potent and broad neutralizing activity against HIV by immunization remains a challenge. Several monoclonal antibodies (mAbs isolated from humans with HIV-1 infection exhibit such activity but vaccine immunogens based on structures containing their epitopes have not been successful for their elicitation. All known broadly neutralizing mAbs (bnmAbs are immunoglobulin (Ig Gs (IgGs and highly somatically hypermutated which could impede their elicitation. Ig Ms (IgMs are on average significantly less divergent from germline antibodies and are relevant for the development of vaccine immunogens but are underexplored compared to IgGs. Here we describe the identification and characterization of several human IgM-derived mAbs against HIV-1 which were selected from a large phage-displayed naive human antibody library constructed from blood, lymph nodes and spleens of 59 healthy donors. These antibodies bound with high affinity to recombinant envelope glycoproteins (gp140s, Envs of HIV-1 isolates from different clades. They enhanced or did not neutralize infection by some of the HIV-1 primary isolates using CCR5 as a coreceptor but neutralized all CXCR4 isolates tested although weakly. One of these antibodies with relatively low degree of somatic hypermutation was more extensively characterized. It bound to a highly conserved region partially overlapping with the coreceptor binding site and close to but not overlapping with the CD4 binding site. These results suggest the existence of conserved structures that could direct the immune response to non-neutralizing or even enhancing antibodies which may represent a strategy used by the virus to escape neutralizing immune responses. Further studies will show whether such a strategy plays a role in HIV infection of humans, how important that role could be, and what the mechanisms of infection enhancement are. The newly identified mAbs could be used as reagents to further

  11. HIV-1 tropism for the central nervous system: Brain-derived envelope glycoproteins with lower CD4 dependence and reduced sensitivity to a fusion inhibitor

    International Nuclear Information System (INIS)

    We previously described envelope glycoproteins of an HIV-1 isolate adapted in vitro for growth in microglia that acquired a highly fusogenic phenotype and lower CD4 dependence, as well as resistance to inhibition by anti-CD4 antibodies. Here, we investigated whether similar phenotypic changes are present in vivo. Envelope clones from the brain and spleen of an HIV-1-infected individual with neurological disease were amplified, cloned, and sequenced. Phylogenetic analysis demonstrated clustering of sequences according to the tissue of origin, as expected. Functional clones were then used in cell-to-cell fusion assays to test for CD4 and co-receptor utilization and for sensitivity to various antibodies and inhibitors. Both brain- and spleen-derived envelope clones mediated fusion in cells expressing both CD4 and CCR5 and brain envelopes also used CCR3 as co-receptor. We found that the brain envelopes had a lower CD4 dependence, since they efficiently mediated fusion in the presence of low levels of CD4 on the target cell membrane, and they were significantly more resistant to blocking by anti-CD4 antibodies than the spleen-derived envelopes. In contrast, we observed no difference in sensitivity to the CCR5 antagonist TAK-779. However, brain-derived envelopes were significantly more resistant than those from spleen to the fusion inhibitor T-1249 and concurrently showed slightly greater fusogenicity. Our results suggest an increased affinity for CD4 of brain-derived envelopes that may have originated from in vivo adaptation to replication in microglial cells. Interestingly, we note the presence of envelopes more resistant to a fusion inhibitor in the brain of an untreated, HIV-1-infected individual

  12. Recruitment of HIV-1 envelope occurs subsequent to lipid mixing: a fluorescence microscopic evidence

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    Lin Chi-Hui

    2009-03-01

    Full Text Available Abstract Entry of the human immunodeficiency virus (HIV into the target cell is initiated by fusion with the cell membrane, mediated through the envelope glycoproteins gp120 and gp41, following engagement to CD4 and the co-receptor. Previous fusion kinetics studies on the HXB2 envelope protein (Env revealed that Env recruitment occurred at about 13 min concurrent with the lipid mixing. To resolve the temporal sequence of lipid mixing and recruitment, we employed an inhibitory assay monitored by fluorescence microscopy using a gp41 ectodomain (gp41e fragment, which blocked Env recruitment in stark contrast to the lack of gp41e effect on the lipid mixing. In addition, to demonstrate the mode of action for the inhibition of gp41e, our results strongly suggested that lipid mixing precedes the Env recruitment because lipid mixing can proceed with Env recruitment inhibited by exogeneous gp41e molecules. Importantly, it was found that the random clustering of Env molecules on the membrane surface occurred at ~1 minute whereas the Env recruitment was observed at 13 minutes after the attachment of Env-expressing cell to the target cell. This > 10-fold temporal discrepancy highlights that the productive assembly of Env molecules leading to fusion requires spatio-temporal coordination of several adjacent Env trimers aggregated via directed movement.

  13. CD4-binding site alterations in CCR5-using HIV-1 envelopes influencing gp120-CD4 interactions and fusogenicity

    International Nuclear Information System (INIS)

    CD4-binding site (CD4bs) alterations in gp120 contribute to different pathophysiological phenotypes of CCR5-using (R5) HIV-1 strains, but the potential structural basis is unknown. Here, we characterized functionally diverse R5 envelope (Env) clones (n = 16) to elucidate potential structural alterations within the gp120 CD4bs that influence Env function. Initially, we showed that the magnitude of gp120-CD4-binding correlates with increased fusogenicity and reduced CD4 dependence. Analysis of three-dimensional gp120 structural models revealed two CD4bs variants, D279 and N362, that were associated with reduced CD4 dependence. Further structural analysis showed that a wider aperture of the predicted CD4bs cavity, as constrained by the inner-most atoms at the gp120 V1V2 stem and the V5 loop, was associated with amino acid alterations within V5 and correlated with increased gp120-CD4 binding and increased fusogenicity. Our results provide evidence that the gp120 V5 loop may alter CD4bs conformation and contribute to increased gp120-CD4 interactions and Env fusogenicity.

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

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    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

  15. 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

  16. 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

  17. 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...

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

    International Nuclear Information System (INIS)

    We previously reported that an envelope (Env) glycoprotein immunogen (o-gp140ΔV2SF162) 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 SHIVSF162P4 virus. Extending our studies to subtype C isolate TV1, we have purified o-gp140ΔV2TV1 (subtype C ΔV2 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 ΔV2 trimer; however, we did not observe significant binding for the b12 mAb. The molecular mass of subtype C ΔV2 trimer was found to be 450 kDa, and the hydrodynamic radius was found to be 10.87 nm. Our data suggest that subtype C ΔV2 trimer binds to CD4 with an affinity comparable to o-gp140ΔV2SF162 (subtype B ΔV2 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 ΔV2 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

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

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    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.

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

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    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.

  1. 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.

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

    OpenAIRE

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

    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 VTT-...

  3. 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...

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

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    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.

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

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    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.

  6. 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

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    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.

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

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    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.

  8. Mutagenesis of tyrosine and di-leucine motifs in the HIV-1 envelope cytoplasmic domain results in a loss of Env-mediated fusion and infectivity

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    Claiborne Daniel T

    2011-05-01

    Full Text Available Abstract Background The gp41 component of the Human Immunodeficiency Virus (HIV envelope glycoprotein (Env contains a long cytoplasmic domain (CD with multiple highly conserved tyrosine (Y and dileucine (LL motifs. Studies suggest that the motifs distal to major endocytosis motif (Y712HRL, located at residues 712-715 of Env, may contribute to Env functionality in the viral life cycle. In order to examine the biological contribution of these motifs in the biosynthesis, transport, and function of Env, we constructed two panels of mutants in which the conserved Y- and LL-motifs were sequentially substituted by alternative residues, either in the presence or absence of Y712. Additional mutants targeting individual motifs were then constructed. Results All mutant Envs, when expressed in the absence of other viral proteins, maintained at least WT levels of Env surface staining by multiple antibodies. The Y712 mutation (Y712C contributed to at least a 4-fold increase in surface expression for all mutants containing this change. Sequential mutagenesis of the Y- and LL-motifs resulted in a generally progressive decrease in Env fusogenicity. However, additive mutation of dileucine and tyrosine motifs beyond the tyrosine at residue 768 resulted in the most dramatic effects on Env incorporation into virions, viral infectivity, and virus fusion with target cells. Conclusions From the studies reported here, we show that mutations of the Y- and LL-motifs, which effectively eliminate the amphipathic nature of the lytic peptide 2 (LLP2 domain or disrupt YW and LL motifs in a region spanning residues 795-803 (YWWNLLQYW, just C-terminal of LLP2, can dramatically interfere with biological functions of HIV-1 Env and abrogate virus replication. Because these mutant proteins are expressed at the cell surface, we conclude that tyrosine and di-leucine residues within the cytoplasmic domain of gp41 play critical roles in HIV-1 replication that are distinct from that of

  9. Comparison on virulence and immunogenicity of two recombinant vaccinia vaccines, Tian Tan and Guang9 strains, expressing the HIV-1 envelope gene.

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    Rong Zhu

    Full Text Available 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 VTT-E were evaluated. Our results indicated no obvious difference in range of host cells and diffusion between two recombinant viruses. Neurovirulence for VG9-E in weanling and suckling mice, and skin virulence in rabbits, were lower than that of VTT-E. The humoral immune responses, including binding antibody and neutralizing antibody responses, induced by VG9-E were not significantly different from those for VTT-E whilst IFN-γ response which represented cellular immune response induced by VG9-E was significantly higher than that did by VTT-E. CONCLUSIONS/SIGNIFICANCE: Our results indicated that VG9-E was less virulent, yet induced higher cellular immune response than VTT-E. Therefore, it could be an ideal replicating vaccinia vector for HIV vaccine research and development.

  10. The HIV-1 envelope protein gp120 is captured and displayed for B cell recognition by SIGN-R1(+) lymph node macrophages.

    Science.gov (United States)

    Park, Chung; Arthos, James; Cicala, Claudia; Kehrl, John H

    2015-01-01

    The HIV-1 envelope protein gp120 is both the target of neutralizing antibodies and a major focus of vaccine efforts; however how it is delivered to B cells to elicit an antibody response is unknown. Here, we show that following local gp120 injection lymph node (LN) SIGN-R1(+) sinus macrophages located in interfollicular pockets and underlying SIGN-R1(+) macrophages form a cellular network that rapidly captures gp120 from the afferent lymph. In contrast, two other antigens, phycoerythrin and hen egg lysozyme, were not captured by these cells. Intravital imaging of mouse LNs revealed persistent, but transient interactions between gp120 bearing interfollicular network cells and both trafficking and LN follicle resident gp120 specific B cells. The gp120 specific, but not the control B cells repetitively extracted gp120 from the network cells. Our findings reveal a specialized LN antigen delivery system poised to deliver gp120 and likely other pathogen derived glycoproteins to B cells. PMID:26258881

  11. 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

  12. 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 (...

  13. Role of HIV-1 subtype C envelope V3 to V5 regions in viral entry, coreceptor utilization and replication efficiency in primary T-lymphocytes and monocyte-derived macrophages

    Directory of Open Access Journals (Sweden)

    Gopalan Sarla

    2007-11-01

    Full Text Available Abstract Background Several subtypes of HIV-1 circulate in infected people worldwide, including subtype B in the United States and subtype C in Africa and India. To understand the biological properties of HIV-1 subtype C, including cellular tropism, virus entry, replication efficiency and cytopathic effects, we reciprocally inserted our previously characterized envelope V3–V5 regions derived from 9 subtype C infected patients from India into a subtype B molecular clone, pNL4-3. Equal amounts of the chimeric viruses were used to infect T-lymphocyte cell lines (A3.01 and MT-2, coreceptor cell lines (U373-MAGI-CCR5/CXCR4, primary blood T-lymphocytes (PBL and monocyte-derived macrophages (MDM. Results We found that subtype C envelope V3–V5 region chimeras failed to replicate in T-lymphocyte cell lines but replicated in PBL and MDM. In addition, these chimeras were able to infect U373MAGI-CD4+-CCR5+ but not U373MAGI-CD4+-CXCR4+ cell line, suggesting CCR5 coreceptor utilization and R5 phenotypes. These subtype C chimeras were unable to induce syncytia in MT-2 cells, indicative of non-syncytium inducing (NSI phenotypes. More importantly, the subtype C envelope chimeras replicated at higher levels in PBL and MDM compared with subtype B chimeras and isolates. Furthermore, the higher levels subtype C chimeras replication in PBL and MDM correlated with increased virus entry in U373MAGI-CD4+-CCR5+. Conclusion Taken together, these results suggest that the envelope V3 to V5 regions of subtype C contributed to higher levels of HIV-1 replication compared with subtype B chimeras, which may contribute to higher viral loads and faster disease progression in subtype C infected individuals than other subtypes as well as rapid HIV-1 subtype C spread in India.

  14. 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

  15. 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.

  16. Cellulose acetate phthalate, a common pharmaceutical excipient, inactivates HIV-1 and blocks the coreceptor binding site on the virus envelope glycoprotein gp120

    OpenAIRE

    Li Yun-Yao; Strick Nathan; Neurath A Robert; Debnath Asim K

    2001-01-01

    Abstract Background Cellulose acetate phthalate (CAP), a pharmaceutical excipient used for enteric film coating of capsules and tablets, was shown to inhibit infection by the human immunodeficiency virus type 1 (HIV-1) and several herpesviruses. CAP formulations inactivated HIV-1, herpesvirus types 1 (HSV-1) and 2 (HSV-2) and the major nonviral sexually transmitted disease (STD) pathogens and were effective in animal models for vaginal infection by HSV-2 and simian immunodeficiency virus. Met...

  17. 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

  18. 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

  19. 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.

  20. 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...

  1. Human Non-neutralizing HIV-1 Envelope Monoclonal Antibodies Limit the Number of Founder Viruses during SHIV Mucosal Infection in Rhesus Macaques.

    Directory of Open Access Journals (Sweden)

    Sampa Santra

    2015-08-01

    Full Text Available HIV-1 mucosal transmission begins with virus or virus-infected cells moving through mucus across mucosal epithelium to infect CD4+ T cells. Although broadly neutralizing antibodies (bnAbs are the type of HIV-1 antibodies that are most likely protective, they are not induced with current vaccine candidates. In contrast, antibodies that do not neutralize primary HIV-1 strains in the TZM-bl infection assay are readily induced by current vaccine candidates and have also been implicated as secondary correlates of decreased HIV-1 risk in the RV144 vaccine efficacy trial. Here, we have studied the capacity of anti-Env monoclonal antibodies (mAbs against either the immunodominant region of gp41 (7B2 IgG1, the first constant region of gp120 (A32 IgG1, or the third variable loop (V3 of gp120 (CH22 IgG1 to modulate in vivo rectal mucosal transmission of a high-dose simian-human immunodeficiency virus (SHIV-BaL in rhesus macaques. 7B2 IgG1 or A32 IgG1, each containing mutations to enhance Fc function, was administered passively to rhesus macaques but afforded no protection against productive clinical infection while the positive control antibody CH22 IgG1 prevented infection in 4 of 6 animals. Enumeration of transmitted/founder (T/F viruses revealed that passive infusion of each of the three antibodies significantly reduced the number of T/F genomes. Thus, some antibodies that bind HIV-1 Env but fail to neutralize virus in traditional neutralization assays may limit the number of T/F viruses involved in transmission without leading to enhancement of viral infection. For one of these mAbs, gp41 mAb 7B2, we provide the first co-crystal structure in complex with a common cyclical loop motif demonstrated to be critical for infection by other retroviruses.

  2. 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...

  3. 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...

  4. 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.

  5. 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. PMID:27017055

  6. 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.

  7. 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

  8. HIV-1 therapy with monoclonal antibody 3BNC117 elicits host immune responses against HIV-1

    OpenAIRE

    Schoofs, Till; Klein, Florian; Braunschweig, Malte; Kreider, Edward F.; Feldmann, Anna; Nogueira, Lilian; Oliveira, Thiago; Lorenzi, Julio C. C.; Parrish, Erica H.; Learn, Gerald H.; West, Anthony P.; Bjorkman, Pamela J.; Schlesinger, Sarah J.; Seaman, Michael S.; Czartoski, Julie

    2016-01-01

    3BNC117 is a broad and potent neutralizing antibody to HIV-1 that targets the CD4 binding site on the viral envelope spike. When administered passively, this antibody can prevent infection in animal models and suppress viremia in HIV-1–infected individuals. Here we report that HIV-1 immunotherapy with a single injection of 3BNC117 affects host antibody responses in viremic individuals. In comparison to untreated controls that showed little change in their neutralizing activity over a 6-month ...

  9. In vitro uncoating of HIV-1 cores.

    Science.gov (United States)

    Shah, Vaibhav B; Aiken, Christopher

    2011-01-01

    The genome of the retroviruses is encased in a capsid surrounded by a lipid envelope. For lentiviruses, such as HIV-1, the conical capsid shell is composed of CA protein arranged as a lattice of hexagon. The capsid is closed by 7 pentamers at the broad end and 5 at the narrow end of the cone(1, 2). Encased in this capsid shell is the viral ribonucleoprotein complex, and together they comprise the core. Following fusion of the viral membrane with the target cell membrane, the HIV-1 is released into the cytoplasm. The capsid then disassembles releasing free CA in the soluble form(3) in a process referred to as uncoating. The intracellular location and timing of HIV-1 uncoating are poorly understood. Single amino-acid substitutions in CA that alter the stability of the capsid also impair the ability of HIV-1 to infect cells(4). This indicates that the stability of the capsid is critical for HIV-1 infection. HIV-1 uncoating has been difficult to study due to lack of availability of sensitive and reliable assays for this process. Here we describe a quantitative method for studying uncoating in vitro using cores isolated from infectious HIV-1 particles. The approach involves isolation of cores by sedimentation of concentrated virions through a layer of detergent and into a linear sucrose gradient, in the cold. To quantify uncoating, the isolated cores are incubated at 37°C for various timed intervals and subsequently pelleted by ultracentrifugation. The extent of uncoating is analyzed by quantifying the fraction of CA in the supernatant. This approach has been employed to analyze effects of viral mutations on HIV-1 capsid stability(4, 5, 6). It should also be useful for studying the role of cellular factors in HIV-1 uncoating. PMID:22105356

  10. In vitro Uncoating of HIV-1 Cores

    Science.gov (United States)

    Shah, Vaibhav B.; Aiken, Christopher

    2011-01-01

    The genome of the retroviruses is encased in a capsid surrounded by a lipid envelope. For lentiviruses, such as HIV-1, the conical capsid shell is composed of CA protein arranged as a lattice of hexagon. The capsid is closed by 7 pentamers at the broad end and 5 at the narrow end of the cone1, 2. Encased in this capsid shell is the viral ribonucleoprotein complex, and together they comprise the core. Following fusion of the viral membrane with the target cell membrane, the HIV-1 is released into the cytoplasm. The capsid then disassembles releasing free CA in the soluble form3 in a process referred to as uncoating. The intracellular location and timing of HIV-1 uncoating are poorly understood. Single amino-acid substitutions in CA that alter the stability of the capsid also impair the ability of HIV-1 to infect cells4. This indicates that the stability of the capsid is critical for HIV-1 infection. HIV-1 uncoating has been difficult to study due to lack of availability of sensitive and reliable assays for this process. Here we describe a quantitative method for studying uncoating in vitro using cores isolated from infectious HIV-1 particles. The approach involves isolation of cores by sedimentation of concentrated virions through a layer of detergent and into a linear sucrose gradient, in the cold. To quantify uncoating, the isolated cores are incubated at 37°C for various timed intervals and subsequently pelleted by ultracentrifugation. The extent of uncoating is analyzed by quantifying the fraction of CA in the supernatant. This approach has been employed to analyze effects of viral mutations on HIV-1 capsid stability4, 5, 6. It should also be useful for studying the role of cellular factors in HIV-1 uncoating. PMID:22105356

  11. Revisiting HIV-1 uncoating

    OpenAIRE

    Arhel Nathalie

    2010-01-01

    Abstract HIV uncoating is defined as the loss of viral capsid that occurs within the cytoplasm of infected cells before entry of the viral genome into the nucleus. It is an obligatory step of HIV-1 early infection and accompanies the transition between reverse transcription complexes (RTCs), in which reverse transcription occurs, and pre-integration complexes (PICs), which are competent to integrate into the host genome. The study of the nature and timing of HIV-1 uncoating has been paved wit...

  12. In vitro Uncoating of HIV-1 Cores

    OpenAIRE

    Shah, Vaibhav B.; Aiken, Christopher

    2011-01-01

    The genome of the retroviruses is encased in a capsid surrounded by a lipid envelope. For lentiviruses, such as HIV-1, the conical capsid shell is composed of CA protein arranged as a lattice of hexagon. The capsid is closed by 7 pentamers at the broad end and 5 at the narrow end of the cone1, 2. Encased in this capsid shell is the viral ribonucleoprotein complex, and together they comprise the core.

  13. 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

  14. Imaging HIV-1 nuclear pre-integration complexes.

    Science.gov (United States)

    Cereseto, Anna; Giacca, Mauro

    2014-01-01

    Advancements in fluorescent microscopy techniques now permit investigation of HIV-1 biology exploiting tools alternative to conventional molecular biology. Here we describe a novel, fluorescence-based method to visualize HIV-1 viral particles within intact nuclei of infected cells. This method allows investigating the localization of pre-integration complexes within the nuclear compartment with respect to the nuclear envelope and the chromatin territories. PMID:24158813

  15. 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?

  16. 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...

  17. Recombinant rabies virus as potential live-viral vaccines for HIV-1.

    Science.gov (United States)

    Schnell, M J; Foley, H D; Siler, C A; McGettigan, J P; Dietzschold, B; Pomerantz, R J

    2000-03-28

    Recombinant, replication-competent rabies virus (RV) vaccine strain-based vectors were developed expressing HIV type I (HIV-1) envelope glycoprotein (gp160) from both a laboratory-adapted (CXCR4-tropic) and a primary (dual-tropic) HIV-1 isolate. An additional transcription stop/start unit within the RV genome was used to express HIV-1 gp160 in addition to the other RV proteins. The HIV-1 gp160 protein was stably and functionally expressed, as indicated by fusion of human T cell lines after infection with the recombinant RVs. Inoculation of mice with the recombinant RVs expressing HIV-1 gp160 induced a strong humoral response directed against the HIV-1 envelope protein after a single boost with recombinant HIV-1 gp120 protein. Moreover, high neutralization titers up to 1:800 against HIV-1 could be detected in the mouse sera. These data indicate that a live recombinant RV, a rhabdovirus, expressing HIV-1 gp160 may serve as an effective vector for an HIV-1 vaccine. PMID:10706640

  18. 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.

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

    OpenAIRE

    DelphineMMuriaux; PhilippeBenaroch

    2014-01-01

    HIV-1 is an RNA enveloped virus that preferentially infects CD4+ T lymphocytes and also macrophages. In CD4+ T cells, HIV-1 mainly buds from the host cell plasma membrane. The viral Gag polyprotein targets the plasma membrane and is the orchestrator of the HIV assembly as its expression is sufficient to promote the formation of virus-like particles particles carrying a lipidic envelope deriving from the host cell membrane. Certain lipids are enriched in the viral...

  20. 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 ...

