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Sample records for cd8 t-cell epitopes

  1. Viral Escape Mutant Epitope Maintains TCR Affinity for Antigen yet Curtails CD8 T Cell Responses.

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    Shayla K Shorter

    Full Text Available T cells have the remarkable ability to recognize antigen with great specificity and in turn mount an appropriate and robust immune response. Critical to this process is the initial T cell antigen recognition and subsequent signal transduction events. This antigen recognition can be modulated at the site of TCR interaction with peptide:major histocompatibility (pMHC or peptide interaction with the MHC molecule. Both events could have a range of effects on T cell fate. Though responses to antigens that bind sub-optimally to TCR, known as altered peptide ligands (APL, have been studied extensively, the impact of disrupting antigen binding to MHC has been highlighted to a lesser extent and is usually considered to result in complete loss of epitope recognition. Here we present a model of viral evasion from CD8 T cell immuno-surveillance by a lymphocytic choriomeningitis virus (LCMV escape mutant with an epitope for which TCR affinity for pMHC remains high but where the antigenic peptide binds sub optimally to MHC. Despite high TCR affinity for variant epitope, levels of interferon regulatory factor-4 (IRF4 are not sustained in response to the variant indicating differences in perceived TCR signal strength. The CD8+ T cell response to the variant epitope is characterized by early proliferation and up-regulation of activation markers. Interestingly, this response is not maintained and is characterized by a lack in IL-2 and IFNγ production, increased apoptosis and an abrogated glycolytic response. We show that disrupting the stability of peptide in MHC can effectively disrupt TCR signal strength despite unchanged affinity for TCR and can significantly impact the CD8+ T cell response to a viral escape mutant.

  2. Presentation of an immunodominant immediate-early CD8+ T cell epitope resists human cytomegalovirus immunoevasion.

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    Stefanie Ameres

    Full Text Available Control of human cytomegalovirus (HCMV depends on CD8+ T cell responses that are shaped by an individual's repertoire of MHC molecules. MHC class I presentation is modulated by a set of HCMV-encoded proteins. Here we show that HCMV immunoevasins differentially impair T cell recognition of epitopes from the same viral antigen, immediate-early 1 (IE-1, that are presented by different MHC class I allotypes. In the presence of immunoevasins, HLA-A- and HLA-B-restricted T cell clones were ineffective, but HLA-C*0702-restricted T cell clones recognized and killed infected cells. Resistance of HLA-C*0702 to viral immunoevasins US2 and US11 was mediated by the alpha3 domain and C-terminal region of the HLA heavy chain. In healthy donors, HLA-C*0702-restricted T cells dominated the T cell response to IE-1. The same HLA-C allotype specifically protected infected cells from attack by NK cells that expressed a corresponding HLA-C-specific KIR. Thus, allotype-specific viral immunoevasion allows HCMV to escape control by NK cells and HLA-A- and HLA-B-restricted T cells, while the virus becomes selectively vulnerable to an immunodominant population of HLA-C-restricted T cells. Our work identifies a T cell population that may be of particular efficiency in HCMV-specific immunotherapy.

  3. Programmed death-1 expression on HIV-1-specific CD8+ T cells is shaped by epitope specificity, T-cell receptor clonotype usage and antigen load

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    Kløverpris, Henrik N; McGregor, Reuben; McLaren, James E

    2014-01-01

    of differentiation on HIV-1-specific CD8+ T-cell populations(n = 128) spanning 11 different epitope targets. RESULTS: Expression levels of PD-1, but not CD244 or LAG-3, varied substantially across epitope specificities both within and between individuals. Differential expression of PD-1 on T-cell receptor (TCR...

  4. Programmed Death-1 expression on Epstein Barr virus specific CD8+ T cells varies by stage of infection, epitope specificity, and T-cell receptor usage.

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    Thomas C Greenough

    Full Text Available BACKGROUND: Programmed Death-1 (PD-1 is an inhibitory member of the CD28 family of molecules expressed on CD8+ T cells in response to antigenic stimulation. To better understand the role of PD-1 in antiviral immunity we examined the expression of PD-1 on Epstein-Barr virus (EBV epitope-specific CD8+ T cells during acute infectious mononucleosis (AIM and convalescence. METHODOLOGY/PRINCIPAL FINDINGS: Using flow cytometry, we observed higher frequencies of EBV-specific CD8+ T cells and higher intensity of PD-1 expression on EBV-specific CD8+ T cells during AIM than during convalescence. PD-1 expression during AIM directly correlated with viral load and with the subsequent degree of CD8+ T cell contraction in convalescence. Consistent differences in PD-1 expression were observed between CD8+ T cells with specificity for two different EBV lytic antigen epitopes. Similar differences were observed in the degree to which PD-1 was upregulated on these epitope-specific CD8+ T cells following peptide stimulation in vitro. EBV epitope-specific CD8+ T cell proliferative responses to peptide stimulation were diminished during AIM regardless of PD-1 expression and were unaffected by blocking PD-1 interactions with PD-L1. Significant variability in PD-1 expression was observed on EBV epitope-specific CD8+ T cell subsets defined by V-beta usage. CONCLUSIONS/SIGNIFICANCE: These observations suggest that PD-1 expression is not only dependent on the degree of antigen presentation, but also on undefined characteristics of the responding cell that segregate with epitope specificity and V-beta usage.

  5. Superior control of HIV-1 replication by CD8+ T cells targeting conserved epitopes: implications for HIV vaccine design.

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    Pratima Kunwar

    Full Text Available A successful HIV vaccine will likely induce both humoral and cell-mediated immunity, however, the enormous diversity of HIV has hampered the development of a vaccine that effectively elicits both arms of the adaptive immune response. To tackle the problem of viral diversity, T cell-based vaccine approaches have focused on two main strategies (i increasing the breadth of vaccine-induced responses or (ii increasing vaccine-induced responses targeting only conserved regions of the virus. The relative extent to which set-point viremia is impacted by epitope-conservation of CD8(+ T cell responses elicited during early HIV-infection is unknown but has important implications for vaccine design. To address this question, we comprehensively mapped HIV-1 CD8(+ T cell epitope-specificities in 23 ART-naïve individuals during early infection and computed their conservation score (CS by three different methods (prevalence, entropy and conseq on clade-B and group-M sequence alignments. The majority of CD8(+ T cell responses were directed against variable epitopes (p<0.01. Interestingly, increasing breadth of CD8(+ T cell responses specifically recognizing conserved epitopes was associated with lower set-point viremia (r = - 0.65, p = 0.009. Moreover, subjects possessing CD8(+ T cells recognizing at least one conserved epitope had 1.4 log10 lower set-point viremia compared to those recognizing only variable epitopes (p = 0.021. The association between viral control and the breadth of conserved CD8(+ T cell responses may be influenced by the method of CS definition and sequences used to determine conservation levels. Strikingly, targeting variable versus conserved epitopes was independent of HLA type (p = 0.215. The associations with viral control were independent of functional avidity of CD8(+ T cell responses elicited during early infection. Taken together, these data suggest that the next-generation of T-cell based HIV-1 vaccines should focus

  6. Broadly reactive human CD8 T cells that recognize an epitope conserved between VZV, HSV and EBV.

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    Christopher Chiu

    2014-03-01

    Full Text Available Human herpesviruses are important causes of potentially severe chronic infections for which T cells are believed to be necessary for control. In order to examine the role of virus-specific CD8 T cells against Varicella Zoster Virus (VZV, we generated a comprehensive panel of potential epitopes predicted in silico and screened for T cell responses in healthy VZV seropositive donors. We identified a dominant HLA-A*0201-restricted epitope in the VZV ribonucleotide reductase subunit 2 and used a tetramer to analyze the phenotype and function of epitope-specific CD8 T cells. Interestingly, CD8 T cells responding to this VZV epitope also recognized homologous epitopes, not only in the other α-herpesviruses, HSV-1 and HSV-2, but also the γ-herpesvirus, EBV. Responses against these epitopes did not depend on previous infection with the originating virus, thus indicating the cross-reactive nature of this T cell population. Between individuals, the cells demonstrated marked phenotypic heterogeneity. This was associated with differences in functional capacity related to increased inhibitory receptor expression (including PD-1 along with decreased expression of co-stimulatory molecules that potentially reflected their stimulation history. Vaccination with the live attenuated Zostavax vaccine did not efficiently stimulate a proliferative response in this epitope-specific population. Thus, we identified a human CD8 T cell epitope that is conserved in four clinically important herpesviruses but that was poorly boosted by the current adult VZV vaccine. We discuss the concept of a "pan-herpesvirus" vaccine that this discovery raises and the hurdles that may need to be overcome in order to achieve this.

  7. Identification of a Novel CD8 T Cell Epitope Derived from Plasmodium berghei Protective Liver-Stage Antigen

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    Alexander Pichugin

    2018-01-01

    Full Text Available We recently identified novel Plasmodium berghei (Pb liver stage (LS genes that as DNA vaccines significantly reduce Pb LS parasite burden (LPB in C57Bl/6 (B6 mice through a mechanism mediated, in part, by CD8 T cells. In this study, we sought to determine fine antigen (Ag specificities of CD8 T cells that target LS malaria parasites. Guided by algorithms for predicting MHC class I-restricted epitopes, we ranked sequences of 32 Pb LS Ags and selected ~400 peptides restricted by mouse H-2Kb and H-2Db alleles for analysis in the high-throughput method of caged MHC class I-tetramer technology. We identified a 9-mer H-2Kb restricted CD8 T cell epitope, Kb-17, which specifically recognized and activated CD8 T cell responses in B6 mice immunized with Pb radiation-attenuated sporozoites (RAS and challenged with infectious sporozoites (spz. The Kb-17 peptide is derived from the recently described novel protective Pb LS Ag, PBANKA_1031000 (MIF4G-like protein. Notably, immunization with the Kb-17 epitope delivered in the form of a minigene in the adenovirus serotype 5 vector reduced LPB in mice infected with spz. On the basis of our results, Kb-17 peptide was available for CD8 T cell activation and recall following immunization with Pb RAS and challenge with infectious spz. The identification of a novel MHC class I-restricted epitope from the protective Pb LS Ag, MIF4G-like protein, is crucial for advancing our understanding of immune responses to Plasmodium and by extension, toward vaccine development against malaria.

  8. Identification of CD8(+) T Cell Epitopes in the West Nile Virus Polyprotein by Reverse-Immunology Using NetCTL

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    Larsen, Mette Voldby; Lelic, A.; Parsons, R.

    2010-01-01

    bioinformatics methods to predict WNV-specific CD8(+) T cell epitopes and selected a set of peptides that constitutes maximum coverage of 20 fully-sequenced WNV strains. We then tested these putative epitopes for cellular reactivity in a cohort of WNV-infected patients. We identified 26 new CD8(+) T cell...

  9. AAV capsid CD8+ T-cell epitopes are highly conserved across AAV serotypes

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    Daniel J Hui

    Full Text Available Adeno-associated virus (AAV has become one of the most promising vectors in gene transfer in the last 10 years with successful translation to clinical trials in humans and even market approval for a first gene therapy product in Europe. Administration to humans, however, revealed that adaptive immune responses against the vector capsid can present an obstacle to sustained transgene expression due to the activation and expansion of capsid-specific T cells. The limited number of peripheral blood mononuclear cells (PBMCs obtained from samples within clinical trials allows for little more than monitoring of T-cell responses. We were able to identify immunodominant major histocompatibility complex (MHC class I epitopes for common human leukocyte antigen (HLA types by using spleens isolated from subjects undergoing splenectomy for non-malignant indications as a source of large numbers of lymphocytes and restimulating them with single AAV capsid peptides in vitro. Further experiments confirmed that these epitopes are naturally processed and functionally relevant. The design of more effective and less immunogenic AAV vectors, and precise immune monitoring of vector-infused subjects, are facilitated by these findings.

  10. AAV capsid CD8+ T-cell epitopes are highly conserved across AAV serotypes.

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    Hui, Daniel J; Edmonson, Shyrie C; Podsakoff, Gregory M; Pien, Gary C; Ivanciu, Lacramioara; Camire, Rodney M; Ertl, Hildegund; Mingozzi, Federico; High, Katherine A; Basner-Tschakarjan, Etiena

    2015-01-01

    Adeno-associated virus (AAV) has become one of the most promising vectors in gene transfer in the last 10 years with successful translation to clinical trials in humans and even market approval for a first gene therapy product in Europe. Administration to humans, however, revealed that adaptive immune responses against the vector capsid can present an obstacle to sustained transgene expression due to the activation and expansion of capsid-specific T cells. The limited number of peripheral blood mononuclear cells (PBMCs) obtained from samples within clinical trials allows for little more than monitoring of T-cell responses. We were able to identify immunodominant major histocompatibility complex (MHC) class I epitopes for common human leukocyte antigen (HLA) types by using spleens isolated from subjects undergoing splenectomy for non-malignant indications as a source of large numbers of lymphocytes and restimulating them with single AAV capsid peptides in vitro. Further experiments confirmed that these epitopes are naturally processed and functionally relevant. The design of more effective and less immunogenic AAV vectors, and precise immune monitoring of vector-infused subjects, are facilitated by these findings.

  11. Bacteria modulate the CD8+ T cell epitope repertoire of host cytosol-exposed proteins to manipulate the host immune response.

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    Yaakov Maman

    2011-10-01

    Full Text Available The main adaptive immune response to bacteria is mediated by B cells and CD4+ T-cells. However, some bacterial proteins reach the cytosol of host cells and are exposed to the host CD8+ T-cells response. Both gram-negative and gram-positive bacteria can translocate proteins to the cytosol through type III and IV secretion and ESX-1 systems, respectively. The translocated proteins are often essential for the bacterium survival. Once injected, these proteins can be degraded and presented on MHC-I molecules to CD8+ T-cells. The CD8+ T-cells, in turn, can induce cell death and destroy the bacteria's habitat. In viruses, escape mutations arise to avoid this detection. The accumulation of escape mutations in bacteria has never been systematically studied. We show for the first time that such mutations are systematically present in most bacteria tested. We combine multiple bioinformatic algorithms to compute CD8+ T-cell epitope libraries of bacteria with secretion systems that translocate proteins to the host cytosol. In all bacteria tested, proteins not translocated to the cytosol show no escape mutations in their CD8+ T-cell epitopes. However, proteins translocated to the cytosol show clear escape mutations and have low epitope densities for most tested HLA alleles. The low epitope densities suggest that bacteria, like viruses, are evolutionarily selected to ensure their survival in the presence of CD8+ T-cells. In contrast with most other translocated proteins examined, Pseudomonas aeruginosa's ExoU, which ultimately induces host cell death, was found to have high epitope density. This finding suggests a novel mechanism for the manipulation of CD8+ T-cells by pathogens. The ExoU effector may have evolved to maintain high epitope density enabling it to efficiently induce CD8+ T-cell mediated cell death. These results were tested using multiple epitope prediction algorithms, and were found to be consistent for most proteins tested.

  12. Asymptomatic memory CD8+ T cells

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    Khan, Arif Azam; Srivastava, Ruchi; Lopes, Patricia Prado; Wang, Christine; Pham, Thanh T; Cochrane, Justin; Thai, Nhi Thi Uyen; Gutierrez, Lucas; BenMohamed, Lbachir

    2014-01-01

    Generation and maintenance of high quantity and quality memory CD8+ T cells determine the level of protection from viral, bacterial, and parasitic re-infections, and hence constitutes a primary goal for T cell epitope-based human vaccines and immunotherapeutics. Phenotypically and functionally characterizing memory CD8+ T cells that provide protection against herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) infections, which cause blinding ocular herpes, genital herpes, and oro-facial herpes, is critical for better vaccine design. We have recently categorized 2 new major sub-populations of memory symptomatic and asymptomatic CD8+ T cells based on their phenotype, protective vs. pathogenic function, and anatomical locations. In this report we are discussing a new direction in developing T cell-based human herpes vaccines and immunotherapeutics based on the emerging new concept of “symptomatic and asymptomatic memory CD8+ T cells.” PMID:24499824

  13. Analysis of the T Cell Response to Zika Virus and Identification of a Novel CD8+ T Cell Epitope in Immunocompetent Mice.

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    Ryan D Pardy

    2017-02-01

    Full Text Available Zika virus (ZIKV is an emerging arbovirus of the Flaviviridae family. Although ZIKV infection is typically mild and self-limiting in healthy adults, infection has been associated with neurological symptoms such as Guillain-Barré syndrome, and a causal link has been established between fetal microcephaly and ZIKV infection during pregnancy. These risks, and the magnitude of the ongoing ZIKV pandemic, have created an urgent need for the development of animal models to study the immune response to ZIKV infection. Previous animal models have primarily focused on pathogenesis in immunocompromised mice. In this study, we provide a model of ZIKV infection in wild-type immunocompetent C57BL/6 mice, and have provided an analysis of the immune response to infection. We evaluated the activation of several innate immune cell types, and studied the kinetics, phenotype, and functionality of T cell responses to ZIKV infection. Our results demonstrate that ZIKV infection is mild in wild-type immunocompetent C57BL/6 mice, resulting in minimal morbidity. Our data establish that at the peak of the adaptive response, antigen-experienced CD4+ T cells polarize to a Th1 phenotype, and antigen-experienced CD8+ T cells exhibit an activated effector phenotype, producing both effector cytokines and cytolytic molecules. Furthermore, we have identified a novel ZIKV CD8+ T cell epitope in the envelope protein that is recognized by the majority of responding cells. Our model provides an important reference point that will help dissect the impact of polymorphisms in the circulating ZIKV strains on the immune response and ZIKV pathogenesis. In addition, the identification of a ZIKV epitope will allow for the design of tetramers to study epitope-specific T cell responses, and will have important implications for the design and development of ZIKV vaccine strategies.

  14. Distinct Escape Pathway by Hepatitis C Virus Genotype 1a from a Dominant CD8+ T Cell Response by Selection of Altered Epitope Processing.

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    Walker, Andreas; Skibbe, Kathrin; Steinmann, Eike; Pfaender, Stephanie; Kuntzen, Thomas; Megger, Dominik A; Groten, Svenja; Sitek, Barbara; Lauer, Georg M; Kim, Arthur Y; Pietschmann, Thomas; Allen, Todd M; Timm, Joerg

    2016-01-01

    Antiviral CD8(+) T cells are a key component of the adaptive immune response against HCV, but their impact on viral control is influenced by preexisting viral variants in important target epitopes and the development of viral escape mutations. Immunodominant epitopes highly conserved across genotypes therefore are attractive for T cell based prophylactic vaccines. Here, we characterized the CD8(+) T cell response against the highly conserved HLA-B*51-restricted epitope IPFYGKAI1373-1380 located in the helicase domain of NS3 in people who inject drugs (PWID) exposed predominantly to HCV genotypes 1a and 3a. Despite this epitope being conserved in both genotypes, the corresponding CD8(+) T cell response was detected only in PWID infected with genotype 3a and HCV-RNA negative PWID, but not in PWID infected with genotype 1a. In genotype 3a, the detection of strong CD8(+) T cell responses was associated with epitope variants in the autologous virus consistent with immune escape. Analysis of viral sequences from multiple cohorts confirmed HLA-B*51-associated escape mutations inside the epitope in genotype 3a, but not in genotype 1a. Here, a distinct substitution in the N-terminal flanking region located 5 residues upstream of the epitope (S1368P; P = 0.00002) was selected in HLA-B*51-positive individuals. Functional assays revealed that the S1368P substitution impaired recognition of target cells presenting the endogenously processed epitope. The results highlight that, despite an epitope being highly conserved between two genotypes, there are major differences in the selected viral escape pathways and the corresponding T cell responses. HCV is able to evolutionary adapt to CD8(+) T cell immune pressure in multiple ways. Beyond selection of mutations inside targeted epitopes, this study demonstrates that HCV inhibits epitope processing by modification of the epitope flanking region under T cell immune pressure. Selection of a substitution five amino acids upstream of the

  15. The link between CD8T-cell antigen-sensitivity and HIV-suppressive capacity depends on HLA restriction, target epitope and viral isolate.

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    Lissina, Anna; Fastenackels, Solène; Inglesias, Maria C; Ladell, Kristin; McLaren, James E; Briceño, Olivia; Gostick, Emma; Papagno, Laura; Autran, Brigitte; Sauce, Delphine; Price, David A; Saez-Cirion, Asier; Appay, Victor

    2014-02-20

    Although it is established that CD8 T-cell immunity is critical for the control of HIV replication in vivo, the key factors that determine antiviral efficacy are yet to be fully elucidated. Antigen-sensitivity and T-cell receptor (TCR) avidity have been identified as potential determinants of CD8T-cell efficacy. However, there is no general consensus in this regard because the relationship between these parameters and the control of HIV infection has been established primarily in the context of immunodominant CD8T-cell responses against the Gag₂₆₃₋₂₇₂ KK10 epitope restricted by human leukocyte antigen (HLA)-B27. To investigate the relationship between antigen-sensitivity, TCR avidity and HIV-suppressive capacity in vitro across epitope specificities and HLA class I restriction elements, we used a variety of techniques to study CD8T-cell clones specific for Nef₇₃₋₈₂ QK10 and Gag₂₀₋₂₉ RY10, both restricted by HLA-A3, alongside CD8T-cell clones specific for Gag₂₆₃₋₂₇₂ KK10. For each targeted epitope, the linked parameters of antigen-sensitivity and TCR avidity correlated directly with antiviral efficacy. However, marked differences in HIV-suppressive capacity were observed between epitope specificities, HLA class I restriction elements and viral isolates. Collectively, these data emphasize the central role of the TCR as a determinant of CD8T-cell efficacy and demonstrate that the complexities of antigen recognition across epitope and HLA class I boundaries can confound simple relationships between TCR engagement and HIV suppression.

  16. Phenotypic and Functional Characterization of Herpes Simplex Virus Glycoprotein B Epitope-Specific Effector and Memory CD8+ T Cells from Symptomatic and Asymptomatic Individuals with Ocular Herpes

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    Khan, Arif A.; Srivastava, Ruchi; Spencer, Doran; Garg, Sumit; Fremgen, Daniel; Vahed, Hawa; Lopes, Patricia P.; Pham, Thanh T.; Hewett, Charlie; Kuang, Jasmine; Ong, Nicolas; Huang, Lei; Scarfone, Vanessa M.; Nesburn, Anthony B.

    2015-01-01

    ABSTRACT Herpes simplex virus 1 (HSV-1) glycoprotein B (gB)-specific CD8+ T cells protect mice from herpes infection and disease. However, whether and which HSV-1 gB-specific CD8+ T cells play a key role in the “natural” protection seen in HSV-1-seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. In this study, we have dissected the phenotypes and the functions of HSV-1 gB-specific CD8+ T cells from HLA-A*02:01 positive, HSV-1 seropositive ASYMP and symptomatic (SYMP) individuals (with a history of numerous episodes of recurrent ocular herpes disease). We found the following. (i) Healthy ASYMP individuals maintained a significantly higher proportion of differentiated HSV-1 gB-specific effector memory CD8+ T cells (TEM cells) (CD45RAlow CCR7low CD44high CD62Llow). In contrast, SYMP patients had frequent less-differentiated central memory CD8+ T cells (TCM cells) (CD45RAlow CCR7high CD44low CD62Lhigh). (ii) ASYMP individuals had significantly higher proportions of multifunctional effector CD8+ T cells which responded mainly to gB342–350 and gB561–569 “ASYMP” epitopes, and simultaneously produced IFN-γ, CD107a/b, granzyme B, and perforin. In contrast, effector CD8+ T cells from SYMP individuals were mostly monofunctional and were directed mainly against nonoverlapping gB17–25 and gB183–191 “SYMP” epitopes. (iii) Immunization of an HLA-A*02:01 transgenic mouse model of ocular herpes with “ASYMP” CD8+ TEM cell epitopes, but not with “SYMP” CD8+ TCM cell epitopes, induced a strong CD8+ T cell-dependent protective immunity against ocular herpes infection and disease. Our findings provide insights into the role of HSV-specific CD8+ TEM cells in protection against herpes and should be considered in the development of an effective vaccine. IMPORTANCE A significantly higher proportion of differentiated and multifunctional HSV-1 gB-specific effector memory CD8+ T cells (TEM

  17. Identification of SIV Nef CD8(+) T cell epitopes restricted by a MHC class I haplotype associated with lower viral loads in a macaque AIDS model.

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    Nomura, Takushi; Yamamoto, Hiroyuki; Takahashi, Naofumi; Naruse, Taeko K; Kimura, Akinori; Matano, Tetsuro

    2014-07-25

    Virus-specific CD8(+) T-cell responses are crucial for the control of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) replication. Multiple studies on HIV-infected individuals and SIV-infected macaques have indicated association of several major histocompatibility complex class I (MHC-I) genotypes with lower viral loads and delayed AIDS progression. Understanding of the viral control mechanism associated with these MHC-I genotypes would contribute to the development of intervention strategy for HIV control. We have previously reported a rhesus MHC-I haplotype, 90-120-Ia, associated with lower viral loads after SIVmac239 infection. Gag206-216 and Gag241-249 epitope-specific CD8(+) T-cell responses have been shown to play a central role in the reduction of viral loads, whereas the effect of Nef-specific CD8(+) T-cell responses induced in all the 90-120-Ia(+) macaques on SIV replication remains unknown. Here, we identified three CD8(+) T-cell epitopes, Nef9-19, Nef89-97, and Nef193-203, associated with 90-120-Ia. Nef9-19 and Nef193-203 epitope-specific CD8(+) T-cell responses frequently selected for mutations resulting in viral escape from recognition by these CD8(+) T cells, indicating that these CD8(+) T cells exert strong suppressive pressure on SIV replication. Results would be useful for elucidation of the viral control mechanism associated with 90-120-Ia. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Elimination of immunodominant epitopes from multispecific DNA-based vaccines allows induction of CD8 T cells that have a striking antiviral potential

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    Riedl, Petra; Wieland, Andreas; Lamberth, Kasper

    2009-01-01

    Immunodominance limits the TCR diversity of specific antiviral CD8 T cell responses elicited by vaccination or infection. To prime multispecific T cell responses, we constructed DNA vaccines that coexpress chimeric, multidomain Ags (with CD8 T cell-defined epitopes of the hepatitis B virus (HBV...... cell immunity by multidomain Ags. The "weak" (i.e., easily suppressed) K(b)/C(93-100)-specific CD8 T cell response was efficiently elicited by a HBV core Ag-encoding vector in 1.4HBV-S(mut) tg mice (that harbor a replicating HBV genome that produces HBV surface, core, and precore Ag in the liver). K......(b)/C(93-100)-specific CD8 T cells accumulated in the liver of vaccinated 1.4HBV-S(mut) transgenic mice where they suppressed HBV replication. Subdominant epitopes in vaccines can hence prime specific CD8 T cell immunity in a tolerogenic milieu that delivers specific antiviral effects to HBV...

  19. Single-epitope DNA vaccination prevents exhaustion and facilitates a broad antiviral CD8+ T cell response during chronic viral infection

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    Bartholdy, Christina; Stryhn, Anette; Christensen, Jan Pravsgaard

    2004-01-01

    Induction of a monospecific antiviral CD8+ T cell response may pose a risk to the host due to the narrow T cell response induced. At the individual level, this may result in selection of CD8+ T cell escape variants, particularly during chronic viral infection. Second, prior immunization toward a ...... with escape variants. These findings underscore that a monospecific vaccine may induce efficient protective immunity given the right set of circumstances....... of DNA vaccines encoding immunodominant epitopes of lymphocytic choriomeningitis virus (LCMV). We analyzed the spectrum of the CD8+ T cell response and the susceptibility to infection in H-2(b) and H-2(d) mice. Priming for a monospecific, CD8+ T cell response did not render mice susceptible to viral...... variants. Thus, vaccinated mice were protected against chronic infection with LCMV, and no evidence indicating biologically relevant viral escape was obtained. In parallel, a broad and sustained CD8+ T cell response was generated upon infection, and in H-2(d) mice epitope spreading was observed. Even after...

  20. A DNA vaccine encoding multiple HIV CD4 epitopes elicits vigorous polyfunctional, long-lived CD4+ and CD8+ T cell responses.

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    Daniela Santoro Rosa

    Full Text Available T-cell based vaccines against HIV have the goal of limiting both transmission and disease progression by inducing broad and functionally relevant T cell responses. Moreover, polyfunctional and long-lived specific memory T cells have been associated to vaccine-induced protection. CD4(+ T cells are important for the generation and maintenance of functional CD8(+ cytotoxic T cells. We have recently developed a DNA vaccine encoding 18 conserved multiple HLA-DR-binding HIV-1 CD4 epitopes (HIVBr18, capable of eliciting broad CD4(+ T cell responses in multiple HLA class II transgenic mice. Here, we evaluated the breadth and functional profile of HIVBr18-induced immune responses in BALB/c mice. Immunized mice displayed high-magnitude, broad CD4(+/CD8(+ T cell responses, and 8/18 vaccine-encoded peptides were recognized. In addition, HIVBr18 immunization was able to induce polyfunctional CD4(+ and CD8(+ T cells that proliferate and produce any two cytokines (IFNγ/TNFα, IFNγ/IL-2 or TNFα/IL-2 simultaneously in response to HIV-1 peptides. For CD4(+ T cells exclusively, we also detected cells that proliferate and produce all three tested cytokines simultaneously (IFNγ/TNFα/IL-2. The vaccine also generated long-lived central and effector memory CD4(+ T cells, a desirable feature for T-cell based vaccines. By virtue of inducing broad, polyfunctional and long-lived T cell responses against conserved CD4(+ T cell epitopes, combined administration of this vaccine concept may provide sustained help for CD8(+ T cells and antibody responses- elicited by other HIV immunogens.

  1. Identification of conserved subdominant HIV Type 1 CD8(+) T Cell epitopes restricted within common HLA Supertypes for therapeutic HIV Type 1 vaccines

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    Karlsson, Ingrid; Kløverpris, Henrik; Jensen, Kristoffer Jarlov

    2012-01-01

    The high HIV-1 prevalence, up to 4.6% in Guinea-Bissau, West Africa, makes it a relevant location for testing of therapeutic vaccines. With the aim of performing a clinical study in Guinea-Bissau, after first testing the vaccine for safety in Denmark, Europe, we here describe the design...... of a universal epitope peptide-based T cell vaccine with relevance for any geographic locations. The two major obstacles when designing such a vaccine are the high diversities of the HIV-1 genome and of the human major histocompatibility complex (MHC) class I. We selected 15 CD8-restricted epitopes predicted......-specific, HLA-restricted T cell specificities using peptide-MHC class I tetramer labeling of CD8(+) T cells from HIV-1-infected individuals. The selected vaccine epitopes are infrequently targeted in HIV-1-infected individuals from both locations. Moreover, we HLA-typed HIV-1-infected individuals...

  2. Noncanonical Expression of a Murine Cytomegalovirus Early Protein CD8 T-Cell Epitope as an Immediate Early Epitope Based on Transcription from an Upstream Gene

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    Annette Fink

    2014-02-01

    Full Text Available Viral CD8 T-cell epitopes, represented by viral peptides bound to major histocompatibility complex class-I (MHC-I glycoproteins, are often identified by “reverse immunology”, a strategy not requiring biochemical and structural knowledge of the actual viral protein from which they are derived by antigen processing. Instead, bioinformatic algorithms predicting the probability of C-terminal cleavage in the proteasome, as well as binding affinity to the presenting MHC-I molecules, are applied to amino acid sequences deduced from predicted open reading frames (ORFs based on the genomic sequence. If the protein corresponding to an antigenic ORF is known, it is usually inferred that the kinetic class of the protein also defines the phase in the viral replicative cycle during which the respective antigenic peptide is presented for recognition by CD8 T cells. We have previously identified a nonapeptide from the predicted ORFm164 of murine cytomegalovirus that is presented by the MHC-I allomorph H-2 Dd and that is immunodominant in BALB/c (H-2d haplotype mice. Surprisingly, although the ORFm164 protein gp36.5 is expressed as an Early (E phase protein, the m164 epitope is presented already during the Immediate Early (IE phase, based on the expression of an upstream mRNA starting within ORFm167 and encompassing ORFm164.

  3. Exploring diagnostic opportunities in active and latent TB: Stratifying transmission risk using PCR, and identification of immunogenic CD8+ T-cell epitopes

    DEFF Research Database (Denmark)

    Fløe, Andreas

    2018-01-01

    : Study I: As a single sputum-sample analyzed with PCR for MTB identifies >97% of smear-positive TB patients, and as the majority of missed smear-positive TB patients have only one low-grade smear, de-isolation of patients with a single negative sputum PCR-result is safe. Study II: Six HLA A*0201......-restricted antigen-specific CD8+ T-cells. Study III: The CD8+ T-cell response to MTB is highly variable and unpredictable, targeting a wide panel of differently expressed antigens. However, the novel epitopes described here could play a role in future immunodiagnostic tools as well as in vaccine development...

  4. Multi-level Strategy for Identifying Proteasome-Catalyzed Spliced Epitopes Targeted by CD8+ T Cells during Bacterial Infection

    Directory of Open Access Journals (Sweden)

    Anouk C.M. Platteel

    2017-08-01

    Full Text Available Proteasome-catalyzed peptide splicing (PCPS generates peptides that are presented by MHC class I molecules, but because their identification is challenging, the immunological relevance of spliced peptides remains unclear. Here, we developed a reverse immunology-based multi-level approach to identify proteasome-generated spliced epitopes. Applying this strategy to a murine Listeria monocytogenes infection model, we identified two spliced epitopes within the secreted bacterial phospholipase PlcB that primed antigen-specific CD8+ T cells in L. monocytogenes-infected mice. While reacting to the spliced epitopes, these CD8+ T cells failed to recognize the non-spliced peptide parts in the context of their natural flanking sequences. Thus, we here show that PCPS expands the CD8+ T cell response against L. monocytogenes by exposing spliced epitopes on the cell surface. Moreover, our multi-level strategy opens up opportunities to systematically investigate proteins for spliced epitope candidates and thus strategies for immunotherapies or vaccine design.