  1. A novel small-molecule inhibitor of HIV-1 entry

    Directory of Open Access Journals (Sweden)

    Heredia A

    2015-10-01

    Full Text Available Alonso Heredia,1,3 Olga S Latinovic,2,3 Florent Barbault,4 Erik PH de Leeuw3,5 1Department of Medicine, 2Department of Microbiology and Immunology, 3Institute of Human Virology, University of Maryland Baltimore School of Medicine, Baltimore, MD, USA; 4Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMRCNRS7086, Paris, France; 5Department of Biochemistry and Molecular Biology, University of Maryland Baltimore School of Medicine, Baltimore, MD, USA Background: Antiretroviral therapy has transformed HIV-1 infection into a managed condition with near-normal life expectancy. However, a significant number of patients remain with limited therapeutic options due to HIV-1 resistance, side effects, or drug costs. Further, it is likely that current drugs will not retain efficacy, due to risks of side effects and transmitted resistance.Results: We describe compound 5660386 (3-ethyl-2-[3-(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidene-1-propen-1-yl]-1,3-benzothiazol-3-ium as a novel inhibitor of HIV-1 entry. Compound 5660386 inhibits HIV-1 entry in cell lines and primary cells, binds to HIV-1 envelope protein, and inhibits the interaction of GP120 to CD4. Further, compound 5660386 showed a unique and broad-range activity against primary HIV-1 isolates from different subtypes and geographical areas.Conclusion: Development of small-molecule entry inhibitors of HIV-1 such as 5660386 may lead to novel classes of anti-HIV-1 therapeutics. These inhibitors may be particularly effective against viruses resistant to current antiretroviral drugs and could have potential applications in both treatment and prevention. Keywords: HIV-1, defensin, drug, entry, antiviral therapy, CD4

  2. Revisiting HIV-1 uncoating

    Directory of Open Access Journals (Sweden)

    Arhel Nathalie

    2010-11-01

    Full Text Available Abstract HIV uncoating is defined as the loss of viral capsid that occurs within the cytoplasm of infected cells before entry of the viral genome into the nucleus. It is an obligatory step of HIV-1 early infection and accompanies the transition between reverse transcription complexes (RTCs, in which reverse transcription occurs, and pre-integration complexes (PICs, which are competent to integrate into the host genome. The study of the nature and timing of HIV-1 uncoating has been paved with difficulties, particularly as a result of the vulnerability of the capsid assembly to experimental manipulation. Nevertheless, recent studies of capsid structure, retroviral restriction and mechanisms of nuclear import, as well as the recent expansion of technical advances in genome-wide studies and cell imagery approaches, have substantially changed our understanding of HIV uncoating. Although early work suggested that uncoating occurs immediately following viral entry in the cell, thus attributing a trivial role for the capsid in infected cells, recent data suggest that uncoating occurs several hours later and that capsid has an all-important role in the cell that it infects: for transport towards the nucleus, reverse transcription and nuclear import. Knowing that uncoating occurs at a later stage suggests that the viral capsid interacts extensively with the cytoskeleton and other cytoplasmic components during its transport to the nucleus, which leads to a considerable reassessment of our efforts to identify potential therapeutic targets for HIV therapy. This review discusses our current understanding of HIV uncoating, the functional interplay between infectivity and timely uncoating, as well as exposing the appropriate methods to study uncoating and addressing the many questions that remain unanswered.

  3. Revisiting HIV-1 uncoating.

    Science.gov (United States)

    Arhel, Nathalie

    2010-01-01

    HIV uncoating is defined as the loss of viral capsid that occurs within the cytoplasm of infected cells before entry of the viral genome into the nucleus. It is an obligatory step of HIV-1 early infection and accompanies the transition between reverse transcription complexes (RTCs), in which reverse transcription occurs, and pre-integration complexes (PICs), which are competent to integrate into the host genome. The study of the nature and timing of HIV-1 uncoating has been paved with difficulties, particularly as a result of the vulnerability of the capsid assembly to experimental manipulation. Nevertheless, recent studies of capsid structure, retroviral restriction and mechanisms of nuclear import, as well as the recent expansion of technical advances in genome-wide studies and cell imagery approaches, have substantially changed our understanding of HIV uncoating. Although early work suggested that uncoating occurs immediately following viral entry in the cell, thus attributing a trivial role for the capsid in infected cells, recent data suggest that uncoating occurs several hours later and that capsid has an all-important role in the cell that it infects: for transport towards the nucleus, reverse transcription and nuclear import. Knowing that uncoating occurs at a later stage suggests that the viral capsid interacts extensively with the cytoskeleton and other cytoplasmic components during its transport to the nucleus, which leads to a considerable reassessment of our efforts to identify potential therapeutic targets for HIV therapy. This review discusses our current understanding of HIV uncoating, the functional interplay between infectivity and timely uncoating, as well as exposing the appropriate methods to study uncoating and addressing the many questions that remain unanswered. PMID:21083892

  4. Recombinant rabies virus as potential live-viral vaccines for HIV-1

    OpenAIRE

    Schnell, Matthias J.; Foley, Heather D.; Siler, Catherine A.; McGettigan, James P.; Dietzschold, Bernhard; Pomerantz, Roger J.

    2000-01-01

    Recombinant, replication-competent rabies virus (RV) vaccine strain-based vectors were developed expressing HIV type I (HIV-1) envelope glycoprotein (gp160) from both a laboratory-adapted (CXCR4-tropic) and a primary (dual-tropic) HIV-1 isolate. An additional transcription stop/start unit within the RV genome was used to express HIV-1 gp160 in addition to the other RV proteins. The HIV-1 gp160 protein was stably and functionally expressed, as indicated by fusion of human T cell lines after in...

  5. 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 ...

  6. Gp120 on HIV-1 Virions Lacks O-Linked Carbohydrate.

    Science.gov (United States)

    Stansell, Elizabeth; Panico, Maria; Canis, Kevin; Pang, Poh-Choo; Bouché, Laura; Binet, Daniel; O'Connor, Michael-John; Chertova, Elena; Bess, Julian; Lifson, Jeffrey D; Haslam, Stuart M; Morris, Howard R; Desrosiers, Ronald C; Dell, Anne

    2015-01-01

    As HIV-1-encoded envelope protein traverses the secretory pathway, it may be modified with N- and O-linked carbohydrate. When the gp120s of HIV-1 NL4-3, HIV-1 YU2, HIV-1 Bal, HIV-1 JRFL, and HIV-1 JRCSF were expressed as secreted proteins, the threonine at consensus position 499 was found to be O-glycosylated. For SIVmac239, the corresponding threonine was also glycosylated when gp120 was recombinantly expressed. Similarly-positioned, highly-conserved threonines in the influenza A virus H1N1 HA1 and H5N1 HA1 envelope proteins were also found to carry O-glycans when expressed as secreted proteins. In all cases, the threonines were modified predominantly with disialylated core 1 glycans, together with related core 1 and core 2 structures. Secreted HIV-1 gp140 was modified to a lesser extent with mainly monosialylated core 1 O-glycans, suggesting that the ectodomain of the gp41 transmembrane component may limit the accessibility of Thr499 to glycosyltransferases. In striking contrast to these findings, gp120 on purified virions of HIV-1 Bal and SIV CP-MAC lacked any detectable O-glycosylation of the C-terminal threonine. Our results indicate the absence of O-linked carbohydrates on Thr499 as it exists on the surface of virions and suggest caution in the interpretation of analyses of post-translational modifications that utilize recombinant forms of envelope protein. PMID:25915761

  7. Isolation of antigenic substances from HIV-1 envelope gp160 gene transfectants by mild acid elution and X-irradiation treatment. For the development of CTL-based immunotherapy

    International Nuclear Information System (INIS)

    Cytotoxic T lymphocytes (CTLs) play a central role in a broad spectrum of tumor immunity. Such CTLs generally recognize processed antigenic fragments in association with class I major histocompatibility complex (MHC) molecules. Thus, it is important to identify naturally processed antigens associated with class I MHC molecules to generate and activate antigen-specific CTLs. Those processed antigens fitted in the groove of class I MHC molecules are fixed by the β2-microglobulin. Mild acid elution is one method used to isolate antigenic fragments from class I MHC molecules on tumor cells by unfastening a clasp of β2-microglobulin, a critical component for stabilizing class I MHC molecules on the cell surface. Indeed, after the mild acid treatment, the expression of class I MHC molecules was temporarily down-modulated and a strong antigenic fraction for CTL recognition was obtained. To our surprise, such down-modulation of class I MHC molecule expression was also observed when the tumor cells were irradiated. Therefore, using human immunodeficiency virus type I (HIV-1) gp160 env gene transfectants, we examined the effect of X-irradiation on releasing the loaded antigenic fragments. Functional extracts were obtained from X-irradiated cell supernatants that sensitized syngeneic fibroblasts for specific CTL recognition, suggesting that X-irradiation extracts would also contain known antigenic epitopes. These results indicate that, in addition to the conventional mild acid elution treatment, X-irradiation method shown in this paper may provide a new approach for CTL-based vaccine development via isolating antigenic molecules from various tumors or virally infected cells. (author)

  8. 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...

  9. Regional Differences in Prevalence of HIV-1 Discordance in Africa and Enrollment of HIV-1 Discordant Couples into an HIV-1 Prevention Trial

    OpenAIRE

    Jairam R Lingappa; Lambdin, Barrot; Bukusi, Elizabeth Ann; Ngure, Kenneth; Kavuma, Linda; Inambao, Mubiana; Kanweka, William; Allen, Susan; Kiarie, James N.; Were, Edwin; Manongi, Rachel; Coetzee, David; de Bruyn, Guy; Delany-Moretlwe, Sinead; MAGARET, Amalia

    2008-01-01

    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 preval...

  10. 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...

  11. 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.

  12. 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.

  13. 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...

  14. HIV-1 Uncoating Is Facilitated by Dynein and Kinesin 1

    OpenAIRE

    Lukic, Zana; Dharan, Adarsh; Fricke, Thomas; Diaz-Griffero, Felipe; Campbell, Edward M

    2014-01-01

    Following entry into the target cell, human immunodeficiency virus type 1 (HIV-1) must reverse transcribe its RNA genome to DNA and traffic to the nuclear envelope, where the viral genome is translocated into the nucleus for subsequent integration into the host cell chromosome. During this time, the viral core, which houses the genome, undergoes a poorly understood process of disassembly, known as uncoating. Collectively, many studies suggest that uncoating is tightly regulated to allow nucle...

  15. 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

  16. 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.

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

    International Nuclear Information System (INIS)

    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

  18. HIV-1 genotypes and phenotypes associated with mother to child transmission

    OpenAIRE

    BERKHOUT, B; Paxton, W.A.; Pollakis, G.; van de Baan, E

    2013-01-01

    Many viral as well as host factors can be associated with the risk of HIV-1 mother to child transmission (MTCT). The better understanding of such factors as well as the molecular interactions involved will ultimately lead to the development of new products with the capacity to inhibit transmission. In this thesis we aimed to better define the viral gp120 envelope characteristics, both genotypic and phenotypic, associated with HIV-1 transmission and more so via the MTCT route. We also aimed to...

  19. 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 ...

  20. Identification of dual-tropic HIV-1 using evolved neural networks.

    Science.gov (United States)

    Fogel, Gary B; Lamers, Susanna L; Liu, Enoch S; Salemi, Marco; McGrath, Michael S

    2015-11-01

    Blocking the binding of the envelope HIV-1 protein to immune cells is a popular concept for development of anti-HIV therapeutics. R5 HIV-1 binds CCR5, X4 HIV-1 binds CXCR4, and dual-tropic HIV-1 can bind either coreceptor for cellular entry. R5 viruses are associated with early infection and over time can evolve to X4 viruses that are associated with immune failure. Dual-tropic HIV-1 is less studied; however, it represents functional antigenic intermediates during the transition of R5 to X4 viruses. Viral tropism is linked partly to the HIV-1 envelope V3 domain, where the amino acid sequence helps dictate the receptor a particular virus will target; however, using V3 sequence information to identify dual-tropic HIV-1 isolates has remained difficult. Our goal in this study was to elucidate features of dual-tropic HIV-1 isolates that assist in the biological understanding of dual-tropism and develop an approach for their detection. Over 1559 HIV-1 subtype B sequences with known tropisms were analyzed. Each sequence was represented by 73 structural, biochemical and regional features. These features were provided to an evolved neural network classifier and evaluated using balanced and unbalanced data sets. The study resolved R5X4 viruses from R5 with an accuracy of 81.8% and from X4 with an accuracy of 78.8%. The approach also identified a set of V3 features (hydrophobicity, structural and polarity) that are associated with tropism transitions. The ability to distinguish R5X4 isolates will improve computational tropism decisions for R5 vs. X4 and assist in HIV-1 research and drug development efforts. PMID:26419858

  1. 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.

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

    Science.gov (United States)

    Schiavone, Marco; Fiume, Giuseppe; Caivano, Antonella; de Laurentiis, Annamaria; Falcone, Cristina; Masci, Francesca Fasanella; Iaccino, Enrico; Mimmi, Selena; Palmieri, Camillo; Pisano, Antonio; Pontoriero, Marilena; Rossi, Annalisa; Scialdone, Annarita; Vecchio, Eleonora; Andreozzi, Concetta; Trovato, Maria; Rafay, Jan; Ferko, Boris; Montefiori, David; Lombardi, Angela; Morsica, Giulia; Poli, Guido; Quinto, Ileana; Pavone, Vincenzo; de Berardinis, Piergiuseppe; Scala, Giuseppe

    2012-01-01

    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. PMID:22754323

  3. Role of Gag and lipids during HIV-1 assembly in CD4+ T cells and macrophages

    OpenAIRE

    Mariani, Charlotte; Desdouits, Marion; Favard, Cyril; Benaroch, Philippe; Muriaux, Delphine M.

    2014-01-01

    HIV-1 is an RNA enveloped virus that preferentially infects CD4+ T lymphocytes and also macrophages. In CD4+ T cells, HIV-1 mainly buds from the host cell plasma membrane. The viral Gag polyprotein targets the plasma membrane and is the orchestrator of the HIV assembly as its expression is sufficient to promote the formation of virus-like particles carrying a lipidic envelope derived from the host cell membrane. Certain lipids are enriched in the viral membrane and are thought to play a key r...

  4. 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.

  5. 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)

    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

  6. 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.

  7. 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.

  8. Anti-HIV-1 activity of anionic polymers: a comparative study of candidate microbicides

    Directory of Open Access Journals (Sweden)

    Li Yun-Yao

    2002-11-01

    Full Text Available Abstract Background Cellulose acetate phthalate (CAP in soluble form blocks coreceptor binding sites on the virus envelope glycoprotein gp120 and elicits gp41 six-helix bundle formation, processes involved in virus inactivation. CAP is not soluble at pH Methods Enzyme linked immunosorbent assays (ELISA were used to (1 study HIV-1 IIIB and BaL binding to micronized CAP; (2 detect virus disintegration; and (3 measure gp41 six-helix bundle formation. Cells containing integrated HIV-1 LTR linked to the β-gal gene and expressing CD4 and coreceptors CXCR4 or CCR5 were used to measure virus infectivity. Results 1 HIV-1 IIIB and BaL, respectively, effectively bound to micronized CAP. 2 The interaction between HIV-1 and micronized CAP led to: (a gp41 six-helix bundle formation; (b virus disintegration and shedding of envelope glycoproteins; and (c rapid loss of infectivity. Polymers other than CAP, except Carbomer 974P, elicited gp41 six-helix bundle formation in HIV-1 IIIB but only poly(napthalene sulfonate, in addition to CAP, had this effect on HIV-1 BaL. These polymers differed with respect to their virucidal activities, the differences being more pronounced for HIV-1 BaL. Conclusions Micronized CAP is the only candidate topical microbicide with the capacity to remove rapidly by adsorption from physiological fluids HIV-1 of both the X4 and R5 biotypes and is likely to prevent virus contact with target cells. The interaction between micronized CAP and HIV-1 leads to rapid virus inactivation. Among other anionic polymers, cellulose sulfate, BufferGel and aryl sulfonates appear most effective in this respect.

  9. 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.

  10. 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...

  11. 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.

  12. 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

  13. 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.

  14. Protein methylation is required to maintain optimal HIV-1 infectivity

    Directory of Open Access Journals (Sweden)

    Piller Sabine C

    2006-12-01

    Full Text Available Abstract Background: Protein methylation is recognized as a major protein modification pathway regulating diverse cellular events such as protein trafficking, transcription, and signal transduction. More recently, protein arginine methyltransferase activity has been shown to regulate HIV-1 transcription via Tat. In this study, adenosine periodate (AdOx was used to globally inhibit protein methyltransferase activity so that the effect of protein methylation on HIV-1 infectivity could be assessed. Results: Two cell culture models were used: HIV-1-infected CEM T-cells and HEK293T cells transfected with a proviral DNA plasmid. In both models, AdOx treatment of cells increased the levels of virion in culture supernatant. However, these viruses had increased levels of unprocessed or partially processed Gag-Pol, significantly increased diameter, and displayed reduced infectivity in a MAGI X4 assay. AdOx reduced infectivity equally in both dividing and non-dividing cells. However, infectivity was further reduced if Vpr was deleted suggesting virion proteins, other than Vpr, were affected by protein methylation. Endogenous reverse transcription was not inhibited in AdOx-treated HIV-1, and infectivity could be restored by pseudotyping HIV with VSV-G envelope protein. These experiments suggest that AdOx affects an early event between receptor binding and uncoating, but not reverse transcription. Conclusion: Overall, we have shown for the first time that protein methylation contributes towards maximal virus infectivity. Furthermore, our results also indicate that protein methylation regulates HIV-1 infectivity in a complex manner most likely involving the methylation of multiple viral or cellular proteins and/or multiple steps of replication.

  15. 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

  16. 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...

  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. 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; Schuitemaker, Hanneke; Bowles, Emma; Buonaguro, Luigi; Grevstad, Berit; Vinner, Lasse; Vereecken, Katleen; Parker, Joe; Ramaswamy, Meghna; Biswas, Priscilla; Vanham, Guido; Scarlatti, Gabriella; Fomsgaard, Anders

    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 of an...

  19. 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.

  20. Cytoplasmic Dynein Promotes HIV-1 Uncoating

    OpenAIRE

    Paulina Pawlica; Lionel Berthoux

    2014-01-01

    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 d...

  1. HIV-1 associated dementia: symptoms and causes

    OpenAIRE

    Khalili Kamel; Amini Shohreh; Ghafouri Mohammad; Sawaya Bassel E

    2006-01-01

    Abstract Despite the use of highly active antiretroviral therapy (HAART), neuronal cell death remains a problem that is frequently found in the brains of HIV-1-infected patients. HAART has successfully prevented many of the former end-stage complications of AIDS, however, with increased survival times, the prevalence of minor HIV-1 associated cognitive impairment appears to be rising among AIDS patients. Further, HIV-1 associated dementia (HAD) is still prevalent in treated patients as well a...

  2. Sialoadhesin expressed on IFN-induced monocytes binds HIV-1 and enhances infectivity.

    Directory of Open Access Journals (Sweden)

    Hans Rempel

    Full Text Available BACKGROUND: HIV-1 infection dysregulates the immune system and alters gene expression in circulating monocytes. Differential gene expression analysis of CD14(+ monocytes from subjects infected with HIV-1 revealed increased expression of sialoadhesin (Sn, CD169, Siglec 1, a cell adhesion molecule first described in a subset of macrophages activated in chronic inflammatory diseases. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed sialoadhesin expression on CD14(+ monocytes by flow cytometry and found significantly higher expression in subjects with elevated viral loads compared to subjects with undetectable viral loads. In cultured CD14(+ monocytes isolated from healthy individuals, sialoadhesin expression was induced by interferon-alpha and interferon-gamma but not tumor necrosis factor-alpha. Using a stringent binding assay, sialoadhesin-expressing monocytes adsorbed HIV-1 through interaction with the sialic acid residues on the viral envelope glycoprotein gp120. Furthermore, monocytes expressing sialoadhesin facilitated HIV-1 trans infection of permissive cells, which occurred in the absence of monocyte self-infection. CONCLUSIONS/SIGNIFICANCE: Increased sialoadhesin expression on CD14(+ monocytes occurred in response to HIV-1 infection with maximum expression associated with high viral load. We show that interferons induce sialoadhesin in primary CD14(+ monocytes, which is consistent with an antiviral response during viremia. Our findings suggest that circulating sialoadhesin-expressing monocytes are capable of binding HIV-1 and effectively delivering virus to target cells thereby enhancing the distribution of HIV-1. Sialoadhesin could disseminate HIV-1 to viral reservoirs during monocyte immunosurveillance or migration to sites of inflammation and then facilitate HIV-1 infection of permissive cells.

  3. HIV-1 gp120 induces antioxidant response element-mediated expression in primary astrocytes: Role in HIV associated neurocognitive disorder

    OpenAIRE

    Reddy, Pichili Vijaya Bhaskar; Gandhi, Nimisha; Samikkannu, Thangavel; Saiyed, Zainulabedin; Agudelo, Marisela; Yndart, Adriana; Khatavkar, Pradnya; Nair, Madhavan PN

    2011-01-01

    HIV infection affects the central nervous system resulting in HIV associated neurocognitive disorder (HAND), which is characterized by depression, behavioral and motor dysfunctions. The HIV-1 viral envelope protein gp120 is known to induce the release of neurotoxic factors which lead to apoptotic cell death. Although the exact mechanisms involved in HIV-1 gp120-induced neurotoxicity are not completely understood, oxidative stress is suggested to play a vital role in the neuropathogenesis of H...

  4. An ancestral HIV-2/simian immunodeficiency virus peptide with potent HIV-1 and HIV-2 fusion inhibitor activity

    OpenAIRE

    Borrego, Pedro; Calado, Rita; Marcelino, José M.; Pereira, Patrícia MR; Quintas, Alexandre; Barroso, Helena; Taveira, Nuno

    2013-01-01

    "Objectives: To produce new fusion inhibitor peptides for HIV-1 and HIV-2 based on ancestral envelope sequences. Methods: HIV-2/simian immunodeficiency virus (SIV) ancestral transmembrane protein sequences were reconstructed and ancestral peptides were derived from the helical region 2 (HR2). The activity of one ancestral peptide (named P3) was examined against a panel of HIV-1 and HIV-2 primary isolates in TZM-bl cells and peripheral blood mononuclear cells and compared to ...

  5. 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...

  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. 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.

  8. 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. PMID:26567131

  9. Cytoplasmic dynein promotes HIV-1 uncoating.

    Science.gov (United States)

    Pawlica, Paulina; Berthoux, Lionel

    2014-11-01

    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. PMID:25375884

  10. 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.

  11. 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

  12. HIV-1 Eradication: Early Trials (and Tribulations).

    Science.gov (United States)

    Spivak, Adam M; Planelles, Vicente

    2016-01-01

    Antiretroviral therapy (ART) has rendered HIV-1 infection a manageable illness for those with access to treatment. However, ART does not lead to viral eradication owing to the persistence of replication-competent, unexpressed proviruses in long-lived cellular reservoirs. The potential for long-term drug toxicities and the lack of access to ART for most people living with HIV-1 infection have fueled scientific interest in understanding the nature of this latent reservoir. Exploration of HIV-1 persistence at the cellular and molecular level in resting memory CD4(+) T cells, the predominant viral reservoir in patients on ART, has uncovered potential strategies to reverse latency. We review recent advances in pharmacologically based 'shock and kill' HIV-1 eradication strategies, including comparative analysis of early clinical trials. PMID:26691297

  13. 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...

  14. 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

  15. 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

  16. 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...

  17. 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.

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

    International Nuclear Information System (INIS)

    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 125I iodination procedure

  19. Inhibition of HIV-1 infection by synthetic peptides derived CCR5 fragments

    International Nuclear Information System (INIS)

    HIV-1 infection requires interaction of viral envelope protein gp160 with CD4 and a chemokine receptor, CCR5 or CXCR4 as entry coreceptor. We designed HIV-inhibitory peptides targeted to CCR5 using a novel computer program (ANTIS), which searched all possible sense-antisense amino acid pairs between proteins. Seven AHBs were found in CCR5 receptor. All AHB peptides were synthesized and tested for their ability to prevent HIV-1 infection to human T cells. A peptide fragment (LC5) which is a part of the CCR5 receptor corresponding to the loop between the fifth and sixth transmembrane regions (amino acids 222-240) proved to inhibit HIV-1IIIB infection of MT-4 cells. Interaction of these antisense peptides could be involved in sustaining HIV-1 infectivity. LC5 effectively indicated dose-dependent manner, and the suppression was enhanced additively by T20 peptide, which inhibits infection in vitro by disrupting the gp41 conformational changes necessary for membrane fusion. Thus, these results indicate that CCR5-derived AHB peptides could provide a useful tool to define the mechanism(s) of HIV infection, and may provide insight which will contribute to the development of an anti-HIV-1 reagent

  20. 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.