  5. Strategy for eliciting antigen-specific CD8+ T cell-mediated immune response against a cryptic CTL epitope of merkel cell polyomavirus large T antigen

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    Gomez Bianca P

    2012-10-01

    Full Text Available Abstract Background Merkel cell carcinoma (MCC is a relatively new addition to the expanding category of oncovirus-induced cancers. Although still comparably rare, the number of cases has risen dramatically in recent years. Further complicating this trend is that MCC is an extremely aggressive neoplasm with poor patient prognosis and limited treatment options for advanced disease. The causative agent of MCC has been identified as the merkel cell polyomavirus (MCPyV. The MCPyV-encoded large T (LT antigen is an oncoprotein that is theorized to be essential for virus-mediated tumorigenesis and is therefore, an excellent MCC antigen for the generation of antitumor immune responses. As a foreign antigen, the LT oncoprotein avoids the obstacle of immune tolerance, which normally impedes the development of antitumor immunity. Ergo, it is an excellent target for anti-MCC immunotherapy. Since tumor-specific CD8+ T cells lead to better prognosis for MCC and numerous other cancers, we have generated a DNA vaccine that is capable of eliciting LT-specific CD8+ T cells. The DNA vaccine (pcDNA3-CRT/LT encodes the LT antigen linked to a damage-associated molecular pattern, calreticulin (CRT, as it has been demonstrated that the linkage of CRT to antigens promotes the induction of antigen-specific CD8+ T cells. Results The present study shows that DNA vaccine-induced generation of LT-specific CD8+ T cells is augmented by linking CRT to the LT antigen. This is relevant since the therapeutic effects of the pcDNA3-CRT/LT DNA vaccine is mediated by LT-specific CD8+ T cells. Mice vaccinated with the DNA vaccine produced demonstrably more LT-specific CD8+ T cells. The DNA vaccine was also able to confer LT-specific CD8+ T cell-mediated protective and therapeutic effects to prolong the survival of mice with LT-expressing tumors. In the interest of determining the LT epitope which most MCC-specific CD8+ T cells recognize, we identified the amino acid sequence of the

  6. Overlapping CD8+ and CD4+ T-cell epitopes identification for the progression of epitope-based peptide vaccine from nucleocapsid and glycoprotein of emerging Rift Valley fever virus using immunoinformatics approach.

    Science.gov (United States)

    Adhikari, Utpal Kumar; Rahman, M Mizanur

    2017-12-01

    Rift Valley fever virus (RVFV) is an emergent arthropod-borne zoonotic infectious viral pathogen which causes fatal diseases in the humans and ruminants. Currently, no effective and licensed vaccine is available for the prevention of RVFV infection in endemic as well as in non-endemic regions. So, an immunoinformatics-driven genome-wide screening approach was performed for the identification of overlapping CD8+ and CD4+ T-cell epitopes and also linear B-cell epitopes from the conserved sequences of the nucleocapsid (N) and glycoprotein (G) of RVFV. We identified overlapping 99.39% conserved 1 CD8+ T-cell epitope (MMHPSFAGM) from N protein and 100% conserved 7 epitopes (AVFALAPVV, LAVFALAPV, FALAPVVFA, VFALAPVVF, IAMTVLPAL, FFDWFSGLM, and FLLIYLGRT) from G protein and also identified IL-4 and IFN-γ induced (99.39% conserved) 1 N protein CD4+ T-cell epitope (HMMHPSFAGMVDPSL) and 100% conserved 5 G protein CD4+ T-cell epitopes (LPALAVFALAPVVFA, PALAVFALAPVVFAE, GIAMTVLPALAVFAL, GSWNFFDWFSGLMSW, and FFLLIYLGRTGLSKM). The overlapping CD8+ and CD4+ T-cell epitopes were bound with most conserved HLA-C*12:03 and HLA-DRB1*01:01, respectively with the high binding affinity (kcal/mol). The combined population coverage analysis revealed that the allele frequencies of these epitopes are high in endemic and non-endemic regions. Besides, we found 100% conserved and non-allergenic 2 decamer B-cell epitopes, GVCEVGVQAL and RVFNCIDWVH of G protein had the sequence similarity with the nonamer CD8+ T-cell epitopes, VCEVGVQAL and RVFNCIDWV, respectively. Consequently, these epitopes may be used for the development of epitope-based peptide vaccine against emerging RVFV. However, in vivo and in vitro experiments are required for their efficient use as a vaccine. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Differential presentation of endogenous and exogenous hepatitis B surface antigens influences priming of CD8(+) T cells in an epitope-specific manner.

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    Riedl, Petra; Reiser, Michael; Stifter, Katja; Krieger, Jana; Schirmbeck, Reinhold

    2014-07-01

    Little is known about whether presentation of endogenous and exogenous hepatitis B virus (HBV) surface antigens on APCs targeted by vaccination and/or virus-harboring hepatocytes influences de novo priming of CD8(+) T cells. We showed that surface antigen-expressing transfectants exclusively display a K(b) /S190 epitope, whereas cells pulsed with recombinant surface particles (rSPs) exclusively present a K(b) /S208 epitope to CD8(+) T cells. The differential presentation of these epitopes largely reflects the selective, but not exclusive, priming of K(b) /S190- and K(b) /S208-specific T cells in C57BL/6 mice by endogenous/DNA- or exogenous/protein-based vaccines, respectively. Silencing the K(b) /S190 epitope (K(b) /S190V194F ) in antigen-expressing vectors rescued the presentation of the K(b) /S208 epitope in stable transfectants and significantly enhanced priming of K(b) /S208-specific T cells in C57BL/6 mice. A K(b) /S190-mediated immunodominance operating in surface antigen-expressing cells, but not in rSP-pulsed cells, led to an efficient suppression in the presentation of the K(b) /S208 epitope and a consequent decrease in the priming of K(b) /S208-specific T cells. This K(b) /S190-mediated immunodominance also operated in 1.4HBV-S(mut) transgenic (tg) hepatocytes selectively expressing endogenous surface antigens and allowed priming of K(b) /S208- but not K(b) /S190-specific T cells in 1.4HBV-S(mut) tg mice. However, IFN-γ(+) K(b) /S208-specific T cells could not inhibit HBV replication in the liver of 1.4HBV-S(mut) tg mice. These results have practical implications for the design of T-cell-stimulating therapeutic vaccines. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Vaccine Targeting of Subdominant CD8+ T Cell Epitopes Increases the Breadth of the T Cell Response upon Viral Challenge, but May Impair Immediate Virus Control

    DEFF Research Database (Denmark)

    Steffensen, Maria A; Pedersen, Louise Holm; Jahn, Marie Louise

    2016-01-01

    As a result of the difficulties in making efficient vaccines against genetically unstable viruses such as HIV, it has been suggested that future vaccines should preferentially target subdominant epitopes, the idea being that this should allow a greater breadth of the induced T cell response and, ...... a limitation of our model, but clearly our findings underscore the importance of carefully weighing the pros and cons of changes in epitope targeting before any implementation.......As a result of the difficulties in making efficient vaccines against genetically unstable viruses such as HIV, it has been suggested that future vaccines should preferentially target subdominant epitopes, the idea being that this should allow a greater breadth of the induced T cell response and......, hence, a greater efficiency in controlling escape variants. However, to our knowledge the evidence supporting this concept is limited at best. To improve upon this, we used the murine lymphocytic choriomeningitis virus model and adenoviral vectors to compare a vaccine expressing unmodified Ag...

  9. Human influenza viruses and CD8(+) T cell responses.

    Science.gov (United States)

    Grant, Emma J; Quiñones-Parra, Sergio M; Clemens, E Bridie; Kedzierska, Katherine

    2016-02-01

    Influenza A viruses (IAVs) cause significant morbidity and mortality worldwide, despite new strain-specific vaccines being available annually. As IAV-specific CD8(+) T cells promote viral control in the absence of neutralizing antibodies, and can mediate cross-reactive immunity toward distinct IAVs to drive rapid recovery from both mild and severe influenza disease, there is great interest in developing a universal T cell vaccine. However, despite detailed studies in mouse models of influenza virus infection, there is still a paucity of data on human epitope-specific CD8(+) T cell responses to IAVs. This review focuses on our current understanding of human CD8(+) T cell immunity against distinct IAVs and discusses the possibility of achieving a CD8(+) T cell mediated-vaccine that protects against multiple, distinct IAV strains across diverse human populations. We also review the importance of CD8(+) T cell immunity in individuals highly susceptible to severe influenza infection, including those hospitalised with influenza, the elderly and Indigenous populations. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Therapeutic immunization with a mixture of herpes simplex virus 1 glycoprotein D-derived “asymptomatic” human CD8+ T-cell epitopes decreases spontaneous ocular shedding in latently infected HLA transgenic rabbits: association with low frequency of local PD-1+ TIM-3+ CD8+ exhausted T cells.

    Science.gov (United States)

    Khan, Arif A; Srivastava, Ruchi; Chentoufi, Aziz A; Geertsema, Roger; Thai, Nhi Thi Uyen; Dasgupta, Gargi; Osorio, Nelson; Kalantari, Mina; Nesburn, Anthony B; Wechsler, Steven L; BenMohamed, Lbachir

    2015-07-01

    Most blinding ocular herpetic disease is due to reactivation of herpes simplex virus 1 (HSV-1) from latency rather than to primary acute infection. No herpes simplex vaccine is currently available for use in humans. In this study, we used the HLA-A*02:01 transgenic (HLA Tg) rabbit model of ocular herpes to assess the efficacy of a therapeutic vaccine based on HSV-1 gD epitopes that are recognized mainly by CD8(+) T cells from "naturally" protected HLA-A*02:01-positive, HSV-1-seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease). Three ASYMP CD8(+) T-cell epitopes (gD(53-61), gD(70-78), and gD(278-286)) were linked with a promiscuous CD4(+) T-cell epitope (gD(287-317)) to create 3 separate pairs of CD4-CD8 peptides, which were then each covalently coupled to an Nε-palmitoyl-lysine moiety, a Toll-like receptor 2 (TLR-2) ligand. This resulted in the construction of 3 CD4-CD8 lipopeptide vaccines. Latently infected HLA Tg rabbits were immunized with a mixture of these 3 ASYMP lipopeptide vaccines, delivered as eye drops in sterile phosphate-buffered saline (PBS). The ASYMP therapeutic vaccination (i) induced HSV-specific CD8(+) T cells that prevent HSV-1 reactivation ex vivo from latently infected explanted trigeminal ganglia (TG), (ii) significantly reduced HSV-1 shedding detected in tears, (iii) boosted the number and function of HSV-1 gD epitope-specific CD8(+) T cells in draining lymph nodes (DLN), conjunctiva, and TG, and (iv) was associated with fewer exhausted HSV-1 gD-specific PD-1(+) TIM-3+ CD8(+) T cells. The results underscore the potential of an ASYMP CD8(+) T-cell epitope-based therapeutic vaccine strategy against recurrent ocular herpes. Seventy percent to 90% of adults harbor herpes simplex virus 1 (HSV-1), which establishes lifelong latency in sensory neurons of the trigeminal ganglia. This latent state sporadically switches to spontaneous reactivation, resulting in viral shedding in tears. Most blinding

  11. Asymptomatic HLA-A*02:01–Restricted Epitopes from Herpes Simplex Virus Glycoprotein B Preferentially Recall Polyfunctional CD8+ T Cells from Seropositive Asymptomatic Individuals and Protect HLA Transgenic Mice against Ocular Herpes

    Science.gov (United States)

    Dervillez, Xavier; Qureshi, Huma; Chentoufi, Aziz A.; Khan, Arif A.; Kritzer, Elizabeth; Yu, David C.; Diaz, Oscar R.; Gottimukkala, Chetan; Kalantari, Mina; Villacres, Maria C.; Scarfone, Vanessa M.; McKinney, Denise M.; Sidney, John; Sette, Alessandro; Nesburn, Anthony B.; Wechsler, Steven L.; BenMohamed, Lbachir

    2014-01-01

    Evidence from C57BL/6 mice suggests that CD8+ T cells, specific to the immunodominant HSV-1 glycoprotein B (gB) H-2b–restricted epitope (gB498–505), protect against ocular herpes infection and disease. However, the possible role of CD8+ T cells, specific to HLA-restricted gB epitopes, in protective immunity seen in HSV-1–seropositive asymptomatic (ASYMP) healthy individuals (who have never had clinical herpes) remains to be determined. In this study, we used multiple prediction algorithms to identify 10 potential HLA-A*02:01–restricted CD8+ T cell epitopes from the HSV-1 gB amino acid sequence. Six of these epitopes exhibited high-affinity binding to HLA-A*02:01 molecules. In 10 sequentially studied HLA-A*02:01–positive, HSV-1–seropositive ASYMP individuals, the most frequent, robust, and polyfunctional CD8+ T cell responses, as assessed by a combination of tetramer, IFN-γ-ELISPOT, CFSE proliferation, CD107a/b cytotoxic degranulation, and multiplex cytokine assays, were directed mainly against epitopes gB342–350 and gB561–569. In contrast, in 10 HLA-A*02:01–positive, HSV-1–seropositive symptomatic (SYMP) individuals (with a history of numerous episodes of recurrent clinical herpes disease) frequent, but less robust, CD8+ T cell responses were directed mainly against nonoverlapping epitopes (gB183–191 and gB441–449). ASYMP individuals had a significantly higher proportion of HSV-gB–specific CD8+ T cells expressing CD107a/b degranulation marker and producing effector cytokines IL-2, IFN-γ, and TNF-α than did SYMP individuals. Moreover, immunization of a novel herpes-susceptible HLA-A*02:01 transgenic mouse model with ASYMP epitopes, but not with SYMP epitopes, induced strong CD8+ T cell–dependent protective immunity against ocular herpes infection and disease. These findings should guide the development of a safe and effective T cell–based herpes vaccine. PMID:24101547

  12. Expanding specificity of class I restricted CD8+ T cells for viral epitopes following multiple inoculations of swine with a human adenovirus vectored foot-and-mouth disease virus (FMDV) vaccine

    DEFF Research Database (Denmark)

    Pedersen, Lasse E.; Patch, Jared R; Kenney, Mary

    2016-01-01

    The immune response to the highly acute foot-and-mouth disease virus (FMDV) is routinely reported as a measure of serum antibody. However, a critical effector function of immune responses combating viral infection of mammals is the cytotoxic T lymphocyte (CTL) response mediated by virus specific CD...... show that the specificity of the CD8(+) T cell response to Ad5-FMDV-T varies between cohorts of genetically identical animals. Further, we demonstrate epitope specificity of CD8(+) T cells expands following multiple immunizations with this vaccine....

  13. Immune hierarchy among HIV-1 CD8+ T cell epitopes delivered by dendritic cells depends on MHC-I binding irrespective of mode of loading and immunization in HLA-A*0201 mice

    DEFF Research Database (Denmark)

    Kloverpris, Henrik N; Karlsson, Ingrid; Thorn, Mette

    2009-01-01

    Recent human immunodeficiency virus type 1 (HIV-1) vaccination strategies aim at targeting a broad range of cytotoxic T lymphocyte (CTL) epitopes from different HIV-1 proteins by immunization with multiple CTL epitopes simultaneously. However, this may establish an immune hierarchical response......, where the immune system responds to only a small number of the epitopes administered. To evaluate the feasibility of such vaccine strategies, we used the human leukocyte antigen (HLA)-A*0201 transgenic (tg) HHD murine in vivo model and immunized with dendritic cells pulsed with seven HIV-1-derived HLA......-gamma)-producing CD8(+) T cells, mainly focused on two of seven administered epitopes. The magnitude of individual T-cell responses induced by immunization with multiple peptides correlated with their individual immunogenicity that depended on major histocompatibility class I binding and was not influenced by mode...

  14. Biological and immunological characterization of recombinant Yellow Fever 17D Viruses expressing a Trypanosoma cruzi Amastigote Surface Protein-2 CD8+ T cell epitope at two distinct regions of the genome

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    Bonaldo Myrna C

    2011-03-01

    Full Text Available Abstract Background The attenuated Yellow fever (YF 17D vaccine virus is one of the safest and most effective viral vaccines administered to humans, in which it elicits a polyvalent immune response. Herein, we used the YF 17D backbone to express a Trypanosoma cruzi CD8+ T cell epitope from the Amastigote Surface Protein 2 (ASP-2 to provide further evidence for the potential of this virus to express foreign epitopes. The TEWETGQI CD8+ T cell epitope was cloned and expressed based on two different genomic insertion sites: in the fg loop of the viral Envelope protein and the protease cleavage site between the NS2B and NS3. We investigated whether the site of expression had any influence on immunogenicity of this model epitope. Results Recombinant viruses replicated similarly to vaccine virus YF 17D in cell culture and remained genetically stable after several serial passages in Vero cells. Immunogenicity studies revealed that both recombinant viruses elicited neutralizing antibodies to the YF virus as well as generated an antigen-specific gamma interferon mediated T-cell response in immunized mice. The recombinant viruses displayed a more attenuated phenotype than the YF 17DD vaccine counterpart in mice. Vaccination of a mouse lineage highly susceptible to infection by T. cruzi with a homologous prime-boost regimen of recombinant YF viruses elicited TEWETGQI specific CD8+ T cells which might be correlated with a delay in mouse mortality after a challenge with a lethal dose of T. cruzi. Conclusions We conclude that the YF 17D platform is useful to express T. cruzi (Protozoan antigens at different functional regions of its genome with minimal reduction of vector fitness. In addition, the model T. cruzi epitope expressed at different regions of the YF 17D genome elicited a similar T cell-based immune response, suggesting that both expression sites are useful. However, the epitope as such is not protective and it remains to be seen whether expression

  15. CD8+ T cells in inflammatory demyelinating disease

    DEFF Research Database (Denmark)

    Weiss, Hanne A; Millward, Jason M; Owens, Trevor

    2007-01-01

    We review the contribution made by CD8+ T cells to inflammation in the central nervous system (CNS) in Multiple Sclerosis (MS), and discuss their role in the animal model Experimental Autoimmune Encephalomyelitis (EAE). We show that the inflammatory cytokines interferon-gamma and interleukin-17...... are differentially regulated in CNS-infiltrating CD4+ and CD8+ T cells in EAE, and that CD8+ T cells regulate disease. In MS, CD8+ T cells appear to play a role in promotion of disease, so cytokine regulation is likely different in CD8+ T cells in MS and EAE...

  16. Induction of novel CD8+ T-cell responses during chronic untreated HIV-1 infection by immunization with subdominant cytotoxic T-lymphocyte epitopes

    DEFF Research Database (Denmark)

    Kloverpris, Henrik; Karlsson, Ingrid; Bonde, Jesper

    2009-01-01

    OBJECTIVE:: To investigate the potential to induce additional cytotoxic T-lymphocyte (CTL) immunity during chronic HIV-1 infection. DESIGN:: We selected infrequently targeted or subdominant but conserved HLA-A*0201-binding epitopes in Gag, Pol, Env, Vpu and Vif. These relatively immune silent...... epitopes were modified as anchor-optimized peptides to improve immunogenicity and delivered on autologous monocyte-derived dendritic cells (MDDCs). METHODS:: Twelve treatment-naïve HLA-A*0201 HIV-1-infected Danish individuals received 1 x 10 MDDCs subcutaneously (s.c.) (weeks 0, 2, 4 and 8), pulsed......-cell counts was observed. CONCLUSION:: These data show that it is possible to generate new T-cell responses in treatment-naive HIV-1-infected individuals despite high viral loads, and thereby redirect immunity to target new multiple and rationally selected subdominant CTL epitopes. Further optimization could...

  17. CD4+/CD8+ double-positive T cells

    DEFF Research Database (Denmark)

    Overgaard, Nana H; Jung, Ji-Won; Steptoe, Raymond J

    2015-01-01

    CD4(+)/CD8(+) DP thymocytes are a well-described T cell developmental stage within the thymus. However, once differentiated, the CD4(+) lineage or the CD8(+) lineage is generally considered to be fixed. Nevertheless, mature CD4(+)/CD8(+) DP T cells have been described in the blood and peripheral...... cells, CD4(+)/CD8(+) T cell populations, outside of the thymus, have recently been described to express concurrently ThPOK and Runx3. Considerable heterogeneity exists within the CD4(+)/CD8(+) DP T cell pool, and the function of CD4(+)/CD8(+) T cell populations remains controversial, with conflicting...... reports describing cytotoxic or suppressive roles for these cells. In this review, we describe how transcriptional regulation, lineage of origin, heterogeneity of CD4 and CD8 expression, age, species, and specific disease settings influence the functionality of this rarely studied T cell population....

  18. Early events governing memory CD8+ T-cell differentiation.

    Science.gov (United States)

    Obar, Joshua J; Lefrançois, Leo

    2010-08-01

    Understanding the regulation of the CD8(+) T-cell response and how protective memory cells are generated has been intensely studied. It is now appreciated that a naive CD8(+) T cell requires at least three signals to mount an effective immune response: (i) TCR triggering, (ii) co-stimulation and (iii) inflammatory cytokines. Only recently have we begun to understand the molecular integration of those signals and how early events regulate the fate decisions of the responding CD8(+) T cells. This review will discuss the recent findings about both the extracellular and intracellular factors that regulate the destiny of responding CD8(+) T cells.

  19. A Herpes Simplex Virus Type 1 Human Asymptomatic CD8+ T-Cell Epitopes-Based Vaccine Protects Against Ocular Herpes in a “Humanized” HLA Transgenic Rabbit Model

    Science.gov (United States)

    Srivastava, Ruchi; Khan, Arif A.; Huang, Jiawei; Nesburn, Anthony B.; Wechsler, Steven L.; BenMohamed, Lbachir

    2015-01-01

    Purpose. A clinical vaccine that protects from ocular herpes simplex virus type 1 (HSV-1) infection and disease still is lacking. In the present study, preclinical vaccine trials of nine asymptomatic (ASYMP) peptides, selected from HSV-1 glycoproteins B (gB), and tegument proteins VP11/12 and VP13/14, were performed in the “humanized” HLA–transgenic rabbit (HLA-Tg rabbit) model of ocular herpes. We recently reported that these peptides are highly recognized by CD8+ T cells from “naturally” protected HSV-1–seropositive healthy ASYMP individuals (who have never had clinical herpes disease). Methods. Mixtures of three ASYMP CD8+ T-cell peptides derived from either HSV-1 gB, VP11/12, or VP13/14 were delivered subcutaneously to different groups of HLA-Tg rabbits (n = 10) in incomplete Freund's adjuvant, twice at 15-day intervals. The frequency and function of HSV-1 epitope-specific CD8+ T cells induced by these peptides and their protective efficacy, in terms of survival, virus replication in the eye, and ocular herpetic disease were assessed after an ocular challenge with HSV-1 (strain McKrae). Results. All mixtures elicited strong and polyfunctional IFN-γ– and TNF-α–producing CD107+CD8+ cytotoxic T cells, associated with a significant reduction in death, ocular herpes infection, and disease (P herpes, and provide a prototype vaccine formulation that may be highly efficacious for preventing ocular herpes in humans. PMID:26098469

  20. Epigenetic control of CD8+ T cell differentiation.

    Science.gov (United States)

    Henning, Amanda N; Roychoudhuri, Rahul; Restifo, Nicholas P

    2018-05-01

    Upon stimulation, small numbers of naive CD8 + T cells proliferate and differentiate into a variety of memory and effector cell types. CD8 + T cells can persist for years and kill tumour cells and virally infected cells. The functional and phenotypic changes that occur during CD8 + T cell differentiation are well characterized, but the epigenetic states that underlie these changes are incompletely understood. Here, we review the epigenetic processes that direct CD8 + T cell differentiation and function. We focus on epigenetic modification of DNA and associated histones at genes and their regulatory elements. We also describe structural changes in chromatin organization that affect gene expression. Finally, we examine the translational potential of epigenetic interventions to improve CD8 + T cell function in individuals with chronic infections and cancer.

  1. Memory CD8 T cells mediate severe immunopathology following respiratory syncytial virus infection.

    Directory of Open Access Journals (Sweden)

    Megan E Schmidt

    2018-01-01

    Full Text Available Memory CD8 T cells can provide protection from re-infection by respiratory viruses such as influenza and SARS. However, the relative contribution of memory CD8 T cells in providing protection against respiratory syncytial virus (RSV infection is currently unclear. To address this knowledge gap, we utilized a prime-boost immunization approach to induce robust memory CD8 T cell responses in the absence of RSV-specific CD4 T cells and antibodies. Unexpectedly, RSV infection of mice with pre-existing CD8 T cell memory led to exacerbated weight loss, pulmonary disease, and lethal immunopathology. The exacerbated disease in immunized mice was not epitope-dependent and occurred despite a significant reduction in RSV viral titers. In addition, the lethal immunopathology was unique to the context of an RSV infection as mice were protected from a normally lethal challenge with a recombinant influenza virus expressing an RSV epitope. Memory CD8 T cells rapidly produced IFN-γ following RSV infection resulting in elevated protein levels in the lung and periphery. Neutralization of IFN-γ in the respiratory tract reduced morbidity and prevented mortality. These results demonstrate that in contrast to other respiratory viruses, RSV-specific memory CD8 T cells can induce lethal immunopathology despite mediating enhanced viral clearance.

  2. The role of CD8+ T cells during allograft rejection

    Directory of Open Access Journals (Sweden)

    V. Bueno

    2002-11-01

    Full Text Available Organ transplantation can be considered as replacement therapy for patients with end-stage organ failure. The percent of one-year allograft survival has increased due, among other factors, to a better understanding of the rejection process and new immunosuppressive drugs. Immunosuppressive therapy used in transplantation prevents activation and proliferation of alloreactive T lymphocytes, although not fully preventing chronic rejection. Recognition by recipient T cells of alloantigens expressed by donor tissues initiates immune destruction of allogeneic transplants. However, there is controversy concerning the relative contribution of CD4+ and CD8+ T cells to allograft rejection. Some animal models indicate that there is an absolute requirement for CD4+ T cells in allogeneic rejection, whereas in others CD4-depleted mice reject certain types of allografts. Moreover, there is evidence that CD8+ T cells are more resistant to immunotherapy and tolerance induction protocols. An intense focal infiltration of mainly CD8+CTLA4+ T lymphocytes during kidney rejection has been described in patients. This suggests that CD8+ T cells could escape from immunosuppression and participate in the rejection process. Our group is primarily interested in the immune mechanisms involved in allograft rejection. Thus, we believe that a better understanding of the role of CD8+ T cells in allograft rejection could indicate new targets for immunotherapy in transplantation. Therefore, the objective of the present review was to focus on the role of the CD8+ T cell population in the rejection of allogeneic tissue.

  3. T-cell help permits memory CD8(+) T-cell inflation during cytomegalovirus latency.

    Science.gov (United States)

    Walton, Senta M; Torti, Nicole; Mandaric, Sanja; Oxenius, Annette

    2011-08-01

    CD4(+) T cells are implied to sustain CD8(+) T-cell responses during persistent infections. As CD4(+) T cells are often themselves antiviral effectors, they might shape CD8(+) T-cell responses via help or via controlling antigen load. We used persistent murine CMV (MCMV) infection to dissect the impact of CD4(+) T cells on virus-specific CD8(+) T cells, distinguishing between increased viral load in the absence of CD4(+) T cells and CD4(+) T-cell-mediated helper mechanisms. Absence of T-helper cells was associated with sustained lytic MCMV replication and led to a slow and gradual reduction of the size and function of the MCMV-specific CD8(+) T-cell pool. However, when virus replication was controlled in the absence of CD4(+) T cells, CD8(+) T-cell function was comparably impaired, but in addition CD8(+) T-cell inflation, a hallmark of CMV infection, was completely abolished. Thus, CD8(+) T-cell inflation during latent CMV infection is strongly dependent on CD4(+) T-cell helper functions, which can partially be compensated by ongoing lytic viral replication in the absence of CD4(+) T cells. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Genome-Based In Silico Identification of New Mycobacterium tuberculosis Antigens Activating Polyfunctional CD8+ T Cells in Human Tuberculosis

    DEFF Research Database (Denmark)

    Tang, Sheila Tuyet; van Meijgaarden, Krista E.; Caccamo, Nadia

    2011-01-01

    8(+) T cell proliferation assays (CFSE dilution) in 41 M. tuberculosis-responsive donors identified 70 new M. tuberculosis epitopes. Using HLA/peptide tetramers for the 18 most prominently recognized HLA-A*0201-binding M. tuberculosis peptides, recognition by cured TB patients' CD8(+) T cells......-epitope/Ag repertoire for human CD8(+) T cells is much broader than hitherto suspected, and the newly identified M. tuberculosis Ags are recognized by (poly) functional CD8(+) T cells during control of infection. These results impact on TB-vaccine design and biomarker identification. The Journal of Immunology, 2011...

  5. Prolonged activation of virus-specific CD8+T cells after acute B19 infection

    DEFF Research Database (Denmark)

    Isa, Adiba; Kasprowicz, Victoria; Norbeck, Oscar

    2005-01-01

    BACKGROUND: Human parvovirus B19 (B19) is a ubiquitous and clinically significant pathogen, causing erythema infectiosum, arthropathy, transient aplastic crisis, and intrauterine fetal death. The phenotype of CD8+ T cells in acute B19 infection has not been studied previously. METHODS AND FINDINGS......: The number and phenotype of B19-specific CD8+ T cell responses during and after acute adult infection was studied using HLA-peptide multimeric complexes. Surprisingly, these responses increased in magnitude over the first year post-infection despite resolution of clinical symptoms and control of viraemia......, with T cell populations specific for individual epitopes comprising up to 4% of CD8+ T cells. B19-specific T cells developed and maintained an activated CD38+ phenotype, with strong expression of perforin and CD57 and downregulation of CD28 and CD27. These cells possessed strong effector function...

  6. Functional heterogeneity of human effector CD8+ T cells.

    Science.gov (United States)

    Takata, Hiroshi; Naruto, Takuya; Takiguchi, Masafumi

    2012-02-09

    Effector CD8(+) T cells are believed to be terminally differentiated cells having cytotoxic activity and the ability to produce effector cytokines such as INF-γ and TNF-α. We investigated the difference between CXCR1(+) and CXCR1(-) subsets of human effector CD27(-)CD28(-)CD8(+) T cells. The subsets expressed cytolytic molecules similarly and exerted substantial cytolytic activity, whereas only the CXCR1(-) subset had IL-2 productivity and self-proliferative activity and was more resistant to cell death than the CXCR1(+) subset. These differences were explained by the specific up-regulation of CAMK4, SPRY2, and IL-7R in the CXCR1(-) subset and that of pro-apoptotic death-associated protein kinase 1 (DAPK1) in the CXCR1(+) subset. The IL-2 producers were more frequently found in the IL-7R(+) subset of the CXCR1(-) effector CD8(+) T cells than in the IL-7R(-) subset. IL-7/IL-7R signaling promoted cell survival only in the CXCR1(-) subset. The present study has highlighted a novel subset of effector CD8(+) T cells producing IL-2 and suggests the importance of this subset in the homeostasis of effector CD8(+) T cells.

  7. HLA-A02:01-restricted epitopes identified from the herpes simplex virus tegument protein VP11/12 preferentially recall polyfunctional effector memory CD8+ T cells from seropositive asymptomatic individuals and protect humanized HLA-A*02:01 transgenic mice against ocular herpes.

    Science.gov (United States)

    Srivastava, Ruchi; Khan, Arif A; Spencer, Doran; Vahed, Hawa; Lopes, Patricia P; Thai, Nhi Thi Uyen; Wang, Christine; Pham, Thanh T; Huang, Jiawei; Scarfone, Vanessa M; Nesburn, Anthony B; Wechsler, Steven L; BenMohamed, Lbachir

    2015-03-01

    The HSV type 1 tegument virion phosphoprotein (VP) 11/12 (VP11/12) is a major Ag targeted by CD8(+) T cells from HSV-seropositive individuals. However, whether and which VP11/12 epitope-specific CD8(+) T cells play a role in the "natural" protection seen in seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. In this study, we used multiple prediction computer-assisted algorithms to identify 10 potential HLA-A*02:01-restricted CD8(+) T cell epitopes from the 718-aa sequence of VP11/12. Three of 10 epitopes exhibited high-to-moderate binding affinity to HLA-A*02:01 molecules. In 10 sequentially studied HLA-A*02:01-positive and HSV-1-seropositive ASYMP individuals, the most frequent, robust, and polyfunctional effector CD8(+) T cell responses, as assessed by a combination of tetramer frequency, granzyme B, granzyme K, perforin, CD107(a/b) cytotoxic degranulation, IFN-γ, and multiplex cytokines assays, were predominantly directed against three epitopes: VP11/1266-74, VP11/12220-228, and VP11/12702-710. Interestingly, ASYMP individuals had a significantly higher proportion of CD45RA(low)CCR7(low)CD44(high)CD62L(low)CD27(low)CD28(low)CD8(+) effector memory CD8(+) T cells (TEMs) specific to the three epitopes, compared with symptomatic individuals (with a history of numerous episodes of recurrent ocular herpetic disease). Moreover, immunization of HLA-A*02:01 transgenic mice with the three ASYMP CD8(+) TEM cell epitopes induced robust and polyfunctional epitope-specific CD8(+) TEM cells that were associated with a strong protective immunity against ocular herpes infection and disease. Our findings outline phenotypic and functional features of protective HSV-specific CD8(+) T cells that should guide the development of an effective T cell-based herpes vaccine. Copyright © 2015 by The American Association of Immunologists, Inc.

  8. CD8(+) T cells of Listeria monocytogenes-infected mice recognize both linear and spliced proteasome products

    NARCIS (Netherlands)

    Platteel, Anouk C M; Mishto, Michele; Textoris-Taube, Kathrin; Keller, Christin; Liepe, Juliane; Busch, Dirk H; Kloetzel, Peter M; Sijts, Alice J A M

    CD8(+) T cells responding to infection recognize pathogen-derived epitopes presented by MHC class-I molecules. While most of such epitopes are generated by proteasome-mediated antigen cleavage, analysis of tumor antigen processing has revealed that epitopes may also derive from proteasome-catalyzed

  9. FOXO3 regulates CD8 T cell memory by T cell-intrinsic mechanisms.

    Directory of Open Access Journals (Sweden)

    Jeremy A Sullivan

    2012-02-01

    Full Text Available CD8 T cell responses have three phases: expansion, contraction, and memory. Dynamic alterations in proliferation and apoptotic rates control CD8 T cell numbers at each phase, which in turn dictate the magnitude of CD8 T cell memory. Identification of signaling pathways that control CD8 T cell memory is incomplete. The PI3K/Akt signaling pathway controls cell growth in many cell types by modulating the activity of FOXO transcription factors. But the role of FOXOs in regulating CD8 T cell memory remains unknown. We show that phosphorylation of Akt, FOXO and mTOR in CD8 T cells occurs in a dynamic fashion in vivo during an acute viral infection. To elucidate the potentially dynamic role for FOXO3 in regulating homeostasis of activated CD8 T cells in lymphoid and non-lymphoid organs, we infected global and T cell-specific FOXO3-deficient mice with Lymphocytic Choriomeningitis Virus (LCMV. We found that FOXO3 deficiency induced a marked increase in the expansion of effector CD8 T cells, preferentially in the spleen, by T cell-intrinsic mechanisms. Mechanistically, the enhanced accumulation of proliferating CD8 T cells in FOXO3-deficient mice was not attributed to an augmented rate of cell division, but instead was linked to a reduction in cellular apoptosis. These data suggested that FOXO3 might inhibit accumulation of growth factor-deprived proliferating CD8 T cells by reducing their viability. By virtue of greater accumulation of memory precursor effector cells during expansion, the numbers of memory CD8 T cells were strikingly increased in the spleens of both global and T cell-specific FOXO3-deficient mice. The augmented CD8 T cell memory was durable, and FOXO3 deficiency did not perturb any of the qualitative attributes of memory T cells. In summary, we have identified FOXO3 as a critical regulator of CD8 T cell memory, and therapeutic modulation of FOXO3 might enhance vaccine-induced protective immunity against intracellular pathogens.

  10. Measuring the diaspora for virus-specific CD8+ T cells

    Science.gov (United States)

    Marshall, Dana R.; Turner, Stephen J.; Belz, Gabrielle T.; Wingo, Suzette; Andreansky, Samita; Sangster, Mark Y.; Riberdy, Janice M.; Liu, Tiebin; Tan, Ming; Doherty, Peter C.

    2001-01-01

    The CD8+ T cell diaspora has been analyzed after secondary challenge with an influenza A virus that replicates only in the respiratory tract. Numbers of DbNP366- and DbPA224-specific CD8+ T cells were measured by tetramer staining at the end of the recall response, then followed sequentially in the lung, lymph nodes, spleen, blood, and other organs. The extent of clonal expansion did not reflect the sizes of the preexisting memory T cell pools. Although the high-frequency CD8+ tetramer+ populations in the pneumonic lung and mediastinal lymph nodes fell rapidly from peak values, the “whole mouse” virus-specific CD8+ T cell counts decreased only 2-fold over the 4 weeks after infection, then subsided at a fairly steady rate to reach a plateau at about 2 months. The largest numbers were found throughout in the spleen, then the bone marrow. The CD8+DbNP366+ and CD8+DbPA224+ sets remained significantly enlarged for at least 4 months, declining at equivalent rates while retaining the nucleoprotein > acid polymerase immunodominance hierarchy characteristic of the earlier antigen-driven phase. Lowest levels of the CD69 “activation marker” were detected consistently on virus-specific CD8+ T cells in the blood, then the spleen. Those in the bone marrow and liver were intermediate, and CD69hi T cells were very prominent in the regional lymph nodes and the nasal-associated lymphoid tissue. Any population of “resting” CD8+ memory T cells is thus phenotypically heterogeneous, widely dispersed, and subject to broad homeostatic and local environmental effects irrespective of epitope specificity or magnitude. PMID:11344265

  11. Identification and HLA-Tetramer-Validation of Human CD4(+) and CD8(+) T Cell Responses against HCMV Proteins IE1 and IE2

    DEFF Research Database (Denmark)

    Braendstrup, Peter; Mortensen, Bo Kok; Justesen, Sune Frederik Lamdahl

    2014-01-01

    tumor development. Both CD4(+) and CD8(+) T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8(+) T cell...

  12. The CD8 T Cell Response to Respiratory Virus Infections.

    Science.gov (United States)

    Schmidt, Megan E; Varga, Steven M

    2018-01-01

    Humans are highly susceptible to infection with respiratory viruses including respiratory syncytial virus (RSV), influenza virus, human metapneumovirus, rhinovirus, coronavirus, and parainfluenza virus. While some viruses simply cause symptoms of the common cold, many respiratory viruses induce severe bronchiolitis, pneumonia, and even death following infection. Despite the immense clinical burden, the majority of the most common pulmonary viruses lack long-lasting efficacious vaccines. Nearly all current vaccination strategies are designed to elicit broadly neutralizing antibodies, which prevent severe disease following a subsequent infection. However, the mucosal antibody response to many respiratory viruses is not long-lasting and declines with age. CD8 T cells are critical for mediating clearance following many acute viral infections in the lung. In addition, memory CD8 T cells are capable of providing protection against secondary infections. Therefore, the combined induction of virus-specific CD8 T cells and antibodies may provide optimal protective immunity. Herein, we review the current literature on CD8 T cell responses induced by respiratory virus infections. Additionally, we explore how this knowledge could be utilized in the development of future vaccines against respiratory viruses, with a special emphasis on RSV vaccination.

  13. CD4+ T cell effects on CD8+ T cell location defined using bioluminescence.

    Directory of Open Access Journals (Sweden)

    Mitra Azadniv

    2011-01-01

    Full Text Available T lymphocytes of the CD8+ class are critical in delivering cytotoxic function and in controlling viral and intracellular infections. These cells are "helped" by T lymphocytes of the CD4+ class, which facilitate their activation, clonal expansion, full differentiation and the persistence of memory. In this study we investigated the impact of CD4+ T cells on the location of CD8+ T cells, using antibody-mediated CD4+ T cell depletion and imaging the antigen-driven redistribution of bioluminescent CD8+ T cells in living mice. We documented that CD4+ T cells influence the biodistribution of CD8+ T cells, favoring their localization to abdominal lymph nodes. Flow cytometric analysis revealed that this was associated with an increase in the expression of specific integrins. The presence of CD4+ T cells at the time of initial CD8+ T cell activation also influences their biodistribution in the memory phase. Based on these results, we propose the model that one of the functions of CD4+ T cell "help" is to program the homing potential of CD8+ T cells.

  14. Cytokines and the Inception of CD8 T Cell Responses

    Science.gov (United States)

    Cox, Maureen A.; Harrington, Laurie E.; Zajac, Allan J.

    2011-01-01

    The activation and differentiation of CD8 T cells is a necessary first step that endows these cells with the phenotypic and functional properties required for the control of intracellular pathogens. The induction of the CD8 T cell responses typically results in the development of a massive overall population of effector cells, comprised of both highly functional but short-lived terminally differentiated cells, as well as a smaller subset of precursors that are predisposed to survive and transition into the memory T cell pool. In this article we discuss how inflammatory cytokines and IL-2 bias the initial response towards short-lived effector generation and also highlight the potential counterbalancing role of IL-21. PMID:21371940

  15. Prolonged activation of virus-specific CD8+T cells after acute B19 infection.

    Directory of Open Access Journals (Sweden)

    Adiba Isa

    2005-12-01

    Full Text Available Human parvovirus B19 (B19 is a ubiquitous and clinically significant pathogen, causing erythema infectiosum, arthropathy, transient aplastic crisis, and intrauterine fetal death. The phenotype of CD8+ T cells in acute B19 infection has not been studied previously.The number and phenotype of B19-specific CD8+ T cell responses during and after acute adult infection was studied using HLA-peptide multimeric complexes. Surprisingly, these responses increased in magnitude over the first year post-infection despite resolution of clinical symptoms and control of viraemia, with T cell populations specific for individual epitopes comprising up to 4% of CD8+ T cells. B19-specific T cells developed and maintained an activated CD38+ phenotype, with strong expression of perforin and CD57 and downregulation of CD28 and CD27. These cells possessed strong effector function and intact proliferative capacity. Individuals tested many years after infection exhibited lower frequencies of B19-specific cytotoxic T lymphocytes, typically 0.05%-0.5% of CD8+ T cells, which were perforin, CD38, and CCR7 low.This is the first example to our knowledge of an "acute" human viral infection inducing a persistent activated CD8+ T cell response. The likely explanation--analogous to that for cytomegalovirus infection--is that this persistent response is due to low-level antigen exposure. CD8+ T cells may contribute to the long-term control of this significant pathogen and should be considered during vaccine development.

  16. Prolonged activation of virus-specific CD8+T cells after acute B19 infection.

    Directory of Open Access Journals (Sweden)

    2005-12-01

    Full Text Available BACKGROUND: Human parvovirus B19 (B19 is a ubiquitous and clinically significant pathogen, causing erythema infectiosum, arthropathy, transient aplastic crisis, and intrauterine fetal death. The phenotype of CD8+ T cells in acute B19 infection has not been studied previously. METHODS AND FINDINGS: The number and phenotype of B19-specific CD8+ T cell responses during and after acute adult infection was studied using HLA-peptide multimeric complexes. Surprisingly, these responses increased in magnitude over the first year post-infection despite resolution of clinical symptoms and control of viraemia, with T cell populations specific for individual epitopes comprising up to 4% of CD8+ T cells. B19-specific T cells developed and maintained an activated CD38+ phenotype, with strong expression of perforin and CD57 and downregulation of CD28 and CD27. These cells possessed strong effector function and intact proliferative capacity. Individuals tested many years after infection exhibited lower frequencies of B19-specific cytotoxic T lymphocytes, typically 0.05%-0.5% of CD8+ T cells, which were perforin, CD38, and CCR7 low. CONCLUSION: This is the first example to our knowledge of an "acute" human viral infection inducing a persistent activated CD8+ T cell response. The likely explanation--analogous to that for cytomegalovirus infection--is that this persistent response is due to low-level antigen exposure. CD8+ T cells may contribute to the long-term control of this significant pathogen and should be considered during vaccine development.

  17. HLA-A*0201-restricted CD8+ cytotoxic T lymphocyte epitopes identified from herpes simplex virus glycoprotein D

    DEFF Research Database (Denmark)

    Chentoufi, Aziz Alami; Zhang, Xiuli; Lamberth, Kasper

    2008-01-01

    Evidence obtained from both animal models and humans suggests that T cells specific for HSV-1 and HSV-2 glycoprotein D (gD) contribute to protective immunity against herpes infection. However, knowledge of gD-specific human T cell responses is limited to CD4+ T cell epitopes, with no CD8+ T cell ...... following ocular or genital infection with either HSV-1 or HSV-2. The functional gD CD8+ T cell epitopes described herein are potentially important components of clinical immunotherapeutic and immunoprophylactic herpes vaccines.......Evidence obtained from both animal models and humans suggests that T cells specific for HSV-1 and HSV-2 glycoprotein D (gD) contribute to protective immunity against herpes infection. However, knowledge of gD-specific human T cell responses is limited to CD4+ T cell epitopes, with no CD8+ T cell...

  18. Human Asymptomatic Epitope Peptide/CXCL10-Based Prime/Pull Vaccine Induces Herpes Simplex Virus-Specific Gamma Interferon-Positive CD107+ CD8+ T Cells That Infiltrate the Cornea and Trigeminal Ganglia of Humanized HLA Transgenic Rabbits and Protect against Ocular Herpes Challenge.

    Science.gov (United States)

    Khan, Arif A; Srivastava, Ruchi; Vahed, Hawa; Roy, Soumyabrata; Walia, Sager S; Kim, Grace J; Fouladi, Mona A; Yamada, Taikun; Ly, Vincent T; Lam, Cynthia; Lou, Anthony; Nguyen, Vivianna; Boldbaatar, Undariya; Geertsema, Roger; Fraser, Nigel W; BenMohamed, Lbachir

    2018-06-13

    Herpes simplex virus 1 (HSV-1) is a prevalent human pathogen that infects the cornea causing potentially blinding herpetic disease. A clinical herpes vaccine is still lacking. In the present study, a novel prime/pull vaccine was tested in Human Leukocyte Antigen- (HLA-) transgenic rabbit model of ocular herpes (HLA Tg rabbit). Three asymptomatic (ASYMP) peptide epitopes were selected from the HSV-1 membrane glycoprotein C (UL44 400-408 ), the DNA replication binding helicase (UL9 196-204 ), and the tegument protein (UL25 572-580 ), all preferentially recognized by CD8 + T cells from "naturally protected" HSV-1-seropositive healthy ASYMP individuals (who never had recurrent corneal herpetic disease). HLA Tg rabbits were immunized with a mixture of these three ASYMP CD8 + T cell peptide epitopes (UL44 400-408 , UL9 196-204 and UL25 572-580 ), delivered subcutaneously with CpG 2007 adjuvant (prime). Fifteen days later, half of the rabbits received a topical ocular treatment with a recombinant neurotropic AAV8 vector, expressing the T cell-attracting CXCL10 chemokine (pull). The frequency, function of HSV-specific CD8 + T cells induced by the prime/pull vaccine were assessed in peripheral blood, cornea, and trigeminal ganglia (TG). Compared to peptides alone, the peptides/CXCL10 prime/pull vaccine generated frequent polyfunctional gamma interferon-positive (IFN-γ + ) CD107 + CD8 + T cells that infiltrated both the cornea and TG. CD8 + T cells mobilization into cornea and TG of prime/pull- vaccinated rabbits was associated with a significant reduction in corneal herpes infection and disease following an ocular HSV-1 challenge (McKrae). These findings draw attention to the novel prime/pull vaccine strategy to mobilize anti-viral CD8 + T cells into tissues protecting them against herpes infection and disease. IMPORTANCE There is an urgent need for a vaccine against widespread herpes simplex virus infections. The present study demonstrates that immunization of HLA

  19. Protective Role of Cross-Reactive CD8 T Cells Against Dengue Virus Infection

    Directory of Open Access Journals (Sweden)

    Annie Elong Ngono

    2016-11-01

    Full Text Available Infection with one of the four dengue virus serotypes (DENV1-4 presumably leads to lifelong immunity against the infecting serotype but not against heterotypic reinfection, resulting in a greater risk of developing Dengue Hemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS during secondary infection. Both antibodies and T cell responses have been implicated in DHF/DSS pathogenesis. According to the T cell-based hypothesis termed “original antigenic sin,” secondary DENV infection is dominated by non-protective, cross-reactive T cells that elicit an aberrant immune response. The goal of our study was to compare the roles of serotype-specific and cross-reactive T cells in protection vs. pathogenesis during DENV infection in vivo. Specifically, we utilized IFN-α/βR−/− HLA*B0702 transgenic mice in the context of peptide vaccination with relevant human CD8 T cell epitopes. IFN-α/βR−/− HLA*B0702 transgenic mice were immunized with DENV serotype 2 (DENV2-specific epitopes or variants found in any of the other three serotypes (DENV1, DENV3 or DENV4, followed by challenge with DENV. Although cross-reactive T cell responses were lower than responses elicited by serotype-specific T cells, immunization with either serotype-specific or variant peptide epitopes enhanced viral clearance, demonstrating that both serotype-specific and cross-reactive T cells can contribute to protection in vivo against DENV infection.

  20. Cross-reactive microbial peptides can modulate HIV-specific CD8+ T cell responses.

    Directory of Open Access Journals (Sweden)

    Christopher W Pohlmeyer

    Full Text Available Heterologous immunity is an important aspect of the adaptive immune response. We hypothesized that this process could modulate the HIV-1-specific CD8+ T cell response, which has been shown to play an important role in HIV-1 immunity and control. We found that stimulation of peripheral blood mononuclear cells (PBMCs from HIV-1-positive subjects with microbial peptides that were cross-reactive with immunodominant HIV-1 epitopes resulted in dramatic expansion of HIV-1-specific CD8+ T cells. Interestingly, the TCR repertoire of HIV-1-specific CD8+ T cells generated by ex vivo stimulation of PBMCs using HIV-1 peptide was different from that of cells stimulated with cross-reactive microbial peptides in some HIV-1-positive subjects. Despite these differences, CD8+ T cells stimulated with either HIV-1 or cross-reactive peptides effectively suppressed HIV-1 replication in autologous CD4+ T cells. These data suggest that exposure to cross-reactive microbial antigens can modulate HIV-1-specific immunity.

  1. A viral long terminal repeat expressed in CD4+CD8+ precursors is downregulated in mature peripheral CD4-CD8+ or CD4+CD8- T cells.

    OpenAIRE

    Paquette, Y; Doyon, L; Laperrière, A; Hanna, Z; Ball, J; Sekaly, R P; Jolicoeur, P

    1992-01-01

    The long terminal repeat from a thymotropic mouse mammary tumor virus variant, DMBA-LV, was used to drive the expression of two reporter genes, murine c-myc and human CD4, in transgenic mice. Expression was observed specifically in thymic immature cells. Expression of c-myc in these cells induced oligoclonal CD4+ CD8+ T-cell thymomas. Expression of human CD4 was restricted to thymic progenitor CD4- CD8- and CD4+ CD8+ T cells and was shut off in mature CD4+ CD8- and CD4- CD8+ T cells, known to...

  2. A highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirus B19 infection in HLA-A*2402-positive individuals

    DEFF Research Database (Denmark)

    Kasprowicz, V; Isa, Adiba; Jeffery, K

    2006-01-01

    Six of seven HLA-A*2402-positive individuals with acute parvovirus B19 infections made vigorous CD8-positive cytotoxic T-cell (CTL) responses to the viral epitope FYTPLADQF. All responders showed highly focused T-cell receptor (TCR) usage, using almost exclusively BV5.1. The BV5.1 TCR dominated...

  3. Decline of influenza-specific CD8+ T cell repertoire in healthy geriatric donors

    Directory of Open Access Journals (Sweden)

    Ramachandra Lakshmi

    2011-08-01

    Full Text Available Abstract Background While influenza vaccination results in protective antibodies against primary infections, clearance of infection is primarily mediated through CD8+ T cells. Studying the CD8+ T cell response to influenza epitopes is crucial in understanding the disease associated morbidity and mortality especially in at risk populations such as the elderly. We compared the CD8+ T cell response to immunodominant and subdominant influenza epitopes in HLA-A2+ control, adult donors, aged 21-42, and in geriatric donors, aged 65 and older. Results We used a novel artificial Antigen Presenting Cell (aAPC based stimulation assay to reveal responses that could not be detected by enzyme-linked immunosorbent spot (ELISpot. 14 younger control donors and 12 geriatric donors were enrolled in this study. The mean number of influenza-specific subdominant epitopes per control donor detected by ELISpot was only 1.4 while the mean detected by aAPC assay was 3.3 (p = 0.0096. Using the aAPC assay, 92% of the control donors responded to at least one subdominant epitopes, while 71% of control donors responded to more than one subdominant influenza-specific response. 66% of geriatric donors lacked a subdominant influenza-specific response and 33% of geriatric donors responded to only 1 subdominant epitope. The difference in subdominant response between age groups is statistically significant (p = 0.0003. Conclusion Geriatric donors lacked the broad, multi-specific response to subdominant epitopes seen in the control donors. Thus, we conclude that aging leads to a decrease in the subdominant influenza-specific CTL responses which may contribute to the increased morbidity and mortality in older individuals.

  4. Peptide pool immunization and CD8+ T cell reactivity

    DEFF Research Database (Denmark)

    Rasmussen, Susanne B; Harndahl, Mikkel N; Buus, Anette Stryhn

    2013-01-01

    Mice were immunized twice with a pool of five peptides selected among twenty 8-9-mer peptides for their ability to form stable complexes at 37°C with recombinant H-2K(b) (half-lives 10-15h). Vaccine-induced immunity of splenic CD8(+) T cells was studied in a 24h IFNγ Elispot assay. Surprisingly...... peptides induced normal peptide immunity i.e. the specific T cell reactivity in the Elispot culture was strictly dependent on exposure to the immunizing peptide ex vivo. However, immunization with two of the peptides, a VSV- and a Mycobacterium-derived peptide, resulted in IFNγ spot formation without...... peptide in the Elispot culture. Immunization with a mixture of the VSV-peptide and a "normal" peptide also resulted in IFNγ spot formation without addition of peptide to the assay culture. Peptide-tetramer staining of CD8(+) T cells from mice immunized with a mixture of VSV-peptide and "normal" peptide...

  5. Empty conformers of HLA-B preferentially bind CD8 and regulate CD8+ T cell function.

    Science.gov (United States)

    Geng, Jie; Altman, John D; Krishnakumar, Sujatha; Raghavan, Malini

    2018-05-09

    When complexed with antigenic peptides, human leukocyte antigen (HLA) class I (HLA-I) molecules initiate CD8 + T cell responses via interaction with the T cell receptor (TCR) and co-receptor CD8. Peptides are generally critical for the stable cell surface expression of HLA-I molecules. However, for HLA-I alleles such as HLA-B*35:01, peptide-deficient (empty) heterodimers are thermostable and detectable on the cell surface. Additionally, peptide-deficient HLA-B*35:01 tetramers preferentially bind CD8 and to a majority of blood-derived CD8 + T cells via a CD8-dependent binding mode. Further functional studies reveal that peptide-deficient conformers of HLA-B*35:01 do not directly activate CD8 + T cells, but accumulate at the immunological synapse in antigen-induced responses, and enhance cognate peptide-induced cell adhesion and CD8 + T cell activation. Together, these findings indicate that HLA-I peptide occupancy influences CD8 binding affinity, and reveal a new set of regulators of CD8 + T cell activation, mediated by the binding of empty HLA-I to CD8. © 2018, Geng et al.

  6. Weak anti-HIV CD8+ T-cell effector activity in HIV primary infection

    Science.gov (United States)

    Dalod, Marc; Dupuis, Marion; Deschemin, Jean-Christophe; Goujard, Cécile; Deveau, Christiane; Meyer, Laurence; Ngo, Nicole; Rouzioux, Christine; Guillet, Jean-Gérard; Delfraissy, Jean-François; Sinet, Martine; Venet, Alain

    1999-01-01

    HIV-specific CD8+ T cells play a major role in the control of virus during HIV primary infection (PI) but do not completely prevent viral replication. We used IFN-γ enzyme-linked immunospot assay and intracellular staining to characterize the ex vivo CD8+ T-cell responses to a large variety of HIV epitopic peptides in 24 subjects with early HIV PI. We observed HIV-specific responses in 71% of subjects. Gag and Nef peptides were more frequently recognized than Env and Pol peptides. The number of peptides recognized was low (median 2, range 0–6). In contrast, a much broader response was observed in 30 asymptomatic subjects with chronic infection: all were responders with a median of 5 peptides recognized (range 1–13). The frequency of HIV-specific CD8+ T cells among PBMC for a given peptide was of the same order of magnitude in both groups. The proportion of HIV-specific CD8+CD28– terminally differentiated T cells was much lower in PI than at the chronic stage of infection. The weakness of the immune response during HIV PI could partially account for the failure to control HIV. These findings have potential importance for defining immunotherapeutic strategies and establishing the goals for effective vaccination. J. Clin. Invest. 104:1431–1439 (1999). PMID:10562305

  7. CD8+ T cells in human autoimmune arthritis : The unusual suspects

    NARCIS (Netherlands)

    Petrelli, Alessandra; Van Wijk, Femke

    2016-01-01

    CD8+ T cells are key players in the body's defence against viral infections and cancer. To date, data on the role of CD8+ T cells in autoimmune diseases have been scarce, especially when compared with the wealth of research on CD4+ T cells. However, growing evidence suggests that CD8+ T-cell

  8. Targeting CD8+ T-cell tolerance for cancer immunotherapy.

    Science.gov (United States)

    Jackson, Stephanie R; Yuan, Jinyun; Teague, Ryan M

    2014-01-01

    In the final issue of Science in 2013, the American Association of Science recognized progress in the field of cancer immunotherapy as the 'Breakthrough of the Year.' The achievements were actually twofold, owing to the early success of genetically engineered chimeric antigen receptors (CAR) and to the mounting clinical triumphs achieved with checkpoint blockade antibodies. While fundamentally very different, the common thread of these independent strategies is the ability to prevent or overcome mechanisms of CD8(+) T-cell tolerance for improved tumor immunity. Here we discuss how circumventing T-cell tolerance has provided experimental insights that have guided the field of clinical cancer immunotherapy to a place where real breakthroughs can finally be claimed.

  9. CD4/CD8/Dendritic cell complexes in the spleen: CD8+ T cells can directly bind CD4+ T cells and modulate their response

    Science.gov (United States)

    Barinov, Aleksandr; Galgano, Alessia; Krenn, Gerald; Tanchot, Corinne; Vasseur, Florence

    2017-01-01

    CD4+ T cell help to CD8+ T cell responses requires that CD4+ and CD8+ T cells interact with the same antigen presenting dendritic cell (Ag+DC), but it remains controversial whether helper signals are delivered indirectly through a licensed DC and/or involve direct CD4+/CD8+ T cell contacts and/or the formation of ternary complexes. We here describe the first in vivo imaging of the intact spleen, aiming to evaluate the first interactions between antigen-specific CD4+, CD8+ T cells and Ag+DCs. We show that in contrast to CD4+ T cells which form transient contacts with Ag+DC, CD8+ T cells form immediate stable contacts and activate the Ag+DC, acquire fragments of the DC membranes by trogocytosis, leading to their acquisition of some of the DC properties. They express MHC class II, and become able to present the specific Marilyn peptide to naïve Marilyn CD4+ T cells, inducing their extensive division. In vivo, these CD8+ T cells form direct stable contacts with motile naïve CD4+ T cells, recruiting them to Ag+DC binding and to the formation of ternary complexes, where CD4+ and CD8+ T cells interact with the DC and with one another. The presence of CD8+ T cells during in vivo immune responses leads to the early activation and up-regulation of multiple functions by CD4+ T lymphocytes. Thus, while CD4+ T cell help is important to CD8+ T cell responses, CD8+ T cells can interact directly with naïve CD4+ T cells impacting their recruitment and differentiation. PMID:28686740

  10. CD8αα expression marks terminally differentiated human CD8+ T cells expanded in chronic viral infection

    Directory of Open Access Journals (Sweden)

    Lucy Jane Walker

    2013-08-01

    Full Text Available The T cell co-receptor CD8αβ enhances T cell sensitivity to antigen, however studies indicate CD8αα has the converse effect and acts as a co-repressor. Using a combination of Thymic Leukaemia antigen (TL tetramer, which directly binds CD8αα, anti-CD161 and anti-Vα7.2 antibodies we have been able for the first time to clearly define CD8αα expression on human CD8 T cells subsets. In healthy controls CD8αα is most highly expressed by CD161 bright (CD161++ mucosal associated invariant T (MAIT cells, with CD8αα expression highly restricted to the TCR Vα7.2+ cells of this subset. We also identified CD8αα-expressing populations within the CD161 mid (CD161+ and negative (CD161- non-MAIT CD8 T cell subsets and show TL-tetramer binding to correlate with expression of CD8β at low levels in the context of maintained CD8α expression (CD8α+CD8βlow. In addition, we found CD161-CD8α+CD8βlow populations to be significantly expanded in the peripheral blood of HIV-1 and hepatitis B (mean of 47% and 40% of CD161- T cells respectively infected individuals. Such CD8αα expressing T cells are an effector-memory population (CD45RA-, CCR7-, CD62L- that express markers of activation and maturation (HLA-DR+, CD28-, CD27-, CD57+ and are functionally distinct, expressing greater levels of TNF-α and IFN-γ on stimulation and perforin at rest than their CD8α+CD8βhigh counterparts. Antigen-specific T cells in HLA-B*4201+HIV-1 infected patients are found within both the CD161-CD8α+CD8βhigh and CD161-CD8α+CD8βlow populations. Overall we have clearly defined CD8αα expressing human T cell subsets using the TL-tetramer, and have demonstrated CD161-CD8α+CD8βlow populations, highly expanded in disease settings, to co-express CD8αβ and CD8αα. Co-expression of CD8αα on CD8αβ T cells may impact on their overall function in-vivo and contribute to the distinctive phenotype of highly differentiated populations in HBV and HIV-1 infection.

  11. Identification of immediate early gene products of bovine herpes virus 1 (BHV-1) as dominant antigens recognized by CD8 T cells in immune cattle

    DEFF Research Database (Denmark)

    Hart, Jane; MacHugh, Niall D.; Sheldrake, Tara

    2017-01-01

    candidate viral gene products with CD8 T-cell lines from 3 BHV-1-immune cattle of defined MHC genotypes identified 4 antigens, including 3 immediate early (IE) gene products (ICP4, ICP22 and Circ) and a tegument protein (UL49). Identification of the MHC restriction specificities revealed that the antigens...... cases refined, the identity of the epitopes. Analyses of the epitope specificity of the CD8 T-cell lines showed that a large component of the response is directed against these IE epitopes. The results indicate that these IE gene products are dominant targets of the CD8 T-cell response in BHV...

  12. The administration route is decisive for the ability of the vaccine adjuvant CAF09 to induce antigen-specific CD8(+) T-cell responses

    DEFF Research Database (Denmark)

    Schmidt, Signe Tandrup; Khadke, Swapnil; Korsholm, Karen Smith

    2016-01-01

    A prerequisite for vaccine-mediated induction of CD8(+) T-cell responses is the targeting of dendritic cell (DC) subsets specifically capable of cross-presenting antigen epitopes to CD8(+) T cells. Administration of a number of cationic adjuvants via the intraperitoneal (i.p.) route has been show...

  13. Killing of targets by effector CD8 T cells in the mouse spleen follows the law of mass action

    Energy Technology Data Exchange (ETDEWEB)

    Ganusov, Vitaly V [Los Alamos National Laboratory

    2009-01-01

    In contrast with antibody-based vaccines, it has been difficult to measure the efficacy of T cell-based vaccines and to correlate the efficacy of CD8 T cell responses with protection again viral infections. In part, this difficulty is due to poor understanding of the in vivo efficacy of CD8 T cells produced by vaccination. Using a: recently developed experimental method of in vivo cytotoxicity we have investigated quantitative aspects of killing of peptide-pulsed targets by effector and memory CD8 T cells, specific to three epitopes of lymphocytic choriomeningitis virus (LCMV), in the mouse spleen. By analyzing data on killing of targets with varying number of epitope-specific effector and memory CD8 T cells, we find that killing of targets by effectors follows the law of mass-action, that is the death rate of peptide-pulsed targets is proportional to the frequency of CTLs in the spleen. In contrast, killing of targets by memory CD8 T cells does not follow the mass action law because the death rate of targets saturates at high frequencies of memory CD8 T cells. For both effector and memory cells, we also find little support for the killing term that includes the decrease of the death rate of targets with target cell density. Interestingly, our analysis suggests that at low CD8 T cell frequencies, memory CD8 T cells on the per capita basis are more efficient at killing peptide-pulsed targets than effectors, but at high frequencies, effectors are more efficient killers than memory T cells. Comparison of the estimated killing efficacy of effector T cells with the value that is predicted from theoretical physics and based on motility of T cells in lymphoid tissues, suggests that limiting step in the killing of peptide-pulsed targets is delivering the lethal hit and not finding the target. Our results thus form a basis for quantitative understanding of the process of killing of virus-infected cells by T cell responses in tissues and can be used to correlate the

  14. Differential immunodominance hierarchy of CD8+ T-cell responses in HLA-B*27

    DEFF Research Database (Denmark)

    Adland, Emily; Hill, Matilda; Lavandier, Nora

    2018-01-01

    The well-characterized association between HLA-B*27:05 and protection against HIV disease progression has been linked to immunodominant HLA-B*27:05- restricted CD8+ T-cell responses toward the conserved Gag KK10 (residues 263 to 272) and polymerase (Pol) KY9 (residues 901 to 909) epitopes. We stu...

  15. Increased numbers of preexisting memory CD8 T cells and decreased T-bet expression can restrain terminal differentiation of secondary effector and memory CD8 T cells.

    Science.gov (United States)

    Joshi, Nikhil S; Cui, Weiguo; Dominguez, Claudia X; Chen, Jonathan H; Hand, Timothy W; Kaech, Susan M

    2011-10-15

    Memory CD8 T cells acquire effector memory cell properties after reinfection and may reach terminally differentiated, senescent states ("Hayflick limit") after multiple infections. The signals controlling this process are not well understood, but we found that the degree of secondary effector and memory CD8 T cell differentiation was intimately linked to the amount of T-bet expressed upon reactivation and preexisting memory CD8 T cell number (i.e., primary memory CD8 T cell precursor frequency) present during secondary infection. Compared with naive cells, memory CD8 T cells were predisposed toward terminal effector (TE) cell differentiation because they could immediately respond to IL-12 and induce T-bet, even in the absence of Ag. TE cell formation after secondary (2°) or tertiary infections was dependent on increased T-bet expression because T-bet(+/-) cells were resistant to these phenotypic changes. Larger numbers of preexisting memory CD8 T cells limited the duration of 2° infection and the amount of IL-12 produced, and consequently, this reduced T-bet expression and the proportion of 2° TE CD8 T cells that formed. Together, these data show that over repeated infections, memory CD8 T cell quality and proliferative fitness is not strictly determined by the number of serial encounters with Ag or cell divisions, but is a function of the CD8 T cell differentiation state, which is genetically controlled in a T-bet-dependent manner. This differentiation state can be modulated by preexisting memory CD8 T cell number and the intensity of inflammation during reinfection. These results have important implications for vaccinations involving prime-boost strategies.

  16. Cytomegalovirus vector expressing RAE-1γ induces enhanced anti-tumor capacity of murine CD8+ T cells.

    Science.gov (United States)

    Tršan, Tihana; Vuković, Kristina; Filipović, Petra; Brizić, Ana Lesac; Lemmermann, Niels A W; Schober, Kilian; Busch, Dirk H; Britt, William J; Messerle, Martin; Krmpotić, Astrid; Jonjić, Stipan

    2017-08-01

    Designing CD8 + T-cell vaccines, which would provide protection against tumors is still considered a great challenge in immunotherapy. Here we show the robust potential of cytomegalovirus (CMV) vector expressing the NKG2D ligand RAE-1γ as CD8 + T cell-based vaccine against malignant tumors. Immunization with the CMV vector expressing RAE-1γ, delayed tumor growth or even provided complete protection against tumor challenge in both prophylactic and therapeutic settings. Moreover, a potent tumor control in mice vaccinated with this vector can be further enhanced by blocking the immune checkpoints TIGIT and PD-1. CMV vector expressing RAE-1γ potentiated expansion of KLRG1 + CD8 + T cells with enhanced effector properties. This vaccination was even more efficient in neonatal mice, resulting in the expansion and long-term maintenance of epitope-specific CD8 + T cells conferring robust resistance against tumor challenge. Our data show that immunomodulation of CD8 + T-cell responses promoted by herpesvirus expressing a ligand for NKG2D receptor can provide a powerful platform for the prevention and treatment of CD8 + T-cell sensitive tumors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. TCR stimulation strength is inversely associated with establishment of functional brain-resident memory CD8 T cells during persistent viral infection.

    Science.gov (United States)

    Maru, Saumya; Jin, Ge; Schell, Todd D; Lukacher, Aron E

    2017-04-01

    Establishing functional tissue-resident memory (TRM) cells at sites of infection is a newfound objective of T cell vaccine design. To directly assess the impact of antigen stimulation strength on memory CD8 T cell formation and function during a persistent viral infection, we created a library of mouse polyomavirus (MuPyV) variants with substitutions in a subdominant CD8 T cell epitope that exhibit a broad range of efficiency in stimulating TCR transgenic CD8 T cells. By altering a subdominant epitope in a nonstructural viral protein and monitoring memory differentiation of donor monoclonal CD8 T cells in immunocompetent mice, we circumvented potentially confounding changes in viral infection levels, virus-associated inflammation, size of the immunodominant virus-specific CD8 T cell response, and shifts in TCR affinity that may accompany temporal recruitment of endogenous polyclonal cells. Using this strategy, we found that antigen stimulation strength was inversely associated with the function of memory CD8 T cells during a persistent viral infection. We further show that CD8 TRM cells recruited to the brain following systemic infection with viruses expressing epitopes with suboptimal stimulation strength respond more efficiently to challenge CNS infection with virus expressing cognate antigen. These data demonstrate that the strength of antigenic stimulation during recruitment of CD8 T cells influences the functional integrity of TRM cells in a persistent viral infection.

  18. TCR stimulation strength is inversely associated with establishment of functional brain-resident memory CD8 T cells during persistent viral infection.