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

    International Nuclear Information System (INIS)

    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

  2. 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

  3. Stabilization of HIV-1 gp120-CD4 Receptor Complex through Targeted Interchain Disulfide Exchange*

    OpenAIRE

    Cerutti, Nichole; Mendelow, Barry V.; Napier, Grant B.; Papathanasopoulos, Maria A.; Killick, Mark; Khati, Makobetsa; Stevens, Wendy; Capovilla, Alexio

    2010-01-01

    HIV-1 enters cells via interaction between the trimeric envelope (Env) glycoprotein gp120/gp41 and the host cell surface receptor molecule CD4. The requirement of CD4 for viral entry has rationalized the development of recombinant CD4-based proteins as competitive viral attachment inhibitors and immunotherapeutic agents. In this study, we describe a novel recombinant CD4 protein designed to bind gp120 through a targeted disulfide-exchange mechanism. According to structural models of the gp120...

  4. 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

  5. μ-opioid modulation of HIV-1 coreceptor expressionand HIV-1 replication

    International Nuclear Information System (INIS)

    A substantial proportion of HIV-1-infected individuals are intravenous drug users (IVDUs) who abuse opiates. Opioids induce a number of immunomodulatory effects that may directly influence HIV-1 disease progression. In the present report, we have investigated the effect of opioids on the expression of the major HIV-1 coreceptors CXCR4 and CCR5. For these studies we have focused on opiates which are ligands for the μ-opioid receptor. Our results show that DAMGO, a selective μ-opioid agonist, increases CXCR4 and CCR5 expression in both CD3+ lymphoblasts and CD14+ monocytes three- to fivefold. Furthermore, DAMGO-induced elevation of HIV-1 coreceptor expression translates into enhanced replication of both X4 and R5 viral strains of HIV-1. We have confirmed the role of the μ-opioid receptor based on the ability of a μ-opioid receptor-selective antagonist to block the effects of DAMGO. We have also found that morphine enhances CXCR4 and CCR5 expression and subsequently increases both X4 and R5 HIV-1 infection. We suggest that the capacity of μ-opioids to increase HIV-1 coreceptor expression and replication may promote viral binding, trafficking of HIV-1-infected cells, and enhanced disease progression

  6. 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. PMID:27049645

  7. 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

  8. TopoisomeraseIIβ in HIV-1 transactivation.

    Science.gov (United States)

    Chekuri, Anil; Bhaskar, C; Bollimpelli, V Satish; Kondapi, Anand K

    2016-03-01

    TopoisomeraseIIβ, an isoform of type II topoisomerase, was found to be functional in various viral infections. Its plausible role in HIV life cycle was also suggested earlier, but not clearly established. In the present study, we have investigated the role of TopoIIβ in HIV-1 infection by its gain and loss of function. Overexpression of TopoIIβ lead to an increase in viral replication, resulting in enhanced virion production. HIV-1 replication was impaired when TopoIIβ was down regulated by siRNA and inhibited by ICRF-193 and merbarone. The role of TopoIIβ in HIV-1 transcription was shown through its interaction with Tat and recruitement to long terminal repeat (LTR) region by co-immunoprecipitation and ChIP assays. Involvement of TopoIIβ in transactivation of HIV-1 LTR was confirmed by luciferase assay in reporter cell line, TZM bl and also by transfection of reporter exogenously. It was also observed that LTR transactivation commensurated with the expression of TopoIIβ in the presence of Tat. In addition, a decreased viral gene expression on treatment with merbarone exemplifies the importance of catalytic activity of TopoIIβ in viral replication. These observations indicate that TopoIIβ is involved in the cascade of coactivator complexes that are recruited to LTR for regulation of HIV-1 transcription. PMID:26876283

  9. 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

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

    OpenAIRE

    Mouinga-Ondeme, A.; Mabika-Mabika, A.; Alalade, P.; Mongo, A. D.; Sica, J.; Liégeois, Florian; Rouet, F.

    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 (R) and Nuclisens HIV-1 EasyQ (R) 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 an...

  11. Inhibition of certain strains of HIV-1 by cell surface polyanions in the form of cholesterol-labeled oligonucleotides

    International Nuclear Information System (INIS)

    Cholesterol-labeled oligonucleotides were found several years ago to inhibit HIV-1 in tissue culture at nanomolar concentrations. We present evidence that this is mainly due to an electrostatic interaction between polyanionic oligonucleotide concentrated at the cell surface and a positively charged region in the V3 loop of the HIV-1 envelope protein. When added to tissue culture, cholesterol-labeled oligonucleotides became concentrated at the plasma membrane and potently inhibited virus entry and cell fusion mediated by the envelope protein of some X4 strains of HIV-1, but had little effect on fusion mediated by R5 strains of HIV-1, amphotropic MLV envelope protein, or VSV-G protein. Noncholesterol-labeled oligonucleotides did not bind to the cell surface or inhibit fusion. The pattern of susceptibility to cholesterol-labeled oligonucleotides among HIV-1 strains was the same as reported for nonmembrane-associating polyanions such as dextran sulfate, but the cholesterol-labeled oligonucleotides were effective at lower concentrations. Substitution of a basic 33 amino acid V3 loop sequence from the envelope protein of a resistant strain into a susceptible strain made the envelope protein resistant to inhibition. Inhibition by cholesterol-labeled oligonucleotides was abrogated by the polycation DEAE-dextran. Cholesterol-labeled oligonucleotides bound to nonraft regions of the plasma membrane and did not inhibit HIV virus binding to cells. Many infectious agents first associate with target cells via relatively nonspecific charge interactions; our data suggest that molecules that combine a membrane-targeting motif with multiple negative charges might be useful to modify these interactions

  12. Broad-Spectrum Inhibition of HIV-1 by a Monoclonal Antibody Directed against a gp120-Induced Epitope of CD4

    OpenAIRE

    Burastero, Samuele E.; Frigerio, Barbara; Lopalco, Lucia; Sironi, Francesca; Breda, Daniela; Longhi, Renato; Scarlatti, Gabriella; Canevari, Silvana; Figini, Mariangela; Lusso, Paolo

    2011-01-01

    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 conta...

  13. 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...

  14. 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...

  15. Lipid domains in HIV-1 assembly

    OpenAIRE

    CyrilFavard

    2014-01-01

    In CD+ 4 T cells, HIV-1 buds from the host cell plasma membrane. The viral Gag polyprotein is mainly responsible for this process. However, the intimate interaction of Gag and lipids at the plasma membrane as well as its consequences, in terms of lipids lateral organization and virus assembly, is still under debate. In this review we propose to revisit the role of plasma membrane lipids in HIV-1 Gag targeting and assembly, at the light of lipid membranes biophysics and literature dealing with...

  16. 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

  17. 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.

  18. 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

  19. 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...

  20. Multivalent dendrimeric compounds containing carbohydrates expressed on immune cells inhibit infection by primary isolates of HIV-1

    International Nuclear Information System (INIS)

    Specific glycosphingolipids (GSL), found on the surface of target immune cells, are recognized as alternate cell surface receptors by the human immunodeficiency virus type 1 (HIV-1) external envelope glycoprotein. In this study, the globotriose and 3'-sialyllactose carbohydrate head groups found on two GSL were covalently attached to a dendrimer core to produce two types of unique multivalent carbohydrates (MVC). These MVC inhibited HIV-1 infection of T cell lines and primary peripheral blood mononuclear cells (PBMC) by T cell line-adapted viruses or primary isolates, with IC50s ranging from 0.1 to 7.4 μg/ml. Inhibition of Env-mediated membrane fusion by MVC was also observed using a dye-transfer assay. These carbohydrate compounds warrant further investigation as a potential new class of HIV-1 entry inhibitors. The data presented also shed light on the role of carbohydrate moieties in HIV-1 virus-host cell interactions. -- Research Highlights: →Multivalent carbohydrates (MVCs) inhibited infection of PBMCs by HIV-1. →MVCs inhibited infection by T cell line-adapted viruses. →MVCs inhibited infection by primary isolates of HIV-1. →MVCs inhibited Env-mediated membrane fusion.

  1. 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.

  2. 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.

  3. Enhanced clearance of HIV-1-infected cells by broadly neutralizing antibodies against HIV-1 in vivo.

    Science.gov (United States)

    Lu, Ching-Lan; Murakowski, Dariusz K; Bournazos, Stylianos; Schoofs, Till; Sarkar, Debolina; Halper-Stromberg, Ariel; Horwitz, Joshua A; Nogueira, Lilian; Golijanin, Jovana; Gazumyan, Anna; Ravetch, Jeffrey V; Caskey, Marina; Chakraborty, Arup K; Nussenzweig, Michel C

    2016-05-20

    Antiretroviral drugs and antibodies limit HIV-1 infection by interfering with the viral life cycle. In addition, antibodies also have the potential to guide host immune effector cells to kill HIV-1-infected cells. Examination of the kinetics of HIV-1 suppression in infected individuals by passively administered 3BNC117, a broadly neutralizing antibody, suggested that the effects of the antibody are not limited to free viral clearance and blocking new infection but also include acceleration of infected cell clearance. Consistent with these observations, we find that broadly neutralizing antibodies can target CD4(+) T cells infected with patient viruses and can decrease their in vivo half-lives by a mechanism that requires Fcγ receptor engagement in a humanized mouse model. The results indicate that passive immunotherapy can accelerate elimination of HIV-1-infected cells. PMID:27199430

  4. 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

  5. Solution Properties of Murine Leukemia Virus Gag Protein: Differences from HIV-1 Gag

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Siddhartha A.K.; Zuo, Xiaobing; Clark, Patrick K.; Campbell, Stephen J.; Wang, Yun-Xing; Rein, Alan (SAIC); (NCI)

    2012-05-09

    Immature retrovirus particles are assembled from the multidomain Gag protein. In these particles, the Gag proteins are arranged radially as elongated rods. We have previously characterized the properties of HIV-1 Gag in solution. In the absence of nucleic acid, HIV-1 Gag displays moderately weak interprotein interactions, existing in monomer-dimer equilibrium. Neutron scattering and hydrodynamic studies suggest that the protein is compact, and biochemical studies indicate that the two ends can approach close in three-dimensional space, implying the need for a significant conformational change during assembly. We now describe the properties of the Gag protein of Moloney murine leukemia virus (MLV), a gammaretrovirus. We found that this protein is very different from HIV-1 Gag: it has much weaker protein-protein interaction and is predominantly monomeric in solution. This has allowed us to study the protein by small-angle X-ray scattering and to build a low-resolution molecular envelope for the protein. We found that MLV Gag is extended in solution, with an axial ratio of {approx}7, comparable to its dimensions in immature particles. Mutational analysis suggests that runs of prolines in its matrix and p12 domains and the highly charged stretch at the C terminus of its capsid domain all contribute to this extended conformation. These differences between MLV Gag and HIV-1 Gag and their implications for retroviral assembly are discussed.

  6. 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

  7. Bispecific Anti-HIV-1 Antibodies with Enhanced Breadth and Potency.

    Science.gov (United States)

    Bournazos, Stylianos; Gazumyan, Anna; Seaman, Michael S; Nussenzweig, Michel C; Ravetch, Jeffrey V

    2016-06-16

    Broadly neutralizing antibodies (bNAbs) against the HIV-1 envelope glycoprotein (Env) suppress viremia in animal models of HIV-1 and humans. To achieve potent activity without the emergence of viral escape mutants, co-administration of different bNAbs is necessary to target distinct epitopes essential for viral fitness. Here, we report the development of bispecific anti-Env neutralizing antibodies (biNAbs) with potent activity. Synergistic activity of biNAbs was achieved by combining an engineered hinge domain of IgG3 to increase Fab domain flexibility necessary for hetero-bivalent binding to the Env trimer while retaining the functional properties of the IgG1-Fc. Compared to unmodified biNAbs, hinge domain variants exhibited substantially improved neutralization activity, with particular combinations showing evidence of synergistic neutralization potency in vitro and enhanced in vivo therapeutic activity in HIV-1-infected humanized mice. These findings suggest innovative strategies for generating biNAbs with enhanced neutralization breadth and potency, representing ideal candidate molecules for the control of HIV-1 infection. PMID:27315478

  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. Glycosphingolipid-functionalized nanoparticles recapitulate CD169-dependent HIV-1 uptake and trafficking in dendritic cells

    Science.gov (United States)

    Yu, Xinwei; Feizpour, Amin; Ramirez, Nora-Guadalupe P.; Wu, Linxi; Akiyama, Hisashi; Xu, Fangda; Gummuluru, Suryaram; Reinhard, Björn M.

    2014-06-01

    Ganglioside GM3, a host-derived glycosphingolipid incorporated in the membrane of human immunodeficiency virus-1 (HIV-1) viral particles, mediates interactions between HIV-1 and Siglec1/CD169, a protein expressed on dendritic cells (DCs). Such interactions, which seem to be independent of viral envelope glycoprotein gp120, are poorly understood. Here we develop a model system consisting of self-assembled artificial virus nanoparticles (AVNs) that are free of viral glycoproteins or other host-derived glycolipids and glycoproteins. These plasmonic AVNs contain a membrane of defined composition wrapped around a solid metal core. GM3-containing AVNs are captured by CD169-expressing HeLa cells or mature DCs, and are sequestered within non-lysosomal tetraspanin-positive compartments. This distribution is reminiscent of CD169-dependent HIV-1 sequestration in mature DCs. Our results highlight GM3-CD169 binding as a gp120-independent signal for sequestration and preservation of HIV-1 infectivity. They also indicate that plasmonic AVNs offer improved features over liposome-based systems and represent a versatile tool for probing specific virus-cell interactions.

  10. 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.

  11. Novel HIV-1 Therapeutics through Targeting Altered Host Cell Pathways

    OpenAIRE

    Coley, William; Kehn-Hall, Kylene; Van Duyne, Rachel; KASHANCHI, FATAH

    2009-01-01

    The emergence of drug-resistant human immunodeficiency virus type I (HIV-1) strains presents a challenge for the design of new drugs. Anti-HIV compounds currently in use are the subject of advanced clinical trials using either HIV-1 reverse-transcriptase, viral protease, or integrase inhibitors. Recent studies show an increase in the number of HIV-1 variants resistant to anti-retroviral agents in newly infected individuals. Targeting host cell factors involved in the regulation of HIV-1 repli...

  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. Anti-HIV-1 activity of cellulose acetate phthalate: Synergy with soluble CD4 and induction of "dead-end" gp41 six-helix bundles

    Directory of Open Access Journals (Sweden)

    Li Yun-Yao

    2002-04-01

    Full Text Available Abstract Background Cellulose acetate phthalate (CAP, a promising candidate microbicide for prevention of sexual transmission of the human immunodeficiency virus type 1 (HIV-1 and other sexually transmitted disease (STD pathogens, was shown to inactivate HIV-1 and to block the coreceptor binding site on the virus envelope glycoprotein gp120. It did not interfere with virus binding to CD4. Since CD4 is the primary cellular receptor for HIV-1, it was of interest to study CAP binding to HIV-1 complexes with soluble CD4 (sCD4 and its consequences, including changes in the conformation of the envelope glycoprotein gp41 within virus particles. Methods Enzyme-linked immunosorbent assays (ELISA were used to study CAP binding to HIV-1-sCD4 complexes and to detect gp41 six-helix bundles accessible on virus particles using antibodies specific for the α-helical core domain of gp41. Results 1 Pretreatment of HIV-1 with sCD4 augments subsequent binding of CAP; 2 there is synergism between CAP and sCD4 for inhibition of HIV-1 infection; 3 treatment of HIV-1 with CAP induced the formation of gp41 six-helix bundles. Conclusions CAP and sCD4 bind to distinct sites on HIV-1 IIIB and BaL virions and their simultaneous binding has profound effects on virus structure and infectivity. The formation of gp41 six-helical bundles, induced by CAP, is known to render the virus incompetent for fusion with target cells thus preventing infection.

  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. 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.

  16. 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.

  17. Novel Approaches to Inhibiting HIV-1 Replication

    OpenAIRE

    Adamson, Catherine S.; Freed, Eric O.

    2009-01-01

    Considerable success has been achieved in the treatment of HIV-1 infection, and more than two-dozen antiretroviral drugs are available targeting several distinct steps in the viral replication cycle. However, resistance to these compounds emerges readily, even in the context of combination therapy. Drug toxicity, adverse drug-drug interactions, and accompanying poor patient adherence can also lead to treatment failure. These considerations make continued development of novel antiretroviral th...

  18. 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...

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

    International Nuclear Information System (INIS)

    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

  20. 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...

  1. 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.

  2. A radiometric assay for HIV-1 protease

    International Nuclear Information System (INIS)

    A rapid, high-throughput radiometric assay for HIV-1 protease has been developed using ion-exchange chromatography performed in 96-well filtration plates. The assay monitors the activity of the HIV-1 protease on the radiolabeled form of a heptapeptide substrate, [tyrosyl-3,5-3H]Ac-Ser-Gln-Asn-Tyr-Pro-Val-Val-NH2, which is based on the p17-p24 cleavage site found in the viral polyprotein substrate Pr55gag. Specific cleavage of this uncharged heptapeptide substrate by HIV-1 protease releases the anionic product [tyrosyl-3,5-3H]Ac-Ser-Gln-Asn-Tyr, which is retained upon minicolumns of the anion-exchange resin AG1-X8. Protease activity is determined from the recovery of this radiolabeled product following elution with formic acid. This facile and highly sensitive assay may be utilized for steady-state kinetic analysis of the protease, for measurements of enzyme activity during its purification, and as a routine assay for the evaluation of protease inhibitors from natural product or synthetic sources

  3. Inhibition of highly productive HIV-1 infection in T cells, primary human macrophages, microglia, and astrocytes by Sargassum fusiforme

    Directory of Open Access Journals (Sweden)

    Veille Jean-Claude

    2006-05-01

    Full Text Available Abstract Background The high rate of HIV-1 mutation and increasing resistance to currently available antiretroviral (ART therapies highlight the need for new antiviral agents. Products derived from natural sources have been shown to inhibit HIV-1 replication during various stages of the virus life cycle, and therefore represent a potential source of novel therapeutic agents. To expand our arsenal of therapeutics against HIV-1 infection, we investigated aqueous extract from Sargassum fusiforme (S. fusiforme for ability to inhibit HIV-1 infection in the periphery, in T cells and human macrophages, and for ability to inhibit in the central nervous system (CNS, in microglia and astrocytes. Results S. fusiforme extract blocked HIV-1 infection and replication by over 90% in T cells, human macrophages and microglia, and it also inhibited pseudotyped HIV-1 (VSV/NL4-3 infection in human astrocytes by over 70%. Inhibition was mediated against both CXCR4 (X4 and CCR5 (R5-tropic HIV-1, was dose dependant and long lasting, did not inhibit cell growth or viability, was not toxic to cells, and was comparable to inhibition by the nucleoside analogue 2', 3'-didoxycytidine (ddC. S. fusiforme treatment blocked direct cell-to-cell infection spread. To investigate at which point of the virus life cycle this inhibition occurs, we infected T cells and CD4-negative primary human astrocytes with HIV-1 pseudotyped with envelope glycoprotein of vesicular stomatitis virus (VSV, which bypasses the HIV receptor requirements. Infection by pseudotyped HIV-1 (VSV/NL4-3 was also inhibited in a dose dependant manner, although up to 57% less, as compared to inhibition of native NL4-3, indicating post-entry interferences. Conclusion This is the first report demonstrating S. fusiforme to be a potent inhibitor of highly productive HIV-1 infection and replication in T cells, in primary human macrophages, microglia, and astrocytes. Results with VSV/NL4-3 infection, suggest inhibition

  4. Peptide P5 (residues 628–683, comprising the entire membrane proximal region of HIV-1 gp41 and its calcium-binding site, is a potent inhibitor of HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Clavel François

    2008-10-01

    Full Text Available Abstract The membrane proximal region (MPR of the transmembrane subunit, gp41, of the HIV envelope glycoprotein plays a critical role in HIV-1 infection of CD4+ target cells and CD4-independent mucosal entry. It contains continuous epitopes recognized by neutralizing IgG antibodies 2F5, 4E10 and Z13, and is therefore considered to be a promising target for vaccine design. Moreover, some MPR-derived peptides, such as T20 (enfuvirtide, are in clinical use as HIV-1 inhibitors. We have shown that an extended MPR peptide, P5, harbouring the lectin-like domain of gp41 and a calcium-binding site, is implicated in the interaction of HIV with its mucosal receptor. We now investigate the potential antiviral activities of P5 and other such long MPR-derived peptides. Structural studies of gp41 MPR-derived peptides using circular dichroism showed that the peptides P5 (a.a.628–683, P1 (a.a.648–683, P5L (a.a.613–683 and P7 (a.a.613–746 displayed a well-defined α-helical structure. Peptides P5 inhibited HIV-1 envelope mediated cell-cell fusion and infection of peripheral blood mononuclear cells by both X4- and R5-tropic HIV-1 strains, whereas peptides P5 mutated in the calcium binding site or P1 lacked antiviral activity, when P5L blocked cell fusion in contrast to P7. Strikingly, P5 inhibited CD4-dependent infection by T20-resistant R5-tropic HIV-1 variants. Cell-cell fusion studies indicated that the anti-HIV-1 activity of P5, unlike T20, could not be abrogated in the presence of the N-terminal leucine zipper domain (LZ. These results suggested that P5 could serve as a potent fusion inhibitor.

  5. 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.

  6. 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. PMID:26650729

  7. Efficient Quantification of HIV-1 in Heparin Plasma Spiked with Cultured HIV-1 by the Roche Cobas TaqMan and Abbott RealTime HIV-1 Tests

    OpenAIRE

    Jagodzinski, Linda L; Weston, Holly R.; Liu, Ying; O'Connell, Robert J.; Peel, Sheila A

    2012-01-01

    The current automated real-time HIV-1 viral load assays, the Roche Cobas AmpliPrep/Cobas TaqMan test and the Abbott RealTime test, are FDA cleared for use with EDTA plasma. We show that both real-time reverse transcription-PCR (RT-PCR) tests reliably quantify HIV-1 RNA in heparin plasma specimens spiked with HIV-1 isolate MN.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. HIV-1 subtype distribution in the Gambia and the significant presence of CRF49_cpx, a novel circulating recombinant form

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    Foley Brian

    2010-10-01

    Full Text Available Abstract Background Detailed local HIV-1 sequence data are essential for monitoring the HIV epidemic, for maintaining sensitive sequence-based diagnostics, and to aid in designing vaccines. Results Reported here are full envelope sequences derived from 38 randomly selected HIV-1 infections identified at a Gambian clinic between 1991 and 2009. Special care was taken to generate sequences from circulating viral RNA as uncloned products, either by limiting dilution or single genome amplification polymerase chain reaction (PCR. Within these 38 isolates, eight were subtyped as A and 18 as CRF02_AG. A small number of subtype B, C, D viruses were identified. Surprising, however, was the identification of six isolates with subtype J-like envelopes, a subtype found normally in Central Africa and the Democratic Republic of the Congo (DRC, with gag p24 regions that clustered with subtype A sequences. Near full-length sequence from three of these isolates confirmed that these represent a novel circulating recombinant form of HIV-1, now named CRF49_cpx. Conclusions This study expands the HIV-1 sequence database from the Gambia and will provide important data for HIV diagnostics, patient care, and vaccine development.

  15. 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, M 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

  16. 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.

  17. 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...

  18. 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...

  19. LEDGF dominant interference proteins demonstrate prenuclear exposure of HIV-1 integrase and synergize with LEDGF depletion to destroy viral infectivity.

    Science.gov (United States)

    Meehan, Anne M; Saenz, Dyana T; Morrison, James; Hu, Chunling; Peretz, Mary; Poeschla, Eric M

    2011-04-01

    Target cell overexpression of the integrase binding domain (IBD) of LEDGF/p75 (LEDGF) inhibits HIV-1 replication. The mechanism and protein structure requirements for this dominant interference are unclear. More generally, how and when HIV-1 uncoating occurs postentry is poorly defined, and it is unknown whether integrase within the evolving viral core becomes accessible to cellular proteins prior to nuclear entry. We used LEDGF dominant interference to address the latter question while characterizing determinants of IBD antiviral activity. Fusions of green fluorescent protein (GFP) with multiple C-terminal segments of LEDGF inhibited HIV-1 replication substantially, but minimal chimeras of either polarity (GFP-IBD or IBD-GFP) were most effective. Combining GFP-IBD expression with LEDGF depletion was profoundly antiviral. CD4(+) T cell lines were rendered virtually uninfectable, with single-cycle HIV-1 infectivity reduced 4 logs and high-input (multiplicity of infection = 5.0) replication completely blocked. We restricted GFP-IBD to specific intracellular locations and found that antiviral activity was preserved when the protein was confined to the cytoplasm or directed to the nuclear envelope. The life cycle block triggered by the cytoplasm-restricted protein manifested after nuclear entry, at the level of integration. We conclude that integrase within the viral core becomes accessible to host cell protein interaction in the cytoplasm. LEDGF dominant interference and depletion impair HIV-1 integration at distinct postentry stages. GFP-IBD may trigger premature or improper integrase oligomerization. PMID:21270171

  20. Functional constraints on HIV-1 capsid: their impacts on the viral immune escape potency

    OpenAIRE

    TaichiroTakemura

    2012-01-01

    In mature HIV-1 particles, viral capsid (CA) proteins form the conical core structure that encapsidates two copies of the viral RNA genome. After fusion of the viral envelope and cellular membranes, the CA core enters into the cytoplasm of the target cells. CA proteins then interact with a variety of viral other protein as well as host factors, which may either support or inhibit replication of the virus. Recent studies have revealed that CA proteins are important not only for the uncoating s...

  1. Small-Molecule CD4-Mimics: Structure-Based Optimization of HIV-1 Entry Inhibition.

    Science.gov (United States)

    Melillo, Bruno; Liang, Shuaiyi; Park, Jongwoo; Schön, Arne; Courter, Joel R; LaLonde, Judith M; Wendler, Daniel J; Princiotto, Amy M; Seaman, Michael S; Freire, Ernesto; Sodroski, Joseph; Madani, Navid; Hendrickson, Wayne A; Smith, Amos B

    2016-03-10

    The optimization, based on computational, thermodynamic, and crystallographic data, of a series of small-molecule ligands of the Phe43 cavity of the envelope glycoprotein gp120 of human immunodeficiency virus (HIV) has been achieved. Importantly, biological evaluation revealed that the small-molecule CD4 mimics (4-7) inhibit HIV-1 entry into target cells with both significantly higher potency and neutralization breadth than previous congeners, while maintaining high selectivity for the target virus. Their binding mode was characterized via thermodynamic and crystallographic studies. PMID:26985324

  2. 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; Palm, Angelica A; Gerstoft, Jan; Kronborg, Gitte; Hønge, Bo Langhoff; Jespersen, Sanne; da Silva, Zacarias José; Karlsson, Ingrid; Fomsgaard, Anders

    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...... 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...

  3. Novel approaches to inhibiting HIV-1 replication.

    Science.gov (United States)

    Adamson, Catherine S; Freed, Eric O

    2010-01-01

    Considerable success has been achieved in the treatment of HIV-1 infection, and more than two-dozen antiretroviral drugs are available targeting several distinct steps in the viral replication cycle. However, resistance to these compounds emerges readily, even in the context of combination therapy. Drug toxicity, adverse drug-drug interactions, and accompanying poor patient adherence can also lead to treatment failure. These considerations make continued development of novel antiretroviral therapeutics necessary. In this article, we highlight a number of steps in the HIV-1 replication cycle that represent promising targets for drug discovery. These include lipid raft microdomains, the RNase H activity of the viral enzyme reverse transcriptase, uncoating of the viral core, host cell machinery involved in the integration of the viral DNA into host cell chromatin, virus assembly, maturation, and budding, and the functions of several viral accessory proteins. We discuss the relevant molecular and cell biology, and describe progress to date in developing inhibitors against these novel targets. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010. PMID:19782103

  4. Rational development of radiopharmaceuticals for HIV-1

    International Nuclear Information System (INIS)

    The global battle against HIV-1 would benefit from a sensitive and specific radiopharmaceutical to localize HIV-infected cells. Ideally, this probe would be able to identify latently infected host cells containing replication competent HIV sequences. Clinical and research applications would include assessment of reservoirs, informing clinical management by facilitating assessment of burden of infection in different compartments, monitoring disease progression and monitoring response to therapy. A “rational” development approach could facilitate efficient identification of an appropriate targeted radiopharmaceutical. Rational development starts with understanding characteristics of the disease that can be effectively targeted and then engineering radiopharmaceuticals to hone in on an appropriate target, which in the case of HIV-1 (HIV) might be an HIV-specific product on or in the host cell, a differentially expressed gene product, an integrated DNA sequence specific enzymatic activity, part of the inflammatory response, or a combination of these. This is different from the current approach that starts with a radiopharmaceutical for a target associated with a disease, mostly from autopsy studies, without a strong rationale for the potential to impact patient care. At present, no targeted therapies are available for HIV latency, although a number of approaches are under study. Here we discuss requirements for a radiopharmaceutical useful in strategies targeting persistently infected cells. The radiopharmaceutical for HIV should be developed based on HIV biology, studied in an animal model and then in humans, and ultimately used in clinical and research settings

  5. Identification of N-phenyl-N'-(2,2,6,6-tetramethyl-piperidin-4-yl)-oxalamides as a new class of HIV-1 entry inhibitors that prevent gp120 binding to CD4

    International Nuclear Information System (INIS)

    We have identified two N-phenyl-N'-(2,2,6,6-tetramethyl-piperidin-4-yl)-oxalamide analogs as a novel class of human immunodeficiency virus type 1 (HIV-1) entry inhibitors that block the gp120-CD4 interaction, using database screening techniques. The lead compounds, NBD-556 and NBD-557, are small molecule organic compounds with drug-like properties. These compounds showed potent cell fusion and virus-cell fusion inhibitory activity at low micromolar levels. A systematic study showed that these compounds target viral entry by inhibiting the binding of HIV-1 envelope glycoprotein gp120 to the cellular receptor CD4 but did not inhibit reverse transcriptase, integrase, or protease, indicating that they do not target the later stages of the HIV-1 life cycle to inhibit HIV-1 infection. These compounds were equally potent inhibitors of both X4 and R5 viruses tested in CXCR4 and CCR5 expressing cell lines, respectively, indicating that their anti-HIV-1 activity is not dependent on the coreceptor tropism of the virus. A surface plasmon resonance study, which measures binding affinity, clearly demonstrated that these compounds bind to unliganded HIV-1 gp120 but not to the cellular receptor CD4. NBD-556 and NBD-557 were active against HIV-1 laboratory-adapted strains including an AZT-resistant strain and HIV-1 primary isolates, indicating that these compounds can potentially be further modified to become potent HIV-1 entry inhibitors

  6. 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.

  7. Enveloping algebras

    International Nuclear Information System (INIS)

    Since the works of Gelfand, Harish-Chandra, Kostant and Duflo, a new theory has earned its place in the field of mathematics, due to the abundance of its results and the coherence of its methods: the theory of enveloping algebras. This study is the first to present the whole subject in textbook form. The most recent results are included, as well as complete proofs, starting from the elementary theory of Lie algebras. (Auth.)

  8. 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.

  9. 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.

  10. 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

  11. HIV-1 evades innate immune recognition through specific cofactor recruitment

    OpenAIRE

    Jane Rasaiyaah; Choon Ping Tan; Fletcher, Adam J.; Price, Amanda J.; Caroline Blondeau; Laura Hilditch; Jacques, David A.; Selwood, David L.; James, Leo C.; Mahdad Noursadeghi; Towers, Greg J.

    2013-01-01

    Human immunodeficiency virus (HIV)-1 is able to replicate in primary human macrophages without stimulating innate immunity despite reverse transcription of genomic RNA into double-stranded DNA, an activity that might be expected to trigger innate pattern recognition receptors. We reasoned that if correctly orchestrated HIV-1 uncoating and nuclear entry is important for evasion of innate sensors then manipulation of specific interactions between HIV-1 capsid and host factors that putatively re...

  12. 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 ...

  13. 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...

  14. Current Perspectives on HIV-1 Antiretroviral Drug Resistance

    OpenAIRE

    Pinar Iyidogan; Anderson, Karen S.

    2014-01-01

    Current advancements in antiretroviral therapy (ART) have turned HIV-1 infection into a chronic and manageable disease. However, treatment is only effective until HIV-1 develops resistance against the administered drugs. The most recent antiretroviral drugs have become superior at delaying the evolution of acquired drug resistance. In this review, the viral fitness and its correlation to HIV-1 mutation rates and drug resistance are discussed while emphasizing the concept of lethal mutagenesis...

  15. 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.

  16. HIV-1 western blot assay: What determines an indeterminate status?

    OpenAIRE

    Syed Iqbal; Balakrishnan P; Solomon Sunil; Murugavel K; Kumarasamy N; Vidya S; Martin S; Thyagarajan S; Mayer Kenneth; Solomon S

    2005-01-01

    Background: The Western blot assay is the gold standard for the detection of antibodies to human immunodeficiency virus type1 (HIV-1). However, indeterminate Western blot reactivity to HIV-1 proteins may occur in individuals, who may not be infected with HIV. Aim: This retrospective study was aimed to determine the diagnostic value of the interpretation criteria in relation to commercial kits for HIV -1 diagnosis. Methods and Materials: A total of 556 serum/plasma specimens collected from h...

  17. Characteristics of HIV-1 Serodiscordant Couples Enrolled in a Clinical Trial of Antiretroviral Pre-Exposure Prophylaxis for HIV-1 Prevention

    OpenAIRE

    Mujugira, Andrew; Baeten, Jared M.; Donnell, Deborah; Ndase, Patrick; MUGO, Nelly R.; Barnes, Linda; Campbell, James D.; Wangisi, Jonathan; Tappero, Jordan W.; Bukusi, Elizabeth; Cohen, Craig R.; Katabira, Elly; Ronald, Allan; Tumwesigye, Elioda; Were, Edwin

    2011-01-01

    Introduction 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. Methods HIV-1...

  18. 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...

  19. 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...

  20. A single amino acid substitution in the C4 region in gp120 confers enhanced neutralization of HIV-1 by modulating CD4 binding sites and V3 loop

    OpenAIRE

    Ringe, Rajesh; Sharma, Deepak; Zolla-Pazner, Susan; Phogat, Sanjay; Risbud, Arun; Thakar, Madhuri; Paranjape, Ramesh; Bhattacharya, Jayanta

    2011-01-01

    Identification of vulnerability in the HIV-1 envelope (Env) will aid in Env-based vaccine design. We recently found an HIV-1 clade C Env clone (4-2.J45) amplified from a recently infected Indian patient showing exceptional neutralization sensitivity to autologous plasma in contrast to other autologous Envs obtained at the same time point. By constructing chimeric Envs and fine mapping between sensitive and resistant Env clones, we found that substitution of highly conserved isoleucine (I) wit...

  1. Coamplification of HIV-1 Proviral DNA and Viral RNA in Assays Used for Quantification of HIV-1 RNA▿

    OpenAIRE

    Wan, H; Seth, A; Rainen, L; Fernandes, H.

    2010-01-01

    Elevated HIV-1 viral load (VL) observed in specimens frozen in situ in plasma preparation tubes (PPTs) compared to EDTA plasma specimens may affect therapeutic monitoring of HIV-infected patients. The increase in viral load is cell associated and minimized when plasma from the PPT is aspirated or recentrifuged prior to freezing. This study investigates the contribution of integrated HIV-1 proviral DNA to elevated VL in the quantification of HIV-1 RNA in plasma. Fifty paired specimens collecte...

  2. 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

  3. Sphingopeptides: dihydrosphingosine-based fusion inhibitors against wild-type and enfuvirtide-resistant HIV-1.

    Science.gov (United States)

    Ashkenazi, Avraham; Viard, Mathias; Unger, Linor; Blumenthal, Robert; Shai, Yechiel

    2012-11-01

    Understanding the structural organization of lipids in the cell and viral membranes is essential for elucidating mechanisms of viral fusion that lead to entry of enveloped viruses into their host cells. The HIV lipidome shows a remarkable enrichment in dihydrosphingomyelin, an unusual sphingolipid formed by a dihydrosphingosine backbone. Here we investigated the ability of dihydrosphingosine to incorporate into the site of membrane fusion mediated by the HIV envelope (Env) protein. Dihydrosphingosine as well as cholesterol, fatty acid, and tocopherol was conjugated to highly conserved, short HIV-1 Env-derived peptides with no antiviral activity otherwise. We showed that dihydrosphingosine exclusively endowed nanomolar antiviral activity to the peptides (IC(50) as low as 120 nM) in HIV-1 infection on TZM-bl cells and on Jurkat T cells, as well as in the cell-cell fusion assay. These sphingopeptides were active against enfuvirtide-resistant and wild-type CXCR4 and CCR5 tropic HIV strains. The anti-HIV activity was determined by both the peptides and their dihydrosphingosine conjugate. Moreover, their mode of action involved accumulation in the cells and viruses and binding to membranes enriched in sphingomyelin and cholesterol. The data suggest that sphingopeptides are recruited to the HIV membrane fusion site and provide a general concept in developing inhibitors of sphingolipid-mediated biological systems. PMID:22872679

  4. 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

  5. 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

  6. Protonation states in HIV-1 proteas

    International Nuclear Information System (INIS)

    Molecular dynamics simulations combined with the molecular mechanics-Poisson/Boltzmann surface area (MM-PBSA) are used to study the different protonation states in HIV-1 protease and ABT-538. The results obtained demonstrate that different protonation states have strong influence on the B-factor of protease, the binding free energy between protease and inhibitor and the hydrogen bond. The computation using the MM-PBSA method shows that protonation at the OD1 of Asp25 in B chain has the strongest binding free energy and the B-factor calculated is in agreement with the experiment data. Otherwise, the hydrogen analysis shows the hydrogen bonds between the inhibitor and protease, inhibitor and the bridged-water (W301), and W301 and protease are most stable in the MD. (authors)

  7. MxB binds to the HIV-1 core and prevents the uncoating process of HIV-1

    OpenAIRE

    Fricke, Thomas; White, Tommy E; Schulte, Bianca; de Souza Aranha Vieira, Daniel A.; Dharan, Adarsh; Campbell, Edward M; Brandariz-Nuñez, Alberto; Diaz-Griffero, Felipe

    2014-01-01

    Background The IFN-α-inducible restriction factor MxB blocks HIV-1 infection after reverse transcription but prior to integration. Genetic evidence suggested that capsid is the viral determinant for restriction by MxB. This work explores the ability of MxB to bind to the HIV-1 core, and the role of capsid-binding in restriction. Results We showed that MxB binds to the HIV-1 core and that this interaction leads to inhibition of the uncoating process of HIV-1. These results identify MxB as an e...

  8. 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; Hansen, J E

    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...

  9. Quantitative Correlation between Infectivity and Gp120 Density on HIV-1 Virions Revealed by Optical Trapping Virometry.

    Science.gov (United States)

    DeSantis, Michael C; Kim, Jin H; Song, Hanna; Klasse, Per Johan; Cheng, Wei

    2016-06-17

    The envelope glycoprotein (Env) gp120/gp41 is required for HIV-1 infection of host cells. Although in general it has been perceived that more Env gives rise to higher infectivity, the precise quantitative dependence of HIV-1 virion infectivity on Env density has remained unknown. Here we have developed a method to examine this dependence. This method involves 1) production of a set of single-cycle HIV-1 virions with varied density of Env on their surface, 2) site-specific labeling of Env-specific antibody Fab with a fluorophore at high efficiency, and 3) optical trapping virometry to measure the number of gp120 molecules on individual HIV-1 virions. The resulting gp120 density per virion is then correlated with the infectivity of the virions measured in cell culture. In the presence of DEAE-dextran, the polycation known to enhance HIV-1 infectivity in cell culture, virion infectivity follows gp120 density as a sigmoidal dependence and reaches an apparent plateau. This quantitative dependence can be described by a Hill equation, with a Hill coefficient of 2.4 ± 0.6. In contrast, in the absence of DEAE-dextran, virion infectivity increases monotonically with gp120 density and no saturation is observed under the experimental conditions. These results provide the first quantitative evidence that Env trimers cooperate on the virion surface to mediate productive infection by HIV-1. Moreover, as a result of the low number of Env trimers on individual virions, the number of additional Env trimers per virion that is required for the optimal infectivity will depend on the inclusion of facilitating agents during infection. PMID:27129237

  10. 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.

  11. ANAMNESTIC IMMUNE RESPONSE EIGHT YEARS AFTER IMMUNIZATION OF PRIMATES WITH A MULTIVALENT HIV-1 GP120 VARIABLE PEPTIDE VACCINE

    Directory of Open Access Journals (Sweden)

    Rebecca Rivera

    2013-01-01

    Full Text Available Successful development of an effective HIV vaccine hasn’t occurred yet partly as a consequence of the antigenic variation deployed by HIV-1 to escape the immune system. Our laboratory is dedicated to develop a single peptide synthesis approach to create multivalent peptides representing hypervariable epitopes of the gp120 envelope glycoprotein of HIV-1. Our previous study showed that our HIV HECs are potent immunogens that activate both humoral and cellular arms of the acquired immune response and that these responses are broadly reactive, recognizing epitopes from divergent strains of HIV-1. To detect the long term duration of memory response induced by HIV HECs, two rhesus macaques were immunized at weeks 0 and 8 and euthanized two weeks after a third immunization at week 393 (more than 8 years later. Antibody response to individual components of HIV HEC immunogens and HIV HEC-induced cross-reactive antibody response were determined by an Enzyme-Linked Immunosorbent Assay (ELISA. The antibody titer to individual HIV HEC components and a mixture of the five peptides was greater than 1:5000 dilution. Antibodies from HIV HEC-immunized macaques recognized HIV HEC analogs representing the monovalent epitopes of five variable regions of gp120 from subtype B HIV-1 MN, HIV-1 RF and HIV-1 SF2 isolates with an antibody titer greater than 1: 500 dilution. Moreover, lymphocytes from lymph nodes of HIV HEC-immunized macaques showed T cell proliferative responses specific to HIV HEC individual components and to the five HIV HEC peptides combined. Our results clearly show that in these two macaques, HIV HECs induced strong, long-lasting anamnestic immune responses 8 years after immunization.

  12. 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.

  13. The Fate of HIV-1 Capsid: A Biochemical Assay for HIV-1 Uncoating

    OpenAIRE

    Yang, Yang; Luban, Jeremy; Diaz-Griffero, Felipe

    2014-01-01

    The uncoating process of HIV-1 is a poorly understood process, so the development of a reliable assay to study uncoating is critical for moving the field forward. Here we describe an uncoating assay that currently represents the state-of-the-art biochemical procedure for monitoring uncoating and core stability during infection. This assay is based on the biochemical separation of soluble capsid protein from particulate capsid cores and provides information about the fate of the capsid during ...

  14. The fate of HIV-1 capsid: a biochemical assay for HIV-1 uncoating.

    Science.gov (United States)

    Yang, Yang; Luban, Jeremy; Diaz-Griffero, Felipe

    2014-01-01

    The uncoating process of HIV-1 is a poorly understood process, so the development of a reliable assay to study uncoating is critical for moving the field forward. Here we describe an uncoating assay that currently represents the state-of-the-art biochemical procedure for monitoring uncoating and core stability during infection. This assay is based on the biochemical separation of soluble capsid protein from particulate capsid cores and provides information about the fate of the capsid during infection. PMID:24158811

  15. 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

  16. 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

  17. 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....

  18. 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.

  19. Iron chelators ICL670 and 311 inhibit HIV-1 transcription

    International Nuclear Information System (INIS)

    HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics

  20. 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 indi...

  1. Dipyridodiazepinone derivatives; synthesis and anti HIV-1 activity

    OpenAIRE

    Nisachon Khunnawutmanotham; Nitirat Chimnoi; Arunee Thitithanyanont; Patchreenart Saparpakorn; Kiattawee Choowongkomon; Pornpan Pungpo; Supa Hannongbua; Supanna Techasakul

    2009-01-01

    Ten dipyridodiazepinone derivatives were synthesized and evaluated for their anti HIV-1 reverse transcriptase activity against wild-type and mutant type enzymes, K103N and Y181C. Two of them were found to be promising inhibitors for HIV-1 RT.

  2. 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.

  3. Schistosomiasis and HIV-1 infection in rural Zimbabwe

    DEFF Research Database (Denmark)

    Kallestrup, Per; Zinyama, Rutendo; Gomo, Exnevia; Butterworth, Anthony E; van Dam, Govert J; Erikstrup, Christian; Ullum, Henrik

    2005-01-01

    Stunted development and reduced fecundity of Schistosoma parasites in immunodeficient mice and the impaired ability of human immunodeficiency virus 1 (HIV-1)-infected humans to excrete schistosome eggs have been described. This study explores the effect that HIV-1-associated immunodeficiency has ...

  4. 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

  5. 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.

  6. Comparison of glycerolisation with cryopreservation methods on HIV-1 inactivation

    International Nuclear Information System (INIS)

    Cryopreservation and glycerolisation are two successful long-term preservation methods for human cadaveric donor skin, which is used in the treatment of bum patients. High concentrations of glycerol has been shown to be antibacterial and virucidal. Because fear of possible transmission of HIV-1 following allograft transplantation, this study was undertaken to investigate whether HIV can be effectively eliminated from skin explants. HIV-1 Ba-L, which has been shown to infect monocytes in skin explants and also dendritic cells, was. For the experiments we used cell-free virus, exogenously HIV infected peripheral blood mononuclear cells (PBMCs) and exogenously HIV infected cadaver split skin. Different concentrations of glycerol at various temperatures and the glycerolisation procedure as used by the Euro Skin Bank were used to determine the effects on HIV-1 Ba-L infectivity. For the cryopreservation technique we used 10% DMSO and a controlled rate freezer. HIV-1 Ba-L transfer was determined by adding uninfected PBMCs to the infected material and reverse transcriptase was measured. Cell-free HIV-1 Ba-L was not inactivated by 50% glycerol but was effectively inactivated within 30 minutes by 70% and 85% glycerol at 4 degree C, room temperature and 37 degree C. In contrast, cell-free HIV-1 Ba-L was not inactivated by cryopreservation. Most importantly, we have shown that HIV-1 Ba-L present in split skin is inactivated by incubating skin in 70% glycerol for three hours at 37-C. HIV in exogenously infected skin was not inactivated by cryopreservation. High concentrations of glycerol effectively inactivates free HIV-1 Ba-L and intracellular HIV-1 Ba-L. Also the current glycerolisation procedure carried out by the Euro Skin Bank effectively inactivates infectious virus. However, the cryopreservation technique did not show any reduction in HIV-1 Ba-L infectivity

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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...... 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...