    Directory of Open Access Journals (Sweden)

    Saumya Maru

    2017-04-01

    Full Text Available Establishing functional tissue-resident memory (TRM cells at sites of infection is a newfound objective of T cell vaccine design. To directly assess the impact of antigen stimulation strength on memory CD8 T cell formation and function during a persistent viral infection, we created a library of mouse polyomavirus (MuPyV variants with substitutions in a subdominant CD8 T cell epitope that exhibit a broad range of efficiency in stimulating TCR transgenic CD8 T cells. By altering a subdominant epitope in a nonstructural viral protein and monitoring memory differentiation of donor monoclonal CD8 T cells in immunocompetent mice, we circumvented potentially confounding changes in viral infection levels, virus-associated inflammation, size of the immunodominant virus-specific CD8 T cell response, and shifts in TCR affinity that may accompany temporal recruitment of endogenous polyclonal cells. Using this strategy, we found that antigen stimulation strength was inversely associated with the function of memory CD8 T cells during a persistent viral infection. We further show that CD8 TRM cells recruited to the brain following systemic infection with viruses expressing epitopes with suboptimal stimulation strength respond more efficiently to challenge CNS infection with virus expressing cognate antigen. These data demonstrate that the strength of antigenic stimulation during recruitment of CD8 T cells influences the functional integrity of TRM cells in a persistent viral infection.

  19. CD4+CD25+ regulatory T cells control CD8+ T-cell effector differentiation by modulating IL-2 homeostasis

    Science.gov (United States)

    McNally, Alice; Hill, Geoffrey R.; Sparwasser, Tim; Thomas, Ranjeny; Steptoe, Raymond J.

    2011-01-01

    CD4+CD25+ regulatory T cells (Treg) play a crucial role in the regulation of immune responses. Although many mechanisms of Treg suppression in vitro have been described, the mechanisms by which Treg modulate CD8+ T cell differentiation and effector function in vivo are more poorly defined. It has been proposed, in many instances, that modulation of cytokine homeostasis could be an important mechanism by which Treg regulate adaptive immunity; however, direct experimental evidence is sparse. Here we demonstrate that CD4+CD25+ Treg, by critically regulating IL-2 homeostasis, modulate CD8+ T-cell effector differentiation. Expansion and effector differentiation of CD8+ T cells is promoted by autocrine IL-2 but, by competing for IL-2, Treg limit CD8+ effector differentiation. Furthermore, a regulatory loop exists between Treg and CD8+ effector T cells, where IL-2 produced during CD8+ T-cell effector differentiation promotes Treg expansion. PMID:21502514

  20. Induction and maintenance of protective CD8+ T cells against malaria liver stages: implications for vaccine development

    Directory of Open Access Journals (Sweden)

    Sze-Wah Tse

    2011-08-01

    Full Text Available CD8+ T cells against malaria liver stages represent a major protective immune mechanism against infection. Following induction in the peripheral lymph nodes by dendritic cells (DCs, these CD8+ T cells migrate to the liver and eliminate parasite infected hepatocytes. The processing and presentation of sporozoite antigen requires TAP mediated transport of major histocompatibility complex class I epitopes to the endoplasmic reticulum. Importantly, in DCs this process is also dependent on endosome-mediated cross presentation while this mechanism is not required for epitope presentation on hepatocytes. Protective CD8+ T cell responses are strongly dependent on the presence of CD4+ T cells and the capacity of sporozoite antigen to persist for a prolonged period of time. While human trials with subunit vaccines capable of inducing antibodies and CD4+ T cell responses have yielded encouraging results, an effective anti-malaria vaccine will likely require vaccine constructs designed to induce protective CD8+ T cells against malaria liver stages.

  1. Protective antibody and CD8+ T-cell responses to the Plasmodium falciparum circumsporozoite protein induced by a nanoparticle vaccine.

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    Stephen A Kaba

    Full Text Available The worldwide burden of malaria remains a major public health problem due, in part, to the lack of an effective vaccine against the Plasmodium falciparum parasite. An effective vaccine will most likely require the induction of antigen specific CD8(+ and CD4(+ T-cells as well as long-lasting antibody responses all working in concert to eliminate the infection. We report here the effective modification of a self-assembling protein nanoparticle (SAPN vaccine previously proven effective in control of a P. berghei infection in a rodent model to now present B- and T-cell epitopes of the human malaria parasite P. falciparum in a platform capable of being used in human subjects.To establish the basis for a SAPN-based vaccine, B- and CD8(+ T-cell epitopes from the P. falciparum circumsporozoite protein (PfCSP and the universal CD4 T-helper epitope PADRE were engineered into a versatile small protein (∼125 amino acids that self-assembles into a spherical nanoparticle repetitively displaying the selected epitopes. P. falciparum epitope specific immune responses were evaluated in mice using a transgenic P. berghei malaria parasite of mice expressing the human malaria full-length P. falciparum circumsporozoite protein (Tg-Pb/PfCSP. We show that SAPN constructs, delivered in saline, can induce high-titer, long-lasting (1 year protective antibody and poly-functional (IFNγ(+, IL-2(+ long-lived central memory CD8(+ T-cells. Furthermore, we demonstrated that these Ab or CD8(+ T-cells can independently provide sterile protection against a lethal challenge of the transgenic parasites.The SAPN construct induces long-lasting antibody and cellular immune responses to epitope specific sequences of the P. falciparum circumsporozoite protein (PfCSP and prevents infection in mice by a transgenic P. berghei parasite displaying the full length PfCSP.

  2. Conventional CD4+ T cells present bacterial antigens to induce cytotoxic and memory CD8+ T cell responses.

    Science.gov (United States)

    Cruz-Adalia, Aránzazu; Ramirez-Santiago, Guillermo; Osuna-Pérez, Jesús; Torres-Torresano, Mónica; Zorita, Virgina; Martínez-Riaño, Ana; Boccasavia, Viola; Borroto, Aldo; Martínez Del Hoyo, Gloria; González-Granado, José María; Alarcón, Balbino; Sánchez-Madrid, Francisco; Veiga, Esteban

    2017-11-17

    Bacterial phagocytosis and antigen cross-presentation to activate CD8 + T cells are principal functions of professional antigen presenting cells. However, conventional CD4 + T cells also capture and kill bacteria from infected dendritic cells in a process termed transphagocytosis (also known as transinfection). Here, we show that transphagocytic T cells present bacterial antigens to naive CD8 + T cells, which proliferate and become cytotoxic in response. CD4 + T-cell-mediated antigen presentation also occurs in vivo in the course of infection, and induces the generation of central memory CD8 + T cells with low PD-1 expression. Moreover, transphagocytic CD4 + T cells induce protective anti-tumour immune responses by priming CD8 + T cells, highlighting the potential of CD4 + T cells as a tool for cancer immunotherapy.

  3. Incomplete effector/memory differentiation of antigen-primed CD8+ T cells in gene gun DNA-vaccinated mice

    DEFF Research Database (Denmark)

    Bartholdy, Christina; Stryhn, Anette; Hansen, Nils Jacob Vest

    2003-01-01

    DNA vaccination is an efficient way to induce CD8+ T cell memory, but it is still unclear to what extent such memory responses afford protection in vivo. To study this, we induced CD8+ memory responses directed towards defined viral epitopes, using DNA vaccines encoding immunodominant MHC class I......-restricted epitopes of lymphocytic choriomeningitis virus covalently linked to beta2-microglobulin. This vaccine construct primed for a stronger recall response than did a more conventional minigene construct. Despite this, vaccinated mice were only protected against systemic infection whereas protection against...... sites. Thus, our DNA vaccine induces a long-lived memory CD8+ T cell population that provides efficient protection against high-dose systemic infection. However, viral replication in solid non-lymphoid organs is not curtailed sufficiently fast to prevent significant virus-induced inflammation. Our...

  4. Comprehensive Analysis of CD8+-T-Cell Responses against Hepatitis C Virus Reveals Multiple Unpredicted Specificities

    OpenAIRE

    Lauer, Georg M.; Ouchi, Kei; Chung, Raymond T.; Nguyen, Tam N.; Day, Cheryl L.; Purkis, Deborah R.; Reiser, Markus; Kim, Arthur Y.; Lucas, Michaela; Klenerman, Paul; Walker, Bruce D.

    2002-01-01

    The hepatitis C virus (HCV)-specific CD8+-T-cell response is thought to play a critical role in HCV infection. Studies of these responses have largely relied on the analysis of a small number of previously described or predicted HCV epitopes, mostly restricted by HLA A2. In order to determine the actual breadth and magnitude of CD8+-T-cell responses in the context of diverse HLA class I alleles, we performed a comprehensive analysis of responses to all expressed HCV proteins. By using a panel...

  5. Local induction of immunosuppressive CD8+ T cells in the gut-associated lymphoid tissues.

    Directory of Open Access Journals (Sweden)

    Diana Fleissner

    Full Text Available BACKGROUND: In contrast to intestinal CD4(+ regulatory T cells (T(regs, the generation and function of immunomodulatory intestinal CD8(+ T cells is less well defined. To dissect the immunologic mechanisms of CD8(+ T cell function in the mucosa, reactivity against hemagglutinin (HA expressed in intestinal epithelial cells of mice bearing a MHC class-I-restricted T-cell-receptor specific for HA was studied. METHODOLOGY AND PRINCIPAL FINDINGS: HA-specific CD8(+ T cells were isolated from gut-associated tissues and phenotypically and functionally characterized for the expression of Foxp3(+ and their suppressive capacity. We demonstrate that intestinal HA expression led to peripheral induction of HA-specific CD8(+Foxp3(+ T cells. Antigen-experienced CD8(+ T cells in this transgenic mouse model suppressed the proliferation of CD8(+ and CD4(+ T cells in vitro. Gene expression analysis of suppressive HA-specific CD8(+ T cells revealed a specific up-regulation of CD103, Nrp1, Tnfrsf9 and Pdcd1, molecules also expressed on CD4(+ T(reg subsets. Finally, gut-associated dendritic cells were able to induce HA-specific CD8(+Foxp3(+ T cells. CONCLUSION AND SIGNIFICANCE: We demonstrate that gut specific antigen presentation is sufficient to induce CD8(+ T(regsin vivo which may maintain intestinal homeostasis by down-modulating effector functions of T cells.

  6. Local induction of immunosuppressive CD8+ T cells in the gut-associated lymphoid tissues.

    Science.gov (United States)

    Fleissner, Diana; Hansen, Wiebke; Geffers, Robert; Buer, Jan; Westendorf, Astrid M

    2010-10-20

    In contrast to intestinal CD4(+) regulatory T cells (T(regs)), the generation and function of immunomodulatory intestinal CD8(+) T cells is less well defined. To dissect the immunologic mechanisms of CD8(+) T cell function in the mucosa, reactivity against hemagglutinin (HA) expressed in intestinal epithelial cells of mice bearing a MHC class-I-restricted T-cell-receptor specific for HA was studied. HA-specific CD8(+) T cells were isolated from gut-associated tissues and phenotypically and functionally characterized for the expression of Foxp3(+) and their suppressive capacity. We demonstrate that intestinal HA expression led to peripheral induction of HA-specific CD8(+)Foxp3(+) T cells. Antigen-experienced CD8(+) T cells in this transgenic mouse model suppressed the proliferation of CD8(+) and CD4(+) T cells in vitro. Gene expression analysis of suppressive HA-specific CD8(+) T cells revealed a specific up-regulation of CD103, Nrp1, Tnfrsf9 and Pdcd1, molecules also expressed on CD4(+) T(reg) subsets. Finally, gut-associated dendritic cells were able to induce HA-specific CD8(+)Foxp3(+) T cells. We demonstrate that gut specific antigen presentation is sufficient to induce CD8(+) T(regs)in vivo which may maintain intestinal homeostasis by down-modulating effector functions of T cells.

  7. T Cell Receptor Vβ Staining Identifies the Malignant Clone in Adult T cell Leukemia and Reveals Killing of Leukemia Cells by Autologous CD8+ T cells.

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    Aileen G Rowan

    2016-11-01

    Full Text Available There is growing evidence that CD8+ cytotoxic T lymphocyte (CTL responses can contribute to long-term remission of many malignancies. The etiological agent of adult T-cell leukemia/lymphoma (ATL, human T lymphotropic virus type-1 (HTLV-1, contains highly immunogenic CTL epitopes, but ATL patients typically have low frequencies of cytokine-producing HTLV-1-specific CD8+ cells in the circulation. It remains unclear whether patients with ATL possess CTLs that can kill the malignant HTLV-1 infected clone. Here we used flow cytometric staining of TCRVβ and cell adhesion molecule-1 (CADM1 to identify monoclonal populations of HTLV-1-infected T cells in the peripheral blood of patients with ATL. Thus, we quantified the rate of CD8+-mediated killing of the putative malignant clone in ex vivo blood samples. We observed that CD8+ cells from ATL patients were unable to lyse autologous ATL clones when tested directly ex vivo. However, short in vitro culture restored the ability of CD8+ cells to kill ex vivo ATL clones in some donors. The capacity of CD8+ cells to lyse HTLV-1 infected cells which expressed the viral sense strand gene products was significantly enhanced after in vitro culture, and donors with an ATL clone that expressed the HTLV-1 Tax gene were most likely to make a detectable lytic CD8+ response to the ATL cells. We conclude that some patients with ATL possess functional tumour-specific CTLs which could be exploited to contribute to control of the disease.

  8. Stepwise identification of HLA-A*0201-restricted CD8+ T-cell epitope peptides from herpes simplex virus type 1 genome boosted by a StepRank scheme.

    Science.gov (United States)

    Bi, Jianjun; Song, Rengang; Yang, Huilan; Li, Bingling; Fan, Jianyong; Liu, Zhongrong; Long, Chaoqin

    2011-01-01

    Identification of immunodominant epitopes is the first step in the rational design of peptide vaccines aimed at T-cell immunity. To date, however, it is yet a great challenge for accurately predicting the potent epitope peptides from a pool of large-scale candidates with an efficient manner. In this study, a method that we named StepRank has been developed for the reliable and rapid prediction of binding capabilities/affinities between proteins and genome-wide peptides. In this procedure, instead of single strategy used in most traditional epitope identification algorithms, four steps with different purposes and thus different computational demands are employed in turn to screen the large-scale peptide candidates that are normally generated from, for example, pathogenic genome. The steps 1 and 2 aim at qualitative exclusion of typical nonbinders by using empirical rule and linear statistical approach, while the steps 3 and 4 focus on quantitative examination and prediction of the interaction energy profile and binding affinity of peptide to target protein via quantitative structure-activity relationship (QSAR) and structure-based free energy analysis. We exemplify this method through its application to binding predictions of the peptide segments derived from the 76 known open-reading frames (ORFs) of herpes simplex virus type 1 (HSV-1) genome with or without affinity to human major histocompatibility complex class I (MHC I) molecule HLA-A*0201, and find that the predictive results are well compatible with the classical anchor residue theory and perfectly match for the extended motif pattern of MHC I-binding peptides. The putative epitopes are further confirmed by comparisons with 11 experimentally measured HLA-A*0201-restrcited peptides from the HSV-1 glycoproteins D and K. We expect that this well-designed scheme can be applied in the computational screening of other viral genomes as well.

  9. Retinol as a micronutrients related to cervical local immunity: The expression of tumor necrosis factor-alpha specifically stimulated with E6 epitope of human papillomavirus type-16 and ratio of CD4+/CD8+ T cell in natural history of cervical cancer

    Science.gov (United States)

    Utami, T. W.; Aziz, M. F.; Ibrahim, F.; Andrijono

    2017-08-01

    Retinol is one of the antioxidant micronutrients that plays essential roles in the immune system, by preventing the persistence of modulating CD4+ and CD8+ T cells and cytokines production. Tumor Necrosis Factor-Alpha (TNF-α) is an acute pro-inflammatory cytokine which has many crucial roles in controlling HPV. In contrast, when persistent infection occurs, TNF-α induces carcinogenesis. The ratio of CD4+ cells to CD8+ T cells and adequate TNF-α production in acute HPV infection are key points for clearance. The aim of this research is to analyze the sufficiency level of retinol deposit, the expression of TNF-α, and the ratio of CD4+: CD8+ T cells in a normal cervix, clearance and persistent HPV subclinical infection, and cervical cancer group. The sufficiency level of retinol deposit was analyzed from peripheral blood using the ELISA method. The cervico-vaginal secretions, which were incubated for 24 hours, were stimulated specifically by E6 epitope HPV type-16, measuring TNF-α expression semi-quantitatively by the ELISpot method and CD4+/CD8+ T cells quantitatively by flowcytometry method. The sufficient level of retinol deposit in a normal cervix, clearance HPV subclinical infection, persistent, and cervical cancer group was 85%, 75% (OR 1.89), 33.3% (OR 11.33), and 75% (OR 1.89), respectively. The expression of TNF-α in normal cervix group was 10%, while for cervical cancer it was 75% (OR 27.00; p CD4+: CD8+ T cells in the normal cervix and cervical cancer group was 10% and 25% (OR 0.33). There was no high ratio of CD4+: CD8+ T cells in clearance (OR 1.22) and persistent (OR 0.95) HPV subclinical infection groups. This study was able to prove that the normal cervix group has the highest retinol deposit sufficiency level and the cervical cancer group has the highest TNF-α expression (OR 27; p < 0.001). The lowest of retinol deposit sufficiency level was not in cervical cancer, but in the persistent HPV subclinical infection group (OR 11.33). There was

  10. Contribution of herpesvirus specific CD8 T cells to anti-viral T cell response in humans.

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    Elena Sandalova

    Full Text Available Herpesviruses infect most humans. Their infections can be associated with pathological conditions and significant changes in T cell repertoire but evidences of symbiotic effects of herpesvirus latency have never been demonstrated. We tested the hypothesis that HCMV and EBV-specific CD8 T cells contribute to the heterologous anti-viral immune response. Volume of activated/proliferating virus-specific and total CD8 T cells was evaluated in 50 patients with acute viral infections: 20 with HBV, 12 with Dengue, 12 with Influenza, 3 with Adenovirus infection and 3 with fevers of unknown etiology. Virus-specific (EBV, HCMV, Influenza pentamer+ and total CD8 T cells were analyzed for activation (CD38/HLA-DR, proliferation (Ki-67/Bcl-2(low and cytokine production. We observed that all acute viral infections trigger an expansion of activated/proliferating CD8 T cells, which differs in size depending on the infection but is invariably inflated by CD8 T cells specific for persistent herpesviruses (HCMV/EBV. CD8 T cells specific for other non-related non persistent viral infection (i.e. Influenza were not activated. IL-15, which is produced during acute viral infections, is the likely contributing mechanism driving the selective activation of herpesvirus specific CD8 T cells. In addition we were able to show that herpesvirus specific CD8 T cells displayed an increased ability to produce the anti-viral cytokine interferon-gamma during the acute phase of heterologous viral infection. Taken together, these data demonstrated that activated herpesvirus specific CD8 T cells inflate the activated/proliferating CD8 T cells population present during acute viral infections in human and can contribute to the heterologous anti-viral T cell response.

  11. Mast-Cell-Derived TNF Amplifies CD8+ Dendritic Cell Functionality and CD8+ T Cell Priming

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    Jan Dudeck

    2015-10-01

    Full Text Available Mast cells are critical promoters of adaptive immunity in the contact hypersensitivity model, but the mechanism of allergen sensitization is poorly understood. Using Mcpt5-CreTNFFL/FL mice, we show here that the absence of TNF exclusively in mast cells impaired the expansion of CD8+ T cells upon sensitization and the T-cell-driven adaptive immune response to elicitation. T cells primed in the absence of mast cell TNF exhibited a diminished efficiency to transfer sensitization to naive recipients. Specifically, mast cell TNF promotes CD8+ dendritic cell (DC maturation and migration to draining lymph nodes. The peripherally released mast cell TNF further critically boosts the CD8+ T-cell-priming efficiency of CD8+ DCs, thereby linking mast cell effects on T cells to DC modulation. Collectively, our findings identify the distinct potential of mast cell TNF to amplify CD8+ DC functionality and CD8+ T-cell-dominated adaptive immunity, which may be of great importance for immunotherapy and vaccination approaches.

  12. Sustained CD8+ T-cell responses induced after acute parvovirus B19 infection in humans

    DEFF Research Database (Denmark)

    Norbeck, Oscar; Isa, Adiba; Pöhlmann, Christoph

    2005-01-01

    Murine models have suggested that CD8+ T-cell responses peak early in acute viral infections and are not sustained, but no evidence for humans has been available. To address this, we longitudinally analyzed the CD8+ T-cell response to human parvovirus B19 in acutely infected individuals. We...... observed striking CD8+ T-cell responses, which were sustained or even increased over many months after the resolution of acute disease, indicating that CD8+ T cells may play a prominent role in the control of parvovirus B19 and other acute viral infections of humans, including potentially those generated...

  13. Prediction of CD8+ Epitopes in Leishmania braziliensis Proteins Using EPIBOT: In Silico Search and In Vivo Validation.

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    Angelo Duarte

    Full Text Available Leishmaniasis is caused by intracellular Leishmania parasites that induce a T-cell mediated response associated with recognition of CD4+ and CD8+ T cell Line 1Lineepitopes. Identification of CD8+ antigenic determinants is crucial for vaccine and therapy development. Herein, we developed an open-source software dedicated to search and compile data obtained from currently available on line prediction algorithms.We developed a two-phase algorithm and implemented in an open source software called EPIBOT, that consolidates the results obtained with single prediction algorithms, generating a final output in which epitopes are ranked. EPIBOT was initially trained using a set of 831 known epitopes from 397 proteins from IEDB. We then screened 63 Leishmania braziliensis vaccine candidates with the EPIBOT trained tool to search for CD8+ T cell epitopes. A proof-of-concept experiment was conducted with the top eight CD8+ epitopes, elected by EPIBOT. To do this, the elected peptides were synthesized and validated for their in vivo cytotoxicity. Among the tested epitopes, three were able to induce lysis of pulsed-target cells.Our results show that EPIBOT can successfully search across existing prediction tools, generating a compiled list of candidate CD8+ epitopes. This software is fast and a simple search engine that can be customized to search over different MHC alleles or HLA haplotypes.

  14. CD8+ T cells induce thyroid epithelial cell hyperplasia and fibrosis.

    Science.gov (United States)

    Yu, Shiguang; Fang, Yujiang; Sharav, Tumenjargal; Sharp, Gordon C; Braley-Mullen, Helen

    2011-02-15

    CD8(+) T cells can be important effector cells in autoimmune inflammation, generally because they can damage target cells by cytotoxicity. This study shows that activated CD8(+) T cells induce thyroid epithelial cell hyperplasia and proliferation and fibrosis in IFN-γ(-/-) NOD.H-2h4 SCID mice in the absence of CD4(+) T cells. Because CD8(+) T cells induce proliferation rather than cytotoxicity of target cells, these results describe a novel function for CD8(+) T cells in autoimmune disease. In contrast to the ability of purified CD8(+) T cells to induce thyrocyte proliferation, CD4(+) T cells or CD8 T cell-depleted splenocytes induced only mild thyroid lesions in SCID recipients. T cells in both spleens and thyroids highly produce TNF-α. TNF-α promotes proliferation of thyrocytes in vitro, and anti-TNF-α inhibits development of thyroid epithelial cell hyperplasia and proliferation in SCID recipients of IFN-γ(-/-) splenocytes. This suggests that targeting CD8(+) T cells and/or TNF-α may be effective for treating epithelial cell hyperplasia and fibrosis.

  15. Collapse of Cytolytic Potential in SIV-Specific CD8+ T Cells Following Acute SIV Infection in Rhesus Macaques.

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    Emily R Roberts

    2016-12-01

    Full Text Available Poor maintenance of cytotoxic factor expression among HIV-specific CD8+ T cells, in part caused by dysregulated expression of the transcription factor T-bet, is associated with HIV disease progression. However, the precise evolution and context in which CD8+ T cell cytotoxic functions become dysregulated in HIV infection remain unclear. Using the rhesus macaque (RM SIV infection model, we evaluated the kinetics of SIV-specific CD8+ T cell cytolytic factor expression in peripheral blood, lymph node, spleen, and gut mucosa from early acute infection through chronic infection. We identified rapid acquisition of perforin and granzyme B expression in SIV-specific CD8+ T cells in blood, secondary lymphoid tissues and gut mucosa that collapsed rapidly during the transition to chronic infection. The evolution of this expression profile was linked to low expression of T-bet and occurred independent of epitope specificity, viral escape patterns and tissue origin. Importantly, during acute infection SIV-specific CD8+ T cells that maintained T-bet expression retained the ability to express granzyme B after stimulation, but this relationship was lost in chronic infection. Together, these data demonstrate the loss of cytolytic machinery in SIV-specific CD8+ T cells in blood and at tissue sites of viral reservoir and active replication during the transition from acute to chronic infection. This phenomenon occurs despite persistent high levels of viremia suggesting that an inability to maintain properly regulated cytotoxic T cell responses in all tissue sites enables HIV/SIV to avoid immune clearance, establish persistent viral reservoirs in lymphoid tissues and gut mucosa, and lead ultimately to immunopathogenesis and death.

  16. CD103 is a marker for alloantigen-induced regulatory CD8+ T cells

    NARCIS (Netherlands)

    Uss, Elena; Rowshani, Ajda T.; Hooibrink, Berend; Lardy, Neubury M.; van Lier, René A. W.; ten Berge, Ineke J. M.

    2006-01-01

    The alphaEbeta7 integrin CD103 may direct lymphocytes to its ligand E-cadherin. CD103 is expressed on T cells in lung and gut and on allograft-infiltrating T cells. Moreover, recent studies have documented expression of CD103 on CD4+ regulatory T cells. Approximately 4% of circulating CD8+ T cells

  17. Memory CD8+ T cells protect dendritic cells from CTL killing

    NARCIS (Netherlands)

    Watchmaker, Payal B.; Urban, Julie A.; Berk, Erik; Nakamura, Yutaro; Mailliard, Robbie B.; Watkins, Simon C.; van Ham, S. Marieke; Kalinski, Pawel

    2008-01-01

    CD8(+) T cells have been shown to be capable of either suppressing or promoting immune responses. To reconcile these contrasting regulatory functions, we compared the ability of human effector and memory CD8(+) T cells to regulate survival and functions of dendritic cells (DC). We report that, in

  18. Human CD8 T cells generated in vitro from hematopoietic stem cells are functionally mature

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    Zúñiga-Pflücker Juan

    2011-03-01

    Full Text Available Abstract Background T cell development occurs within the highly specialized thymus. Cytotoxic CD8 T cells are critical in adaptive immunity by targeting virally infected or tumor cells. In this study, we addressed whether functional CD8 T cells can be generated fully in vitro using human umbilical cord blood (UCB hematopoietic stem cells (HSCs in coculture with OP9-DL1 cells. Results HSC/OP9-DL1 cocultures supported the differentiation of CD8 T cells, which were TCR/CD3hi CD27hi CD1aneg and thus phenotypically resembled mature functional CD8 single positive thymocytes. These in vitro-generated T cells also appeared to be conventional CD8 cells, as they expressed high levels of Eomes and low levels of Plzf, albeit not identical to ex vivo UCB CD8 T cells. Consistent with the phenotypic and molecular characterization, upon TCR-stimulation, in vitro-generated CD8 T cells proliferated, expressed activation markers (MHC-II, CD25, CD38, secreted IFN-γ and expressed Granzyme B, a cytotoxic T-cell effector molecule. Conclusion Taken together, the ability to direct human hematopoietic stem cell or T-progenitor cells towards a mature functional phenotype raises the possibility of establishing cell-based treatments for T-immunodeficiencies by rapidly restoring CD8 effector function, thereby mitigating the risks associated with opportunistic infections.

  19. An unexpected antibody response to an engineered influenza virus modifies CD8+ T cell responses.

    Science.gov (United States)

    Thomas, Paul G; Brown, Scott A; Yue, Wen; So, Jenny; Webby, Richard J; Doherty, Peter C

    2006-02-21

    The ovalbumin(323-339) peptide that binds H2I-A(b) was engineered into the globular heads of hemagglutinin (H) molecules from serologically non-cross-reactive H1N1 and H3N2 influenza A viruses, the aim being to analyze recall CD4+ T cell responses in a virus-induced respiratory disease. Prime/challenge experiments with these H1ova and H3ova viruses in H2(b) mice gave the predicted, ovalbumin-specific CD4+ T cell response but showed an unexpectedly enhanced, early expansion of viral epitope-specific CD8+ T cells in spleen and a greatly diminished inflammatory process in the virus-infected respiratory tract. At the same time, the primary antibody response to the H3N2 challenge virus was significantly reduced, an effect that has been associated with preexisting neutralizing antibody in other experimental systems. Analysis of serum from the H1ova-primed mice showed low-level binding to H3ova but not to the wild-type H3N2 virus. Experiments with CD4+ T cell-depleted and Ig-/- mice indicated that this cross-reactive Ig is indeed responsible for the modified pathogenesis after respiratory challenge. Furthermore, the effect does not seem to be virus-dose related, although it does require infection. These findings suggest intriguing possibilities for vaccination and, at the same time, emphasize that engineered modifications in viruses may have unintended immunological consequences.

  20. Intrinsic and extrinsic contributors to defective CD8+ T cell responses with aging.

    Science.gov (United States)

    Jergović, Mladen; Smithey, Megan J; Nikolich-Žugich, Janko

    2018-05-01

    Aging has a profound effect on the immune system, and both innate and adaptive arms of the immune system show functional decline with age. In response to infection with intracellular microorganisms, old animals mobilize decreased numbers of antigen-specific CD8+ T cells with reduced production of effector molecules and impaired cytolytic activity. However, the CD8+ T cell-intrinsic contribution to, and molecular mechanisms behind, these defects remain unclear. In this review we will discuss the mechanistic contributions of age related changes in the CD8+ T cell pool and the relative roles of intrinsic functional defects in aged CD8+ T cells vs. defects in the aged environment initiating the CD8+ T cell response. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Potentiating the antitumour response of CD8+ T cells by modulating cholesterol metabolism

    Science.gov (United States)

    Yang, Wei; Bai, Yibing; Xiong, Ying; Zhang, Jin; Chen, Shuokai; Zheng, Xiaojun; Meng, Xiangbo; Li, Lunyi; Wang, Jing; Xu, Chenguang; Yan, Chengsong; Wang, Lijuan; Chang, Catharine C. Y.; Chang, Ta-Yuan; Zhang, Ti; Zhou, Penghui; Song, Bao-Liang; Liu, Wanli; Sun, Shao-cong; Liu, Xiaolong; Li, Bo-liang; Xu, Chenqi

    2016-01-01

    CD8+ T cells have a central role in antitumour immunity, but their activity is suppressed in the tumour microenvironment1–4. Reactivating the cytotoxicity of CD8+ T cells is of great clinical interest in cancer immunotherapy. Here we report a new mechanism by which the antitumour response of mouse CD8+ T cells can be potentiated by modulating cholesterol metabolism. Inhibiting cholesterol esterification in T cells by genetic ablation or pharmacological inhibition of ACAT1, a key cholesterol esterification enzyme5, led to potentiated effector function and enhanced proliferation of CD8+ but not CD4+ T cells. This is due to the increase in the plasma membrane cholesterol level of CD8+ T cells, which causes enhanced T-cell receptor clustering and signalling as well as more efficient formation of the immunological synapse. ACAT1-deficient CD8+ T cells were better than wild-type CD8+ T cells at controlling melanoma growth and metastasis in mice. We used the ACAT inhibitor avasimibe, which was previously tested in clinical trials for treating atherosclerosis and showed a good human safety profile6,7, to treat melanoma in mice and observed a good antitumour effect. A combined therapy of avasimibe plus an anti-PD-1 antibody showed better efficacy than monotherapies in controlling tumour progression. ACAT1, an established target for atherosclerosis, is therefore also a potential target for cancer immunotherapy. PMID:26982734

  2. Acetyl CoA Carboxylase 2 Is Dispensable for CD8+ T Cell Responses.

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    Jang Eun Lee

    Full Text Available Differentiation of T cells is closely associated with dynamic changes in nutrient and energy metabolism. However, the extent to which specific metabolic pathways and molecular components are determinative of CD8+ T cell fate remains unclear. It has been previously established in various tissues that acetyl CoA carboxylase 2 (ACC2 regulates fatty acid oxidation (FAO by inhibiting carnitine palmitoyltransferase 1 (CPT1, a rate-limiting enzyme of FAO in mitochondria. Here, we explore the cell-intrinsic role of ACC2 in T cell immunity in response to infections. We report here that ACC2 deficiency results in a marginal increase of cellular FAO in CD8+ T cells, but does not appear to influence antigen-specific effector and memory CD8+ T cell responses during infection with listeria or lymphocytic choriomeningitis virus. These results suggest that ACC2 is dispensable for CD8+ T cell responses.

  3. CD8 T-cells and E-cadherin in host responses against oropharyngeal candidiasis

    Science.gov (United States)

    Quimby, K.; Lilly, E.A.; Zacharek, M.; McNulty, K.; Leigh, J.E.; Vazquez, J.E.; Fidel, P.L.

    2011-01-01

    Oropharyngeal candidiasis (OPC) is the most common oral infection in HIV+ persons. Previous studies suggest a role for CD8+ T-cells against OPC when CD4+ T-cells are lost, but enhanced susceptibility to infection occurs when CD8+ T-cell migration is inhibited by reduced tissue E-cadherin. Objective Conduct a longitudinal study of tissue CD8+ T-cells and E-cadherin expression before, during, and after episodes of OPC. Methods Oral fungal burden was monitored and tissue was evaluated for CD8+ T-cells and E-cadherin over a one-year period in HIV+ persons with a history of, or an acute episode of OPC. Results While longitudinal analyses precluded formal interpretations, point prevalence analyses of the dataset revealed that when patients experiencing OPC were successfully treated, tissue E-cadherin expression was similar to patients who had not experienced OPC, and higher numbers of CD8+ T-cells were distributed throughout OPC− tissue under normal expression of E-cadherin. Conclusion These results suggest that 1) reduction in tissue E-cadherin expression in OPC+ patients is not permanent, and 2) high numbers of CD8+ T-cells can be distributed throughout OPC− tissue under normal E-cadherin expression. Together these results extend our previous studies and continue to support a role for CD8+ T-cells in host defense against OPC. PMID:21958417

  4. CD8 Follicular T Cells Promote B Cell Antibody Class Switch in Autoimmune Disease.

    Science.gov (United States)

    Valentine, Kristen M; Davini, Dan; Lawrence, Travis J; Mullins, Genevieve N; Manansala, Miguel; Al-Kuhlani, Mufadhal; Pinney, James M; Davis, Jason K; Beaudin, Anna E; Sindi, Suzanne S; Gravano, David M; Hoyer, Katrina K

    2018-05-09

    CD8 T cells can play both a protective and pathogenic role in inflammation and autoimmune development. Recent studies have highlighted the ability of CD8 T cells to function as T follicular helper (Tfh) cells in the germinal center in the context of infection. However, whether this phenomenon occurs in autoimmunity and contributes to autoimmune pathogenesis is largely unexplored. In this study, we show that CD8 T cells acquire a CD4 Tfh profile in the absence of functional regulatory T cells in both the IL-2-deficient and scurfy mouse models. Depletion of CD8 T cells mitigates autoimmune pathogenesis in IL-2-deficient mice. CD8 T cells express the B cell follicle-localizing chemokine receptor CXCR5, a principal Tfh transcription factor Bcl6, and the Tfh effector cytokine IL-21. CD8 T cells localize to the B cell follicle, express B cell costimulatory proteins, and promote B cell differentiation and Ab isotype class switching. These data reveal a novel contribution of autoreactive CD8 T cells to autoimmune disease, in part, through CD4 follicular-like differentiation and functionality. Copyright © 2018 by The American Association of Immunologists, Inc.

  5. Antigen Requirements for Efficient Priming of CD8+ T Cells by Leishmania major-Infected Dendritic Cells

    Science.gov (United States)

    Bertholet, Sylvie; Debrabant, Alain; Afrin, Farhat; Caler, Elisabeth; Mendez, Susana; Tabbara, Khaled S.; Belkaid, Yasmine; Sacks, David L.

    2005-01-01

    CD4+ and CD8+ T-cell responses have been shown to be critical for the development and maintenance of acquired resistance to infections with the protozoan parasite Leishmania major. Monitoring the development of immunodominant or clonally restricted T-cell subsets in response to infection has been difficult, however, due to the paucity of known epitopes. We have analyzed the potential of L. major transgenic parasites, expressing the model antigen ovalbumin (OVA), to be presented by antigen-presenting cells to OVA-specific OT-II CD4+ or OT-I CD8+ T cells. Truncated OVA was expressed in L. major as part of a secreted or nonsecreted chimeric protein with L. donovani 3′ nucleotidase (NT-OVA). Dendritic cells (DC) but not macrophages infected with L. major that secreted NT-OVA could prime OT-I T cells to proliferate and release gamma interferon. A diminished T-cell response was observed when DC were infected with parasites expressing nonsecreted NT-OVA or with heat-killed parasites. Inoculation of mice with transgenic parasites elicited the proliferation of adoptively transferred OT-I T cells and their recruitment to the site of infection in the skin. Together, these results demonstrate the possibility of targeting heterologous antigens to specific cellular compartments in L. major and suggest that proteins secreted or released by L. major in infected DC are a major source of peptides for the generation of parasite-specific CD8+ T cells. The ability of L. major transgenic parasites to activate OT-I CD8+ T cells in vivo will permit the analysis of parasite-driven T-cell expansion, differentiation, and recruitment at the clonal level. PMID:16177338

  6. Neonatal CD8+ T-cell differentiation is dependent on interleukin-12.

    LENUS (Irish Health Repository)

    McCarron, Mark J

    2012-02-01

    Neonatal CD8(+) T-cell activation is significantly impaired compared with that in adults. Recent studies have demonstrated that interleukin (IL)-12 is necessary as a third signal, in addition to antigen and co-stimulation, to authorize the differentiation of naive CD8(+) T cells. We examined whether human neonatal CD8(+) T cells, which possess an exclusively naive T-cell phenotype, required a third signal to authorize a productive T-cell response. IL-12 enhanced activated naive CD8(+) T-cell survival, expansion, CD25 expression, and IL-2 production. Activated CD8(+) T cells produced interferon-gamma and intracellular granzyme B and were cytotoxic only in the presence of IL-12. Sustained IL-12 signaling for 72 hours was required for optimal interferon-gamma production. IL-12, in concert with T cell receptor (TCR) stimulation, sustained late-stage (48-72 hours) intracellular phosphorylation and particularly total protein levels of the proximal TCR components, Lck, and CD3xi. The requirement for a third signal for productive human neonatal CD8(+) T-cell differentiation may have implications for neonatal vaccination strategies.

  7. CD8+ T Cells Specific to Apoptosis-Associated Antigens Predict the Response to Tumor Necrosis Factor Inhibitor Therapy in Rheumatoid Arthritis.

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    Alessandra Citro

    Full Text Available CD8+ T cells specific to caspase-cleaved antigens derived from apoptotic T cells (apoptotic epitopes represent a principal player in chronic immune activation, which is known to amplify immunopathology in various inflammatory diseases. The purpose of the present study was to investigate the relationship involving these autoreactive T cells, the rheumatoid arthritis immunopathology, and the response to tumor necrosis factor-α inhibitor therapy. The frequency of autoreactive CD8+ T cells specific to various apoptotic epitopes, as detected by both enzyme-linked immunospot assay and dextramers of major histocompatibility complex class I molecules complexed with relevant apoptotic epitopes, was longitudinally analyzed in the peripheral blood of rheumatoid arthritis patients who were submitted to etanercept treatment (or other tumor necrosis factor inhibitors as a control. The percentage of apoptotic epitope-specific CD8+ T cells was significantly higher in rheumatoid arthritis patients than in healthy donors, and correlated with the disease activity. More important, it was significantly more elevated in responders to tumor necrosis factor-α inhibitor therapy than in non-responders before the start of therapy; it significantly dropped only in the former following therapy. These data indicate that apoptotic epitope-specific CD8+ T cells may be involved in rheumatoid arthritis immunopathology through the production of inflammatory cytokines and that they may potentially represent a predictive biomarker of response to tumor necrosis factor-α inhibitor therapy to validate in a larger cohort of patients.

  8. Metabolic Adaptation of Human CD4+ and CD8+ T-Cells to T-Cell Receptor-Mediated Stimulation

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    Nicholas Jones

    2017-11-01

    Full Text Available Linking immunometabolic adaptation to T-cell function provides insight for the development of new therapeutic approaches in multiple disease settings. T-cell activation and downstream effector functions of CD4+ and CD8+ T-cells are controlled by the strength of interaction between the T-cell receptor (TCR and peptides presented by human leukocyte antigens (pHLA. The role of TCR–pHLA interactions in modulating T-cell metabolism is unknown. Here, for the first time, we explore the relative contributions of the main metabolic pathways to functional responses in human CD4+ and CD8+ T-cells. Increased expression of hexokinase II accompanied by higher basal glycolysis is demonstrated in CD4+ T-cells; cytokine production in CD8+ T-cells is more reliant on oxidative phosphorylation. Using antigen-specific CD4+ and CD8+ T-cell clones and altered peptide ligands, we demonstrate that binding affinity tunes the underlying metabolic shift. Overall, this study provides important new insight into how metabolic pathways are controlled during antigen-specific activation of human T-cells.

  9. NOD1 cooperates with TLR2 to enhance T cell receptor-mediated activation in CD8 T cells.

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    Blandine C Mercier

    Full Text Available Pattern recognition receptors (PRR, like Toll-like receptors (TLR and NOD-like receptors (NLR, are involved in the detection of microbial infections and tissue damage by cells of the innate immune system. Recently, we and others have demonstrated that TLR2 can additionally function as a costimulatory receptor on CD8 T cells. Here, we establish that the intracytosolic receptor NOD1 is expressed and functional in CD8 T cells. We show that C12-iEDAP, a synthetic ligand for NOD1, has a direct impact on both murine and human CD8 T cells, increasing proliferation and effector functions of cells activated via their T cell receptor (TCR. This effect is dependent on the adaptor molecule RIP2 and is associated with an increased activation of the NF-κB, JNK and p38 signaling pathways. Furthermore, we demonstrate that NOD1 stimulation can cooperate with TLR2 engagement on CD8 T cells to enhance TCR-mediated activation. Altogether our results indicate that NOD1 might function as an alternative costimulatory receptor in CD8 T cells. Our study provides new insights into the function of NLR in T cells and extends to NOD1 the recent concept that PRR stimulation can directly control T cell functions.

  10. Accumulation of cytolytic CD8{sup +} T cells in B16-melanoma and proliferation of mature T cells in TIS21-knockout mice after T cell receptor stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Min Sook [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Woo, Min-Yeong [Department of Microbiology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Department of Biomedical Sciences, The Graduate School, Ajou University (Korea, Republic of); Kwon, Daeho [Department of Microbiology, Kwandong University College of Medicine, Gangneung, Gangwon-do 210-701 (Korea, Republic of); Hong, Allen E. [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Song, Kye Yong [Department of Pathology, Chung-Ang University College of Medicine, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Park, Sun [Department of Microbiology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Lim, In Kyoung [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of)

    2014-10-01

    In vivo and in vitro effects of TIS21 gene on the mature T cell activation and antitumor activities were explored by employing MO5 melanoma orthograft and splenocytes isolated from the TIS21-knockout (KO) mice. Proliferation and survival of mature T cells were significantly increased in the KO than the wild type (WT) cells, indicating that TIS21 inhibits the rate of mature T cell proliferation and its survival. In MO5 melanoma orthograft model, the KO mice recruited much more CD8{sup +} T cells into the tumors at around day 14 after tumor cell injection along with reduced tumor volumes compared with the WT. The increased frequency of granzyme B{sup +} CD8{sup +} T cells in splenocytes of the KO mice compared with the WT may account for antitumor-immunity of TIS21 gene in the melanoma orthograft. In contrast, reduced frequencies of CD107a{sup +} CD8{sup +} T cells in the splenocytes of KO mice may affect the loss of CD8{sup +} T cell infiltration in the orthograft at around day 19. These results indicate that TIS21 exhibits antiproliferative and proapoptotic effects in mature T cells, and differentially affects the frequencies of granzyme B{sup +} CD8{sup +} T-cells and CD107a{sup +} CD8{sup +} T-cells, thus transiently regulating in vivo anti-tumor immunity. - Highlights: • Constitutive expression of TIS21 in splenocytes and upregulation by TCR stimulation. • Proliferation of mature T-cells in spleen of TIS21KO mice after TCR stimulation. • Inhibition of cell death in mature T-cells of TIS21KO mice compared with the wild type. • Inhibition of melanoma growth in TIS21KO mice and CD8{sup +} T cell infiltration in tumor. • Reduction of CD 107{sup +}CD8{sup +} T cells, but increased granzyme B{sup +} CD8{sup +} T cells in TIS21KO mice.

  11. Acute Viral Respiratory Infection Rapidly Induces a CD8+ T Cell Exhaustion-like Phenotype.

    Science.gov (United States)

    Erickson, John J; Lu, Pengcheng; Wen, Sherry; Hastings, Andrew K; Gilchuk, Pavlo; Joyce, Sebastian; Shyr, Yu; Williams, John V

    2015-11-01

    Acute viral infections typically generate functional effector CD8(+) T cells (TCD8) that aid in pathogen clearance. However, during acute viral lower respiratory infection, lung TCD8 are functionally impaired and do not optimally control viral replication. T cells also become unresponsive to Ag during chronic infections and cancer via signaling by inhibitory receptors such as programmed cell death-1 (PD-1). PD-1 also contributes to TCD8 impairment during viral lower respiratory infection, but how it regulates TCD8 impairment and the connection between this state and T cell exhaustion during chronic infections are unknown. In this study, we show that PD-1 operates in a cell-intrinsic manner to impair lung TCD8. In light of this, we compared global gene expression profiles of impaired epitope-specific lung TCD8 to functional spleen TCD8 in the same human metapneumovirus-infected mice. These two populations differentially regulate hundreds of genes, including the upregulation of numerous inhibitory receptors by lung TCD8. We then compared the gene expression of TCD8 during human metapneumovirus infection to those in acute or chronic lymphocytic choriomeningitis virus infection. We find that the immunophenotype of lung TCD8 more closely resembles T cell exhaustion late into chronic infection than do functional effector T cells arising early in acute infection. Finally, we demonstrate that trafficking to the infected lung alone is insufficient for TCD8 impairment or inhibitory receptor upregulation, but that viral Ag-induced TCR signaling is also required. Our results indicate that viral Ag in infected lungs rapidly induces an exhaustion-like state in lung TCD8 characterized by progressive functional impairment and upregulation of numerous inhibitory receptors. Copyright © 2015 by The American Association of Immunologists, Inc.

  12. Mycobacterium tuberculosis specific CD8(+ T cells rapidly decline with antituberculosis treatment.

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    Melissa R Nyendak

    Full Text Available Biomarkers associated with response to therapy in tuberculosis could have broad clinical utility. We postulated that the frequency of Mycobacterium tuberculosis (Mtb specific CD8(+ T cells, by virtue of detecting intracellular infection, could be a surrogate marker of response to therapy and would decrease during effective antituberculosis treatment.We sought to determine the relationship of Mtb specific CD4(+ T cells and CD8(+ T cells with duration of antituberculosis treatment.We performed a prospective cohort study, enrolling between June 2008 and August 2010, of HIV-uninfected Ugandan adults (n = 50 with acid-fast bacillus smear-positive, culture confirmed pulmonary TB at the onset of antituberculosis treatment and the Mtb specific CD4(+ and CD8(+ T cell responses to ESAT-6 and CFP-10 were measured by IFN-γ ELISPOT at enrollment, week 8 and 24.There was a significant difference in the Mtb specific CD8(+ T response, but not the CD4(+ T cell response, over 24 weeks of antituberculosis treatment (p<0.0001, with an early difference observed at 8 weeks of therapy (p = 0.023. At 24 weeks, the estimated Mtb specific CD8(+ T cell response decreased by 58%. In contrast, there was no significant difference in the Mtb specific CD4(+ T cell during the treatment. The Mtb specific CD4(+ T cell response, but not the CD8(+ response, was negatively impacted by the body mass index.Our data provide evidence that the Mtb specific CD8(+ T cell response declines with antituberculosis treatment and could be a surrogate marker of response to therapy. Additional research is needed to determine if the Mtb specific CD8(+ T cell response can detect early treatment failure, relapse, or to predict disease progression.

  13. Blimp-1–mediated CD4 T cell exhaustion causes CD8 T cell dysfunction during chronic toxoplasmosis

    Science.gov (United States)

    Cobb, Dustin A.; Bhadra, Rajarshi

    2016-01-01

    CD8, but not CD4, T cells are considered critical for control of chronic toxoplasmosis. Although CD8 exhaustion has been previously reported in Toxoplasma encephalitis (TE)–susceptible model, our current work demonstrates that CD4 not only become exhausted during chronic toxoplasmosis but this dysfunction is more pronounced than CD8 T cells. Exhausted CD4 population expressed elevated levels of multiple inhibitory receptors concomitant with the reduced functionality and up-regulation of Blimp-1, a transcription factor. Our data demonstrates for the first time that Blimp-1 is a critical regulator for CD4 T cell exhaustion especially in the CD4 central memory cell subset. Using a tamoxifen-dependent conditional Blimp-1 knockout mixed bone marrow chimera as well as an adoptive transfer approach, we show that CD4 T cell–intrinsic deletion of Blimp-1 reversed CD8 T cell dysfunction and resulted in improved pathogen control. To the best of our knowledge, this is a novel finding, which demonstrates the role of Blimp-1 as a critical regulator of CD4 dysfunction and links it to the CD8 T cell dysfunctionality observed in infected mice. The critical role of CD4-intrinsic Blimp-1 expression in mediating CD4 and CD8 T cell exhaustion may provide a rational basis for designing novel therapeutic approaches. PMID:27481131

  14. CD8+ T cells provide immune protection against murine disseminated endotheliotropic Orientia tsutsugamushi infection.

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    Guang Xu

    2017-07-01

    Full Text Available Scrub typhus, caused by a Gram-negative obligately intracellular coccobacillus, Orientia tsutsugamushi, is a long neglected but important tropical disease. Orientia tsutsugamushi causes illness in one million people each year, and 1 billion people are at risk. Without appropriate diagnosis and treatment, the disease can cause severe multiorgan failure with a case fatality rate of 7-15%. The current gaps in knowledge of immunity include the unknown mechanisms of host immunity to O. tsutsugamushi. Using an intravenous (i.v. disseminated infection mouse model, we observed that more CD8+ T cells than CD4+ T cells were present in the spleen of infected mice at 12 dpi. We also determined that Treg cells and the proportion of T cells producing IL-10 were significantly increased from 6 dpi, which correlated with the onset of illness, body weight loss, and increased bacterial loads. We further studied CD8-/-, MHC I-/- and wild type control (WT C57BL/6J mice to determine the importance of CD8+ T cells and MHC I molecules. After infection with an ordinarily sub-lethal dose of O. tsutsugamushi, all CD8-/- and MHC I-/- mice were moribund between 12 and 15 dpi, whereas all WT mice survived. Bacterial loads in the lung, kidney, liver and spleen of CD8-/- and MHC I-/- mice were significantly greater than those in WT mice. Interferon-γ (IFN-γ and granzyme B mRNA levels in the liver of CD8-/- and MHC I-/- mice were significantly greater than in WT mice. In addition, more severe histopathologic lesions were observed in CD8-/- mice. Finally, adoptive transfer confirmed a major role of immune CD8+ T cells as well as a less effective contribution by immune CD8 T cell-depleted splenocytes in protection against O. tsutsugamushi infection. These studies demonstrated the critical importance of CD8+ T cells in the host immune response during O. tsutsugamushi infection.

  15. Latent HIV reservoirs exhibit inherent resistance to elimination by CD8+ T cells.

    Science.gov (United States)

    Huang, Szu-Han; Ren, Yanqin; Thomas, Allison S; Chan, Dora; Mueller, Stefanie; Ward, Adam R; Patel, Shabnum; Bollard, Catherine M; Cruz, Conrad Russell; Karandish, Sara; Truong, Ronald; Macedo, Amanda B; Bosque, Alberto; Kovacs, Colin; Benko, Erika; Piechocka-Trocha, Alicja; Wong, Hing; Jeng, Emily; Nixon, Douglas F; Ho, Ya-Chi; Siliciano, Robert F; Walker, Bruce D; Jones, R Brad

    2018-02-01

    The presence of persistent, latent HIV reservoirs in CD4+ T cells obstructs current efforts to cure infection. The so-called kick-and-kill paradigm proposes to purge these reservoirs by combining latency-reversing agents with immune effectors such as cytotoxic T lymphocytes. Support for this approach is largely based on success in latency models, which do not fully reflect the makeup of latent reservoirs in individuals on long-term antiretroviral therapy (ART). Recent studies have shown that CD8+ T cells have the potential to recognize defective proviruses, which comprise the vast majority of all infected cells, and that the proviral landscape can be shaped over time due to in vivo clonal expansion of infected CD4+ T cells. Here, we have shown that treating CD4+ T cells from ART-treated individuals with combinations of potent latency-reversing agents and autologous CD8+ T cells consistently reduced cell-associated HIV DNA, but failed to deplete replication-competent virus. These CD8+ T cells recognized and potently eliminated CD4+ T cells that were newly infected with autologous reservoir virus, ruling out a role for both immune escape and CD8+ T cell dysfunction. Thus, our results suggest that cells harboring replication-competent HIV possess an inherent resistance to CD8+ T cells that may need to be addressed to cure infection.

  16. Systemic immunological tolerance to ocular antigens is mediated by TRAIL-expressing CD8+ T cells.

    Science.gov (United States)

    Griffith, Thomas S; Brincks, Erik L; Gurung, Prajwal; Kucaba, Tamara A; Ferguson, Thomas A

    2011-01-15

    Systemic immunological tolerance to Ag encountered in the eye restricts the formation of potentially damaging immune responses that would otherwise be initiated at other anatomical locations. We previously demonstrated that tolerance to Ag administered via the anterior chamber (AC) of the eye required Fas ligand-mediated apoptotic death of inflammatory cells that enter the eye in response to the antigenic challenge. Moreover, the systemic tolerance induced after AC injection of Ag was mediated by CD8(+) regulatory T cells. This study examined the mechanism by which these CD8(+) regulatory T cells mediate tolerance after AC injection of Ag. AC injection of Ag did not prime CD4(+) T cells and led to increased TRAIL expression by splenic CD8(+) T cells. Unlike wild-type mice, Trail(-/-) or Dr5(-/-) mice did not develop tolerance to Ag injected into the eye, even though responding lymphocytes underwent apoptosis in the AC of the eyes of these mice. CD8(+) T cells from Trail(-/-) mice that were first injected via the AC with Ag were unable to transfer tolerance to naive recipient wild-type mice, but CD8(+) T cells from AC-injected wild-type or Dr5(-/-) mice could transfer tolerance. Importantly, the transferred wild-type (Trail(+/+)) CD8(+) T cells were also able to decrease the number of infiltrating inflammatory cells into the eye; however, Trail(-/-) CD8(+) T cells were unable to limit the inflammatory cell ingress. Together, our data suggest that "helpless" CD8(+) regulatory T cells generated after AC injection of Ag enforce systemic tolerance in a TRAIL-dependent manner to inhibit inflammation in the eye.

  17. Involvement of CD8+ T cell-mediated immune responses in LcrV DNA vaccine induced protection against lethal Yersinia pestis challenge.

    Science.gov (United States)

    Wang, Shixia; Goguen, Jon D; Li, Fusheng; Lu, Shan

    2011-09-09

    Yersinia pestis (Y. pestis) is the causative pathogen of plague, a highly fatal disease for which an effective vaccine, especially against mucosal transmission, is still not available. Like many bacterial infections, antigen-specific antibody responses have been traditionally considered critical, if not solely responsible, for vaccine-induced protection against Y. pestis. Studies in recent years have suggested the importance of T cell immune responses against Y. pestis infection but information is still limited about the details of Y. pestis antigen-specific T cell immune responses. In current report, studies are conducted to identify the presence of CD8+ T cell epitopes in LcrV protein, the leading antigen of plague vaccine development. Furthermore, depletion of CD8+ T cells in LcrV DNA vaccinated Balb/C mice led to reduced protection against lethal intranasal challenge of Y. pestis. These findings establish that an LcrV DNA vaccine is able to elicit CD8+ T cell immune responses against specific epitopes of this key plague antigen and that a CD8+ T cell immune response is involved in LcrV DNA vaccine-elicited protection. Future studies in plague vaccine development will need to examine if the presence of detectable T cell immune responses, in particular CD8+ T-cell immune responses, will enhance the protection against Y. pestis in higher animal species or humans. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Tumor-Induced CD8+ T-Cell Dysfunction in Lung Cancer Patients

    Directory of Open Access Journals (Sweden)

    Heriberto Prado-Garcia

    2012-01-01

    Full Text Available Lung cancer is the leading cause of cancer deaths worldwide and one of the most common types of cancers. The limited success of chemotherapy and radiotherapy regimes have highlighted the need to develop new therapies like antitumor immunotherapy. CD8+ T-cells represent a major arm of the cell-mediated anti-tumor response and a promising target for developing T-cell-based immunotherapies against lung cancer. Lung tumors, however, have been considered to possess poor immunogenicity; even so, lung tumor-specific CD8+ T-cell clones can be established that possess cytotoxicity against autologous tumor cells. This paper will focus on the alterations induced in CD8+ T-cells by lung cancer. Although memory CD8+ T-cells infiltrate lung tumors, in both tumor-infiltrating lymphocytes (TILs and malignant pleural effusions, these cells are dysfunctional and the effector subset is reduced. We propose that chronic presence of lung tumors induces dysfunctions in CD8+ T-cells and sensitizes them to activation-induced cell death, which may be associated with the poor clinical responses observed in immunotherapeutic trials. Getting a deeper knowledge of the evasion mechanisms lung cancer induce in CD8+ T-cells should lead to further understanding of lung cancer biology, overcome tumor evasion mechanisms, and design improved immunotherapeutic treatments for lung cancer.

  19. Role of CD5-negative CD8 T Cells in Adaptation to Antigenic ...

    African Journals Online (AJOL)

    Plasma HIV-1 load was measured by Versant™ ... process leads to substantial progress in the .... cells/µl/month in patients with baseline viral load ... in blood CD8+ T cell count during anolignan A treatment using logistic regression models.

  20. Oral Salmonella: malaria circumsporozoite recombinants induce specific CD8+ cytotoxic T cells

    OpenAIRE

    1990-01-01

    Oral immunization with an attenuated Salmonella typhimurium recombinant containing the full-length Plasmodium berghei circumsporozoite (CS) gene induces protective immunity against P. berghei sporozoite challenge in the absence of antibody. We found that this immunity was mediated through the induction of specific CD8+ T cells since in vivo elimination of CD8+ cells abrogated protection. In vitro studies revealed that this Salmonella-P. berghei CS recombinant induced class I- restricted CD8+ ...

  1. Strong homeostatic TCR signals induce formation of self-tolerant virtual memory CD8 T cells.

    Science.gov (United States)

    Drobek, Ales; Moudra, Alena; Mueller, Daniel; Huranova, Martina; Horkova, Veronika; Pribikova, Michaela; Ivanek, Robert; Oberle, Susanne; Zehn, Dietmar; McCoy, Kathy D; Draber, Peter; Stepanek, Ondrej

    2018-05-11

    Virtual memory T cells are foreign antigen-inexperienced T cells that have acquired memory-like phenotype and constitute 10-20% of all peripheral CD8 + T cells in mice. Their origin, biological roles, and relationship to naïve and foreign antigen-experienced memory T cells are incompletely understood. By analyzing T-cell receptor repertoires and using retrogenic monoclonal T-cell populations, we demonstrate that the virtual memory T-cell formation is a so far unappreciated cell fate decision checkpoint. We describe two molecular mechanisms driving the formation of virtual memory T cells. First, virtual memory T cells originate exclusively from strongly self-reactive T cells. Second, the stoichiometry of the CD8 interaction with Lck regulates the size of the virtual memory T-cell compartment via modulating the self-reactivity of individual T cells. Although virtual memory T cells descend from the highly self-reactive clones and acquire a partial memory program, they are not more potent in inducing experimental autoimmune diabetes than naïve T cells. These data underline the importance of the variable level of self-reactivity in polyclonal T cells for the generation of functional T-cell diversity. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

  2. Superior induction and maintenance of protective CD8 T cells in mice infected with mouse cytomegalovirus vector expressing RAE-1γ.

    Science.gov (United States)

    Trsan, Tihana; Busche, Andreas; Abram, Maja; Wensveen, Felix M; Lemmermann, Niels A; Arapovic, Maja; Babic, Marina; Tomic, Adriana; Golemac, Mijo; Brinkmann, Melanie M; Jäger, Wiebke; Oxenius, Annette; Polic, Bojan; Krmpotic, Astrid; Messerle, Martin; Jonjic, Stipan

    2013-10-08

    Due to a unique pattern of CD8 T-cell response induced by cytomegaloviruses (CMVs), live attenuated CMVs are attractive candidates for vaccine vectors for a number of clinically relevant infections and tumors. NKG2D is one of the most important activating NK cell receptors that plays a role in costimulation of CD8 T cells. Here we demonstrate that the expression of CD8 T-cell epitope of Listeria monocytogenes by a recombinant mouse CMV (MCMV) expressing the NKG2D ligand retinoic acid early-inducible protein 1-gamma (RAE-1γ) dramatically enhanced the effectiveness and longevity of epitope-specific CD8 T-cell response and conferred protection against a subsequent challenge infection with Listeria monocytogenes. Unexpectedly, the attenuated growth in vivo of the CMV vector expressing RAE-1γ and its capacity to enhance specific CD8 T-cell response were preserved even in mice lacking NKG2D, implying additional immune function for RAE-1γ beyond engagement of NKG2D. Thus, vectors expressing RAE-1γ represent a promising approach in the development of CD8 T-cell-based vaccines.

  3. CD8+ T cells complement antibodies in protecting against yellow fever virus.

    Science.gov (United States)

    Bassi, Maria R; Kongsgaard, Michael; Steffensen, Maria A; Fenger, Christina; Rasmussen, Michael; Skjødt, Karsten; Finsen, Bente; Stryhn, Anette; Buus, Søren; Christensen, Jan P; Thomsen, Allan R

    2015-02-01

    The attenuated yellow fever (YF) vaccine (YF-17D) was developed in the 1930s, yet little is known about the protective mechanisms underlying its efficiency. In this study, we analyzed the relative contribution of cell-mediated and humoral immunity to the vaccine-induced protection in a murine model of YF-17D infection. Using different strains of knockout mice, we found that CD4(+) T cells, B cells, and Abs are required for full clinical protection of vaccinated mice, whereas CD8(+) T cells are dispensable for long-term survival after intracerebral challenge. However, by analyzing the immune response inside the infected CNS, we observed an accelerated T cell influx into the brain after intracerebral challenge of vaccinated mice, and this T cell recruitment correlated with improved virus control in the brain. Using mice deficient in B cells we found that, in the absence of Abs, YF vaccination can still induce some antiviral protection, and in vivo depletion of CD8(+) T cells from these animals revealed a pivotal role for CD8(+) T cells in controlling virus replication in the absence of a humoral response. Finally, we demonstrated that effector CD8(+) T cells also contribute to viral control in the presence of circulating YF-specific Abs. To our knowledge, this is the first time that YF-specific CD8(+) T cells have been demonstrated to possess antiviral activity in vivo. Copyright © 2015 by The American Association of Immunologists, Inc.

  4. Transmitted/Founder Viruses Rapidly Escape from CD8+ T Cell Responses in Acute Hepatitis C Virus Infection.

    Science.gov (United States)

    Bull, Rowena A; Leung, Preston; Gaudieri, Silvana; Deshpande, Pooja; Cameron, Barbara; Walker, Melanie; Chopra, Abha; Lloyd, Andrew R; Luciani, Fabio

    2015-05-01

    The interaction between hepatitis C virus (HCV) and cellular immune responses during very early infection is critical for disease outcome. To date, the impact of antigen-specific cellular immune responses on the evolution of the viral population establishing infection and on potential escape has not been studied. Understanding these early host-virus dynamics is important for the development of a preventative vaccine. Three subjects who were followed longitudinally from the detection of viremia preseroconversion until disease outcome were analyzed. The evolution of transmitted/founder (T/F) viruses was undertaken using deep sequencing. CD8(+) T cell responses were measured via enzyme-linked immunosorbent spot (ELISpot) assay using HLA class I-restricted T/F epitopes. T/F viruses were rapidly extinguished in all subjects associated with either viral clearance (n = 1) or replacement with viral variants leading to establishment of chronic infection (n = 2). CD8(+) T cell responses against 11 T/F epitopes were detectable by 33 to 44 days postinfection, and 5 of these epitopes had not previously been reported. These responses declined rapidly in those who became chronically infected and were maintained in the subject who cleared infection. Higher-magnitude CD8(+) T cell responses were associated with rapid development of immune escape variants at a rate of up to 0.1 per day. Rapid escape from CD8(+) T cell responses has been quantified for the first time in the early phase of primary HCV infection. These rapid escape dynamics were associated with higher-magnitude CD8(+) T cell responses. These findings raise questions regarding optimal selection of immunogens for HCV vaccine development and suggest that detailed analysis of individual epitopes may be required. A major limitation in our detailed understanding of the role of immune response in HCV clearance has been the lack of data on very early primary infection when the transmitted viral variants successfully establish

  5. CD8+ T cell infiltration in breast and colon cancer: A histologic and statistical analysis.

    Directory of Open Access Journals (Sweden)

    James Ziai

    Full Text Available The prevalence of cytotoxic tumor infiltrating lymphocytes (TILs has demonstrated prognostic value in multiple tumor types. In particular, CD8 counts (in combination with CD3 and CD45RO have been shown to be superior to traditional UICC staging in colon cancer patients and higher total CD8 counts have been associated with better survival in breast cancer patients. However, immune infiltrate heterogeneity can lead to potentially significant misrepresentations of marker prevalence in routine histologic sections. We examined step sections of breast and colorectal cancer samples for CD8+ T cell prevalence by standard chromogenic immunohistochemistry to determine marker variability and inform practice of T cell biomarker assessment in formalin-fixed, paraffin-embedded (FFPE tissue samples. Stained sections were digitally imaged and CD8+ lymphocytes within defined regions of interest (ROI including the tumor and surrounding stroma were enumerated. Statistical analyses of CD8+ cell count variability using a linear model/ANOVA framework between patients as well as between levels within a patient sample were performed. Our results show that CD8+ T-cell distribution is highly homogeneous within a standard tissue sample in both colorectal and breast carcinomas. As such, cytotoxic T cell prevalence by immunohistochemistry on a single level or even from a subsample of biopsy fragments taken from that level can be considered representative of cytotoxic T cell infiltration for the entire tumor section within the block. These findings support the technical validity of biomarker strategies relying on CD8 immunohistochemistry.

  6. Immune Checkpoint Function of CD85j in CD8 T Cell Differentiation and Aging

    Directory of Open Access Journals (Sweden)

    Claire E. Gustafson

    2017-06-01

    Full Text Available Aging is associated with an increased susceptibility to infection and a failure to control latent viruses thought to be driven, at least in part, by alterations in CD8 T cell function. The aging T cell repertoire is characterized by an accumulation of effector CD8 T cells, many of which express the negative regulatory receptor CD85j. To define the biological significance of CD85j expression on CD8 T cells and to address the question whether presence of CD85j in older individuals is beneficial or detrimental for immune function, we examined the specific attributes of CD8 T cells expressing CD85j as well as the functional role of CD85j in antigen-specific CD8 T cell responses during immune aging. Here, we show that CD85j is mainly expressed by terminally differentiated effector (TEMRAs CD8 T cells, which increase with age, in cytomegalovirus (CMV infection and in males. CD85j+ CMV-specific cells demonstrate clonal expansion. However, TCR diversity is similar between CD85j+ and CD85j− compartments, suggesting that CD85j does not directly impact the repertoire of antigen-specific cells. Further phenotypic and functional analyses revealed that CD85j identifies a specific subset of CMV-responsive CD8 T cells that coexpress a marker of senescence (CD57 but retain polyfunctional cytokine production and expression of cytotoxic mediators. Blocking CD85j binding enhanced proliferation of CMV-specific CD8 T cells upon antigen stimulation but did not alter polyfunctional cytokine production. Taken together, these data demonstrate that CD85j characterizes a population of “senescent,” but not exhausted antigen-specific effector CD8 T cells and indicates that CD85j is an important checkpoint regulator controlling expansion of virus-specific T cells during aging. Inhibition of CD85j activity may be a mechanism to promote stronger CD8 T cell effector responses during immune aging.