  13. Performance Characteristics of Human Immunodeficiency Virus Type 1 (HIV-1) Genotyping Systems in Sequence-Based Analysis of Subtypes Other than HIV-1 Subtype B

    OpenAIRE

    Jagodzinski, Linda L; Cooley, John D.; Weber, Mark; Michael, Nelson L.

    2003-01-01

    Given the diversity of human immunodeficiency virus type 1 (HIV-1) subtypes and the emergence of subtypes other than HIV-1 subtype B in the United States, genotypic assays must be capable of delivering sequence data on diverse HIV-1 subtypes. We evaluated the performance of Visible Genetics TRUGENE HIV-1 genotyping kit and Applied Biosystems ViroSeq HIV-1 genotyping system on a panel of 34 well-characterized HIV-1 viral stocks (subtypes A through H). Both assays perform well on diverse HIV-1 ...

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. Extreme genetic fragility of the HIV-1 capsid.

    Science.gov (United States)

    Rihn, Suzannah J; Wilson, Sam J; Loman, Nick J; Alim, Mudathir; Bakker, Saskia E; Bhella, David; Gifford, Robert J; Rixon, Frazer J; Bieniasz, Paul D

    2013-01-01

    Genetic robustness, or fragility, is defined as the ability, or lack thereof, of a biological entity to maintain function in the face of mutations. Viruses that replicate via RNA intermediates exhibit high mutation rates, and robustness should be particularly advantageous to them. The capsid (CA) domain of the HIV-1 Gag protein is under strong pressure to conserve functional roles in viral assembly, maturation, uncoating, and nuclear import. However, CA is also under strong immunological pressure to diversify. Therefore, it would be particularly advantageous for CA to evolve genetic robustness. To measure the genetic robustness of HIV-1 CA, we generated a library of single amino acid substitution mutants, encompassing almost half the residues in CA. Strikingly, we found HIV-1 CA to be the most genetically fragile protein that has been analyzed using such an approach, with 70% of mutations yielding replication-defective viruses. Although CA participates in several steps in HIV-1 replication, analysis of conditionally (temperature sensitive) and constitutively non-viable mutants revealed that the biological basis for its genetic fragility was primarily the need to coordinate the accurate and efficient assembly of mature virions. All mutations that exist in naturally occurring HIV-1 subtype B populations at a frequency >3%, and were also present in the mutant library, had fitness levels that were >40% of WT. However, a substantial fraction of mutations with high fitness did not occur in natural populations, suggesting another form of selection pressure limiting variation in vivo. Additionally, known protective CTL epitopes occurred preferentially in domains of the HIV-1 CA that were even more genetically fragile than HIV-1 CA as a whole. The extreme genetic fragility of HIV-1 CA may be one reason why cell-mediated immune responses to Gag correlate with better prognosis in HIV-1 infection, and suggests that CA is a good target for therapy and vaccination strategies

  1. The anti-HIV-1 effect of scutellarin

    International Nuclear Information System (INIS)

    Scutellarin was purified from the plant Erigeron breviscapus (Vant.) Hand.-Mazz. The activity against 3 strains of human immunodeficiency virus (HIV) was determined in vitro in this study. These were laboratory-derived virus (HIV-1IIIB), drug-resistant virus (HIV-174V), and low-passage clinical isolated virus (HIV-1KM018). From syncytia inhibition study, the EC50 of scutellarin against HIV-1IIIB direct infection in C8166 cells was 26 μM with a therapeutic index of 36. When the mode of infection changed from acute infection to cell-to-cell infection, this compound became even more potent and the EC50 reduced to 15 μM. This suggested that cell fusion might be affected by this compound. By comparing the inhibitory effects on p24 antigen, scutellarin was also found to be active against HIV-174V (EC50 253 μM) and HIV-1KM018 (EC50 136 μM) infection with significant difference in potency. The mechanism of its action was also explored in this study. At a concentration of 433 μM, scutellarin inhibited 48% of the cell free recombinant HIV-1 RT activity. It also caused 82% inhibition of HIV-1 particle attachment and 45% inhibition of fusion at the concentrations of 54 μM. In summary, scutellarin was found to inhibit several strains of HIV-1 replication with different potencies. It appeared to inhibit HIV-1 RT activity, HIV-1 particle attachment and cell fusion. These are essential activities for viral transmission and replication

  2. 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.

  3. Exploring the membrane fusion mechanism through force-induced disassembly of HIV-1 six-helix bundle.

    Science.gov (United States)

    Gao, Kai; Zhang, Yong; Lou, Jizhong

    2016-05-13

    Enveloped virus, such as HIV-1, employs membrane fusion mechanism to invade into host cell. HIV-1 gp41 ectodomain uses six-helix bundle configuration to accomplish this process. Using molecular dynamic simulations, we confirmed the stability of this six-helix bundle by showing high occupancy of hydrogen bonds and hydrophobic interactions. Key residues and interactions important for the bundle integration were characterized by force-induced unfolding simulations of six-helix bundle, exhibiting the collapse order of these groups of interactions. Moreover, our results in some way concerted with a previous theory that the formation of coiled-coil choose a route which involved cooperative interactions between the N-terminal and C-terminal helix. PMID:27079239

  4. 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.

  5. 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

  6. 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...

  7. 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.

  8. 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

  9. Structure-based, targeted deglycosylation of HIV-1 gp120 and effects on neutralization sensitivity and antibody recognition

    International Nuclear Information System (INIS)

    The human immunodeficiency virus (HIV-1) exterior envelope glycoprotein, gp120, mediates receptor binding and is the major target for neutralizing antibodies. Primary HIV-1 isolates are characteristically more resistant to broadly neutralizing antibodies, although the structural basis for this resistance remains obscure. Most broadly neutralizing antibodies are directed against functionally conserved gp120 regions involved in binding to either the primary virus receptor, CD4, or the viral coreceptor molecules that normally function as chemokine receptors. These antibodies are known as CD4 binding site (CD4BS) and CD4-induced (CD4i) antibodies, respectively. Inspection of the gp120 crystal structure reveals that although the receptor-binding regions lack glycosylation, sugar moieties lie proximal to both receptor-binding sites on gp120 and thus in proximity to both the CD4BS and the CD4i epitopes. In this study, guided by the X-ray crystal structure of gp120, we deleted four N-linked glycosylation sites that flank the receptor-binding regions. We examined the effects of selected changes on the sensitivity of two prototypic HIV-1 primary isolates to neutralization by antibodies. Surprisingly, removal of a single N-linked glycosylation site at the base of the gp120 third variable region (V3 loop) increased the sensitivity of the primary viruses to neutralization by CD4BS antibodies. Envelope glycoprotein oligomers on the cell surface derived from the V3 glycan-deficient virus were better recognized by a CD4BS antibody and a V3 loop antibody than were the wild-type glycoproteins. Absence of all four glycosylation sites rendered a primary isolate sensitive to CD4i antibody-mediated neutralization. Thus, carbohydrates that flank receptor-binding regions on gp120 protect primary HIV-1 isolates from antibody-mediated neutralization

  10. Inhibition of human immunodeficiency virus type-1 (HIV-1 glycoprotein-mediated cell-cell fusion by immunor (IM28

    Directory of Open Access Journals (Sweden)

    Akoume Marie-Yvonne

    2005-02-01

    Full Text Available Abstract Background Immunor (IM28, an analog of dehydroepiandrosterone (DHEA, inhibits human immunodeficiency virus type-1 (HIV-1 by inhibiting reverse transcriptase. We assessed the ability of IM28 to inhibit the cell-cell fusion mediated by HIV envelope glycoprotein in an in vitro system. For this purpose, we co-cultured TF228.1.16, a T-cell line expressing stably HIV-1 glycoprotein envelopes, with an equal number of 293/CD4+, another T cell line expressing CD4, and with the SupT1 cell line with or without IM28. Results In the absence of IM28, TF228.1.16 fused with 293/CD4+, inducing numerous large syncytia. Syncytia appeared more rapidly when TF228.1.16 was co-cultured with SupT1 cells than when it was co-cultured with the 293/CD4+ cell line. IM28 (1.6 – 45 μg/ml completely inhibits cell-cell fusion. IM28 also prevented the development of new syncytia in infected cells and protected naive SupT1 cells from HIV-1 infection. Evaluation of 50% inhibitory dose (IC50 of IM28 revealed a decrease in HIV-1 replication with an IC50 of 22 mM and 50% cytotoxicity dose (CC50 as determined on MT2 cells was 75 mM giving a selectivity index of 3.4 Conclusions These findings suggest that IM28 exerts an inhibitory action on the env proteins that mediate cell-cell fusion between infected and healthy cells. They also suggest that IM28 interferes with biochemical processes to stop the progression of existing syncytia. This property may lead to the development of a new class of therapeutic drug.

  11. Inhibiting Early-Stage Events in HIV-1 Replication by Small-Molecule Targeting of the HIV-1 Capsid

    OpenAIRE

    Kortagere, Sandhya; Madani, Navid; Mankowski, Marie K.; Schön, Arne; Zentner, Isaac; Swaminathan, Gokul; Princiotto, Amy; Anthony, Kevin; Oza, Apara; Sierra, Luz-Jeannette; Passic, Shendra R.; Wang, Xiaozhao; Jones, David M; Stavale, Eric; Fred C. Krebs

    2012-01-01

    The HIV-1 capsid (CA) protein plays essential roles in both early and late stages of virl replication and has emerged as a novel drug target. We report hybrid structure-based virtual screening to identify small molecules with the potential to interact with the N-terminal domain (NTD) of HIV-1 CA and disrupt early, preintegration steps of the HIV-1 replication cycle. The small molecule 4,4′-[dibenzo[b,d]furan-2,8-diylbis(5-phenyl-1H-imidazole-4,2-diyl)]dibenzoic acid (CK026), which had anti-HI...

  12. 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...

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

    OpenAIRE

    C. Wejse; C.B. Patsche; Kühle, A.; F.J.V. Bamba; Mendes, M. S.; G. Lemvik; V.F. Gomes; F. Rudolf

    2015-01-01

    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 ...

  14. 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...

  15. 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

  16. Neutralizing antibody and anti-retroviral drug sensitivities of HIV-1 isolates resistant to small molecule CCR5 inhibitors

    International Nuclear Information System (INIS)

    The small molecule CCR5 inhibitors are a new class of drugs for treating infection by human immunodeficiency virus type 1 (HIV-1). They act by binding to the CCR5 co-receptor and preventing its use during HIV-1-cell fusion. Escape mutants can be raised against CCR5 inhibitors in vitro and will arise when these drugs are used clinically. Here, we have assessed the responses of CCR5 inhibitor-resistant viruses to other anti-retroviral drugs that act by different mechanisms, and their sensitivities to neutralizing antibodies (NAbs). The rationale for the latter study is that the resistance pathway for CCR5 inhibitors involves changes in the HIV-1 envelope glycoproteins (Env), which are also targets for NAbs. The escape mutants CC101.19 and D1/85.16 were selected for resistance to AD101 and vicriviroc (VVC), respectively, from the primary R5 HIV-1 isolate CC1/85. Each escape mutant was cross-resistant to other small molecule CCR5 inhibitors (aplaviroc, maraviroc, VVC, AD101 and CMPD 167), but sensitive to protein ligands of CCR5: the modified chemokine PSC-RANTES and the humanized MAb PRO-140. The resistant viruses also retained wild-type sensitivity to the nucleoside reverse transcriptase inhibitor (RTI) zidovudine, the non-nucleoside RTI nevirapine, the protease inhibitor atazanavir and other attachment and fusion inhibitors that act independently of CCR5 (BMS-806, PRO-542 and enfuvirtide). Of note is that the escape mutants were more sensitive than the parental CC1/85 isolate to a subset of neutralizing monoclonal antibodies and to some sera from HIV-1-infected people, implying that sequence changes in Env that confer resistance to CCR5 inhibitors can increase the accessibility of some NAb epitopes. The need to preserve NAb resistance may therefore be a constraint upon how escape from CCR5 inhibitors occurs in vivo

  17. 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.

  18. Perinuclear localization of the HIV-1 regulatory protein Vpr is important for induction of G2-arrest

    International Nuclear Information System (INIS)

    The HIV-1 accessory protein Vpr induces G2 cell cycle arrest and apoptosis. Previous studies indicate that the induction of G2-arrest requires the localization of Vpr to the nuclear envelope. Here we show that treatment of Vpr-expressing HeLa cells with the caspase 3 inhibitor Z-DEVD-fmk induced accumulation of Vpr at the nuclear lamina, while other proteins or structures of the nuclear envelope were not influenced. Furthermore, Z-DEVD-fmk enhances the Vpr-mediated G2-arrest that even occurred in HIV-1NL4–3-infected T-cells. Mutation of Pro-35, which is important for the integrity of helix-α1 in Vpr, completely abrogated the Z-DEVD-fmk-mediated accumulation of Vpr at the nuclear lamina and the enhancement of G2-arrest. As expected, inhibition of caspase 3 reduced the induction of apoptosis by Vpr. Taken together, we could show that besides its role in Vpr-mediated apoptosis induction caspase 3 influences the localization of Vpr at the nuclear envelope and thereby augments the Vpr-induced G2-arrest.

  19. 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.

  20. Chimpanzee reservoirs of pandemic and nonpandemic HIV-1.

    Science.gov (United States)

    Keele, Brandon F; Van Heuverswyn, Fran; Li, Yingying; Bailes, Elizabeth; Takehisa, Jun; Santiago, Mario L; Bibollet-Ruche, Frederic; Chen, Yalu; Wain, Louise V; Liegeois, Florian; Loul, Severin; Ngole, Eitel Mpoudi; Bienvenue, Yanga; Delaporte, Eric; Brookfield, John F Y; Sharp, Paul M; Shaw, George M; Peeters, Martine; Hahn, Beatrice H

    2006-07-28

    Human immunodeficiency virus type 1 (HIV-1), the cause of human acquired immunodeficiency syndrome (AIDS), is a zoonotic infection of staggering proportions and social impact. Yet uncertainty persists regarding its natural reservoir. The virus most closely related to HIV-1 is a simian immunodeficiency virus (SIV) thus far identified only in captive members of the chimpanzee subspecies Pan troglodytes troglodytes. Here we report the detection of SIVcpz antibodies and nucleic acids in fecal samples from wild-living P. t. troglodytes apes in southern Cameroon, where prevalence rates in some communities reached 29 to 35%. By sequence analysis of endemic SIVcpz strains, we could trace the origins of pandemic (group M) and nonpandemic (group N) HIV-1 to distinct, geographically isolated chimpanzee communities. These findings establish P. t. troglodytes as a natural reservoir of HIV-1. PMID:16728595

  1. HIV-1 infected monozygotic twins: a tale of two outcomes

    OpenAIRE

    Pérez-Losada Marcos; Orsega Susan; Metcalf Julia A; Hirschfeld Steven; Imamichi Hiromi; Tazi Loubna; Posada David; Lane H Clifford; Crandall Keith A

    2011-01-01

    Abstract Background Replicate experiments are often difficult to find in evolutionary biology, as this field is inherently an historical science. However, viruses, bacteria and phages provide opportunities to study evolution in both natural and experimental contexts, due to their accelerated rates of evolution and short generation times. Here we investigate HIV-1 evolution by using a natural model represented by monozygotic twins infected synchronically at birth with an HIV-1 population from ...

  2. 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...

  3. Cell-free Assays for HIV-1 Uncoating

    OpenAIRE

    Aiken, Christopher

    2009-01-01

    Uncoating is an essential step in the retrovirus life cycle about which little is known. Uncoating is defined as the specific dissociation of the capsid shell from the viral core in the host cell cytoplasm. In this chapter, biochemical assays for studying HIV-1 uncoating in vitro are described. These techniques have proven useful for characterizing HIV-1 mutants that exhibit defects in the uncoating step of infection.

  4. Cell-free assays for HIV-1 uncoating.

    Science.gov (United States)

    Aiken, Christopher

    2009-01-01

    Uncoating is an essential step in the retrovirus life cycle about which little is known. Uncoating is defined as the specific dissociation of the capsid shell from the viral core in the host cell cytoplasm. In this chapter, biochemical assays for studying HIV-1 uncoating in vitro are described. These techniques have proven useful for characterizing HIV-1 mutants that exhibit defects in the uncoating step of infection. PMID:19020817

  5. Protein methylation is required to maintain optimal HIV-1 infectivity

    OpenAIRE

    Piller Sabine C; Warrilow David; Apolloni Ann; Bodetti Tracey J; Hitchen Eleanor M; Willemsen Nicole M; Harrich David

    2006-01-01

    Abstract Background: Protein methylation is recognized as a major protein modification pathway regulating diverse cellular events such as protein trafficking, transcription, and signal transduction. More recently, protein arginine methyltransferase activity has been shown to regulate HIV-1 transcription via Tat. In this study, adenosine periodate (AdOx) was used to globally inhibit protein methyltransferase activity so that the effect of protein methylation on HIV-1 infectivity could be asses...

  6. Lipids and Membrane Microdomains in HIV-1 Replication

    OpenAIRE

    Waheed, Abdul A.; Freed, Eric O.

    2009-01-01

    Several critical steps in the replication cycle of human immunodeficiency virus type 1 (HIV-1) – entry, assembly and budding – are complex processes that take place at the plasma membrane of the host cell. A growing body of data indicates that these early and late steps in HIV-1 replication take place in specialized plasma membrane microdomains, and that many of the viral and cellular components required for entry, assembly, and budding are concentrated in these microdomains. In particular, a...

  7. 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...

  8. Molecular dynamics simulations of HIV-1 protease complexed with saquinavir

    OpenAIRE

    Watson, S. J.

    2009-01-01

    Inhibition of the Human Immunode�ficiency virus type-1 (HIV-1) protease enzyme blocks HIV-1 replication. Protease inhibitor drugs have successfully been used as a therapy for HIV-infected individuals to reduce their viral loads and slow the progression to Acquired Immune Defi�ciency Syndrome (AIDS). However, mutations readily and rapidly accrue in the protease gene resulting in a reduced sensitivity of the protein to the inhibitor. In this thesis, molecular dynamics simulations (MDS)...

  9. 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

  10. Targeting HIV-1 entry and reverse transcription by vaccination

    OpenAIRE

    Zuber, Bartek

    2002-01-01

    Human immunodeficiency virus type I (HIV-1) is a complex retrovirus, which uses the CD4 receptor and chemokine receptors to infect its target cells. The chemokine receptor CCR5 is essential for primary HIV-1 infection. The hallmark of retroviruses is the enzyme reverse transcriptase (RT), which transcribes the virus genome from RNA to DNA. RT is a major target for HIV drugs but antiviral treatment often selects for drug resistant virus variants. RT lacks proofreading, which ...

  11. Stabilization of HIV-1 gp120-CD4 receptor complex through targeted interchain disulfide exchange.

    Science.gov (United States)

    Cerutti, Nichole; Mendelow, Barry V; Napier, Grant B; Papathanasopoulos, Maria A; Killick, Mark; Khati, Makobetsa; Stevens, Wendy; Capovilla, Alexio

    2010-08-13

    HIV-1 enters cells via interaction between the trimeric envelope (Env) glycoprotein gp120/gp41 and the host cell surface receptor molecule CD4. The requirement of CD4 for viral entry has rationalized the development of recombinant CD4-based proteins as competitive viral attachment inhibitors and immunotherapeutic agents. In this study, we describe a novel recombinant CD4 protein designed to bind gp120 through a targeted disulfide-exchange mechanism. According to structural models of the gp120-CD4 receptor complex, substitution of Ser(60) on the CD4 domain 1 alpha-helix with Cys positions a thiol in proximity of the gp120 V1/V2 loop disulfide (Cys(126)-Cys(196)), satisfying the stereochemical and geometric conditions for redox exchange between CD4 Cys(60) and gp120 Cys(126), and the consequent formation of an interchain disulfide bond. In this study, we provide experimental evidence for this effect by describing the expression, purification, refolding, receptor binding and antiviral activity analysis of a recombinant two-domain CD4 variant containing the S60C mutation (2dCD4-S60C). We show that 2dCD4-S60C binds HIV-1 gp120 with a significantly higher affinity than wild-type protein under conditions that facilitate disulfide exchange and that this translates into a corresponding increase in the efficacy of CD4-mediated viral entry inhibition. We propose that targeted redox exchange between conserved gp120 disulfides and nucleophilic moieties positioned strategically on CD4 (or CD4-like scaffolds) conceptualizes a new strategy in the development of high affinity HIV-1 Env ligands, with important implications for therapy and vaccine development. More generally, this chalcogen substitution approach provides a general means of stabilizing receptor-ligand complexes where the structural and biophysical conditions for disulfide exchange are satisfied. PMID:20538591

  12. Stabilization of HIV-1 gp120-CD4 Receptor Complex through Targeted Interchain Disulfide Exchange*

    Science.gov (United States)

    Cerutti, Nichole; Mendelow, Barry V.; Napier, Grant B.; Papathanasopoulos, Maria A.; Killick, Mark; Khati, Makobetsa; Stevens, Wendy; Capovilla, Alexio

    2010-01-01

    HIV-1 enters cells via interaction between the trimeric envelope (Env) glycoprotein gp120/gp41 and the host cell surface receptor molecule CD4. The requirement of CD4 for viral entry has rationalized the development of recombinant CD4-based proteins as competitive viral attachment inhibitors and immunotherapeutic agents. In this study, we describe a novel recombinant CD4 protein designed to bind gp120 through a targeted disulfide-exchange mechanism. According to structural models of the gp120-CD4 receptor complex, substitution of Ser60 on the CD4 domain 1 α-helix with Cys positions a thiol in proximity of the gp120 V1/V2 loop disulfide (Cys126–Cys196), satisfying the stereochemical and geometric conditions for redox exchange between CD4 Cys60 and gp120 Cys126, and the consequent formation of an interchain disulfide bond. In this study, we provide experimental evidence for this effect by describing the expression, purification, refolding, receptor binding and antiviral activity analysis of a recombinant two-domain CD4 variant containing the S60C mutation (2dCD4-S60C). We show that 2dCD4-S60C binds HIV-1 gp120 with a significantly higher affinity than wild-type protein under conditions that facilitate disulfide exchange and that this translates into a corresponding increase in the efficacy of CD4-mediated viral entry inhibition. We propose that targeted redox exchange between conserved gp120 disulfides and nucleophilic moieties positioned strategically on CD4 (or CD4-like scaffolds) conceptualizes a new strategy in the development of high affinity HIV-1 Env ligands, with important implications for therapy and vaccine development. More generally, this chalcogen substitution approach provides a general means of stabilizing receptor-ligand complexes where the structural and biophysical conditions for disulfide exchange are satisfied. PMID:20538591

  13. VSV-G pseudotyping rescues HIV-1 CA mutations that impair core assembly or stability

    Directory of Open Access Journals (Sweden)

    Chaloin Laurent

    2008-07-01

    Full Text Available Abstract Background The machinery of early HIV-1 replication still remains to be elucidated. Recently the viral core was reported to persist in the infected cell cytoplasm as an assembled particle, giving rise to the reverse transcription complex responsible for the synthesis of proviral DNA and its transport to the nucleus. Numerous studies have demonstrated that reverse transcription of the HIV-1 genome into proviral DNA is tightly dependent upon proper assembly of the capsid (CA protein into mature cores that display appropriate stability. The functional impact of structural properties of the core in early replicative steps has yet to be determined. Results Here, we show that infectivity of HIV-1 mutants bearing S149A and S178A mutations in CA can be efficiently restored when pseudotyped with vesicular stomatitis virus envelope glycoprotein, that addresses the mutant cores through the endocytic pathway rather than by fusion at the plasma membrane. The mechanisms by which these mutations disrupt virus infectivity were investigated. S149A and S178A mutants were unable to complete reverse transcription and/or produce 2-LTR DNA. Morphological analysis of viral particles and in vitro uncoating assays of isolated cores demonstrated that infectivity defects resulted from disruption of the viral core assembly and stability for S149A and S178A mutants, respectively. Consistent with these results, both mutants failed to saturate TRIM-antiviral restriction activity. Conclusion Defects generated at the level of core assembly and stability by S149A and S178A mutations are sensitive to the way of delivery of viral nucleoprotein complexes into the target cell. Addressing CA mutants through the endocytic pathway may compensate for defects generated at the reverse transcription/nuclear import level subsequent to impairment of core assembly or stability.