  7. Regulation of CD8+ T cell responses to retinal antigen by local FoxP3+ regulatory T cells

    Directory of Open Access Journals (Sweden)

    Scott W McPherson

    2012-06-01

    Full Text Available While pathogenic CD4 T cells are well known mediators of autoimmune uveoretinitis, CD8 T cells can also be uveitogenic. Since preliminary studies indicated that C57BL/6 mice were minimally susceptible to autoimmune uveoretinitis induction by CD8 T cells, the basis of the retinal disease resistance was sought. Mice that express β-galactosidase (βgal on a retina-specific promoter (arrβgal mice were backcrossed to mice expressing green fluorescent protein and diphtheria toxin receptor under control of the Foxp3 promoter (Foxp3-DTR/GFP mice, and to T cell receptor transgenic mice that produce βgal specific CD8 T cells (BG1 mice. These mice were used to explore the role of regulatory T cells in the resistance to retinal autoimmune disease. Experiments with T cells from double transgenic BG1 x Foxp3-DTR/GFP mice transferred into Foxp3-DTR/GFP x arrβgal mice confirmed that the retina was well protected from attempts to induce disease by adoptive transfer of activated BG1 T cells. The successful induction of retinal disease following unilateral intraocular administration of diphtheria toxin to deplete regulatory T cells showed that the protective activity was dependent on local, toxin-sensitive regulatory T cells; the opposite, untreated eye remained disease-free. Although there were very few Foxp3+ regulatory T cells in the parenchyma of quiescent retina, and they did not accumulate in retina, their depletion by local toxin administration led to disease susceptibility. We propose that these regulatory T cells modulate the pathogenic activity of βgal-specific CD8 T cells in the retinas of arrβgal mice on a local basis, allowing immunoregulation to be responsive to local conditions.

  8. Ikaros imposes a barrier to CD8+ T cell differentiation by restricting autocrine IL-2 production.

    Science.gov (United States)

    O'Brien, Shaun; Thomas, Rajan M; Wertheim, Gerald B; Zhang, Fuqin; Shen, Hao; Wells, Andrew D

    2014-06-01

    Naive CD4(+) T cells require signals from the TCR and CD28 to produce IL-2, expand, and differentiate. However, these same signals are not sufficient to induce autocrine IL-2 production by naive CD8(+) T cells, which require cytokines provided by other cell types to drive their differentiation. The basis for failed autocrine IL-2 production by activated CD8(+) cells is unclear. We find that Ikaros, a transcriptional repressor that silences IL-2 in anergic CD4(+) T cells, also restricts autocrine IL-2 production by CD8(+) T cells. We find that CD8(+) T cell activation in vitro in the absence of exogenous cytokines and CD4 help leads to marked induction of Ikaros, a known repressor of the Il2 gene. Naive murine CD8 T cells haplo-insufficient for Ikzf1 failed to upregulate Ikaros, produced autocrine IL-2, and differentiated in an IL-2-dependent manner into IFN-γ-producing CTLs in response to TCR/CD28 stimulation alone. Furthermore, Ikzf1 haplo-insufficient CD8(+) T cells were more effective at controlling Listeria infection and B16 melanoma growth in vivo, and they could provide help to neighboring, non-IL-2-producing cells to differentiate into IFN-γ-producing effectors. Therefore, by repressing autocrine IL-2 production, Ikaros ensures that naive CD8(+) T cells remain dependent on licensing by APCs and CD4(+) T cells, and it may therefore act as a cell-intrinsic safeguard against inappropriate CTL differentiation and immunopathology. Copyright © 2014 by The American Association of Immunologists, Inc.

  9. Neutrophil trails guide influenza-specific CD8T cells in the airways.

    Science.gov (United States)

    Lim, Kihong; Hyun, Young-Min; Lambert-Emo, Kris; Capece, Tara; Bae, Seyeon; Miller, Richard; Topham, David J; Kim, Minsoo

    2015-09-04

    During viral infections, chemokines guide activated effector T cells to infection sites. However, the cells responsible for producing these chemokines and how such chemokines recruit T cells are unknown. Here, we show that the early recruitment of neutrophils into influenza-infected trachea is essential for CD8(+) T cell-mediated immune protection in mice. We observed that migrating neutrophils leave behind long-lasting trails that are enriched in the chemokine CXCL12. Experiments with granulocyte-specific CXCL12 conditionally depleted mice and a CXCR4 antagonist revealed that CXCL12 derived from neutrophil trails is critical for virus-specific CD8(+) T cell recruitment and effector functions. Collectively, these results suggest that neutrophils deposit long-lasting, chemokine-containing trails, which may provide both chemotactic and haptotactic cues for efficient CD8(+) T cell migration and localization in influenza-infected tissues. Copyright © 2015, American Association for the Advancement of Science.

  10. Neutrophil trails guide influenza-specific CD8+ T cells in the airways

    Science.gov (United States)

    Lim, Kihong; Hyun, Young-Min; Lambert-Emo, Kris; Capece, Tara; Bae, Seyeon; Miller, Richard; Topham, David J.; Kim, Minsoo

    2016-01-01

    During viral infections, chemokines guide activated effector T cells to infection sites. However, the cells responsible for producing these chemokines and how such chemokines recruit T cells is unknown. Here, we show that the early recruitment of neutrophils into influenza-infected trachea is essential for CD8+ T cell-mediated immune protection in mice. We observed that migrating neutrophils leave behind long-lasting trails that are enriched in the chemokine CXCL12. Experiments with granulocyte-specific CXCL12 conditional knock-out mice and a CXCR4 antagonist revealed that CXCL12 derived from neutrophil trails is critical for virus-specific CD8+ T cell recruitment and effector functions. Collectively, these results suggest neutrophils deposit long-lasting, chemokine-containing trails, which may provide both chemotactic and haptotactic cues for efficient CD8+ T cell migration and localization in influenza-infected tissues. PMID:26339033

  11. Impact of clonal competition for peptide-MHC complexes on the CD8[superscript +] T-cell repertoire selection in a persistent viral infection

    Energy Technology Data Exchange (ETDEWEB)

    Wynn, Katherine K.; Fulton, Zara; Cooper, Leanne; Silins, Sharon L.; Gras, Stephanie; Archbold, Julia K.; Tynan, Fleur E.; Miles, John J.; McCluskey, James; Burrows, Scott R.; Rossjohn, Jamie; Khanna, Rajiv (Monash); (Queensland Inst. of Med. Rsrch.); (Melbourne)

    2008-04-29

    CD8{sup +} T-cell responses to persistent viral infections are characterized by the accumulation of an oligoclonal T-cell repertoire and a reduction in the naive T-cell pool. However, the precise mechanism for this phenomenon remains elusive. Here we show that human cytomegalovirus (HCMV)-specific CD8{sup +} T cells recognizing distinct epitopes from the pp65 protein and restricted through an identical HLA class I allele (HLA B*3508) exhibited either a highly conserved public T-cell repertoire or a private, diverse T-cell response, which was uniquely altered in each donor following in vitro antigen exposure. Selection of a public T-cell receptor (TCR) was coincident with an atypical major histocompatibility complex (MHC)-peptide structure, in that the epitope adopted a helical conformation that bulged from the peptide-binding groove, while a diverse TCR profile was observed in response to the epitope that formed a flatter, more 'featureless' landscape. Clonotypes with biased TCR usage demonstrated more efficient recognition of virus-infected cells, a greater CD8 dependency, and were more terminally differentiated in their phenotype when compared with the T cells expressing diverse TCR. These findings provide new insights into our understanding on how the biology of antigen presentation in addition to the structural features of the pMHC-I might shape the T-cell repertoire and its phenotype.

  12. CD8{sup +}CD25{sup +} T cells reduce atherosclerosis in apoE(−/−) mice

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianchang; Dimayuga, Paul C.; Zhao, Xiaoning; Yano, Juliana; Lio, Wai Man; Trinidad, Portia; Honjo, Tomoyuki; Cercek, Bojan; Shah, Prediman K.; Chyu, Kuang-Yuh, E-mail: Chyuk@cshs.org

    2014-01-17

    Highlights: •The role of a sub-population of CD8{sup +} T cells with suppressor functions was investigated in atherosclerosis. •CD8{sup +}CD25{sup +} T cells from adult apoE(−/−) mice had phenotype characteristics of T suppressor cells. •These CD8{sup +}CD25{sup +} T cells reduced CD4{sup +} T cell proliferation and CD8{sup +} cytotoxic activity in vitro. •Adoptive transfer of CD8{sup +}CD25{sup +} T cells significantly reduced atherosclerosis. •CD8{sup +}CD25{sup +} T cells have a suppressive function in atherosclerosis. -- Abstract: Background: It is increasingly evident that CD8{sup +} T cells are involved in atherosclerosis but the specific subtypes have yet to be defined. CD8{sup +}CD25{sup +} T cells exert suppressive effects on immune signaling and modulate experimental autoimmune disorders but their role in atherosclerosis remains to be determined. The phenotype and functional role of CD8{sup +}CD25{sup +} T cells in experimental atherosclerosis were investigated in this study. Methods and results: CD8{sup +}CD25{sup +} T cells were observed in atherosclerotic plaques of apoE(−/−) mice fed hypercholesterolemic diet. Characterization by flow cytometric analysis and functional evaluation using a CFSE-based proliferation assays revealed a suppressive phenotype and function of splenic CD8{sup +}CD25{sup +} T cells from apoE(−/−) mice. Depletion of CD8{sup +}CD25{sup +} from total CD8{sup +} T cells rendered higher cytolytic activity of the remaining CD8{sup +}CD25{sup −} T cells. Adoptive transfer of CD8{sup +}CD25{sup +} T cells into apoE(−/−) mice suppressed the proliferation of splenic CD4{sup +} T cells and significantly reduced atherosclerosis in recipient mice. Conclusions: Our study has identified an athero-protective role for CD8{sup +}CD25{sup +} T cells in experimental atherosclerosis.

  13. Cooperativity of HIV-Specific Cytolytic CD4 T Cells and CD8 T Cells in Control of HIV Viremia

    Science.gov (United States)

    Johnson, Susan; Eller, Michael; Teigler, Jeffrey E.; Maloveste, Sebastien M.; Schultz, Bruce T.; Soghoian, Damien Z.; Lu, Richard; Oster, Alexander F.; Chenine, Agnès-Laurence; Alter, Galit; Dittmer, Ulf; Marovich, Mary; Robb, Merlin L.; Michael, Nelson L.; Bolton, Diane

    2015-01-01

    ABSTRACT CD4+ T cells play a pivotal role in the control of chronic viral infections. Recently, nontraditional CD4+ T cell functions beyond helper effects have been described, and a role for cytolytic CD4+ T cells in the control of HIV infection has been suggested. We define here the transcriptional, phenotypic, and functional profiles of HIV-specific cytolytic CD4+ T cells. Fluidigm BioMark and multiparameter flow cytometric analysis of HIV-specific cytolytic CD4+ T cells revealed a distinct transcriptional signature compared to Th1 CD4+ cells but shared similar features with HIV-specific cytolytic CD8+ T cells. Furthermore, HIV-specific cytolytic CD4+ T cells showed comparable killing activity relative to HIV-specific CD8+ T cells and worked cooperatively in the elimination of virally infected cells. Interestingly, we found that cytolytic CD4+ T cells emerge early during acute HIV infection and tightly follow acute viral load trajectory. This emergence was associated to the early viral set point, suggesting an involvement in early control, in spite of CD4 T cell susceptibility to HIV infection. Our data suggest cytolytic CD4+ T cells as an independent subset distinct from Th1 cells that show combined activity with CD8+ T cells in the long-term control of HIV infection. IMPORTANCE The ability of the immune system to control chronic HIV infection is of critical interest to both vaccine design and therapeutic approaches. Much research has focused on the effect of the ability of CD8+ T cells to control the virus, while CD4+ T cells have been overlooked as effectors in HIV control due to the fact that they are preferentially infected. We show here that a subset of HIV-specific CD4+ T cells cooperate in the cytolytic control of HIV replication. Moreover, these cells represent a distinct subset of CD4+ T cells showing significant transcriptional and phenotypic differences compared to HIV-specific Th1 cells but with similarities to CD8+ T cells. These findings are

  14. Requirement for CD4 T Cell Help in Generating Functional CD8 T Cell Memory

    Science.gov (United States)

    Shedlock, Devon J.; Shen, Hao

    2003-04-01

    Although primary CD8 responses to acute infections are independent of CD4 help, it is unknown whether a similar situation applies to secondary responses. We show that depletion of CD4 cells during the recall response has minimal effect, whereas depletion during the priming phase leads to reduced responses by memory CD8 cells to reinfection. Memory CD8 cells generated in CD4+/+ mice responded normally when transferred into CD4-/- hosts, whereas memory CD8 cells generated in CD4-/- mice mounted defective recall responses in CD4+/+ adoptive hosts. These results demonstrate a previously undescribed role for CD4 help in the development of functional CD8 memory.

  15. CD27 instructs CD4+ T cells to provide help for the memory CD8+ T cell response after protein immunization

    NARCIS (Netherlands)

    Xiao, Yanling; Peperzak, Victor; Keller, Anna M.; Borst, Jannie

    2008-01-01

    For optimal quality, memory CD8(+) T cells require CD4(+) T cell help. We have examined whether CD4(+) T cells require CD27 to deliver this help, in a model of intranasal OVA protein immunization. CD27 deficiency reduced the capacity of CD4(+) T cells to support Ag-specific CD8(+) T cell

  16. HIV-Specific CD8+ T Cell-Mediated Viral Suppression Correlates With the Expression of CD57

    DEFF Research Database (Denmark)

    Jensen, Sanne S; Tingstedt, Jeanette Linnea; Larsen, Tine Kochendorf

    2016-01-01

    BACKGROUND: Virus-specific CD8(+) T-cell responses are believed to play an important role in the control of HIV-1 infection; however, what constitutes an effective HIV-1 CD8(+) T-cell response remains a topic of debate. The ex vivo viral suppressive capacity was measured of CD8(+) T cells from 44...

  17. Phenotypic and Functional Alterations in Circulating Memory CD8 T Cells with Time after Primary Infection.

    Directory of Open Access Journals (Sweden)

    Matthew D Martin

    2015-10-01

    Full Text Available Memory CD8 T cells confer increased protection to immune hosts upon secondary viral, bacterial, and parasitic infections. The level of protection provided depends on the numbers, quality (functional ability, and location of memory CD8 T cells present at the time of infection. While primary memory CD8 T cells can be maintained for the life of the host, the full extent of phenotypic and functional changes that occur over time after initial antigen encounter remains poorly characterized. Here we show that critical properties of circulating primary memory CD8 T cells, including location, phenotype, cytokine production, maintenance, secondary proliferation, secondary memory generation potential, and mitochondrial function change with time after infection. Interestingly, phenotypic and functional alterations in the memory population are not due solely to shifts in the ratio of effector (CD62Llo and central memory (CD62Lhi cells, but also occur within defined CD62Lhi memory CD8 T cell subsets. CD62Lhi memory cells retain the ability to efficiently produce cytokines with time after infection. However, while it is was not formally tested whether changes in CD62Lhi memory CD8 T cells over time occur in a cell intrinsic manner or are due to selective death and/or survival, the gene expression profiles of CD62Lhi memory CD8 T cells change, phenotypic heterogeneity decreases, and mitochondrial function and proliferative capacity in either a lymphopenic environment or in response to antigen re-encounter increase with time. Importantly, and in accordance with their enhanced proliferative and metabolic capabilities, protection provided against chronic LCMV clone-13 infection increases over time for both circulating memory CD8 T cell populations and for CD62Lhi memory cells. Taken together, the data in this study reveal that memory CD8 T cells continue to change with time after infection and suggest that the outcome of vaccination strategies designed to elicit

  18. Identification and HLA-tetramer-validation of human CD4+ and CD8+ T cell responses against HCMV proteins IE1 and IE2.

    Science.gov (United States)

    Braendstrup, Peter; Mortensen, Bo Kok; Justesen, Sune; Osterby, Thomas; Rasmussen, Michael; Hansen, Andreas Martin; Christiansen, Claus Bohn; Hansen, Morten Bagge; Nielsen, Morten; Vindeløv, Lars; Buus, Søren; Stryhn, Anette

    2014-01-01

    Human cytomegalovirus (HCMV) is an important human pathogen. It is a leading cause of congenital infection and a leading infectious threat to recipients of solid organ transplants as well as of allogeneic hematopoietic cell transplants. Moreover, it has recently been suggested that HCMV may promote tumor development. Both CD4+ and CD8+ T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8+ T cell responses against the pp65 phosphoprotein. In this study, we have focused on CD4+ and CD8+ T cell responses against the immediate early 1 and 2 proteins (IE1 and IE2). Using overlapping peptides spanning the entire IE1 and IE2 sequences, peripheral blood mononuclear cells from 16 healthy, HLA-typed, donors were screened by ex vivo IFN-γ ELISpot and in vitro intracellular cytokine secretion assays. The specificities of CD4+ and CD8+ T cell responses were identified and validated by HLA class II and I tetramers, respectively. Eighty-one CD4+ and 44 CD8+ T cell responses were identified representing at least seven different CD4 epitopes and 14 CD8 epitopes restricted by seven and 11 different HLA class II and I molecules, respectively, in total covering 91 and 98% of the Caucasian population, respectively. Presented in the context of several different HLA class II molecules, two epitope areas in IE1 and IE2 were recognized in about half of the analyzed donors. These data may be used to design a versatile anti-HCMV vaccine and/or immunotherapy strategy.

  19. Identification and HLA-tetramer-validation of human CD4+ and CD8+ T cell responses against HCMV proteins IE1 and IE2.

    Directory of Open Access Journals (Sweden)

    Peter Braendstrup

    Full Text Available Human cytomegalovirus (HCMV is an important human pathogen. It is a leading cause of congenital infection and a leading infectious threat to recipients of solid organ transplants as well as of allogeneic hematopoietic cell transplants. Moreover, it has recently been suggested that HCMV may promote tumor development. Both CD4+ and CD8+ T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8+ T cell responses against the pp65 phosphoprotein. In this study, we have focused on CD4+ and CD8+ T cell responses against the immediate early 1 and 2 proteins (IE1 and IE2. Using overlapping peptides spanning the entire IE1 and IE2 sequences, peripheral blood mononuclear cells from 16 healthy, HLA-typed, donors were screened by ex vivo IFN-γ ELISpot and in vitro intracellular cytokine secretion assays. The specificities of CD4+ and CD8+ T cell responses were identified and validated by HLA class II and I tetramers, respectively. Eighty-one CD4+ and 44 CD8+ T cell responses were identified representing at least seven different CD4 epitopes and 14 CD8 epitopes restricted by seven and 11 different HLA class II and I molecules, respectively, in total covering 91 and 98% of the Caucasian population, respectively. Presented in the context of several different HLA class II molecules, two epitope areas in IE1 and IE2 were recognized in about half of the analyzed donors. These data may be used to design a versatile anti-HCMV vaccine and/or immunotherapy strategy.

  20. Pre-existing vector immunity does not prevent replication deficient adenovirus from inducing efficient CD8 T-cell memory and recall responses

    DEFF Research Database (Denmark)

    Steffensen, Maria Abildgaard; Jensen, Benjamin Anderschou Holbech; Holst, Peter Johannes

    2012-01-01

    directed against epitopes in the adenoviral vector seemed to correlate with repression of the induced response in re-vaccinated B-cell deficient mice. More importantly, despite a repressed primary effector CD8 T-cell response in Ad5-immune animals subjected to vaccination, memory T cells were generated...... that provided the foundation for an efficient recall response and protection upon subsequent viral challenge. Furthermore, the transgene specific response could be efficiently boosted by homologous re-immunization. Taken together, these studies indicate that adenoviral vectors can be used to induce efficient CD......8 T-cell memory even in individuals with pre-existing vector immunity....

  1. Phenotyping of circulating CD8(+) T cell subsets in human cutaneous leishmaniasis

    Czech Academy of Sciences Publication Activity Database

    Khamesipour, A.; Rostami, M.N.; Tasbihi, M.; Mohammadi, A.M.; Shahrestani, T.; Sarrafnejad, A.; Sohrabi, Yahya; Eskandari, S.E.; Valian, H.K.

    2012-01-01

    Roč. 14, č. 9 (2012), s. 702-711 ISSN 1286-4579 Institutional research plan: CEZ:AV0Z50520514 Institutional support: RVO:68378050 Keywords : CD8(+) T cells * memory T cells * cutaneous leishmania sis * IFN-gamma Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.920, year: 2012

  2. The new numerology of immunity mediated by virus-specific CD8(+) T cells.

    Science.gov (United States)

    Doherty, P C

    1998-08-01

    Our understanding of virus-specific CD8(+) T cell responses is currently being revolutionized by peptide-based assay systems that allow flow cytometric analysis of effector and memory cytotoxic T lymphocyte populations. These techniques are, for the first time, putting the analysis of T-cell-mediated immunity on a quantitative basis.

  3. Role of CD5-negative CD8 + T Cells in Adaptation to Antigenic ...

    African Journals Online (AJOL)

    + T cell recovery in human immunodeficiency virus type 1 (HIV-1) disease. Methods: The increase in the rates of CD8+ T cells over 48 weeks following treatment with 3- oxotirucalla-7, 24-dien-21-oic acid was investigated. Plasma HIV-1 load ...

  4. Proliferation requirements of cytomegalovirus-specific, effector-type human CD8+ T cells

    NARCIS (Netherlands)

    van Leeuwen, Ester M.; Gamadia, Laila E.; Baars, Paul A.; Remmerswaal, Ester B.; ten Berge, Ineke J.; van Lier, René A.

    2002-01-01

    Two prototypic types of virus-specific CD8(+) T cells can be found in latently infected individuals: CD45R0(+)CD27(+)CCR7(-) effector-memory, and CD45RA(+)CD27(-)CCR7(-) effector-type cells. It has recently been implied that CD45RA(+)CD27(-)CCR7(-) T cells are terminally differentiated effector

  5. Human memory CD8 T cell effector potential is epigenetically preserved during in vivo homeostasis.

    Science.gov (United States)

    Abdelsamed, Hossam A; Moustaki, Ardiana; Fan, Yiping; Dogra, Pranay; Ghoneim, Hazem E; Zebley, Caitlin C; Triplett, Brandon M; Sekaly, Rafick-Pierre; Youngblood, Ben

    2017-06-05

    Antigen-independent homeostasis of memory CD8 T cells is vital for sustaining long-lived T cell-mediated immunity. In this study, we report that maintenance of human memory CD8 T cell effector potential during in vitro and in vivo homeostatic proliferation is coupled to preservation of acquired DNA methylation programs. Whole-genome bisulfite sequencing of primary human naive, short-lived effector memory (T EM ), and longer-lived central memory (T CM ) and stem cell memory (T SCM ) CD8 T cells identified effector molecules with demethylated promoters and poised for expression. Effector-loci demethylation was heritably preserved during IL-7- and IL-15-mediated in vitro cell proliferation. Conversely, cytokine-driven proliferation of T CM and T SCM memory cells resulted in phenotypic conversion into T EM cells and was coupled to increased methylation of the CCR7 and Tcf7 loci. Furthermore, haploidentical donor memory CD8 T cells undergoing in vivo proliferation in lymphodepleted recipients also maintained their effector-associated demethylated status but acquired T EM -associated programs. These data demonstrate that effector-associated epigenetic programs are preserved during cytokine-driven subset interconversion of human memory CD8 T cells. © 2017 Abdelsamed et al.

  6. Cloning analysis of HBV-specific CD8 T cell receptor gene in patients with acute hepatitis B

    Directory of Open Access Journals (Sweden)

    Ning DING

    2011-05-01

    Full Text Available Objective To investigate the molecular mechanism of T cell receptor(TCR in CD8 T cell-mediated immune response to HBV in patients with acute hepatitis B(AHB.Methods Peripheral blood mononuclear cells(PBMCs were collected from HLA-A2-positive AHB patients.To determine HBsAg183-191 and HBsAg335-343-specific CD8 T cell frequencies,the PBMCs were stained by fluorescence-labeled anti-CD3,anti-CD8 and pentamers,and analyzed by flow cytometry.PBMCs from 6 patients were stimulated with epitopic peptide HBsAg335-343 in vitro for 3 to 4 weeks.HBV-specific CD8 T cells were isolated by magnetic activated cell sorting followed by flow florescence activated cell sorting.The mRNA of sorted cells was extracted after expanding by IL-2,anti-CD3 and anti-CD8.The full-length gene fragments of variable region of TCR α and β chains were gained by 5’-RACE,and then cloned and sequenced(≥50 clones for single chain of each sample.The gene families of TCR α and β chains were identified and the sequence characters of CDR3 were compared.Results Analysis of more than 600 cloned gene sequences of TCR α and β chains showed that the proliferated HBV-specific CD8 T cells from 6 AHB patients presented a predominant expression in TCR α and chains,with 2-4 α chain families and 1-4 chain families in each case.The α2,α14,α15,β3,β13 and 23 families were detected in more than one case.The chain genes were all 13 for all tested clones in one case.For the same α chain or-chain family,CDR3 sequences tended to be identical in one case but different among cases.Conclusions HBV-specific CD8 T cells with antigenic peptide-induced proliferation present predominance in the usage of TCR α and β chains.This property might be one of the important molecular factors influencing anti-HBV immunity.

  7. Attrition of memory CD8 T cells during sepsis requires LFA-1.

    Science.gov (United States)

    Serbanescu, Mara A; Ramonell, Kimberly M; Hadley, Annette; Margoles, Lindsay M; Mittal, Rohit; Lyons, John D; Liang, Zhe; Coopersmith, Craig M; Ford, Mandy L; McConnell, Kevin W

    2016-11-01

    CD8 T cell loss and dysfunction have been implicated in the increased susceptibility to opportunistic infections during the later immunosuppressive phase of sepsis, but CD8 T cell activation and attrition in early sepsis remain incompletely understood. With the use of a CLP model, we assessed CD8 T cell activation at 5 consecutive time points and found that activation after sepsis results in a distinct phenotype (CD69 + CD25 int CD62L HI ) independent of cognate antigen recognition and TCR engagement and likely through bystander-mediated cytokine effects. Additionally, we observed that sepsis concurrently results in the preferential depletion of a subset of memory-phenotype CD8 T cells that remain "unactivated" (i.e., fail to up-regulate activation markers) by apoptosis. Unactivated CD44 HI OT-I cells were spared from sepsis-induced attrition, as were memory-phenotype CD8 T cells of mice treated with anti-LFA-1 mAb, 1 h after CLP. Perhaps most importantly, we demonstrate that attrition of memory phenotype cells may have a pathologic significance, as elevated IL-6 levels were associated with decreased numbers of memory-phenotype CD8 T cells in septic mice, and preservation of this subset after administration of anti-LFA-1 mAb conferred improved survival at 7 d. Taken together, these data identify potentially modifiable responses of memory-phenotype CD8 T cells in early sepsis and may be particularly important in the application of immunomodulatory therapies in sepsis. © Society for Leukocyte Biology.

  8. LOCAL IMMUNITY BY TISSUE-RESIDENT CD8+ MEMORY T CELLS

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    Thomas eGebhardt

    2012-11-01

    Full Text Available Microbial infection primes a CD8+ cytotoxic T cell response that gives rise to a long-lived population of circulating memory cells able to provide protection against systemic reinfection. Despite this, effective CD8+ T cell surveillance of barrier tissues such as skin and mucosa typically wanes with time, resulting in limited T cell-mediated protection in these peripheral tissues. However, recent evidence suggests that a specialized subset of CD103+ memory T cells can permanently lodge and persist in peripheral tissues, and that these cells can compensate for the loss of peripheral immune surveillance by circulating memory T cells. Here, we review evolving concepts regarding the generation and long-term persistence of these tissue-resident memory T cells (TRM in epithelial and neuronal tissues. We further discuss the role of TRM cells in local infection control and their contribution to localized immune phenomena, in both mice and humans.

  9. Cish actively silences TCR signaling in CD8+ T cells to maintain tumor tolerance.

    Science.gov (United States)

    Palmer, Douglas C; Guittard, Geoffrey C; Franco, Zulmarie; Crompton, Joseph G; Eil, Robert L; Patel, Shashank J; Ji, Yun; Van Panhuys, Nicholas; Klebanoff, Christopher A; Sukumar, Madhusudhanan; Clever, David; Chichura, Anna; Roychoudhuri, Rahul; Varma, Rajat; Wang, Ena; Gattinoni, Luca; Marincola, Francesco M; Balagopalan, Lakshmi; Samelson, Lawrence E; Restifo, Nicholas P

    2015-11-16

    Improving the functional avidity of effector T cells is critical in overcoming inhibitory factors within the tumor microenvironment and eliciting tumor regression. We have found that Cish, a member of the suppressor of cytokine signaling (SOCS) family, is induced by TCR stimulation in CD8(+) T cells and inhibits their functional avidity against tumors. Genetic deletion of Cish in CD8(+) T cells enhances their expansion, functional avidity, and cytokine polyfunctionality, resulting in pronounced and durable regression of established tumors. Although Cish is commonly thought to block STAT5 activation, we found that the primary molecular basis of Cish suppression is through inhibition of TCR signaling. Cish physically interacts with the TCR intermediate PLC-γ1, targeting it for proteasomal degradation after TCR stimulation. These findings establish a novel targetable interaction that regulates the functional avidity of tumor-specific CD8(+) T cells and can be manipulated to improve adoptive cancer immunotherapy.

  10. Suppression of HIV replication by CD8+regulatory T-cells in elite controllers

    Directory of Open Access Journals (Sweden)

    Wei eLu

    2016-04-01

    Full Text Available We previously demonstrated in the Chinese macaque model that an oral vaccine made of inactivated SIV and lactobacillus plantarum induced CD8+regulatory T-cells which suppressed the activation of SIV+CD4+T-cells, prevented SIV replication and protected macaques from SIV challenges.Here ,we sought whether a similar population of CD8+T-regs would induce the suppression of HIV replication in elite controllers (ECs, a small population (3‰ of HIV-infected patients with undetectable HIV replication. For that purpose, we investigated the in vitro antiviral activity of fresh CD8+T-cells on HIV-infected CD4+T-cells taken from 10 ECs. The 10 ECs had a classical genomic profile: all of them carried the KIR3DL1 gene and nine carried at least one allele of HLA-B:Bw4-80Ile ( i.e. with an isoleucine residue at position 80. In the nine HLA-B:Bw4-80Ile positive patients, we demonstrated a strong viral suppression byKIR3DL1-expressing CD8+T-cells that required cell-to-cell contact to switch off the activation signals in infected CD4+T-cells. KIR3DL1-expressing CD8+T-cells withdrawal and KIR3DL1 neutralization by a specific anti-KIR antibody inhibited the suppression of viral replication. Our findings provide the first evidence for an instrumental role of KIR-expressing CD8+ regulatory T- cells in the natural control of HIV-1 infection.

  11. Spontaneous CD8 T cell responses against the melanocyte differentiation antigen RAB38/NY-MEL-1 in melanoma patients.

    Science.gov (United States)

    Walton, Senta M; Gerlinger, Marco; de la Rosa, Olga; Nuber, Natko; Knights, Ashley; Gati, Asma; Laumer, Monika; Strauss, Laura; Exner, Carolin; Schäfer, Niklaus; Urosevic, Mirjana; Dummer, Reinhard; Tiercy, Jean-Marie; Mackensen, Andreas; Jaeger, Elke; Lévy, Frédéric; Knuth, Alexander; Jäger, Dirk; Zippelius, Alfred

    2006-12-01

    The melanocyte differentiation Ag RAB38/NY-MEL-1 was identified by serological expression cloning (SEREX) and is expressed in the vast majority of melanoma lesions. The immunogenicity of RAB38/NY-MEL-1 has been corroborated previously by the frequent occurrence of specific Ab responses in melanoma patients. To elucidate potential CD8 T cell responses, we applied in vitro sensitization with overlapping peptides spanning the RAB38/NY-MEL-1 protein sequence and the reverse immunology approach. The identified peptide RAB38/NY-MEL-1(50-58) exhibited a marked response in ELISPOT assays after in vitro sensitization of CD8 T cells from HLA-A *0201(+) melanoma patients. In vitro digestion assays using purified proteasomes provided evidence of natural processing of RAB38/NY-MEL-1(50-58) peptide. Accordingly, monoclonal RAB38/NY-MEL-1(50-58)-specific T cell populations were capable of specifically recognizing HLA-A2(+) melanoma cell lines expressing RAB38/NY-MEL-1. Applying fluorescent HLA-A2/RAB38/NY-MEL-1(50-58) multimeric constructs, we were able to document a spontaneously developed memory/effector CD8 T cell response against this peptide in a melanoma patient. To elucidate the Ag-processing pathway, we demonstrate that RAB38/NY-MEL-1(50-58) is produced efficiently by the standard proteasome and the immunoproteasome. In addition to the identification of a RAB38/NY-MEL-1-derived immunogenic CD8 T cell epitope, this study is instrumental for both the onset and monitoring of future RAB38/NY-MEL-1-based vaccination trials.

  12. Cooperation between Epstein-Barr Virus Immune Evasion Proteins Spreads Protection from CD8+ T Cell Recognition across All Three Phases of the Lytic Cycle

    Science.gov (United States)

    Quinn, Laura L.; Zuo, Jianmin; Abbott, Rachel J. M.; Shannon-Lowe, Claire; Tierney, Rosemary J.; Hislop, Andrew D.; Rowe, Martin

    2014-01-01

    CD8+ T cell responses to Epstein-Barr virus (EBV) lytic cycle expressed antigens display a hierarchy of immunodominance, in which responses to epitopes of immediate-early (IE) and some early (E) antigens are more frequently observed than responses to epitopes of late (L) expressed antigens. It has been proposed that this hierarchy, which correlates with the phase-specific efficiency of antigen presentation, may be due to the influence of viral immune-evasion genes. At least three EBV-encoded genes, BNLF2a, BGLF5 and BILF1, have the potential to inhibit processing and presentation of CD8+ T cell epitopes. Here we examined the relative contribution of these genes to modulation of CD8+ T cell recognition of EBV lytic antigens expressed at different phases of the replication cycle in EBV-transformed B-cells (LCLs) which spontaneously reactivate lytic cycle. Selective shRNA-mediated knockdown of BNLF2a expression led to more efficient recognition of immediate-early (IE)- and early (E)-derived epitopes by CD8+ T cells, while knock down of BILF1 increased recognition of epitopes from E and late (L)-expressed antigens. Contrary to what might have been predicted from previous ectopic expression studies in EBV-negative model cell lines, the shRNA-mediated inhibition of BGLF5 expression in LCLs showed only modest, if any, increase in recognition of epitopes expressed in any phase of lytic cycle. These data indicate that whilst BNLF2a interferes with antigen presentation with diminishing efficiency as lytic cycle progresses (IE>E>>L), interference by BILF1 increases with progression through lytic cycle (IEevasion functions are actually relevant in the context of lytic virus replication, and secondly identify lytic-cycle phase-specific effects that provide mechanistic insight into the immunodominance pattern seen for CD8+ T cell responses to EBV lytic antigens. PMID:25144360

  13. Experimental myositis inducible with transfer of dendritic cells presenting a skeletal muscle C protein-derived CD8 epitope peptide.

    Science.gov (United States)

    Okiyama, Naoko; Hasegawa, Hisanori; Oida, Takatoku; Hirata, Shinya; Yokozeki, Hiroo; Fujimoto, Manabu; Miyasaka, Nobuyuki; Kohsaka, Hitoshi

    2015-07-01

    It is suggested that polymyositis, an autoimmune inflammatory myopathy, is mediated by autoaggressive CD8 T cells. Skeletal muscle C protein is a self-antigen that induces C protein-induced myositis, a murine model of polymyositis. To establish a new murine model of myositis inducible with a single CD8 T-cell epitope peptide that derives from the C protein, three internet-based prediction systems were employed to identify 24 candidate peptides of the immunogenic fragment of the C protein and bind theoretically to major histocompatibility complex class I molecules of C57BL/6 (B6) mice. RMA-S cell assay revealed that a HILIYSDV peptide, amino acid position 399-406 of the C protein, had the highest affinity to the H2-K(b) molecules. Transfer of mature bone marrow-derived dendritic cells pulsed with HILIYSDV induced myositis in naive B6 mice. This myositis was suppressed by anti-CD8-depleting antibodies but not by anti-CD4-depleting antibodies. Because this myositis model is mediated by CD8 T cells independently of CD4 T cells, it should be a useful tool to investigate pathology of polymyositis and develop therapies targeting CD8 T cells. © The Japanese Society for Immunology. 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Memory CD8+ T Cells: Orchestrators and Key Players of Innate Immunity?

    Directory of Open Access Journals (Sweden)

    Grégoire Lauvau

    2016-09-01

    Full Text Available Over the past decades, the dichotomy between innate and adaptive immune responses has largely dominated our understanding of immunology. Upon primary encounter with microbial pathogens, differentiation of adaptive immune cells into functional effectors usually takes several days or even longer, making them contribute to host protection only late during primary infection. However, once generated, antigen-experienced T lymphocytes can persist in the organism and constitute a pool of memory cells that mediate fast and effective protection to a recall infection with the same microbial pathogen. Herein, we challenge this classical paradigm by highlighting the "innate nature" of memory CD8+ T cells. First, within the thymus or in the periphery, naïve CD8+ T cells may acquire phenotypic and functional characteristics of memory CD8+ T cells independently of challenge with foreign antigens. Second, both the "unconventional" and the "conventional" memory cells can rapidly express protective effector functions in response to sets of inflammatory cytokines and chemokines signals, independent of cognate antigen triggering. Third, memory CD8+ T cells can act by orchestrating the recruitment, activation, and licensing of innate cells, leading to broad antimicrobial states. Thus, collectively, memory CD8+ T cells may represent important actors of innate immune defenses.

  15. Detailed analysis of Epstein–Barr virus-specific CD4+ and CD8+ T cell responses during infectious mononucleosis

    Science.gov (United States)

    Scherrenburg, J; Piriou, E R W A N; Nanlohy, N M; van Baarle, D

    2008-01-01

    We studied simultaneously Epstein–Barr virus (EBV)-specific CD4+ and CD8+ T cell responses during and after infectious mononucleosis (IM), using a previously described 12-day stimulation protocol with EBNA1 or BZLF1 peptide pools. Effector function of EBV-specific T cells was determined after restimulation by measuring intracellular interferon-γ production. During IM, BZLF1-specifc CD4+ T cell responses were dominant compared with CD8+ T cell responses. EBNA1-specific CD4+ and CD8+ T cell responses were low and remained similar for 6 months. However, 6 months after IM, BZLF1-specific CD4+ T cell responses had declined, but CD8+ T cell responses had increased. At diagnosis, EBV-specific CD8+ T cells as studied by human leucocyte antigen class I tetramer staining comprised a tetramerbrightCD8bright population consisting mainly of CD27+ memory T cells and a tetramerdimCD8dim population consisting primarily of CD27- effector T cells. The remaining EBV-specific CD8+ T cell population 6 months after the diagnosis of IM consisted mainly of tetramerbrightCD8bright CD27+ T cells, suggesting preferential preservation of memory T cells after contraction of the EBV-specific T cell pool. PMID:18549439

  16. Comparison of human memory CD8 T cell responses to adenoviral early and late proteins in peripheral blood and lymphoid tissue.

    Directory of Open Access Journals (Sweden)

    Amita Joshi

    Full Text Available Treatment of invasive adenovirus (Ad disease in hematopoietic stem cell transplant (SCT recipients with capsid protein hexon-specific donor T cells is under investigation. We propose that cytotoxic T cells (CTLs targeted to the late protein hexon may be inefficient in vivo because the early Ad protein E3-19K downregulates HLA class I antigens in infected cells. In this study, CD8+ T cells targeted to highly conserved HLA A2-restricted epitopes from the early regulatory protein DNA polymerase (P-977 and late protein hexon (H-892 were compared in peripheral blood (PB and tonsils of naturally infected adults. In tonsils, epitope-specific pentamers detected a significantly higher frequency of P-977+CD8+ T cells compared to H-892+CD8+ T cells; this trend was reversed in PB. Tonsil epitope-specific CD8+ T cells expressed IFN-γ and IL-2 but not perforin or TNF-α, whereas PB T cells were positive for IFN-γ, TNF-α, and perforin. Tonsil epitope-specific T cells expressed lymphoid homing marker CCR7 and exhibited lower levels of the activation marker CD25 but higher proliferative potential than PB T cells. Finally, in parallel with the kinetics of mRNA expression, P-977-specific CTLs lysed targets as early as 8 hrs post infection. In contrast, H-892-specific CTLs did not kill unless infected fibroblasts were pretreated with IFN-γ to up regulate HLA class I antigens, and cytotoxicity was delayed until 16-24 hours. These data show that, in contrast to hexon CTLs, central memory type DNA polymerase CTLs dominate the lymphoid compartment and kill fibroblasts earlier after infection without requiring exogenous IFN-γ. Thus, use of CTLs targeted to both early and late Ad proteins may improve the efficacy of immunotherapy for life-threatening Ad disease in SCT recipients.

  17. Skin vaccination with live virus vectored microneedle arrays induce long lived CD8(+) T cell memory.

    Science.gov (United States)

    Becker, Pablo D; Hervouet, Catherine; Mason, Gavin M; Kwon, Sung-Yun; Klavinskis, Linda S

    2015-09-08

    A simple dissolvable microneedle array (MA) platform has emerged as a promising technology for vaccine delivery, due to needle-free injection with a formulation that preserves the immunogenicity of live viral vectored vaccines dried in the MA matrix. While recent studies have focused largely on design parameters optimized to induce primary CD8(+) T cell responses, the hallmark of a vaccine is synonymous with engendering long-lasting memory. Here, we address the capacity of dried MA vaccination to programme phenotypic markers indicative of effector/memory CD8(+) T cell subsets and also responsiveness to recall antigen benchmarked against conventional intradermal (ID) injection. We show that despite a slightly lower frequency of dividing T cell receptor transgenic CD8(+) T cells in secondary lymphoid tissue at an early time point, the absolute number of CD8(+) T cells expressing an effector memory (CD62L(-)CD127(+)) and central memory (CD62L(+)CD127(+)) phenotype during peak expansion were comparable after MA and ID vaccination with a recombinant human adenovirus type 5 vector (AdHu5) encoding HIV-1 gag. Similarly, both vaccination routes generated CD8(+) memory T cell subsets detected in draining LNs for at least two years post-vaccination capable of responding to secondary antigen. These data suggest that CD8(+) T cell effector/memory generation and long-term memory is largely unaffected by physical differences in vaccine delivery to the skin via dried MA or ID suspension. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Identification of murine T-cell epitopes in Ebola virus nucleoprotein

    International Nuclear Information System (INIS)

    Simmons, Graham; Lee, Anee; Rennekamp, Andrew J.; Fan Xin; Bates, Paul; Shen Hao

    2004-01-01

    CD8 T cells play an important role in controlling Ebola infection and in mediating vaccine-induced protective immunity, yet little is known about antigenic targets in Ebola that are recognized by CD8 T cells. Overlapping peptides were used to identify major histocompatibility complex class I-restricted epitopes in mice immunized with vectors encoding Ebola nucleoprotein (NP). CD8 T-cell responses were mapped to a H-2 d -restricted epitope (NP279-288) and two H-2 b -restricted epitopes (NP44-52 and NP288-296). The identification of these epitopes will facilitate studies of immune correlates of protection and the evaluation of vaccine strategies in murine models of Ebola infection

  19. Cooperativity between CD8+ T cells, non-neutralizing antibodies, and alveolar macrophages is important for heterosubtypic influenza virus immunity.

    Directory of Open Access Journals (Sweden)

    Brian J Laidlaw

    2013-03-01

    Full Text Available Seasonal epidemics of influenza virus result in ∼36,000 deaths annually in the United States. Current vaccines against influenza virus elicit an antibody response specific for the envelope glycoproteins. However, high mutation rates result in the emergence of new viral serotypes, which elude neutralization by preexisting antibodies. T lymphocytes have been reported to be capable of mediating heterosubtypic protection through recognition of internal, more conserved, influenza virus proteins. Here, we demonstrate using a recombinant influenza virus expressing the LCMV GP33-41 epitope that influenza virus-specific CD8+ T cells and virus-specific non-neutralizing antibodies each are relatively ineffective at conferring heterosubtypic protective immunity alone. However, when combined virus-specific CD8 T cells and non-neutralizing antibodies cooperatively elicit robust protective immunity. This synergistic improvement in protective immunity is dependent, at least in part, on alveolar macrophages and/or other lung phagocytes. Overall, our studies suggest that an influenza vaccine capable of eliciting both CD8+ T cells and antibodies specific for highly conserved influenza proteins may be able to provide heterosubtypic protection in humans, and act as the basis for a potential "universal" vaccine.

  20. Memory CD8 T cell inflation vs tissue-resident memory T cells: Same patrollers, same controllers?

    Science.gov (United States)

    Welten, Suzanne P M; Sandu, Ioana; Baumann, Nicolas S; Oxenius, Annette

    2018-05-01

    The induction of long-lived populations of memory T cells residing in peripheral tissues is of considerable interest for T cell-based vaccines, as they can execute immediate effector functions and thus provide protection in case of pathogen encounter at mucosal and barrier sites. Cytomegalovirus (CMV)-based vaccines support the induction and accumulation of a large population of effector memory CD8 T cells in peripheral tissues, in a process called memory inflation. Tissue-resident memory (T RM ) T cells, induced by various infections and vaccination regimens, constitute another subset of memory cells that take long-term residence in peripheral tissues. Both memory T cell subsets have evoked substantial interest in exploitation for vaccine purposes. However, a direct comparison between these two peripheral tissue-localizing memory T cell subsets with respect to their short- and long-term ability to provide protection against heterologous challenge is pending. Here, we discuss communalities and differences between T RM and inflationary CD8 T cells with respect to their development, maintenance, function, and protective capacity. In addition, we discuss differences and similarities between the transcriptional profiles of T RM and inflationary T cells, supporting the notion that they are distinct memory T cell populations. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Interferon-alpha administration enhances CD8+ T cell activation in HIV infection.

    Directory of Open Access Journals (Sweden)

    Maura Manion

    Full Text Available Type I interferons play important roles in innate immune defense. In HIV infection, type I interferons may delay disease progression by inhibiting viral replication while at the same time accelerating disease progression by contributing to chronic immune activation.To investigate the effects of type I interferons in HIV-infection, we obtained cryopreserved peripheral blood mononuclear cell samples from 10 subjects who participated in AIDS Clinical Trials Group Study 5192, a trial investigating the activity of systemic administration of IFNα for twelve weeks to patients with untreated HIV infection. Using flow cytometry, we examined changes in cell cycle status and expression of activation antigens by circulating T cells and their maturation subsets before, during and after IFNα treatment.The proportion of CD38+HLA-DR+CD8+ T cells increased from a mean of 11.7% at baseline to 24.1% after twelve weeks of interferon treatment (p = 0.006. These frequencies dropped to an average of 20.1% six weeks after the end of treatment. In contrast to CD8+ T cells, the frequencies of activated CD4+ T cells did not change with administration of type I interferon (mean percentage of CD38+DR+ cells = 2.62% at baseline and 2.17% after 12 weeks of interferon therapy. As plasma HIV levels fell with interferon therapy, this was correlated with a "paradoxical" increase in CD8+ T cell activation (p<0.001.Administration of type I interferon increased expression of the activation markers CD38 and HLA DR on CD8+ T cells but not on CD4+ T cells of HIV+ persons. These observations suggest that type I interferons may contribute to the high levels of CD8+ T cell activation that occur during HIV infection.

  2. Polyfunctional response by ImmTAC (IMCgp100) redirected CD8+ and CD4+ T cells.

    Science.gov (United States)

    Boudousquie, Caroline; Bossi, Giovanna; Hurst, Jacob M; Rygiel, Karolina A; Jakobsen, Bent K; Hassan, Namir J

    2017-11-01

    The success of immune system-based cancer therapies depends on a broad immune response engaging a range of effector cells and mechanisms. Immune mobilizing monoclonal T cell receptors (TCRs) against cancer (ImmTAC™ molecules: fusion proteins consisting of a soluble, affinity enhanced TCR and an anti-CD3 scFv antibody) were previously shown to redirect CD8 + and CD4 + T cells against tumours. Here we present evidence that IMCgp100 (ImmTAC recognizing a peptide derived from the melanoma-specific protein, gp100, presented by HLA-A*0201) efficiently redirects and activates effector and memory cells from both CD8 + and CD4 + repertoires. Using isolated subpopulations of T cells, we find that both terminally differentiated and effector memory CD8 + T cells redirected by IMCgp100 are potent killers of melanoma cells. Furthermore, CD4 + effector memory T cells elicit potent cytotoxic activity leading to melanoma cell killing upon redirection by IMCgp100. The majority of T cell subsets belonging to both the CD8 + and CD4 + repertoires secrete key pro-inflammatory cytokines (tumour necrosis factor-α, interferon-γ, interleukin-6) and chemokines (macrophage inflammatory protein-1α-β, interferon-γ-inducible protein-10, monocyte chemoattractant protein-1). At an individual cell level, IMCgp100-redirected T cells display a polyfunctional phenotype, which is a hallmark of a potent anti-cancer response. This study demonstrates that IMCgp100 induces broad immune responses that extend beyond the induction of CD8 + T cell-mediated cytotoxicity. These findings are of particular importance because IMCgp100 is currently undergoing clinical trials as a single agent or in combination with check point inhibitors for patients with malignant melanoma. © 2017 The Authors. Immunology Published by John Wiley & Sons Ltd.

  3. Age-related changes in CD8 T cell homeostasis and immunity to infection.

    Science.gov (United States)

    Nikolich-Žugich, Janko; Li, Gang; Uhrlaub, Jennifer L; Renkema, Kristin R; Smithey, Megan J

    2012-10-01

    Studies of CD8 T cell responses to vaccination or infection with various pathogens in both animal models and human subjects have revealed a markedly consistent array of age-related defects. In general, recent work shows that aged CD8 T cell responses are decreased in magnitude, and show poor differentiation into effector cells, with a reduced arsenal of effector functions. Here we review potential mechanisms underlying these defects. We specifically address phenotypic and numeric changes to the naïve CD8 T cell precursor pool, the impact of persistent viral infection(s) and inflammation, and contributions of the aging environment in which these cells are activated. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Bystander chronic infection negatively impacts development of CD8+ T cell memory

    Science.gov (United States)

    Stelekati, Erietta; Shin, Haina; Doering, Travis A.; Dolfi, Douglas V.; Ziegler, Carly G.; Beiting, Daniel P.; Dawson, Lucas; Liboon, Jennifer; Wolski, David; Ali, Mohammed-Alkhatim A.; Katsikis, Peter D.; Shen, Hao; Roos, David S.; Haining, W. Nicholas; Lauer, Georg M.; Wherry, E. John

    2014-01-01

    Summary Epidemiological evidence suggests that chronic infections impair immune responses to unrelated pathogens and vaccines. The underlying mechanisms, however, are unclear and distinguishing effects on priming versus development of immunological memory has been challenging. We investigated whether bystander chronic infections impact differentiation of memory CD8+ T cells, the hallmark of protective immunity against intracellular pathogens. Chronic bystander infections impaired development of memory CD8+ T cells in several mouse models and humans. These effects were independent of initial priming and were associated with chronic inflammatory signatures. Chronic inflammation negatively impacted the number of bystander CD8+ T cells and their memory development. Distinct underlying mechanisms of altered survival and differentiation were revealed with the latter regulated by the transcription factors T-bet and Blimp-1. Thus, exposure to prolonged bystander inflammation impairs the effector to memory transition. These data have relevance for immunity and vaccination during persisting infections and chronic inflammation. PMID:24837104

  5. Distinctive CD8+ T cell and MHC class I signatures in polycythemia vera patients.

    Science.gov (United States)

    Cardoso, Elsa M; Esgalhado, André J; Patrão, Luís; Santos, Mónica; Neves, Vasco Pinto; Martinez, Jorge; Patto, Maria Assunção Vaz; Silva, Helena; Arosa, Fernando A

    2018-05-22

    Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by overproduction of red blood cells. We have performed a comprehensive characterization of blood immune cells for expression of naïve and memory receptors as well as β 2 m-associated and β 2 m-free MHC class I heavy chains, also known as closed and open conformers, respectively, in PV patients and age-matched controls (CTR). We show that the peripheral CD3 + CD8 + T cell pool in PV patients is clearly divided into two discrete populations, a more granular CD3 + CD8 high T cell population enriched in effector-memory CD45RA + T cells (CD8 + TEMRA) when compared to CTR (P e., CD3 + CD8 int CD28 int . While the percentage of CD3 + CD8 int TN cells correlated positively with the number of erythrocytes, the percentage of CD3 + CD8 int TEMRA correlated negatively with the number of platelets. Finally, we report that PV patients' lymphocytes and monocytes display lower levels of closed (W6/32 + ) MHC-I conformers at the cell surface while exhibiting increased amounts of open (HC-10 + ) MHC-I conformers. The implications of this distinctive immune signature are discussed.

  6. Phenotypic alteration of CD8+ T cells in chronic lymphocytic leukemia is associated with epigenetic reprogramming.

    Science.gov (United States)

    Wu, Jiazhu; Xu, Xiaojing; Lee, Eun-Joon; Shull, Austin Y; Pei, Lirong; Awan, Farrukh; Wang, Xiaoling; Choi, Jeong-Hyeon; Deng, Libin; Xin, Hong-Bo; Zhong, Wenxun; Liang, Jinhua; Miao, Yi; Wu, Yujie; Fan, Lei; Li, Jianyong; Xu, Wei; Shi, Huidong

    2016-06-28

    Immunosuppression is a prevalent clinical feature in chronic lymphocytic leukemia (CLL) patients, with many patients demonstrating increased susceptibility to infections as well as increased failure of an antitumor immune response. However, much is currently not understood regarding the precise mechanisms that attribute to this immunosuppressive phenotype in CLL. To provide further clarity to this particular phenomenon, we analyzed the T-cell profile of CLL patient samples within a large cohort and observed that patients with an inverted CD4/CD8 ratio had a shorter time to first treatment as well as overall survival. These observations coincided with higher expression of the immune checkpoint receptor PD-1 in CLL patient CD8+ T cells when compared to age-matched healthy donors. Interestingly, we discovered that increased PD-1 expression in CD8+ T cells corresponds with decreased DNA methylation levels in a distal upstream locus of the PD-1 gene PDCD1. Further analysis using luciferase reporter assays suggests that the identified PDCD1 distal upstream region acts as an enhancer for PDCD1 transcription and this region becomes demethylated during activation of naïve CD8+ T cells by anti-CD3/anti-CD28 antibodies and IL2. Finally, we conducted a genome-wide DNA methylation analysis comparing CD8+ T cells from CLL patients against healthy donors and identified additional differentially methylated genes with known immune regulatory functions including CCR6 and KLRG1. Taken together, our findings reveal the occurrence of epigenetic reprogramming taking place within CLL patient CD8+ T cells and highlight the potential mechanism of how immunosuppression is accomplished in CLL.

  7. CD40L Expression Allows CD8+ T Cells to Promote Their Own Expansion and Differentiation through Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Neil Q. Tay

    2017-11-01

    Full Text Available CD8+ T cells play an important role in providing protective immunity against a wide range of pathogens, and a number of different factors control their activation. Although CD40L-mediated CD40 licensing of dendritic cells (DCs by CD4+ T cells is known to be necessary for the generation of a robust CD8+ T cell response, the contribution of CD8+ T cell-expressed CD40L on DC licensing is less clear. We have previously shown that CD8+ T cells are able to induce the production of IL-12 p70 by DCs in a CD40L-dependent manner, providing some evidence that CD8+ T cell-mediated activation of DCs is possible. To better understand the role of CD40L on CD8+ T cell responses, we generated and characterized CD40L-expressing CD8+ T cells both in vitro and in vivo. We found that CD40L was expressed on 30–50% of effector CD8+ T cells when stimulated and that this expression was transient. The expression of CD40L on CD8+ T cells promoted the proliferation and differentiation of both the CD40L-expressing CD8+ T cells and the bystander effector CD8+ T cells. This process occurred via a cell-extrinsic manner and was mediated by DCs. These data demonstrate the existence of a mechanism where CD8+ T cells and DCs cooperate to maximize CD8+ T cell responses.

  8. CMV-specific CD8 T Cell Differentiation and Localization: Implications for Adoptive Therapies

    Directory of Open Access Journals (Sweden)

    Corinne J Smith

    2016-09-01

    Full Text Available Human cytomegalovirus (HCMV is a ubiquitous virus that causes chronic infection, and thus is one of the most common infectious complications of immune suppression. Adoptive transfer of HCMV-specific T cells has emerged as an effective method to reduce the risk for HCMV infection and/or reactivation by restoring immunity in transplant recipients. However, the CMV-specific CD8+ T cell response is comprised of a heterogenous mixture of subsets with distinct functions and localization and it is not clear if current adoptive immunotherapy protocols can reconstitute the full spectrum of CD8+ T cell immunity. The aim of this review is to briefly summarize the role of these T cell subsets in CMV immunity and to describe how current adoptive immunotherapy practices might affect their reconstitution in patients. The bulk of the CMV-specific CD8+ T cell population is made up of terminally differentiated effector T cells with immediate effector function and a short life span. Self-renewing memory T cells within the CMV-specific population retain the capacity to expand and differentiate upon challenge and are important for the long-term persistence of the CD8+ T cell response. Finally mucosal organs, which are frequent sites of CMV reactivation, are primarily inhabited by tissue resident memory T cells, which do not recirculate. Future work on adoptive transfer strategies may need to focus on striking a balance between the formation of these subsets to ensure the development of long lasting and protective immune responses that can access the organs affected by CMV disease.

  9. Functions of NKG2D in CD8+ T cells: an opportunity for immunotherapy.

    Science.gov (United States)

    Prajapati, Kushal; Perez, Cynthia; Rojas, Lourdes Beatriz Plaza; Burke, Brianna; Guevara-Patino, Jose A

    2018-02-05

    Natural killer group 2 member D (NKG2D) is a type II transmembrane receptor. NKG2D is present on NK cells in both mice and humans, whereas it is constitutively expressed on CD8 + T cells in humans but only expressed upon T-cell activation in mice. NKG2D is a promiscuous receptor that recognizes stress-induced surface ligands. In NK cells, NKG2D signaling is sufficient to unleash the killing response; in CD8 + T cells, this requires concurrent activation of the T-cell receptor (TCR). In this case, the function of NKG2D is to authenticate the recognition of a stressed target and enhance TCR signaling. CD28 has been established as an archetype provider of costimulation during T-cell priming. It has become apparent, however, that signals from other costimulatory receptors, such as NKG2D, are required for optimal T-cell function outside the priming phase. This review will focus on the similarities and differences between NKG2D and CD28; less well-described characteristics of NKG2D, such as the potential role of NKG2D in CD8 + T-cell memory formation, cancer immunity and autoimmunity; and the opportunities for targeting NKG2D in immunotherapy.Cellular and Molecular Immunology advance online publication, 5 February 2018; doi:10.1038/cmi.2017.161.

  10. AMPKα1: a glucose sensor that controls CD8 T-cell memory.

    Science.gov (United States)

    Rolf, Julia; Zarrouk, Marouan; Finlay, David K; Foretz, Marc; Viollet, Benoit; Cantrell, Doreen A

    2013-04-01

    The adenosine monophosphate-activated protein kinase (AMPK) is activated by antigen receptor signals and energy stress in T cells. In many cell types, AMPK can maintain energy homeostasis and can enforce quiescence to limit energy demands. We consequently evaluated the importance of AMPK for controlling the transition of metabolically active effector CD8 T lymphocytes to the metabolically quiescent catabolic memory T cells during the contraction phase of the immune response. We show that AMPKα1 activates rapidly in response to the metabolic stress caused by glucose deprivation of CD8 cytotoxic T lymphocytes (CTLs). Moreover, AMPKα1 restrains mammalian target of rapamycin complex 1 activity under conditions of glucose stress. AMPKα1 activity is dispensable for proliferation and differentiation of CTLs. However, AMPKα1 is required for in vivo survival of CTLs following withdrawal of immune stimulation. AMPKα1(null) T cells also show a striking defect in their ability to generate memory CD8 T-cell responses during Listeria monocytogenes infection. These results show that AMPKα1 monitors energy stress in CTLs and controls CD8 T-cell memory. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Strong vaccine-induced CD8 T-cell responses have cytolytic function in a chimpanzee clearing HCV infection.

    Directory of Open Access Journals (Sweden)

    Babs E Verstrepen

    Full Text Available A single correlate of effective vaccine protection against chronic HCV infection has yet to be defined. In this study, we analyzed T-cell responses in four chimpanzees, immunized with core-E1-E2-NS3 and subsequently infected with HCV1b. Viral clearance was observed in one animal, while the other three became chronically infected. In the animal that cleared infection, NS3-specific CD8 T-cell responses were observed to be more potent in terms of frequency and polyfunctionality of cytokine producing cells. Unique to this animal was the presence of killing-competent CD8 T-cells, specific for NS3 1258-1272, being presented by the chimpanzee MHC class I molecule Patr-A*03∶01, and a high affinity recognition of this epitope. In the animals that became chronically infected, T-cells were able to produce cytokines against the same peptide but no cytolysis could be detected. In conclusion, in the animal that was able to clear HCV infection not only cytokine production was observed but also cytolytic potential against specific MHC class I/peptide-combinations.

  12. Partial reconstitution of virus-specific memory CD8+ T cells following whole body γ-irradiation

    International Nuclear Information System (INIS)

    Grayson, Jason M.; Laniewski, Nathan G.; Holbrook, Beth C.

    2006-01-01

    CD8 + memory T cells are critical in providing immunity to viral infection. Previous studies documented that antigen-specific CD8 + memory T cells are more resistant to radiation-induced apoptosis than naive T cells. Here, we determined the number and in vivo function of memory CD8 + T cells as immune reconstitution progressed following irradiation. Immediately following irradiation, the number of memory CD8 + T cells declined 80%. As reconstitution progressed, the number of memory cells reached a zenith at 33% of pre-irradiation levels, and was maintained for 120 days post-irradiation. In vitro, memory CD8 + T cells were able to produce cytokines at all times post-irradiation, but when adoptively transferred, they were not able to expand upon rechallenge immediately following irradiation, but regained this ability as reconstitution progressed. When proliferation was examined in vitro, irradiated memory CD8 + T cells were able to respond to mitogenic growth but were unable to divide

  13. The simultaneous ex vivo detection of low-frequency antigen-specific CD4+ and CD8+ T-cell responses using overlapping peptide pools.

    Science.gov (United States)

    Singh, Satwinder Kaur; Meyering, Maaike; Ramwadhdoebe, Tamara H; Stynenbosch, Linda F M; Redeker, Anke; Kuppen, Peter J K; Melief, Cornelis J M; Welters, Marij J P; van der Burg, Sjoerd H

    2012-11-01

    The ability to measure antigen-specific T cells at the single-cell level by intracellular cytokine staining (ICS) is a promising immunomonitoring tool and is extensively applied in the evaluation of immunotherapy of cancer. The protocols used to detect antigen-specific CD8+ T-cell responses generally work for the detection of antigen-specific T cells in samples that have undergone at least one round of in vitro pre-stimulation. Application of a common protocol but now using long peptides as antigens was not suitable to simultaneously detect antigen-specific CD8+ and CD4+ T cells directly ex vivo in cryopreserved samples. CD8 T-cell reactivity to monocytes pulsed with long peptides as antigens ranged between 5 and 25 % of that observed against monocytes pulsed with a direct HLA class I fitting minimal CTL peptide epitope. Therefore, we adapted our ICS protocol and show that the use of tenfold higher concentration of long peptides to load APC, the use of IFN-α and poly(I:C) to promote antigen processing and improve T-cell stimulation, does allow for the ex vivo detection of low-frequency antigen-specific CD8+ and CD4+ T cells in an HLA-independent setting. While most of the improvements were related to increasing the ability to measure CD8+ T-cell reactivity following stimulation with long peptides to at least 50 % of the response detected when using a minimal peptide epitope, the final analysis of blood samples from vaccinated patients successfully showed that the adapted ICS protocol also increases the ability to ex vivo detect low-frequency p53-specific CD4+ T-cell responses in cryopreserved PBMC samples.

  14. HIV-specific CD8+ T cells: serial killers condemned to die?

    Science.gov (United States)

    Petrovas, Constantinos; Mueller, Yvonne M; Katsikis, Peter D

    2004-04-01

    An increasing body of evidence supports a key role for cytotoxic CD8+ T cells (CTL) in controlling HIV infection. Although a vigorous HIV-specific CD8+ T cell response is raised during the primary infection, these cells ultimately fail to control virus and prevent disease progression. The failure of CTL to control HIV infection has been attributed to a number of strategies HIV employs to evade the immune system. Recently, intrinsic defects in the CTL themselves have been proposed to contribute to the failure of CTL to control HIV. HIV-specific CD8+ T cells differ in their effector/memory phenotype from other virus-specific CD8+ T cells indicating that their differentiation status differs. This altered differentiation may affect effector functions as well as homing properties of these cells. Other studies have indicated that activation of HIV-specific CTL may be impaired and this contributes to their dysfunction. The effector function of these CTL may also be affected. There are conflicting reports about their ability to kill, whereas IFNgamma production does not appear to be impaired in these cells. In this review we focus on recent work indicating that apoptosis may be an important mechanism through which HIV evades the CTL response. In particular, HIV-specific CD8+ T cells are highly susceptible to CD95/Fas-induced apoptosis. This leads to the hypothesis that virus-specific cytotoxic T cells can be eliminated upon binding CD95L/FasL on HIV-infected cells. Understanding the intrinsic defects of CTL in HIV infection could lead to new therapeutic strategies and optimized vaccination protocols that enhance the HIV-specific cytotoxic response.

  15. T-bet and Eomes Are Differentially Linked to the Exhausted Phenotype of CD8+T Cells in HIV Infection

    DEFF Research Database (Denmark)

    Buggert, Marcus; Tauriainen, Johanna; Yamamoto, Takuya

    2014-01-01

    CD8+ T cell exhaustion represents a major hallmark of chronic HIV infection. Two key transcription factors governing CD8+ T cell differentiation, T-bet and Eomesodermin (Eomes), have previously been shown in mice to differentially regulate T cell exhaustion in part through direct modulation of PD...

  16. Epigenetic landscapes reveal transcription factors that regulate CD8+ T cell differentiation.

    Science.gov (United States)

    Yu, Bingfei; Zhang, Kai; Milner, J Justin; Toma, Clara; Chen, Runqiang; Scott-Browne, James P; Pereira, Renata M; Crotty, Shane; Chang, John T; Pipkin, Matthew E; Wang, Wei; Goldrath, Ananda W

    2017-05-01

    Dynamic changes in the expression of transcription factors (TFs) can influence the specification of distinct CD8 + T cell fates, but the observation of equivalent expression of TFs among differentially fated precursor cells suggests additional underlying mechanisms. Here we profiled the genome-wide histone modifications, open chromatin and gene expression of naive, terminal-effector, memory-precursor and memory CD8 + T cell populations induced during the in vivo response to bacterial infection. Integration of these data suggested that the expression and binding of TFs contributed to the establishment of subset-specific enhancers during differentiation. We developed a new bioinformatics method using the PageRank algorithm to reveal key TFs that influence the generation of effector and memory populations. The TFs YY1 and Nr3c1, both constitutively expressed during CD8 + T cell differentiation, regulated the formation of terminal-effector cell fates and memory-precursor cell fates, respectively. Our data define the epigenetic landscape of differentiation intermediates and facilitate the identification of TFs with previously unappreciated roles in CD8 + T cell differentiation.

  17. Epigenetic landscapes reveal transcription factors regulating CD8+ T cell differentiation

    Science.gov (United States)

    Yu, Bingfei; Zhang, Kai; Milner, J. Justin; Toma, Clara; Chen, Runqiang; Scott-Browne, James P.; Pereira, Renata M.; Crotty, Shane; Chang, John T.; Pipkin, Matthew E.; Wang, Wei; Goldrath, Ananda W.

    2017-01-01

    Dynamic changes in the expression of transcription factors (TFs) can influence specification of distinct CD8+ T cell fates, but the observation of equivalent expression of TF among differentially-fated precursor cells suggests additional underlying mechanisms. Here, we profiled genome-wide histone modifications, open chromatin and gene expression of naive, terminal-effector, memory-precursor and memory CD8+ T cell populations induced during the in vivo response to bacterial infection. Integration of these data suggested that TF expression and binding contributed to establishment of subset-specific enhancers during differentiation. We developed a new bioinformatics method using the PageRank algorithm to reveal novel TFs influencing the generation of effector and memory populations. The TFs YY1 and Nr3c1, both constitutively expressed during CD8+ T cell differentiation, regulated the formation of terminal-effector and memory-precursor cell-fates, respectively. Our data define the epigenetic landscape of differentiation intermediates, facilitating identification of TFs with previously unappreciated roles in CD8+ T cell differentiation. PMID:28288100

  18. Herpes simplex virus-1 evasion of CD8+ T cell accumulation contributes to viral encephalitis.

    Science.gov (United States)

    Koyanagi, Naoto; Imai, Takahiko; Shindo, Keiko; Sato, Ayuko; Fujii, Wataru; Ichinohe, Takeshi; Takemura, Naoki; Kakuta, Shigeru; Uematsu, Satoshi; Kiyono, Hiroshi; Maruzuru, Yuhei; Arii, Jun; Kato, Akihisa; Kawaguchi, Yasushi

    2017-10-02

    Herpes simplex virus-1 (HSV-1) is the most common cause of sporadic viral encephalitis, which can be lethal or result in severe neurological defects even with antiviral therapy. While HSV-1 causes encephalitis in spite of HSV-1-specific humoral and cellular immunity, the mechanism by which HSV-1 evades the immune system in the central nervous system (CNS) remains unknown. Here we describe a strategy by which HSV-1 avoids immune targeting in the CNS. The HSV-1 UL13 kinase promotes evasion of HSV-1-specific CD8+ T cell accumulation in infection sites by downregulating expression of the CD8+ T cell attractant chemokine CXCL9 in the CNS of infected mice, leading to increased HSV-1 mortality due to encephalitis. Direct injection of CXCL9 into the CNS infection site enhanced HSV-1-specific CD8+ T cell accumulation, leading to marked improvements in the survival of infected mice. This previously uncharacterized strategy for HSV-1 evasion of CD8+ T cell accumulation in the CNS has important implications for understanding the pathogenesis and clinical treatment of HSV-1 encephalitis.