  14. Nucleic acids encoding modified human immunodeficiency virus type 1 (HIV-1) group M consensus envelope glycoproteins

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, Barton F. (Durham, NC); Gao, Feng (Durham, NC); Korber, Bette T. (Los Alamos, NM); Hahn, Beatrice H. (Birmingham, AL); Shaw, George M. (Birmingham, AL); Kothe, Denise (Birmingham, AL); Li, Ying Ying (Hoover, AL); Decker, Julie (Alabaster, AL); Liao, Hua-Xin (Chapel Hill, NC)

    2011-12-06

    The present invention relates, in general, to an immunogen and, in particular, to an immunogen for inducing antibodies that neutralizes a wide spectrum of HIV primary isolates and/or to an immunogen that induces a T cell immune response. The invention also relates to a method of inducing anti-HIV antibodies, and/or to a method of inducing a T cell immune response, using such an immunogen. The invention further relates to nucleic acid sequences encoding the present immunogens.

  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. 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.

  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. Structure of HIV-1 protease determined by neutron crystallography

    International Nuclear Information System (INIS)

    HIV-1 protease is an aspartic protease, and plays an essential role in replication of HIV. To develop HIV-1 protease inhibitors through structure-based drug design, it is necessary to understand the catalytic mechanism and inhibitor recognition of HIV-1 protease. We have determined the crystal structure of HIV-1 protease in complex with KNI-272 to 1.9 A resolution by neutron crystallography in combination with 1.4 A resolution X-ray diffraction data. The results show that the carbonyl group of hydroxymethylcarbonyl (HMC) in KNI-272 forms a hydrogen bonding interaction with protonated Asp 25 and the hydrogen atom from the hydroxyl group of HMC forms a hydrogen bonding interaction with the deprotonated Asp125. This is the first neutron report for HIV-1/inhibitor complex and shows directly the locations of key hydrogen atoms in catalysis and in the binding of a transition-state analog. The results confirm key aspect of the presumed catalytic mechanism of HIV-1 protease and will aid in the further development of protease inhibitors. (author)

  20. 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

  1. The evolution of HIV-1 and the origin of AIDS.

    Science.gov (United States)

    Sharp, Paul M; Hahn, Beatrice H

    2010-08-27

    The major cause of acquired immune deficiency syndrome (AIDS) is human immunodeficiency virus type 1 (HIV-1). We have been using evolutionary comparisons to trace (i) the origin(s) of HIV-1 and (ii) the origin(s) of AIDS. The closest relatives of HIV-1 are simian immunodeficiency viruses (SIVs) infecting wild-living chimpanzees (Pan troglodytes troglodytes) and gorillas (Gorilla gorilla gorilla) in west central Africa. Phylogenetic analyses have revealed the origins of HIV-1: chimpanzees were the original hosts of this clade of viruses; four lineages of HIV-1 have arisen by independent cross-species transmissions to humans and one or two of those transmissions may have been via gorillas. However, SIVs are primarily monkey viruses: more than 40 species of African monkeys are infected with their own, species-specific, SIV and in at least some host species, the infection seems non-pathogenic. Chimpanzees acquired from monkeys two distinct forms of SIVs that recombined to produce a virus with a unique genome structure. We have found that SIV infection causes CD4(+) T-cell depletion and increases mortality in wild chimpanzees, and so the origin of AIDS is more ancient than the origin of HIV-1. Tracing the genetic changes that occurred as monkey viruses adapted to infect first chimpanzees and then humans may provide insights into the causes of the pathogenicity of these viruses. PMID:20643738

  2. 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

  3. 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.

  4. An anti-HIV-1 gp120 antibody expressed as an endocytotic transmembrane protein mediates internalization of HIV-1

    International Nuclear Information System (INIS)

    In this study, we used HIV-1 as a model to demonstrate a novel approach for receptor-independent cell entry of virus. The heavy chain of an anti-HIV-1 gp120 antibody was engineered with endocytotic and transmembrane motifs from either the cation-independent mannose 6-phospate receptor or the low-density lipoprotein receptor. Flow cytometry and immunofluorescence studies showed that the chimeric antibodies were expressed on the cell surface and can undergo rapid internalization. Furthermore, one of the chimeric antibodies was able to bind and internalize HIV-1. Using a luciferase reporter HIV-1, we further showed that internalized viruses could undergo replication. Therefore, we have demonstrated a proof-of-principle of a novel method that can be used to internalize virus into cells, without prior knowledge of the cellular receptor for the virus. We propose that this approach would be particularly useful for studying viruses whose cellular receptor(s) is not known

  5. 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

  6. 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

  7. Functional constraints on HIV-1 capsid: their impacts on the viral immune escape potency

    Directory of Open Access Journals (Sweden)

    TaichiroTakemura

    2012-10-01

    Full Text Available In mature HIV-1 particles, viral capsid (CA proteins form the conical core structure that encapsidates two copies of the viral RNA genome. After fusion of the viral envelope and cellular membranes, the CA core enters into the cytoplasm of the target cells. CA proteins then interact with a variety of viral other protein as well as host factors, which may either support or inhibit replication of the virus. Recent studies have revealed that CA proteins are important not only for the uncoating step but also for the later nuclear import step. Identification of proteins that interact with CA to fulfill these functions is, therefore, important for understanding the unknown HIV-1 replication machinery. CA proteins can also be targets of the host immune response. Notably, some HLA-restricted cytotoxic T-lymphocyte (CTL responses that recognize CA functional regions can greatly contribute to delay in AIDS progression. The multi-functionality of the CA protein may limit the flexible virus evolution and reduce the possibility of an escape mutant arising. The presence of many functional regions in CA protein may make it a potential target for effective therapies.

  8. Functional constraints on HIV-1 capsid: their impacts on the viral immune escape potency.

    Science.gov (United States)

    Takemura, Taichiro; Murakami, Tsutomu

    2012-01-01

    In mature HIV-1 particles, viral capsid (CA) proteins form the conical core structure that encapsidates two copies of the viral RNA genome. After fusion of the viral envelope and cellular membranes, the CA core enters into the cytoplasm of the target cells. CA proteins then interact with a variety of viral other protein as well as host factors, which may either support or inhibit replication of the virus. Recent studies have revealed that CA proteins are important not only for the uncoating step but also for the later nuclear import step. Identification of proteins that interact with CA to fulfill these functions is, therefore, important for understanding the unknown HIV-1 replication machinery. CA proteins can also be targets of the host immune response. Notably, some HLA-restricted cytotoxic T-lymphocyte (CTL) responses that recognize CA functional regions can greatly contribute to delay in AIDS progression. The multi-functionality of the CA protein may limit the flexible virus evolution and reduce the possibility of an escape mutant arising. The presence of many functional regions in CA protein may make it a potential target for effective therapies. PMID:23087682

  9. Nuclear import of APOBEC3F-labeled HIV-1 preintegration complexes.

    Science.gov (United States)

    Burdick, Ryan C; Hu, Wei-Shau; Pathak, Vinay K

    2013-12-01

    Human cytidine deaminases APOBEC3F (A3F) and APOBEC3G (A3G) are host factors that incorporate into virions and restrict virus replication. We labeled HIV-1 particles with yellow fluorescent protein (YFP)-tagged APOBEC3 proteins and examined their association with preintegration complexes (PICs) in infected cells. Labeling of PICs with A3F-YFP, and to a lesser extent A3G-YFP, could be used to visualize PICs in the nuclei, which was dependent on nuclear pore protein Nup153 but not TNPO3. We show that reverse transcription is not required for nuclear import of PICs, indicating that a viral core uncoating event associated with reverse transcription, and the central DNA flap that forms during reverse transcription, are not required for nuclear import. We also quantify association of cytoplasmic PICs with nuclear envelope (NE) and report that capsid mutations that increase or decrease core stability dramatically reduce NE association and nuclear import of PICs. In addition, we find that nuclear PICs remain close to the NE and are not distributed throughout the nuclei. These results provide tools for tracking retroviral PICs in infected cells and reveal insights into HIV-1 replication. PMID:24248339

  10. HIV-1 clade promoters strongly influence spatial and temporal dynamics of viral replication in vivo

    Science.gov (United States)

    Centlivre, Mireille; Sommer, Peter; Michel, Marie; Fang, Raphaël Ho Tsong; Gofflo, Sandrine; Valladeau, Jenny; Schmitt, Nathalie; Thierry, Françoise; Hurtrel, Bruno; Wain-Hobson, Simon; Sala, Monica

    2005-01-01

    Although the primary determinant of cell tropism is the interaction of viral envelope or capsid proteins with cellular receptors, other viral elements can strongly modulate viral replication. While the HIV-1 promoter is polymorphic for a variety of transcription factor binding sites, the impact of these polymorphisms on viral replication in vivo is not known. To address this issue, we engineered isogenic SIVmac239 chimeras harboring the core promoter/enhancer from HIV-1 clades B, C, and E. Here it is shown that the clade C and E core promoters/enhancers bear a noncanonical activator protein–1 (AP-1) binding site, absent from the corresponding clade B region. Relative ex vivo replication of chimeras was strongly dependent on the tissue culture system used. Notably, in thymic histocultures, replication of the clade C chimera was favored by IL-7 enrichment, which suggests that the clade C polymorphism in the AP-1 and NF-κB binding sites is involved. Simultaneous infection of rhesus macaques with the 3 chimeras revealed a strong predominance of the clade C chimera during primary infection. Thereafter, the B chimera dominated in all tissues. These data show that the clade C promoter is particularly adapted to sustain viral replication in primary viremia and that clade-specific promoter polymorphisms constitute a major determinant for viral replication. PMID:15690084

  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. Functional characteristics of HIV-1 subtype C compatible with increased heterosexual transmissibility

    DEFF Research Database (Denmark)

    Walter, Brandon L; Armitage, Andrew E; Graham, Stephen C;

    2009-01-01

    BACKGROUND: Despite the existence of over 50 subtypes and circulating recombinant forms of HIV-1, subtype C dominates the heterosexual pandemic causing approximately 56% of all infections. OBJECTIVE: To evaluate whether viral genetic factors may contribute to the observed subtype-C predominance....... METHODS: Chimeric viruses were generated using V1-V3 envelope fragments from a subtype-A/C dually infected woman with preferential genital replication of subtype C. Viral adaptation, spread and cell fusion ability were evaluated in vitro using peripheral blood mononuclear cells and HeLa-CD4-CCR5 cell...... mononuclear cell and cell lines with low CCR5 expression. Structural modeling suggested the formation of an additional hydrogen bond between V3 and CCR5. Moreover, we found preferential selection of HIV with 316T and/or extremely short V1-V2 loops in cervices of three women infected with subtypes A/C, B or C...

  13. Inhibiting early-stage events in HIV-1 replication by small-molecule targeting of the HIV-1 capsid.

    Science.gov (United States)

    Kortagere, Sandhya; Madani, Navid; Mankowski, Marie K; Schön, Arne; Zentner, Isaac; Swaminathan, Gokul; Princiotto, Amy; Anthony, Kevin; Oza, Apara; Sierra, Luz-Jeannette; Passic, Shendra R; Wang, Xiaozhao; Jones, David M; Stavale, Eric; Krebs, Fred C; Martín-García, Julio; Freire, Ernesto; Ptak, Roger G; Sodroski, Joseph; Cocklin, Simon; Smith, Amos B

    2012-08-01

    The HIV-1 capsid (CA) protein plays essential roles in both early and late stages of virl replication and has emerged as a novel drug target. We report hybrid structure-based virtual screening to identify small molecules with the potential to interact with the N-terminal domain (NTD) of HIV-1 CA and disrupt early, preintegration steps of the HIV-1 replication cycle. The small molecule 4,4'-[dibenzo[b,d]furan-2,8-diylbis(5-phenyl-1H-imidazole-4,2-diyl)]dibenzoic acid (CK026), which had anti-HIV-1 activity in single- and multiple-round infections but failed to inhibit viral replication in peripheral blood mononuclear cells (PBMCs), was identified. Three analogues of CK026 with reduced size and better drug-like properties were synthesized and assessed. Compound I-XW-053 (4-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid) retained all of the antiviral activity of the parental compound and inhibited the replication of a diverse panel of primary HIV-1 isolates in PBMCs, while displaying no appreciable cytotoxicity. This antiviral activity was specific to HIV-1, as I-XW-053 displayed no effect on the replication of SIV or against a panel of nonretroviruses. Direct interaction of I-XW-053 was quantified with wild-type and mutant CA protein using surface plasmon resonance and isothermal titration calorimetry. Mutation of Ile37 and Arg173, which are required for interaction with compound I-XW-053, crippled the virus at an early, preintegration step. Using quantitative PCR, we demonstrated that treatment with I-XW-053 inhibited HIV-1 reverse transcription in multiple cell types, indirectly pointing to dysfunction in the uncoating process. In summary, we have identified a CA-specific compound that targets and inhibits a novel region in the NTD-NTD interface, affects uncoating, and possesses broad-spectrum anti-HIV-1 activity. PMID:22647699

  14. 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

  15. 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

  16. 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

  17. 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.

  18. Cellular specificity of HIV-1 replication can be controlled by LTR sequences

    International Nuclear Information System (INIS)

    Two well-established determinants of retroviral tropism are envelope sequences that regulate entry and LTR sequences that can regulate viral expression in a cell-specific manner. Studies with human immunodeficiency virus-1 (HIV-1) have demonstrated that tropism of this virus maps primarily to variable envelope sequences. Studies have demonstrated that T cell and macrophage-specific transcription factor binding motifs exist in the upstream region of the LTR U3; however, the ability of the core enhancer/promoter proximal elements (two NF-κB and three Sp1 sites) to function well in macrophages and T cells have led many to conclude that HIV LTR sequences are not primary determinants of HIV tropism. To determine if cellular specificity could be imparted to HIV by the core enhancer elements, the enhancer/promoter proximal region of the HIV LTR was substituted with motifs that control gene expression in a myeloid-specific manner. The enhancer region from equine infectious anemia virus (EIAV) when substituted for the HIV enhancer/promoter proximal region was found to drive expression in a macrophage-specific manner and was responsive to HIV Tat. The addition of a 5' methylation-dependent binding site (MDBP) and a promoter proximal Sp1 motif increased expression without altering cellular specificity. Spacing between the promoter proximal region and the TATA box was also found to influence LTR activity. Infectivity studies using chimeric LTRs within the context of a dual-tropic infectious molecular clone established that these LTRs directed HIV replication and production of infectious virions in macrophages but not primary T cells or T cell lines. This investigation demonstrates that cellular specificity can be imparted onto HIV-1 replication at the level of viral transcription and not entry

  19. 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....

  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. HIV-1 evades innate immune recognition through specific cofactor recruitment

    Science.gov (United States)

    Rasaiyaah, Jane; Tan, Choon Ping; Fletcher, Adam J.; Price, Amanda J.; Blondeau, Caroline; Hilditch, Laura; Jacques, David A.; Selwood, David L.; James, Leo C.; Noursadeghi, Mahdad; Towers, Greg J.

    2013-11-01

    Human immunodeficiency virus (HIV)-1 is able to replicate in primary human macrophages without stimulating innate immunity despite reverse transcription of genomic RNA into double-stranded DNA, an activity that might be expected to trigger innate pattern recognition receptors. We reasoned that if correctly orchestrated HIV-1 uncoating and nuclear entry is important for evasion of innate sensors then manipulation of specific interactions between HIV-1 capsid and host factors that putatively regulate these processes should trigger pattern recognition receptors and stimulate type 1 interferon (IFN) secretion. Here we show that HIV-1 capsid mutants N74D and P90A, which are impaired for interaction with cofactors cleavage and polyadenylation specificity factor subunit 6 (CPSF6) and cyclophilins (Nup358 and CypA), respectively, cannot replicate in primary human monocyte-derived macrophages because they trigger innate sensors leading to nuclear translocation of NF-κB and IRF3, the production of soluble type 1 IFN and induction of an antiviral state. Depletion of CPSF6 with short hairpin RNA expression allows wild-type virus to trigger innate sensors and IFN production. In each case, suppressed replication is rescued by IFN-receptor blockade, demonstrating a role for IFN in restriction. IFN production is dependent on viral reverse transcription but not integration, indicating that a viral reverse transcription product comprises the HIV-1 pathogen-associated molecular pattern. Finally, we show that we can pharmacologically induce wild-type HIV-1 infection to stimulate IFN secretion and an antiviral state using a non-immunosuppressive cyclosporine analogue. We conclude that HIV-1 has evolved to use CPSF6 and cyclophilins to cloak its replication, allowing evasion of innate immune sensors and induction of a cell-autonomous innate immune response in primary human macrophages.

  2. HIV-1 latency in actively dividing human T cell lines

    Directory of Open Access Journals (Sweden)

    Berkhout Ben

    2008-04-01

    Full Text Available Abstract Background Eradication of HIV-1 from an infected individual cannot be achieved by current drug regimens. Viral reservoirs established early during the infection remain unaffected by anti-retroviral therapy and are able to replenish systemic infection upon interruption of the treatment. Therapeutic targeting of viral latency will require a better understanding of the basic mechanisms underlying the establishment and long-term maintenance of HIV-1 in resting memory CD4 T cells, the most prominent reservoir of transcriptional silent provirus. However, the molecular mechanisms that permit long-term transcriptional control of proviral gene expression in these cells are still not well understood. Exploring the molecular details of viral latency will provide new insights for eventual future therapeutics that aim at viral eradication. Results We set out to develop a new in vitro HIV-1 latency model system using the doxycycline (dox-inducible HIV-rtTA variant. Stable cell clones were generated with a silent HIV-1 provirus, which can subsequently be activated by dox-addition. Surprisingly, only a minority of the cells was able to induce viral gene expression and a spreading infection, eventhough these experiments were performed with the actively dividing SupT1 T cell line. These latent proviruses are responsive to TNFα treatment and alteration of the DNA methylation status with 5-Azacytidine or genistein, but not responsive to the regular T cell activators PMA and IL2. Follow-up experiments in several T cell lines and with wild-type HIV-1 support these findings. Conclusion We describe the development of a new in vitro model for HIV-1 latency and discuss the advantages of this system. The data suggest that HIV-1 proviral latency is not restricted to resting T cells, but rather an intrinsic property of the virus.

  3. 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.

  4. HIV-1 evades innate immune recognition through specific cofactor recruitment.

    Science.gov (United States)

    Rasaiyaah, Jane; Tan, Choon Ping; Fletcher, Adam J; Price, Amanda J; Blondeau, Caroline; Hilditch, Laura; Jacques, David A; Selwood, David L; James, Leo C; Noursadeghi, Mahdad; Towers, Greg J

    2013-11-21

    Human immunodeficiency virus (HIV)-1 is able to replicate in primary human macrophages without stimulating innate immunity despite reverse transcription of genomic RNA into double-stranded DNA, an activity that might be expected to trigger innate pattern recognition receptors. We reasoned that if correctly orchestrated HIV-1 uncoating and nuclear entry is important for evasion of innate sensors then manipulation of specific interactions between HIV-1 capsid and host factors that putatively regulate these processes should trigger pattern recognition receptors and stimulate type 1 interferon (IFN) secretion. Here we show that HIV-1 capsid mutants N74D and P90A, which are impaired for interaction with cofactors cleavage and polyadenylation specificity factor subunit 6 (CPSF6) and cyclophilins (Nup358 and CypA), respectively, cannot replicate in primary human monocyte-derived macrophages because they trigger innate sensors leading to nuclear translocation of NF-κB and IRF3, the production of soluble type 1 IFN and induction of an antiviral state. Depletion of CPSF6 with short hairpin RNA expression allows wild-type virus to trigger innate sensors and IFN production. In each case, suppressed replication is rescued by IFN-receptor blockade, demonstrating a role for IFN in restriction. IFN production is dependent on viral reverse transcription but not integration, indicating that a viral reverse transcription product comprises the HIV-1 pathogen-associated molecular pattern. Finally, we show that we can pharmacologically induce wild-type HIV-1 infection to stimulate IFN secretion and an antiviral state using a non-immunosuppressive cyclosporine analogue. We conclude that HIV-1 has evolved to use CPSF6 and cyclophilins to cloak its replication, allowing evasion of innate immune sensors and induction of a cell-autonomous innate immune response in primary human macrophages. PMID:24196705

  5. 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

  6. 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

  7. 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 ...

  8. Quantitation of HIV-1 RNA in breast milk by real time PCR

    OpenAIRE

    Becquart, Pierre; Foulongne, Vincent; Willumsen, J.; Rouzioux, C; Segondy, Michel; Van De Perre, Philippe

    2006-01-01

    HIV-1 RNA in breast milk is a strong predictor of HIV-1 transmission through breastfeeding. In the present report, breast milk samples from HIV-1 uninfected donors were spiked with dilution of quantified culture supernatant from HIV-1(NDK) infected PBMC. Two RNA extraction techniques based on silica extraction, Nuclisens (R) (BioMerieux) and Triazol (Qiagen), two techniques based on guanidine thiocynanate/chloroforme extraction, TRIzol (Life Technologic) and Amplicor HIV-1 Monitor (TM) (Roche...

  9. DC-specific ICAM-3-grabbing nonintegrin mediates internalization of HIV-1 into human podocytes

    OpenAIRE

    J. Mikulak; TEICHBERG, S; Arora, S.; KUMAR, D; Yadav, A.; Salhan, D.; Pullagura, S.; Mathieson, P. W.; Saleem, M A; Singhal, P. C.

    2010-01-01

    Human immunodeficiency virus (HIV)-1 has been demonstrated to contribute to the pathogenesis of HIV-associated nephropathy. In renal biopsy studies, podocytes have been reported to be infected by HIV-1. However, the mechanism involved in HIV-1 internalization into podocytes is not clear. In the present study, we evaluated the occurrence of HIV-1 internalization into conditionally immortalized human podocytes and the mechanism involved. Human podocytes rapidly internalized R5 and X4 HIV-1 prim...

  10. 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...

  11. 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

  12. 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

  13. 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...

  14. 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

  15. 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.

  16. Genetic Consequences of Antiviral Therapy on HIV-1

    Directory of Open Access Journals (Sweden)

    Miguel Arenas

    2015-01-01

    Full Text Available A variety of enzyme inhibitors have been developed in combating HIV-1, however the fast evolutionary rate of this virus commonly leads to the emergence of resistance mutations that finally allows the mutant virus to survive. This review explores the main genetic consequences of HIV-1 molecular evolution during antiviral therapies, including the viral genetic diversity and molecular adaptation. The role of recombination in the generation of drug resistance is also analyzed. Besides the investigation and discussion of published works, an evolutionary analysis of protease-coding genes collected from patients before and after treatment with different protease inhibitors was included to validate previous studies. Finally, the review discusses the importance of considering genetic consequences of antiviral therapies in models of HIV-1 evolution that could improve current genotypic resistance testing and treatments design.

  17. 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.

  18. 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...

  19. 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....

  20. Oral and systemic manifestations in HIV-1 patients

    Directory of Open Access Journals (Sweden)

    Tatiany Oliveira de Alencar Menezes

    2015-02-01

    Full Text Available INTRODUCTION: This study aimed to estimate the prevalence of the most frequent oral and systemic manifestations in human immunodeficiency virus-1 (HIV-1-positive patients. METHODS: The study was conducted on 300 HIV-1 patients attending the Reference Unit Specialized in Special Infectious Parasitic Diseases in Belém, Pará, Brazil. RESULTS: The most prevalent oral conditions were caries (32.6%, candidiasis (32%, and periodontal disease (17%. Among the systemic manifestations, hepatitis (29.2%, gastritis (16%, arterial hypertension (14.7%, and tuberculosis (12% were the most commonly observed. CONCLUSIONS: We here reported on the most prevalent oral and systemic conditions in HIV-1-positive patients. The healthcare professional's knowledge of the various manifestations among these patients is fundamental to ensure prompt and accurate diagnosis and treatment, and for improving the quality of life of these patients.

  1. 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

  2. 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

  3. 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

  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. 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

  6. Comparison of HIV-1 protease expression in different fusion forms.

    Science.gov (United States)

    Wan, M; Takagi, M; Loh, B N; Imanaka, T

    1995-06-01

    Earlier observations showed that the expression of recombinant protease of human immunodeficiency virus type-1 (HIV-1 PR) was usually in a low level, and its proteolytic activity and hydrophobicity were believed to be toxic for the host cells. Various constructs were investigated that contained an N-terminal extended HIV-1 PR gene (PR107) in order to find a system which can express this protease in high level. The constructs of PR107 gene expressed as fusion proteins either with glutathione S-transferase (GST) by pGEX-PR107 or with maltose-binding protein (MBP) by pMAL-PR107 showed that the full length of fusion protein exhibited self-cleavage in E. coli. The results from expression experiments indicated that the size of the fusion portion does not affect the self-processing of fused HIV-1 PR to release its mature form, despite the attachment of only one subunit of the dimeric protease to GST or MBP. The construct, pET-PR107, under the control of strong bacteriophage T7 promoter system, did not show clear advantages for expression of this HIV-1 PR. Comparing these three constructs, the pGEX-PR107 system showed the highest expression level. Quantitative immuno-blotting indicated that the amount of HIV-1 PR expressed by pGEX-PR107 was twice that expressed by pMAL-PR107, and thrice that expressed by pET-PR107. More than 1 mg of pure HIV-1 PR from per liter culture of E. coli. DH5 alpha containing pGEX-PR107 can be obtained via the purification procedures [Biochem. Mol. Biol. International, (1995) 35:899-912].(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7663445

  7. HIV-1 western blot assay: What determines an indeterminate status?

    Directory of Open Access Journals (Sweden)

    Syed Iqbal

    2005-10-01

    Full Text Available Background: The Western blot assay is the gold standard for the detection of antibodies to human immunodeficiency virus type1 (HIV-1. However, indeterminate Western blot reactivity to HIV-1 proteins may occur in individuals, who may not be infected with HIV. Aim: This retrospective study was aimed to determine the diagnostic value of the interpretation criteria in relation to commercial kits for HIV -1 diagnosis. Methods and Materials: A total of 556 serum/plasma specimens collected from high-risk population attending our HIV clinic from 2000 - 2004 were tested by three different western blot kits: NEW LAV BLOT I (n=244, HIV BLOT 2.2; (n=112, Genetic Systems HIV-1 (n=237. And the results of western blot strips were analyzed using the various interpretation criteria: WHO/NACO, CDC/ ASTPHLD, ARC, FDA, CRSS and JHU. Some specimens were run on more than one kit. RT-PCR assay was performed on 5 specimens, which were indeterminate with LAV BLOT I. Results: The discrepancy in LAV BLOT I positive results were between 157(64-176(72, and indeterminate results were between 44(18 to 63(25. No such variations were observed in genetic systems. There are some HIV negative (by PCR specimens were indeterminate in LAV BLOT I revealing the kit more sensitive and less effective for diagnostic purpose. Conclusion: The genetic systems kit is superior to other kits we analyzed and its results are concordant with HIV-1 PCR results. To report, the choice of western blot commercial kit is paramount important than the use of particular interpretation criteria for the diagnosis of HIV -1.

  8. 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].

  9. 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...

  10. Immunologic Strategies for HIV-1 Remission and Eradication

    OpenAIRE

    Barouch, Dan H.; Deeks, Steven G.

    2014-01-01

    Antiretroviral therapy (ART) is able to suppress HIV-1 replication indefinitely in individuals who have access to these medications, are able to tolerate these drugs, and are motivated to take them daily for life. However, ART is not curative. HIV-1 persists indefinitely during ART as quiescent integrated DNA within memory CD4+ T cells and perhaps other long-lived cellular reservoirs. In this review, we discuss the role of the immune system on the establishment and maintenance of this “latent...

  11. CD4 Receptor is a Key Determinant of Divergent HIV-1 Sensing by Plasmacytoid Dendritic Cells.

    Science.gov (United States)

    O'Brien, Meagan; Manches, Olivier; Wilen, Craig; Gopal, Ramya; Huq, Rumana; Wu, Vernon; Sunseri, Nicole; Bhardwaj, Nina

    2016-04-01

    Plasmacytoid dendritic cells (pDC) are innate immune cells that sense viral nucleic acids through endosomal Toll-like receptor (TLR) 7/9 to produce type I interferon (IFN) and to differentiate into potent antigen presenting cells (APC). Engagement of TLR7/9 in early endosomes appears to trigger the IRF7 pathway for IFN production whereas engagement in lysosomes seems to trigger the NF-κB pathway for maturation into APC. We showed previously that HIV-1 (HIV) localizes predominantly to early endosomes, not lysosomes, and mainly stimulate IRF7 rather than NF-κB signaling pathways in pDC. This divergent signaling may contribute to disease progression through production of pro-apoptotic and pro-inflammatory IFN and inadequate maturation of pDCs. We now demonstrate that HIV virions may be re-directed to lysosomes for NF-κB signaling by either pseudotyping HIV with influenza hemagglutinin envelope or modification of CD4 mediated-intracellular trafficking. These data suggest that HIV envelope-CD4 receptor interactions drive pDC activation toward an immature IFN producing phenotype rather than differentiation into a mature dendritic cell phenotype. PMID:27082754

  12. 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.

  13. 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

  14. 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...

  15. Selection dramatically reduces effective population size in HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Mittler John E

    2008-05-01

    Full Text Available Abstract Background In HIV-1 evolution, a 100–100,000 fold discrepancy between census size and effective population size (Ne has been noted. Although it is well known that selection can reduce Ne, high in vivo mutation and recombination rates complicate attempts to quantify the effects of selection on HIV-1 effective size. Results We use the inbreeding coefficient and the variance in allele frequency at a linked neutral locus to estimate the reduction in Ne due to selection in the presence of mutation and recombination. With biologically realistic mutation rates, the reduction in Ne due to selection is determined by the strength of selection, i.e., the stronger the selection, the greater the reduction. However, the dependence of Ne on selection can break down if recombination rates are very high (e.g., r ≥ 0.1. With biologically likely recombination rates, our model suggests that recurrent selective sweeps similar to those observed in vivo can reduce within-host HIV-1 effective population sizes by a factor of 300 or more. Conclusion Although other factors, such as unequal viral reproduction rates and limited migration between tissue compartments contribute to reductions in Ne, our model suggests that recurrent selection plays a significant role in reducing HIV-1 effective population sizes in vivo.

  16. 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

    recipients (1.5%) and 6 of the 237 placebo recipients (2.5%). The results of the two studies were consistent. At week 16, counting noncompletion as treatment failure, 355 of 458 raltegravir recipients (77.5%) had HIV-1 RNA levels below 400 copies per milliliter, as compared with 99 of 236 placebo recipients...

  17. 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

  18. 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 t...

  19. 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

  20. 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.

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

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    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.

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

    Science.gov (United States)

    Ali, Amjad; 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 HEK-293T cells showed a dose and time dependent degradation of Tat protein. Contrary to this HIV-1 Gag which is a properly folded protein, remained unaffected with curcumin. Semi-quantitative RT-PCR analysis showed that curcumin treatment did not affect Tat gene transcription. Curcumin increased the rate of Tat protein degradation as shown by cycloheximide (CHX) chase assay. Degradation of the Tat protein is accomplished through proteasomal pathway as proteasomal inhibitor MG132 blocked Tat degradation. Curcumin also decreased Tat mediated LTR promoter transactivation and inhibited virus production from HIV-1 infected cells. Taken together our study reveals a novel observation that curcumin causes potent degradation of Tat which may be one of the major mechanisms behind its anti HIV activity. PMID:27283735

  3. Mode of antiviral action of silver nanoparticles against HIV-1

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    Rodriguez-Padilla Cristina

    2010-01-01

    Full Text Available Abstract Background Silver nanoparticles have proven to exert antiviral activity against HIV-1 at non-cytotoxic concentrations, but the mechanism underlying their HIV-inhibitory activity has not been not fully elucidated. In this study, silver nanoparticles are evaluated to elucidate their mode of antiviral action against HIV-1 using a panel of different in vitro assays. Results Our data suggest that silver nanoparticles exert anti-HIV activity at an early stage of viral replication, most likely as a virucidal agent or as an inhibitor of viral entry. Silver nanoparticles bind to gp120 in a manner that prevents CD4-dependent virion binding, fusion, and infectivity, acting as an effective virucidal agent against cell-free virus (laboratory strains, clinical isolates, T and M tropic strains, and resistant strains and cell-associated virus. Besides, silver nanoparticles inhibit post-entry stages of the HIV-1 life cycle. Conclusions These properties make them a broad-spectrum agent not prone to inducing resistance that could be used preventively against a wide variety of circulating HIV-1 strains.

  4. Differentially-Expressed Pseudogenes in HIV-1 Infection

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    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.

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

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    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.

  6. 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...

  7. Computational analysis of HIV-1 protease protein binding pockets.

    Science.gov (United States)

    Ko, Gene M; Reddy, A Srinivas; Kumar, Sunil; Bailey, Barbara A; Garg, Rajni

    2010-10-25

    Mutations that arise in HIV-1 protease after exposure to various HIV-1 protease inhibitors have proved to be a difficult aspect in the treatment of HIV. Mutations in the binding pocket of the protease can prevent the protease inhibitor from binding to the protein effectively. In the present study, the crystal structures of 68 HIV-1 proteases complexed with one of the nine FDA approved protease inhibitors from the Protein Data Bank (PDB) were analyzed by (a) identifying the mutational changes with the aid of a developed mutation map and (b) correlating the structure of the binding pockets with the complexed inhibitors. The mutations of each crystal structure were identified by comparing the amino acid sequence of each structure against the HIV-1 wild-type strain HXB2. These mutations were visually presented in the form of a mutation map to analyze mutation patterns corresponding to each protease inhibitor. The crystal structure mutation patterns of each inhibitor (in vitro) were compared against the mutation patterns observed in in vivo data. The in vitro mutation patterns were found to be representative of most of the major in vivo mutations. We then performed a data mining analysis of the binding pockets from each crystal structure in terms of their chemical descriptors to identify important structural features of the HIV-1 protease protein with respect to the binding conformation of the HIV-1 protease inhibitors. Data mining analysis is performed using several classification techniques: Random Forest (RF), linear discriminant analysis (LDA), and logistic regression (LR). We developed two hybrid models, RF-LDA and RF-LR. Random Forest is used as a feature selection proxy, reducing the descriptor space to a few of the most relevant descriptors determined by the classifier. These descriptors are then used to develop the subsequent LDA, LR, and hierarchical classification models. Clustering analysis of the binding pockets using the selected descriptors used to

  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. Varying modulation of HIV-1 LTR activity by Baf complexes.

    Science.gov (United States)

    Van Duyne, Rachel; Guendel, Irene; Narayanan, Aarthi; Gregg, Edward; Shafagati, Nazly; Tyagi, Mudit; Easley, Rebecca; Klase, Zachary; Nekhai, Sergei; Kehn-Hall, Kylene; Kashanchi, Fatah

    2011-08-19

    The human immunodeficiency virus type 1 (HIV-1) long terminal repeat is present on both ends of the integrated viral genome and contains regulatory elements needed for transcriptional initiation and elongation. Post-integration, a highly ordered chromatin structure consisting of at least five nucleosomes, is found at the 5' long terminal repeat, the location and modification state of which control the state of active viral replication as well as silencing of the latent HIV-1 provirus. In this context, the chromatin remodeling field rapidly emerges as having a critical role in the control of viral gene expression. In the current study, we focused on unique Baf subunits that are common to the most highly recognized of chromatin remodeling proteins, the SWI/SNF (switching-defective-sucrose non-fermenting) complexes. We find that at least two Baf proteins, Baf53 and Baf170, are highly regulated in HIV-1-infected cells. Previously, studies have shown that the depletion of Baf53 in uninfected cells leads to the expansion of chromosomal territories and the decompaction of the chromatin. Baf53, in the presence of HIV-1 infection, co-elutes off of a chromatographic column as a different-sized complex when compared to uninfected cells and appears to be predominantly phosphorylated. The innate function of Baf53-containing complexes appears to be transcriptionally suppressive, in that knocking down Baf53 increases viral gene expression from cells both transiently and chronically infected with HIV-1. Additionally, cdk9/cyclin T in the presence of Tat is able to phosphorylate Baf53 in vitro, implying that this posttranslationally modified form relieves the suppressive effect and allows for viral transcription to proceed. PMID:21699904

  10. Prevalence of genotypic HIV-1 drug resistance in Thailand, 2002

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    Watitpun Chotip

    2003-03-01

    Full Text Available Abstract Background The prices of reverse transcriptase (RT inhibitors in Thailand have been reduced since December 1, 2001. It is expected that reduction in the price of these inhibitors may influence the drug resistance mutation pattern of HIV-1 among infected people. This study reports the frequency of HIV-1 genetic mutation associated with drug resistance in antiretroviral-treated patients from Thailand. Methods Genotypic resistance testing was performed on samples collected in 2002 from 88 HIV-1 infected individuals. Automated DNA sequencing was used to genotype the HIV-1 polymerase gene isolated from patients' plasma. Results Resistance to protease inhibitors, nucleoside and non-nucleoside reverse transcriptase inhibitors were found in 10 (12%, 42 (48% and 19 (21% patients, respectively. The most common drug resistance mutations in the protease gene were at codon 82 (8%, 90 (7% and 54 (6%, whereas resistant mutations at codon 215 (45%, 67 (40%, 41 (38% and 184 (27% were commonly found in the RT gene. This finding indicates that genotypic resistance to nucleoside reverse transcriptase inhibitors was prevalent in 2002. The frequency of resistant mutations corresponding to non-nucleoside reverse transcriptase inhibitors was three times higher-, while resistant mutation corresponding to protease inhibitors was two times lower than those frequencies determined in 2001. Conclusion This study shows that the frequencies of RT inhibitor resistance mutations have been increased after the reduction in the price of RT inhibitors since December 2001. We believe that this was an important factor that influenced the mutation patterns of HIV-1 protease and RT genes in Thailand.

  11. In vitro nuclear interactome of the HIV-1 Tat protein

    Directory of Open Access Journals (Sweden)

    Gautier Virginie W

    2009-05-01

    Full Text Available Abstract 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

  12. 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.

  13. Emergence of HIV-1 drug resistance mutations among antiretroviral-naïve HIV-1-infected patients after rapid scaling up of antiretroviral therapy in Thailand

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    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

  14. 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

  15. Human Ubc9 is involved in intracellular HIV-1 Env stability after trafficking out of the trans-Golgi network in a Gag dependent manner.

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    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.

  16. 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.

  17. Antibody to gp41 MPER alters functional properties of HIV-1 Env without complete neutralization.

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    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.

  18. Emergence of minor drug-resistant HIV-1 variants after triple antiretroviral prophylaxis for prevention of vertical HIV-1 transmission.

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    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

  19. 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

  20. 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.

  1. 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...

  2. HIV-1 Induced Nuclear Factor I-B (NF-IB Expression Negatively Regulates HIV-1 Replication through Interaction with the Long Terminal Repeat Region

    Directory of Open Access Journals (Sweden)

    Sai Vikram Vemula

    2015-02-01

    Full Text Available Background: Retroviruses rely on host factors for cell entry, replication, transcription, and other major steps during their life cycle. Human Immunodeficiency Virus-1 (HIV-1 is well known for utilizing a plethora of strategies to evade the host immune response, including the establishment of latent infection within a subpopulation of susceptible cells. HIV-1 also manipulates cellular factors in latently infected cells and persists for long periods of time, despite the presence of successful highly active antiretroviral therapy (HAART. Results: In this study we demonstrate that Nuclear Factor-IB (NF-IB is induced during HIV-1 infection and its expression negatively impacts viral replication. During HIV-1 infection in peripheral blood mononuclear cells (PBMCs, and the T cell line, Jurkat or during induction of virus replication in latently infected cells, ACH2 and J1.1, we observed a time-dependent alteration in NF-IB expression pattern that correlated with HIV-1 viral expression. Using the Chip assay, we observed an association of NF-IB with the long terminal repeat region of HIV-1 (LTR (-386 to -453 nt, and this association negatively correlated with HIV-1 transcription. Furthermore, knock-down of NF-IB levels in J1.1 cells resulted in an increase of HIV-1 levels. Knock-down of NF-IB levels in J-Lat-Tat-GFP (A1, (a Jurkat cell GFP reporter model for latent HIV-1 infection resulted in an increase in GFP levels, indicating a potential negative regulatory role of NF-IB in HIV-1 replication. Conclusion: Overall, our results suggest that NF-IB may play a role in intrinsic antiretroviral defenses against HIV-1. These observations may offer new insights into the correlation of the latently infected host cell types and HIV-1, and help to define new therapeutic approaches for triggering the switch from latency to active replication thereby eliminating HIV-1 latent infection.

  3. 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.

  4. P24 antigen detection, viral isolation, DNA-PCR and in vitro antibody production for the diagnosis of HIV-1 latent infection in heterosexual women at high risk for HIV-1 infection.

    OpenAIRE

    M. Di Stefano; J.R. Fiore; M. Chironna; G. Buccoliero; Romanelli, C.; La Grasta, L; QUARTO, M.; Angarano, G.; Pastore, G.

    1995-01-01

    INTRODUCTION--The report of the existence of at-risk seronegative subjects, latently infected with HIV-1 and producing "in vitro" HIV-1 specific antibodies, prompted the authors to evaluate extensively twenty-five heterosexual HIV-1 seronegative women at high risk for HIV-1 infection. MATERIAL AND METHODS--The capability of peripheral blood mononuclear cells from such subjects to produce "in vitro" HIV-1 specific antibodies after pokeweed-mitogen stimulation, was studied. Silent HIV-1 infecti...

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

    OpenAIRE

    Sallie R Permar; Fong, Youyi; Vandergrift, Nathan; Genevieve G Fouda; 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. Inhibition of Reverse Transcriptase Activity Increases Stability of the HIV-1 Core

    OpenAIRE

    Yang, Yang; Fricke, Thomas; Diaz-Griffero, Felipe

    2013-01-01

    Previous studies showed that HIV-1 reverse transcription occurs during or before uncoating, linking mechanistically reverse transcription with uncoating. Here we show that inhibition of reverse transcriptase (RT) during HIV-1 infection by pharmacologic or genetic means increased the stability of the HIV-1 core during infection. Interestingly, HIV-1 particles with increased core stability were resistant to the core-destabilizing effects of rhesus TRIM5α (TRIM5αrh). Collectively, this work impl...

  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. 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...

  9. 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 ...

  10. Prevalence and Correlates of Helminth Co-infection in Kenyan HIV-1 Infected Adults

    OpenAIRE

    Walson, Judd L; Stewart, Barclay T; Sangaré, Laura; Mbogo, Loice W.; Otieno, Phelgona A.; Piper, Benjamin K. S.; Richardson, Barbra A.; John-Stewart, Grace

    2010-01-01

    Background Deworming HIV-1 infected individuals may delay HIV-1 disease progression. It is important to determine the prevalence and correlates of HIV-1/helminth co-infection in helminth-endemic areas. Methods HIV-1 infected individuals (CD4>250 cells/ul) were screened for helminth infection at ten sites in Kenya. Prevalence and correlates of helminth infection were determined. A subset of individuals with soil-transmitted helminth infection was re-evaluated 12 weeks following albendazole the...

  11. Up-regulation of alveolar macrophage matrix metalloproteinases in HIV1+ smokers with early emphysema

    OpenAIRE

    Kaner, Robert J.; Santiago, Francisco; Crystal, Ronald G.

    2009-01-01

    HIV1+ smokers develop emphysema at an earlier age and with a higher incidence than HIV1– smokers. Since human alveolar macrophages (AMs) are capable of producing proteases that degrade extracellular matrix components, we hypothesized that up-regulation of AM matrix metalloproteinases may be associated with the emphysema of HIV1+ smokers. Microarray analysis was used to screen which matrix metalloproteinases (MMPs) genes were expressed by AM of HIV1+ smokers with early emphysema. For each of t...

  12. 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. ...

  13. Astrocyte apoptosis induced by HIV-1 transactivation of the c-kit protooncogene

    OpenAIRE

    He, Jianglin; Decastro, Carlos M.; Vandenbark, George R.; Busciglio, Jorge; Gabuzda, Dana

    1997-01-01

    HIV-1 infection of the central nervous system (CNS) frequently causes dementia and other neurological disorders. The mechanisms of CNS injury in HIV-1 infection are poorly understood. Apoptosis of neurons and astrocytes is induced by HIV-1 infection in vitro and in brain tissue from AIDS patients, but the apoptotic stimuli have not been identified. We report herein that HIV-1 infection of primary brain cultures induces the receptor tyrosine kinase protooncogene c-kit and that high levels of c...

  14. 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

  15. 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...

  16. Persistent HIV-1 replication maintains the tissue reservoir during therapy.

    Science.gov (United States)

    Lorenzo-Redondo, Ramon; Fryer, Helen R; Bedford, Trevor; Kim, Eun-Young; Archer, John; Kosakovsky Pond, Sergei L; Chung, Yoon-Seok; Penugonda, Sudhir; Chipman, Jeffrey G; Fletcher, Courtney V; Schacker, Timothy W; Malim, Michael H; Rambaut, Andrew; Haase, Ashley T; McLean, Angela R; Wolinsky, Steven M

    2016-02-01

    Lymphoid tissue is a key reservoir established by HIV-1 during acute infection. It is a site associated with viral production, storage of viral particles in immune complexes, and viral persistence. Although combinations of antiretroviral drugs usually suppress viral replication and reduce viral RNA to undetectable levels in blood, it is unclear whether treatment fully suppresses viral replication in lymphoid tissue reservoirs. Here we show that virus evolution and trafficking between tissue compartments continues in patients with undetectable levels of virus in their bloodstream. We present a spatial and dynamic model of persistent viral replication and spread that indicates why the development of drug resistance is not a foregone conclusion under conditions in which drug concentrations are insufficient to completely block virus replication. These data provide new insights into the evolutionary and infection dynamics of the virus population within the host, revealing that HIV-1 can continue to replicate and replenish the viral reservoir despite potent antiretroviral therapy. PMID:26814962

  17. 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.

  18. 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.

  19. Structure based activity prediction of HIV-1 reverse transcriptase inhibitors.

    Science.gov (United States)

    de Jonge, Marc R; Koymans, Lucien M H; Vinkers, H Maarten; Daeyaert, Frits F D; Heeres, Jan; Lewi, Paul J; Janssen, Paul A J

    2005-03-24

    We have developed a fast and robust computational method for prediction of antiviral activity in automated de novo design of HIV-1 reverse transcriptase inhibitors. This is a structure-based approach that uses a linear relation between activity and interaction energy with discrete orientation sampling and with localized interaction energy terms. The localization allows for the analysis of mutations of the protein target and for the separation of inhibition and a specific binding to the enzyme. We apply the method to the prediction of pIC(50) of HIV-1 reverse transcriptase inhibitors. The model predicts the activity of an arbitrary compound with a q(2) of 0.681 and an average absolute error of 0.66 log value, and it is fast enough to be used in high-throughput computational applications. PMID:15771460

  20. Copy number variation of KIR genes influences HIV-1 control

    DEFF Research Database (Denmark)

    Pelak, Kimberly; Need, Anna C; Fellay, Jacques;

    2011-01-01

    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...

  1. 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.

  2. 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.

  3. 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.

  4. nef gene sequence variation among HIV-1-infected African children

    Czech Academy of Sciences Publication Activity Database

    Chakraborty, R.; Reiniš, Milan; Rostron, T.; Philpott, S.; Dong, T.; D'Agostino, A.; Musoke, R.; de Silva, E.; Stumpf, M.; Weiser, B.; Burger, H.; Rowland-Jones, S.L.

    2006-01-01

    Roč. 7, č. 2 (2006), s. 75-84. ISSN 1464-2662 Grant ostatní: Fogarty International Center, NIH(US) 3D43TW00915; NIH(US) RO1 AI 42555 Institutional research plan: CEZ:AV0Z50520514 Keywords : HIV-1 nef gene * non-clade B * Kenya Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.674, year: 2006

  5. HIV-1 Tat interaction with Dicer: requirement for RNA

    OpenAIRE

    Jeang Kuan-Teh; Bennasser Yamina

    2006-01-01

    Abstract Dicer is an RNase III which processes two classes of cellular small RNAs: the microRNAs (miRNA) and short interfering RNAs (siRNA). Previously, we observed that over-expressed HIV-1 Tat protein can suppress the processing of small RNAs inside cells. Here, we have investigated the requirements for Tat interaction with Dicer. We report that Tat-Dicer interaction depends on RNA, requires the helicase domain of Dicer, and is independent of Tat's transactivation domain.

  6. 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...

  7. TRIM5 and the Regulation of HIV-1 Infectivity

    OpenAIRE

    Jeremy Luban

    2012-01-01

    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 un...

  8. Isolated HIV-1 core is active for reverse transcription

    OpenAIRE

    Harrich David; Stenzel Deborah; Warrilow David

    2007-01-01

    Abstract Whether purified HIV-1 virion cores are capable of reverse transcription or require uncoating to be activated is currently controversial. To address this question we purified cores from a virus culture and tested for the ability to generate authentic reverse transcription products. A dense fraction (approximately 1.28 g/ml) prepared without detergent, possibly derived from disrupted virions, was found to naturally occur as a minor sub-fraction in our preparations. Core-like particles...

  9. Characterization of the in vitro HIV-1 Capsid Assembly Pathway

    OpenAIRE

    Barklis, Eric; Alfadhli, Ayna; McQuaw, Carolyn; Yalamuri, Suraj; Still, Amelia; Barklis, Robin Lid; Kukull, Ben; López, Claudia S.

    2009-01-01

    During morphogenesis of mature HIV-1 cores, the viral capsid (CA) proteins assemble conical or tubular shells around the viral ribonucleoprotein complexes. This assembly step is mimicked in vitro through reactions in which CA proteins oligomerize to form long tubes, and this process can be modeled as consisting of a slow nucleation period followed by a rapid phase of tube growth. We have developed a novel fluorescence microscopy approach to monitor in vitro assembly reactions and have employe...

  10. Extreme genetic fragility of the HIV-1 capsid

    OpenAIRE

    Rihn, S.J.; Wilson, S. J.; Loman, N. J.; Alim, M.; Bakker, S.E.; Bhella, D.; Gifford, R.J.; Rixon, F J; Bieniasz, P D

    2013-01-01

    Genetic robustness, or fragility, is defined as the ability, or lack thereof, of a biological entity to maintain function in the face of mutations. Viruses that replicate via RNA intermediates exhibit high mutation rates, and robustness should be particularly advantageous to them. The capsid (CA) domain of the HIV-1 Gag protein is under strong pressure to conserve functional roles in viral assembly, maturation, uncoating, and nuclear import. However, CA is also under strong immunological pres...

  11. 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.

  12. 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...

  13. 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...

  14. Pursuit eye movement dysfunction in HIV-1 seropositive individuals.

    OpenAIRE

    Sweeney, J A; Brew, B J; Keilp, J G; Sidtis, J J; Price, R W.

    1991-01-01

    Studies of smooth pursuit eye movements were conducted in 30 ambulatory drug-free HIV-1 seropositive patients who did not yet manifest marked clinical signs of the AIDS Dementia Complex. Seropositive patients demonstrated disturbances in pursuit eye movements that were correlated with extent of immunosuppression, with impairments on neuropsychological tests of fine motor control/speed, and with independent clinical staging of the AIDS Dementia Complex. The results provide quantitative evidenc...

  15. 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...

  16. 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...

  17. Exercise and Human Immunodeficiency Virus (HIV-1) Infection

    Science.gov (United States)

    Lawless, DeSales; Jackson, Catherine G. R.; Greenleaf, John E.

    1995-01-01

    The human immune system is highly efficient and remarkably protective when functioning properly. Similar to other physiological systems, it functions best when the body is maintained with a balanced diet, sufficient rest and a moderately stress-free lifestyle. It can be disrupted by inappropriate drug use and extreme emotion or exertion. The functioning of normal or compromised immune systems can be enhanced by properly prescribed moderate exercise conditioning regimens in healthy people, and in some human immunodeficiency virus (HIV-1)-infected patients but not in others who unable to complete an interval training program. Regular exercise conditioning in healthy people reduces cardiovascular risk factors, increases stamina, facilitates bodyweight control, and reduces stress by engendering positive feelings of well-being. Certain types of cancer may also be suppressed by appropriate exercise conditioning. Various exercise regimens are being evaluated as adjunct treatments for medicated patients with the HIV-1 syndrome. Limited anecdotal evidence from patients suggests that moderate exercise conditioning is per se responsible for their survival well beyond expectancy. HIV-1-infected patients respond positively, both physiologically and psychologically, to moderate exercise conditioning. However, the effectiveness of any exercise treatment programme depends on its mode, frequency, intensity and duration when prescribed o complement the pathological condition of the patient. The effectiveness of exercise conditioning regimens in patients with HIV-1 infection is reviewed in this article. In addition, we discuss mechanisms and pathways, involving the interplay of psychological and physiological factors, through which the suppressed immune system can be enhanced. The immune modulators discussed are endogenous opioids, cytokines, neurotransmitters and other hormones. Exercise conditioning treatment appears to be more effective when combined with other stress management

  18. 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.

  19. HMBG-1 and other soluble factors in HIV-1 pathogenesis

    OpenAIRE

    Barqasho, Babilonia

    2009-01-01

    The innate immune system is the first defense mechanism invading pathogens encounter. Macrophages, dendritic cells and cytokines/chemokines are important factors for the functionality of the innate immunity, and provide the adaptive immune system with sufficient signals for the proper action. Immune activation occurring during HIV-1 infection is essential to understand and investigate. The aims of this thesis were to evaluate the role of immune activation factors of the ...

  20. 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...

  1. 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...

  2. Accuracy of the TRUGENE HIV-1 Genotyping Kit

    OpenAIRE

    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...

  3. Molecular epidemiology of HIV-1 in Rio Grande, RS, Brazil

    OpenAIRE

    Martínez Ana Maria Barral de; Barbosa Edel Figueirêdo; Ferreira Paulo César Pelegrino; Cardoso Fabiola Adriene; Silveira Jussara; Sassi Gabriela; Silva Cláudio Moss da; Mendonça-Signorini Vera; Antunes Carlos Maurício de Figueiredo

    2002-01-01

    We conducted a molecular epidemiological study to investigate HIV-1 strains in Rio Grande, southern Brazil, searching for an association with transmission mode and risk behavior. Patients (185) identified at an AIDS treatment reference Hospital, from 1994 to 1997, were included; from which 107 blood samples were obtained. Nested PCR was realized once for each sample; for amplified samples (69) HIV subtypes were classified using the heteroduplex mobility assay. Subtypes identified were B (75%)...

  4. 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.

  5. 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

  6. TRIM5 and the Regulation of HIV-1 Infectivity.

    Science.gov (United States)

    Luban, Jeremy

    2012-01-01

    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. PMID:22701176

  7. 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.)

  8. Innate immune reconstitution with suppression of HIV-1

    Science.gov (United States)

    Scully, Eileen P.; Lockhart, Ainsley; Garcia-Beltran, Wilfredo; Palmer, Christine D.; Musante, Chelsey; Rosenberg, Eric; Allen, Todd M.; Chang, J. Judy; Bosch, Ronald J.; Altfeld, Marcus

    2016-01-01

    Progressive HIV-1 infection leads to both profound immune suppression and pathologic inflammation in the majority of infected individuals. While adaptive immune dysfunction, as evidenced by CD4+ T cell depletion and exhaustion, has been extensively studied, less is known about the functional capacity of innate immune cell populations in the context of HIV-1 infection. Given the broad susceptibility to opportunistic infections and the dysregulated inflammation observed in progressive disease, we hypothesized that there would be significant changes in the innate cellular responses. Using a cohort of patients with multiple samplings before and after antiretroviral therapy (ART) initiation, we demonstrated increased responses to innate immune stimuli following viral suppression, as measured by the production of inflammatory cytokines. Plasma viral load itself had the strongest association with this change in innate functional capacity. We further identified epigenetic modifications in the TNFA promoter locus in monocytes that are associated with viremia, suggesting a molecular mechanism for the observed changes in innate immune function following initiation of ART. These data indicate that suppression of HIV-1 viremia is associated with changes in innate cellular function that may in part determine the restoration of protective immune responses. PMID:27158667

  9. HIV-1 infected monozygotic twins: a tale of two outcomes

    Directory of Open Access Journals (Sweden)

    Pérez-Losada Marcos

    2011-03-01

    Full Text Available Abstract Background Replicate experiments are often difficult to find in evolutionary biology, as this field is inherently an historical science. However, viruses, bacteria and phages provide opportunities to study evolution in both natural and experimental contexts, due to their accelerated rates of evolution and short generation times. Here we investigate HIV-1 evolution by using a natural model represented by monozygotic twins infected synchronically at birth with an HIV-1 population from a shared blood transfusion source. We explore the evolutionary processes and population dynamics that shape viral diversity of HIV in these monozygotic twins. Results Despite the identical host genetic backdrop of monozygotic twins and the identical source and timing of the HIV-1 inoculation, the resulting HIV populations differed in genetic diversity, growth rate, recombination rate, and selection pressure between the two infected twins. Conclusions Our study shows that the outcome of evolution is strikingly different between these two "replicates" of viral evolution. Given the identical starting points at infection, our results support the impact of random epigenetic selection in early infection dynamics. Our data also emphasize the need for a better understanding of the impact of host-virus interactions in viral evolution.

  10. 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.

  11. 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.

  12. 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

  13. 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.)

  14. HIV-1 early diagnosis of men having sex with men in Hong Kong and discovery of novel agents for HIV-1 treatment from traditional Chinese herbal medicine

    OpenAIRE

    Liang, Jianguo; 梁建国

    2013-01-01

    Over the 30 years since it was first identified, the HIV/AIDS epidemic has had historically unprecedented severity and impact. There are approximately 33.4 million people living with HIV-1/AIDS which urges to seek novel approaches for HIV-1 diagnosis and HIV-1 therapy. Men who have sex with men (MSM) are severely affected by HIV-1 and constitute a large proportion of HIV-infected individuals. In Hong Kong, the transmission route of homosexual and bisexual contacts accounted for nearly 50% ...

  15. Cost-effectiveness of voluntary HIV-1 counseling and testing in reducing sexual transmission of HIV-1 in Kenya and Tanzania.

    OpenAIRE

    Sweat, M.; Gregorich , S; Sangiwa , G; Furlonge , C; Balmer, D; Kamenga, C.; Grinstead, O; Coates, T.

    2000-01-01

    Background Access to HIV-1 voluntary counseling and testing (VCT) is severely limited in less-developed countries. We undertook a multisite trial of HIV-1 VCT to assess its impact, cost, and cost-effectiveness in less-developed country settings. Methods The cost-effectiveness of HIV-1 VCT was estimated for a hypothetical cohort of 10 000 people seeking VCT in urban east Africa. Outcomes were modelled based on results from a randomised controlled trial of HIV-1 VCT in Tanzania and Kenya....

  16. 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.

  17. Contribution of MxB Oligomerization to HIV-1 Capsid Binding and Restriction

    OpenAIRE

    Buffone, Cindy; Schulte, Bianca; OPP, Silvana; Diaz-Griffero, Felipe

    2015-01-01

    The alpha interferon (IFN-α)-inducible restriction factor myxovirus B (MxB) blocks HIV-1 infection after reverse transcription but prior to integration. MxB binds to the HIV-1 core, which is composed of capsid protein, and this interaction leads to inhibition of the uncoating process of HIV-1. Previous studies suggested that HIV-1 restriction by MxB requires binding to capsid. This work tests the hypothesis that MxB oligomerization is important for the ability of MxB to bind to the HIV-1 core...

  18. Inhibition of reverse transcriptase activity increases stability of the HIV-1 core.

    Science.gov (United States)

    Yang, Yang; Fricke, Thomas; Diaz-Griffero, Felipe

    2013-01-01

    Previous studies showed that HIV-1 reverse transcription occurs during or before uncoating, linking mechanistically reverse transcription with uncoating. Here we show that inhibition of reverse transcriptase (RT) during HIV-1 infection by pharmacologic or genetic means increased the stability of the HIV-1 core during infection. Interestingly, HIV-1 particles with increased core stability were resistant to the core-destabilizing effects of rhesus TRIM5α (TRIM5α(rh)). Collectively, this work implies that the surface of the HIV-1 core is dynamic and changes upon the ongoing processes within the core. PMID:23077298

  19. HTLV-1/-2 and HIV-1 co-infections: retroviral interference on host immune status

    OpenAIRE

    Pilotti, Elisabetta; Bianchi, Maria V.; De Maria, Andrea; Bozzano, Federica; Romanelli, Maria G.; Bertazzoni, Umberto; Casoli, Claudio

    2013-01-01

    The human retroviruses HIV-1 and HTLV-1/HTLV-2 share similar routes of transmission but cause significantly different diseases. In this review we have outlined the immune mediated mechanisms by which HTLVs affect HIV-1 disease in co-infected hosts. During co-infection with HIV-1, HTLV-2 modulates the cellular microenvironment favoring its own viability and inhibiting HIV-1 progression. This is achieved when the HTLV-2 proviral load is higher than that of HIV-1, and thanks to the ability of HT...

  20. Differences in Clinical Manifestations of Acute and Early HIV-1 Infection between HIV-1 Subtypes in African Women

    OpenAIRE

    Lemonovich, Tracy L.; Watkins, Richard R.; Morrison, Charles S.; Kwok, Cynthia; Chipato, Tsungai; Musoke, Robert; Arts, Eric J; Nankya, Immaculate; Salata, Robert A.

    2015-01-01

    Little is known about the differences in clinical manifestations between women with various HIV-1 subtypes during acute (AI) and early (EI) HIV infection. In a longitudinal cohort study, clinical signs and symptoms among Uganda and Zimbabwe women with AI and EI were compared with HIV-negative controls; symptoms were assessed quarterly for 15 to 24 months. Early HIV infection was defined as the first visit during which a woman tested HIV antibody positive. Women who were HIV negative serologic...

  1. 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...

  2. Molecular epidemiology of HIV-1 in Rio Grande, RS, Brazil Epidemiologia molecular do HIV-1 em Rio Grande, RS, Brasil

    OpenAIRE

    Ana Maria Barral de Martínez; Edel Figueirêdo Barbosa; Paulo César Pelegrino Ferreira; Fabiola Adriene Cardoso; Jussara Silveira; Gabriela Sassi; Cláudio Moss da Silva; Vera Mendonça-Signorini; Carlos Maurício de Figueiredo Antunes

    2002-01-01

    We conducted a molecular epidemiological study to investigate HIV-1 strains in Rio Grande, southern Brazil, searching for an association with transmission mode and risk behavior. Patients (185) identified at an AIDS treatment reference Hospital, from 1994 to 1997, were included; from which 107 blood samples were obtained. Nested PCR was realized once for each sample; for amplified samples (69) HIV subtypes were classified using the heteroduplex mobility assay. Subtypes identified were B (75%)...

  3. 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

  4. Storage envelopes or sleeves

    International Nuclear Information System (INIS)

    A storage envelope or sleeve particularly for processed X-ray films is described. It consists of front and back panels joined together at a hinge line and connected along the intermediate sides by connecting flaps. An inner pocket is formed from a third flap which is folded to lie against the inner face of the back panel. The panels may have additional score lines parallel to the closed sides of the envelope and the inner pocket so that the envelope and the inner pocket can accommodate bulky contents. The free edge of the pocket is inset from the open side of the envelope, and finger cut-outs may be provided to facilitate access to the contents of the envelope and the pocket. (author)

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. HIV-1 RNAs are Not Part of the Argonaute 2 Associated RNA Interference Pathway in Macrophages.

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    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.

  10. 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.

  11. 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.

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    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.

  12. 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

  13. 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

  14. 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.

  15. Synergistic activity profile of griffithsin in combination with tenofovir, maraviroc and enfuvirtide against HIV-1 clade C

    International Nuclear Information System (INIS)

    Griffithsin (GRFT) is possibly the most potent anti-HIV peptide found in natural sources. Due to its potent and broad-spectrum antiviral activity and unique safety profile it has great potential as topical microbicide component. Here, we evaluated various combinations of GRFT against HIV-1 clade B and clade C isolates in primary peripheral blood mononuclear cells (PBMCs) and in CD4+ MT-4 cells. In all combinations tested, GRFT showed synergistic activity profile with tenofovir, maraviroc and enfuvirtide based on the median effect principle with combination indices (CI) varying between 0.34 and 0.79 at the calculated EC95 level. Furthermore, the different glycosylation patterns on the viral envelope of clade B and clade C gp120 had no observable effect on the synergistic interactions. Overall, we can conclude that the evaluated two-drug combination increases their antiviral potency and supports further clinical investigations in pre-exposure prophylaxis for GRFT combinations in the context of HIV-1 clade C infection.

  16. Modeling HIV-1 Induced Neuroinflammation in Mice: Role of Platelets in Mediating Blood-Brain Barrier Dysfunction.

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    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.

  17. 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.

  18. 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

  19. 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

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    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.

  20. 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.

  1. Targeting host-derived glycans on enveloped viruses for antibody-based vaccine design.

    Science.gov (United States)

    Crispin, Max; Doores, Katie J

    2015-04-01

    The surface of enveloped viruses can be extensively glycosylated. Unlike the glycans coating pathogens such as bacteria and fungi, glycans on viruses are added and processed by the host-cell during biosynthesis. Glycoproteins are typically subjected to α-mannosidase processing and Golgi-mediated glycosyltransferase extension to form complex-type glycans. In envelope viruses, exceptions to this default pathway are common and lead to the presence of oligomannose-type glycan structures on the virion surface. In one extreme example, HIV-1 utilises a high density of glycans to limit host antibody recognition of protein. However, the high density limits glycan processing and the resulting oligomannose structures can be recognised by broadly neutralising antibodies isolated from HIV-1 infected patients. Here we discuss how divergence from host-cell glycosylation can be targeted for vaccine design. PMID:25747313

  2. Predicting Bevirimat resistance of HIV-1 from genotype

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    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

  3. HIV-1 Tat interaction with Dicer: requirement for RNA

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    Jeang Kuan-Teh

    2006-12-01

    Full Text Available Abstract Dicer is an RNase III which processes two classes of cellular small RNAs: the microRNAs (miRNA and short interfering RNAs (siRNA. Previously, we observed that over-expressed HIV-1 Tat protein can suppress the processing of small RNAs inside cells. Here, we have investigated the requirements for Tat interaction with Dicer. We report that Tat-Dicer interaction depends on RNA, requires the helicase domain of Dicer, and is independent of Tat's transactivation domain.

  4. Positive Selection of Primate Genes that Promote HIV-1 Replication

    OpenAIRE

    Meyerson, Nicholas R.; Rowley, Paul A.; Swan, Christina H; Le, Dona T.; Wilkerson, Greg K; Sawyer, Sara L

    2014-01-01

    Evolutionary analyses have revealed that most host-encoded restriction factors against HIV-1 have experienced virus-driven selection during primate evolution. However, HIV also depends on the function of many human proteins, called host factors, for its replication. It is not clear whether virus-driven selection shapes the evolution of host factor genes to the extent that it is known to shape restriction factor genes. We show that 5 out of 40 HIV host factor genes (13%) analyzed do bear stron...

  5. Modeling HIV-1 viral capsid nucleation by dynamical systems.

    Science.gov (United States)

    Sadre-Marandi, Farrah; Liu, Yuewu; Liu, Jiangguo; Tavener, Simon; Zou, Xiufen

    2015-12-01

    There are two stages generally recognized in the viral capsid assembly: nucleation and elongation. This paper focuses on the nucleation stage and develops mathematical models for HIV-1 viral capsid nucleation based on six-species dynamical systems. The Particle Swarm Optimization (PSO) algorithm is used for parameter fitting to estimate the association and dissociation rates from biological experiment data. Numerical simulations of capsid protein (CA) multimer concentrations demonstrate a good agreement with experimental data. Sensitivity and elasticity analysis of CA multimer concentrations with respect to the association and dissociation rates further reveals the importance of CA trimer-of- dimers in the nucleation stage of viral capsid self- assembly. PMID:26596714

  6. HIV-1 tuberculosis-associated immune reconstitution inflammatory syndrome.

    Science.gov (United States)

    Lai, Rachel P J; Meintjes, Graeme; Wilkinson, Robert J

    2016-03-01

    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 contributing to TB-IRIS pathogenesis. PMID:26423994

  7. Pin1 liberates the human immunodeficiency virus type-1 (HIV-1): Must we stop it?

    Science.gov (United States)

    Hou, Hai; Wang, Jing-Zhang; Liu, Bao-Guo; Zhang, Ting

    2015-07-01

    Acquired immune deficiency syndrome (AIDS) is mainly caused by the human immunodeficiency virus type-1 (HIV-1). To our knowledge, this is the first review focusing on the vital role of Pin1 in the infection of HIV-1 and the development of AIDS. We and others have demonstrated that Pin1, the only known cis-to-trans isomerase recognizing the pThr/pSer-Pro motifs in proteins, plays striking roles in several human diseases. Interestingly, recent evidence gradually indicates that Pin1 regulates several key steps of the life cycle of HIV-1, including the uncoating of the HIV-1 core, the reverse transcription of the RNA genome of HIV-1, and the integration of the HIV-1 cDNA into human chromosomes. Whereas inhibiting Pin1 suppresses all of these key steps and attenuates the replication of HIV-1, at the same time different PIN1 gene variants are correlated with the susceptibility to HIV-1 infection. Furthermore, Pin1 potentially promotes HIV-1 infection by activating multiple oncogenes and inactivating multiple tumor suppressors, extending the life span of HIV-infected cells. These descriptions suggest Pin1 as a promising therapeutic target for the prevention of HIV-1 and highlight the possibility of blocking the development of AIDS by Pin1 inhibitors. PMID:25913034

  8. 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.

  9. 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