  19. Influence of race on microsatellite instability and CD8+ T cell infiltration in colon cancer.

    Directory of Open Access Journals (Sweden)

    John M Carethers

    Full Text Available African American patients with colorectal cancer show higher mortality than their Caucasian counterparts. Biology might play a partial role, and prior studies suggest a higher prevalence for microsatellite instability (MSI among cancers from African Americans, albeit patients with MSI cancers have improved survival over patients with non-MSI cancers, counter to the outcome observed for African American patients. CD8+ T cell infiltration of colon cancer is postively correlated with MSI tumors, and is also related to improved outcome. Here, we utilized a 503-person, population-based colon cancer cohort comprising 45% African Americans to determine, under blinded conditions from all epidemiological data, the prevalence of MSI and associated CD8+ T cell infiltration within the cancers. Among Caucasian cancers, 14% were MSI, whereas African American cancers demonstrated 7% MSI (P = 0.009. Clinically, MSI cancers between races were similar; among microsatellite stable cancers, African American patients were younger, female, and with proximal cancers. CD8+ T cells were higher in MSI cancers (88.0 vs 30.4/hpf, P<0.0001, but was not different between races. Utilizing this population-based cohort, African American cancers show half the MSI prevalence of Caucasians without change in CD8+ T cell infiltration which may contribute towards their higher mortality from colon cancer.

  20. Role of CD5-negative CD8 T Cells in Adaptation to Antigenic ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of 3-oxotirucalla-7, 24-dien-21-oic acid on CD8+ T cell recovery in human immunodeficiency ..... enhances the probability of immune system recovery. ... PE: Fine tuning of TCR signaling by CD5. J Immunol.

  1. Activated CD8+T cells contribute to clearance of gastric Cryptosporidium muris infections

    Czech Academy of Sciences Publication Activity Database

    Kváč, Martin; Kodádková, Alena; Sak, Bohumil; Květoňová, Dana; Jalovecká, M.; Rost, M.; Salát, Jiří

    2011-01-01

    Roč. 33, č. 4 (2011), 210-216 ISSN 0141-9838 R&D Projects: GA AV ČR KJB500960701 Institutional research plan: CEZ:AV0Z60220518 Keywords : CD4+T-lymphocytes * CD8+T-lymphocytes * Cryptosporidium muris * T-cell-mediated immunity Subject RIV: EC - Immunology Impact factor: 2.601, year: 2011

  2. Increased memory phenotypes of CD4+ and CD8+ T cells in ...

    African Journals Online (AJOL)

    Conclusions: Children with SCA in Tanzania show an absolute increase in all leukocyte types, including lymphocytes, with skewing of both CD4+ and CD8+ T cells towards the memory phenotypes. These findings provide insights on the development of adaptive immunity which may have implications on vaccine ...

  3. CD8+ T Cell-Mediated Immunity during Trypanosoma cruzi Infection: A Path for Vaccine Development?

    Directory of Open Access Journals (Sweden)

    Fernando dos Santos Virgilio

    2014-01-01

    Full Text Available MHC-restricted CD8+ T cells are important during infection with the intracellular protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. Experimental studies performed in the past 25 years have elucidated a number of features related to the immune response mediated by these T cells, which are important for establishing the parasite/host equilibrium leading to chronic infection. CD8+ T cells are specific for highly immunodominant antigens expressed by members of the trans-sialidase family. After infection, their activation is delayed, and the cells display a high proliferative activity associated with high apoptotic rates. Although they participate in parasite control and elimination, they are unable to clear the infection due to their low fitness, allowing the parasite to establish the chronic phase when these cells then play an active role in the induction of heart immunopathology. Vaccination with a number of subunit recombinant vaccines aimed at eliciting specific CD8+ T cells can reverse this path, thereby generating a productive immune response that will lead to the control of infection, reduction of symptoms, and reduction of disease transmission. Due to these attributes, activation of CD8+ T lymphocytes may constitute a path for the development of a veterinarian or human vaccine.

  4. CD8 T cell memory to a viral pathogen requires trans cosignaling between HVEM and BTLA.

    Directory of Open Access Journals (Sweden)

    Rachel Flynn

    Full Text Available Defining the molecular interactions required to program activated CD8 T cells to survive and become memory cells may allow us to understand how to augment anti-viral immunity. HVEM (herpes virus entry mediator is a member of the tumor necrosis factor receptor (TNFR family that interacts with ligands in the TNF family, LIGHT and Lymphotoxin-α, and in the Ig family, B and T lymphocyte attenuator (BTLA and CD160. The Ig family members initiate inhibitory signaling when engaged with HVEM, but may also activate survival gene expression. Using a model of vaccinia virus infection, we made the unexpected finding that deficiency in HVEM or BTLA profoundly impaired effector CD8 T cell survival and development of protective immune memory. Mixed adoptive transfer experiments indicated that BTLA expressed in CD8α+ dendritic cells functions as a trans-activating ligand that delivers positive co-signals through HVEM expressed in T cells. Our data demonstrate a critical role of HVEM-BTLA bidirectional cosignaling system in antiviral defenses by driving the differentiation of memory CD8 T cells.

  5. MicroRNA Expression Patterns of CD8+ T Cells in Acute and Chronic Brucellosis

    Science.gov (United States)

    Budak, Ferah; Bal, S. Haldun; Tezcan, Gulcin; Guvenc, Furkan; Akalin, E. Halis; Goral, Guher; Deniz, Gunnur

    2016-01-01

    Although our knowledge about Brucella virulence factors and the host response increase rapidly, the mechanisms of immune evasion by the pathogen and causes of chronic disease are still unknown. Here, we aimed to investigate the immunological factors which belong to CD8+ T cells and their roles in the transition of brucellosis from acute to chronic infection. Using miRNA microarray, more than 2000 miRNAs were screened in CD8+ T cells of patients with acute or chronic brucellosis and healthy controls that were sorted from peripheral blood with flow cytometry and validated through qRT-PCR. Findings were evaluated using GeneSpring GX (Agilent) 13.0 software and KEGG pathway analysis. Expression of two miRNAs were determined to display a significant fold change in chronic group when compared with acute or control groups. Both miRNAs (miR-126-5p and miR-4753-3p) were decreased (p 2). These miRNAs have the potential to be the regulators of CD8+ T cell-related marker genes for chronic brucellosis infections. The differentially expressed miRNAs and their predicted target genes are involved in MAPK signaling pathway, cytokine-cytokine receptor interactions, endocytosis, regulation of actin cytoskeleton, and focal adhesion indicating their potential roles in chronic brucellosis and its progression. It is the first study of miRNA expression analysis of human CD8+ T cells to clarify the mechanism of inveteracy in brucellosis. PMID:27824867

  6. CD8 T cells protect adult naive mice from JEV-induced morbidity via lytic function.

    Science.gov (United States)

    Jain, Nidhi; Oswal, Neelam; Chawla, Amanpreet Singh; Agrawal, Tanvi; Biswas, Moanaro; Vrati, Sudhanshu; Rath, Satyajit; George, Anna; Bal, Vineeta; Medigeshi, Guruprasad R

    2017-02-01

    Following Japanese encephalitis virus (JEV) infection neutralizing antibodies are shown to provide protection in a significant proportion of cases, but not all, suggesting additional components of immune system might also contribute to elicit protective immune response. Here we have characterized the role of T cells in offering protection in adult mice infected with JEV. Mice lacking α/β-T cells (TCRβ-null) are highly susceptible and die over 10-18 day period as compared to the wild-type (WT) mice which are resistant. This is associated with high viral load, higher mRNA levels of proinflammatory cytokines and breach in the blood-brain-barrier (BBB). Infected WT mice do not show a breach in BBB; however, in contrast to TCRβ-null, they show the presence of T cells in the brain. Using adoptive transfer of cells with specific genetic deficiencies we see that neither the presence of CD4 T cells nor cytokines such as IL-4, IL-10 or interferon-gamma have any significant role in offering protection from primary infection. In contrast, we show that CD8 T cell deficiency is more critical as absence of CD8 T cells alone increases mortality in mice infected with JEV. Further, transfer of T cells from beige mice with defects in granular lytic function into TCRβ-null mice shows poor protection implicating granule-mediated target cell lysis as an essential component for survival. In addition, for the first time we report that γ/δ-T cells also make significant contribution to confer protection from JEV infection. Our data show that effector CD8 T cells play a protective role during primary infection possibly by preventing the breach in BBB and neuronal damage.

  7. CD8 T cells protect adult naive mice from JEV-induced morbidity via lytic function.

    Directory of Open Access Journals (Sweden)

    Nidhi Jain

    2017-02-01

    Full Text Available Following Japanese encephalitis virus (JEV infection neutralizing antibodies are shown to provide protection in a significant proportion of cases, but not all, suggesting additional components of immune system might also contribute to elicit protective immune response. Here we have characterized the role of T cells in offering protection in adult mice infected with JEV. Mice lacking α/β-T cells (TCRβ-null are highly susceptible and die over 10-18 day period as compared to the wild-type (WT mice which are resistant. This is associated with high viral load, higher mRNA levels of proinflammatory cytokines and breach in the blood-brain-barrier (BBB. Infected WT mice do not show a breach in BBB; however, in contrast to TCRβ-null, they show the presence of T cells in the brain. Using adoptive transfer of cells with specific genetic deficiencies we see that neither the presence of CD4 T cells nor cytokines such as IL-4, IL-10 or interferon-gamma have any significant role in offering protection from primary infection. In contrast, we show that CD8 T cell deficiency is more critical as absence of CD8 T cells alone increases mortality in mice infected with JEV. Further, transfer of T cells from beige mice with defects in granular lytic function into TCRβ-null mice shows poor protection implicating granule-mediated target cell lysis as an essential component for survival. In addition, for the first time we report that γ/δ-T cells also make significant contribution to confer protection from JEV infection. Our data show that effector CD8 T cells play a protective role during primary infection possibly by preventing the breach in BBB and neuronal damage.

  8. Methods of Controlling Invasive Fungal Infections Using CD8+ T Cells

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    Pappanaicken R. Kumaresan

    2018-01-01

    Full Text Available Invasive fungal infections (IFIs cause high rates of morbidity and mortality in immunocompromised patients. Pattern-recognition receptors present on the surfaces of innate immune cells recognize fungal pathogens and activate the first line of defense against fungal infection. The second line of defense is the adaptive immune system which involves mainly CD4+ T cells, while CD8+ T cells also play a role. CD8+ T cell-based vaccines designed to prevent IFIs are currently being investigated in clinical trials, their use could play an especially important role in acquired immune deficiency syndrome patients. So far, none of the vaccines used to treat IFI have been approved by the FDA. Here, we review current and future antifungal immunotherapy strategies involving CD8+ T cells. We highlight recent advances in the use of T cells engineered using a Sleeping Beauty vector to treat IFIs. Recent clinical trials using chimeric antigen receptor (CAR T-cell therapy to treat patients with leukemia have shown very promising results. We hypothesized that CAR T cells could also be used to control IFI. Therefore, we designed a CAR that targets β-glucan, a sugar molecule found in most of the fungal cell walls, using the extracellular domain of Dectin-1, which binds to β-glucan. Mice treated with D-CAR+ T cells displayed reductions in hyphal growth of Aspergillus compared to the untreated group. Patients suffering from IFIs due to primary immunodeficiency, secondary immunodeficiency (e.g., HIV, or hematopoietic transplant patients may benefit from bioengineered CAR T cell therapy.

  9. Natural killer cells promote early CD8 T cell responses against cytomegalovirus.

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    Scott H Robbins

    2007-08-01

    Full Text Available Understanding the mechanisms that help promote protective immune responses to pathogens is a major challenge in biomedical research and an important goal for the design of innovative therapeutic or vaccination strategies. While natural killer (NK cells can directly contribute to the control of viral replication, whether, and how, they may help orchestrate global antiviral defense is largely unknown. To address this question, we took advantage of the well-defined molecular interactions involved in the recognition of mouse cytomegalovirus (MCMV by NK cells. By using congenic or mutant mice and wild-type versus genetically engineered viruses, we examined the consequences on antiviral CD8 T cell responses of specific defects in the ability of the NK cells to control MCMV. This system allowed us to demonstrate, to our knowledge for the first time, that NK cells accelerate CD8 T cell responses against a viral infection in vivo. Moreover, we identify the underlying mechanism as the ability of NK cells to limit IFN-alpha/beta production to levels not immunosuppressive to the host. This is achieved through the early control of cytomegalovirus, which dramatically reduces the activation of plasmacytoid dendritic cells (pDCs for cytokine production, preserves the conventional dendritic cell (cDC compartment, and accelerates antiviral CD8 T cell responses. Conversely, exogenous IFN-alpha administration in resistant animals ablates cDCs and delays CD8 T cell activation in the face of NK cell control of viral replication. Collectively, our data demonstrate that the ability of NK cells to respond very early to cytomegalovirus infection critically contributes to balance the intensity of other innate immune responses, which dampens early immunopathology and promotes optimal initiation of antiviral CD8 T cell responses. Thus, the extent to which NK cell responses benefit the host goes beyond their direct antiviral effects and extends to the prevention of innate

  10. The CD8+ memory T-cell state of readiness is actively maintained and reversible

    OpenAIRE

    Allam, Atef; Conze, Dietrich B.; Giardino Torchia, Maria Letizia; Munitic, Ivana; Yagita, Hideo; Sowell, Ryan T.; Marzo, Amanda L.; Ashwell, Jonathan D.

    2009-01-01

    The ability of the adaptive immune system to respond rapidly and robustly upon repeated antigen exposure is known as immunologic memory, and it is thought that acquisition of memory T-cell function is an irreversible differentiation event. In this study, we report that many phenotypic and functional characteristics of antigen-specific CD8 memory T cells are lost when they are deprived of contact with dendritic cells. Under these circumstances, memory T cells reverted from G1 to the G0 cell-cy...

  11. Comparison of Vaccine-Induced Effector CD8 T Cell Responses Directed against Self- and Non-Self-Tumor Antigens

    DEFF Research Database (Denmark)

    Pedersen, Sara R; Sørensen, Maria R; Buus, Søren

    2013-01-01

    It is generally accepted that CD8 T cells play a major role in tumor control, yet vaccination aimed at eliciting potent CD8 T cell responses are rarely efficient in clinical trials. To try and understand why this is so, we have generated potent adenoviral vectors encoding the endogenous tumor Ags...... that low avidity of the self-TA-specific CD8 T cells may represent a major obstacle for efficient immunotherapy of cancer....

  12. Acquired transcriptional programming in functional and exhausted virus-specific CD8 T cells.

    Science.gov (United States)

    Youngblood, Ben; Wherry, E John; Ahmed, Rafi

    2012-01-01

    Failure to control viral infections such as HIV results in T-cell receptor (TCR) and inhibitory receptor driven exhaustion of antigen-specific T cells. Persistent signaling by these receptors during chronic viral infection sculpts the transcriptional regulatory programs of virus-specific T cells. The resulting gene expression profile is tailored to temper the potentially damaging effector functions of cytotoxic T cells and adapt them to an antigen-rich and inflammation-rich environment. Here we review recent studies investigating mechanisms of transcriptional regulation of effector, functional memory, and exhausted T-cell functions during acute versus chronic infections. Patterns of gene expression in virus-specific CD8 T cells are a result of a combination of pro and inhibitory signals from antigen presentation (TCR-mediated) and co-inhibitory receptor ligation (PD-1, 2B4). Further, memory-specific transcriptional regulation of 2B4 expression and signaling impose a self-limiting secondary effector response to a prolonged viral infection. Additionally, differentiation of functional memory CD8 T cells is coupled with acquisition of a repressive epigenetic program for PD-1 expression. However, chronic infection provides a signal that blocks the acquisition of these epigenetic modifications reinforcing the suppression of cytotoxic lymphocyte (CTL) functions in exhausted cells. Current findings suggest that the mechanism(s) that delineate functional memory versus exhaustion are coupled with acquisition of transcriptional programs at the effector stage of differentiation, reinforced by cessation or persistence of TCR signaling.

  13. A novel protective MHC-I haplotype not associated with dominant Gag-specific CD8+ T-cell responses in SIVmac239 infection of Burmese rhesus macaques.

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    Naofumi Takahashi

    Full Text Available Several major histocompatibility complex class I (MHC-I alleles are associated with lower viral loads and slower disease progression in human immunodeficiency virus (HIV and simian immunodeficiency virus (SIV infections. Immune-correlates analyses in these MHC-I-related HIV/SIV controllers would lead to elucidation of the mechanism for viral control. Viral control associated with some protective MHC-I alleles is attributed to CD8+ T-cell responses targeting Gag epitopes. We have been trying to know the mechanism of SIV control in multiple groups of Burmese rhesus macaques sharing MHC-I genotypes at the haplotype level. Here, we found a protective MHC-I haplotype, 90-010-Id (D, which is not associated with dominant Gag-specific CD8+ T-cell responses. Viral loads in five D+ animals became significantly lower than those in our previous cohorts after 6 months. Most D+ animals showed predominant Nef-specific but not Gag-specific CD8+ T-cell responses after SIV challenge. Further analyses suggested two Nef-epitope-specific CD8+ T-cell responses exerting strong suppressive pressure on SIV replication. Another set of five D+ animals that received a prophylactic vaccine using a Gag-expressing Sendai virus vector showed significantly reduced viral loads compared to unvaccinated D+ animals at 3 months, suggesting rapid SIV control by Gag-specific CD8+ T-cell responses in addition to Nef-specific ones. These results present a pattern of SIV control with involvement of non-Gag antigen-specific CD8+ T-cell responses.

  14. Antigen sensitivity is a major determinant of CD8+ T-cell polyfunctionality and HIV-suppressive activity.

    Science.gov (United States)

    Almeida, Jorge R; Sauce, Delphine; Price, David A; Papagno, Laura; Shin, So Youn; Moris, Arnaud; Larsen, Martin; Pancino, Gianfranco; Douek, Daniel C; Autran, Brigitte; Sáez-Cirión, Asier; Appay, Victor

    2009-06-18

    CD8(+) T cells are major players in the immune response against HIV. However, recent failures in the development of T cell-based vaccines against HIV-1 have emphasized the need to reassess our basic knowledge of T cell-mediated efficacy. CD8(+) T cells from HIV-1-infected patients with slow disease progression exhibit potent polyfunctionality and HIV-suppressive activity, yet the factors that unify these properties are incompletely understood. We performed a detailed study of the interplay between T-cell functional attributes using a bank of HIV-specific CD8(+) T-cell clones isolated in vitro; this approach enabled us to overcome inherent difficulties related to the in vivo heterogeneity of T-cell populations and address the underlying determinants that synthesize the qualities required for antiviral efficacy. Conclusions were supported by ex vivo analysis of HIV-specific CD8(+) T cells from infected donors. We report that attributes of CD8(+) T-cell efficacy against HIV are linked at the level of antigen sensitivity. Highly sensitive CD8(+) T cells display polyfunctional profiles and potent HIV-suppressive activity. These data provide new insights into the mechanisms underlying CD8(+) T-cell efficacy against HIV, and indicate that vaccine strategies should focus on the induction of HIV-specific T cells with high levels of antigen sensitivity to elicit potent antiviral efficacy.

  15. Suboptimal T-cell receptor signaling compromises protein translation, ribosome biogenesis, and proliferation of mouse CD8 T cells.

    Science.gov (United States)

    Tan, Thomas C J; Knight, John; Sbarrato, Thomas; Dudek, Kate; Willis, Anne E; Zamoyska, Rose

    2017-07-25

    Global transcriptomic and proteomic analyses of T cells have been rich sources of unbiased data for understanding T-cell activation. Lack of full concordance of these datasets has illustrated that important facets of T-cell activation are controlled at the level of translation. We undertook translatome analysis of CD8 T-cell activation, combining polysome profiling and microarray analysis. We revealed that altering T-cell receptor stimulation influenced recruitment of mRNAs to heavy polysomes and translation of subsets of genes. A major pathway that was compromised, when TCR signaling was suboptimal, was linked to ribosome biogenesis, a rate-limiting factor in both cell growth and proliferation. Defective TCR signaling affected transcription and processing of ribosomal RNA precursors, as well as the translation of specific ribosomal proteins and translation factors. Mechanistically, IL-2 production was compromised in weakly stimulated T cells, affecting the abundance of Myc protein, a known regulator of ribosome biogenesis. Consequently, weakly activated T cells showed impaired production of ribosomes and a failure to maintain proliferative capacity after stimulation. We demonstrate that primary T cells respond to various environmental cues by regulating ribosome biogenesis and mRNA translation at multiple levels to sustain proliferation and differentiation.

  16. The CD8+ memory T-cell state of readiness is actively maintained and reversible

    Science.gov (United States)

    Allam, Atef; Conze, Dietrich B.; Giardino Torchia, Maria Letizia; Munitic, Ivana; Yagita, Hideo; Sowell, Ryan T.; Marzo, Amanda L.

    2009-01-01

    The ability of the adaptive immune system to respond rapidly and robustly upon repeated antigen exposure is known as immunologic memory, and it is thought that acquisition of memory T-cell function is an irreversible differentiation event. In this study, we report that many phenotypic and functional characteristics of antigen-specific CD8 memory T cells are lost when they are deprived of contact with dendritic cells. Under these circumstances, memory T cells reverted from G1 to the G0 cell-cycle state and responded to stimulation like naive T cells, as assessed by proliferation, dependence upon costimulation, and interferon-γ production, without losing cell surface markers associated with memory. The memory state was maintained by signaling via members of the tumor necrosis factor receptor superfamily, CD27 and 4-1BB. Foxo1, a transcription factor involved in T-cell quiescence, was reduced in memory cells, and stimulation of naive CD8 cells via CD27 caused Foxo1 to be phosphorylated and emigrate from the nucleus in a phosphatidylinositol-3 kinase–dependent manner. Consistent with these results, maintenance of G1 in vivo was compromised in antigen-specific memory T cells in vesicular stomatitis virus-infected CD27-deficient mice. Therefore, sustaining the functional phenotype of T memory cells requires active signaling and maintenance. PMID:19617575

  17. CMV driven CD8(+) T-cell activation is associated with acute rejection in lung transplantation.

    Science.gov (United States)

    Roux, Antoine; Mourin, Gisèle; Fastenackels, Solène; Almeida, Jorge R; Iglesias, Maria Candela; Boyd, Anders; Gostick, Emma; Larsen, Martin; Price, David A; Sacre, Karim; Douek, Daniel C; Autran, Brigitte; Picard, Clément; Miranda, Sandra de; Sauce, Delphine; Stern, Marc; Appay, Victor

    2013-07-01

    Lung transplantation is the definitive treatment for terminal respiratory disease, but the associated mortality rate is high. Acute rejection of the transplanted lung is a key determinant of adverse prognosis. Furthermore, an epidemiological relationship has been established between the occurrence of acute lung rejection and cytomegalovirus infection. However, the reasons for this association remain unclear. Here, we performed a longitudinal characterization of CMV-specific T-cell responses and immune activation status in the peripheral blood and bronchoalveolar lavage fluid of forty-four lung transplant patients. Acute rejection was associated with high levels of cellular activation in the periphery, reflecting strong CMV-specific CD8(+) T-cell activity post-transplant. Peripheral and lung CMV-specific CD8(+) T-cell responses were very similar, and related to the presence of CMV in the transplanted organ. These findings support that activated CMV-specific CD8(+) T-cells in the lung may play a role in promoting acute rejection. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Selected microRNAs define cell fate determination of murine central memory CD8 T cells.

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    Gonzalo Almanza

    2010-06-01

    Full Text Available During an immune response T cells enter memory fate determination, a program that divides them into two main populations: effector memory and central memory T cells. Since in many systems protection appears to be preferentially mediated by T cells of the central memory it is important to understand when and how fate determination takes place. To date, cell intrinsic molecular events that determine their differentiation remains unclear. MicroRNAs are a class of small, evolutionarily conserved RNA molecules that negatively regulate gene expression, causing translational repression and/or messenger RNA degradation. Here, using an in vitro system where activated CD8 T cells driven by IL-2 or IL-15 become either effector memory or central memory cells, we assessed the role of microRNAs in memory T cell fate determination. We found that fate determination to central memory T cells is under the balancing effects of a discrete number of microRNAs including miR-150, miR-155 and the let-7 family. Based on miR-150 a new target, KChIP.1 (K (+ channel interacting protein 1, was uncovered, which is specifically upregulated in developing central memory CD8 T cells. Our studies indicate that cell fate determination such as surface phenotype and self-renewal may be decided at the pre-effector stage on the basis of the balancing effects of a discrete number of microRNAs. These results may have implications for the development of T cell vaccines and T cell-based adoptive therapies.

  19. Properties of HTLV-I transformed CD8+ T-cells in response to HIV-1 infection.

    Science.gov (United States)

    Gulzar, N; Shroff, A; Buberoglu, B; Klonowska, D; Kim, J E; Copeland, K F T

    2010-10-25

    HIV-1 infection studies of primary CD8(+) T-cells are hampered by difficulty in obtaining a significant number of targets for infection and low levels of productive infection. Further, there exists a paucity of CD8-expressing T-cell lines to address questions pertaining to the study of CD8(+) T-cells in the context of HIV-1 infection. In this study, a set of CD8(+) T-cell clones were originated through HTLV-I transformation in vitro, and the properties of these cells were examined. The clones were susceptible to T-cell tropic strains of the virus and exhibited HIV-1 production 20-fold greater than primary CD4(+) T-cells. Productive infection resulted in a decrease in expression of CD8 and CXCR4 molecules on the surface of the CD8(+) T-cell clones and antibodies to these molecules abrogated viral binding and replication. These transformed cells provide an important tool in the study of CD8(+) T-cells and may provide important insights into the mechanism(s) behind HIV-1 induced CD8(+) T-cell dysfunction. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Human mesenchymal stromal cells enhance the immunomodulatory function of CD8+CD28− regulatory T cells

    Science.gov (United States)

    Liu, Qiuli; Zheng, Haiqing; Chen, Xiaoyong; Peng, Yanwen; Huang, Weijun; Li, Xiaobo; Li, Gang; Xia, Wenjie; Sun, Qiquan; Xiang, Andy Peng

    2015-01-01

    One important aspect of mesenchymal stromal cells (MSCs)-mediated immunomodulation is the recruitment and induction of regulatory T (Treg) cells. However, we do not yet know whether MSCs have similar effects on the other subsets of Treg cells. Herein, we studied the effects of MSCs on CD8+CD28− Treg cells and found that the MSCs could not only increase the proportion of CD8+CD28− T cells, but also enhance CD8+CD28−T cells' ability of hampering naive CD4+ T-cell proliferation and activation, decreasing the production of IFN-γ by activated CD4+ T cells and inducing the apoptosis of activated CD4+ T cells. Mechanistically, the MSCs affected the functions of the CD8+CD28− T cells partially through moderate upregulating the expression of IL-10 and FasL. The MSCs had no distinct effect on the shift from CD8+CD28+ T cells to CD8+CD28− T cells, but did increase the proportion of CD8+CD28− T cells by reducing their rate of apoptosis. In summary, this study shows that MSCs can enhance the regulatory function of CD8+CD28− Treg cells, shedding new light on MSCs-mediated immune regulation. PMID:25482073

  1. CD8+ T Cells Complement Antibodies in Protecting against Yellow Fever Virus

    DEFF Research Database (Denmark)

    Bassi, Maria R; Kongsgaard, Michael; Steffensen, Maria A

    2015-01-01

    The attenuated yellow fever (YF) vaccine (YF-17D) was developed in the 1930s, yet little is known about the protective mechanisms underlying its efficiency. In this study, we analyzed the relative contribution of cell-mediated and humoral immunity to the vaccine-induced protection in a murine model...... of YF-17D infection. Using different strains of knockout mice, we found that CD4(+) T cells, B cells, and Abs are required for full clinical protection of vaccinated mice, whereas CD8(+) T cells are dispensable for long-term survival after intracerebral challenge. However, by analyzing the immune...... response inside the infected CNS, we observed an accelerated T cell influx into the brain after intracerebral challenge of vaccinated mice, and this T cell recruitment correlated with improved virus control in the brain. Using mice deficient in B cells we found that, in the absence of Abs, YF vaccination...

  2. Extensive CD4 and CD8 T Cell cross-reactivity between alphaherpesviruses

    DEFF Research Database (Denmark)

    Jing, Lichen; Laing, Kerry J.; Dong, Lichun

    2016-01-01

    The Alphaherpesvirinae subfamily includes HSV types 1 and 2 and the sequence-divergent pathogen varicella zoster virus (VZV). T cells, controlled by TCR and HLA molecules that tolerate limited epitope amino acid variation, might cross-react between these microbes. We show that memory PBMC expansi...... be useful for multi-alphaherpesvirus vaccine design and adoptive cellular therapy....

  3. CD4+ and CD8+ T cell activation are associated with HIV DNA in resting CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Leslie R Cockerham

    Full Text Available The association between the host immune environment and the size of the HIV reservoir during effective antiretroviral therapy is not clear. Progress has also been limited by the lack of a well-accepted assay for quantifying HIV during therapy. We examined the association between multiple measurements of HIV and T cell activation (as defined by markers including CD38, HLA-DR, CCR5 and PD-1 in 30 antiretroviral-treated HIV-infected adults. We found a consistent association between the frequency of CD4+ and CD8+ T cells expressing HLA-DR and the frequency of resting CD4+ T cells containing HIV DNA. This study highlights the need to further examine this relationship and to better characterize the biology of markers commonly used in HIV studies. These results may also have implications for reactivation strategies.

  4. TCR Down-Regulation Controls Virus-Specific CD8+ T Cell Responses

    DEFF Research Database (Denmark)

    Bonefeld, Charlotte Menné; Haks, Mariëlle; Nielsen, Bodil

    2008-01-01

    The CD3gamma di-leucine-based motif plays a central role in TCR down-regulation. However, little is understood about the role of the CD3gamma di-leucine-based motif in physiological T cell responses. In this study, we show that the expansion in numbers of virus-specific CD8(+) T cells is impaired...... in mice with a mutated CD3gamma di-leucine-based motif. The CD3gamma mutation did not impair early TCR signaling, nor did it compromise recruitment or proliferation of virus-specific T cells, but it increased the apoptosis rate of the activated T cells by increasing down-regulation of the antiapoptotic...... molecule Bcl-2. This resulted in a 2-fold reduction in the clonal expansion of virus-specific CD8(+) T cells during the acute phase of vesicular stomatitis virus and lymphocytic choriomeningitis virus infections. These results identify an important role of CD3gamma-mediated TCR down-regulation in virus...

  5. Increased numbers of pre-existing memory CD8 T cells and decreased T-bet expression can restrain terminal differentiation of secondary effector and memory CD8 T cells1

    Science.gov (United States)

    Joshi, Nikhil S.; Cui, Weiguo; Dominguez, Claudia; Chen, Jonathan H.; Hand, Timothy W.; Kaech, Susan M.

    2011-01-01

    Memory CD8 T cells acquire TEM properties following reinfection, and may reach terminally differentiated, senescent states (“Hayflick limit”) after multiple infections. The signals controlling this process are not well understood, but we found that the degree of 2o effector and memory CD8 T cell differentiation was intimately linked to the amount of T-bet expressed upon reactivation and pre-existing memory CD8 T cell number (i.e., 1o memory CD8 T cell precursor frequency) present during secondary infection. Compared to naïve cells, memory CD8 T cells were predisposed towards terminal effector (TE) cell differentiation because they could immediately respond to IL-12 and induce T-bet, even in the absence of antigen. TE cell formation following 2o or 3o infections was dependent on increased T-bet expression because T-bet+/− cells were resistant to these phenotypic changes. Larger numbers of pre-existing memory CD8 T cells limited the duration of 2o infection and the amount of IL-12 produced, and consequently, this reduced T-bet expression and the proportion of 2o TE CD8 T cells that formed. Together, these data show that, over repeated infections, memory CD8 T cell quality and proliferative fitness is not strictly determined by the number of serial encounters with antigen or cell divisions, but is a function of the CD8 T cell differentiation state, which is genetically controlled in a T-bet-dependent manner. This differentiation state can be modulated by pre-existing memory CD8 T cell number and the intensity of inflammation during reinfection. These results have important implications for vaccinations involving prime-boost strategies. PMID:21930973

  6. Genetic adjuvantation of recombinant MVA with CD40L potentiates CD8 T cell mediated immunity

    Directory of Open Access Journals (Sweden)

    Henning eLauterbach

    2013-08-01

    Full Text Available Modified vaccinia Ankara (MVA is a safe and promising viral vaccine vector that is currently investigated in several clinical and pre-clinical trials. In contrast to inactivated or sub-unit vaccines, MVA is able to induce strong humoral as well as cellular immune responses. In order to further improve its CD8 T cell inducing capacity, we genetically adjuvanted MVA with the coding sequence of murine CD40L, a member of the tumor necrosis factor (TNF superfamily. Immunization of mice with this new vector led to strongly enhanced primary and memory CD8 T cell responses. Concordant with the enhanced CD8 T cell response, we could detect stronger activation of dendritic cells and higher systemic levels of innate cytokines (including IL-12p70 early after immunization. Interestingly, acquisition of memory characteristics (i.e., IL-7R expression was accelerated after immunization with MVA-CD40L in comparison to non-adjuvanted MVA. Furthermore, the generated CTLs also showed improved functionality as demonstrated by intracellular cytokine staining and in vivo killing activity. Importantly, the superior CTL response after a single MVA-CD40L immunization was able to protect B cell deficient mice against a fatal infection with ectromelia virus. Taken together, we show that genetic adjuvantation of MVA can change strength, quality and functionality of innate and adaptive immune responses. These data should facilitate a rational vaccine design with a focus on rapid induction of large numbers of CD8 T cells able to protect against specific diseases.

  7. CD8+CD122+CD49dlow regulatory T cells maintain T-cell homeostasis by killing activated T cells via Fas/FasL-mediated cytotoxicity.

    Science.gov (United States)

    Akane, Kazuyuki; Kojima, Seiji; Mak, Tak W; Shiku, Hiroshi; Suzuki, Haruhiko

    2016-03-01

    The Fas/FasL (CD95/CD178) system is required for immune regulation; however, it is unclear in which cells, when, and where Fas/FasL molecules act in the immune system. We found that CD8(+)CD122(+) cells, which are mostly composed of memory T cells in comparison with naïve cells in the CD8(+)CD122(-) population, were previously shown to include cells with regulatory activity and could be separated into CD49d(low) cells and CD49d(high) cells. We established in vitro and in vivo experimental systems to evaluate the regulatory activity of CD122(+) cells. Regulatory activity was observed in CD8(+)CD122(+)CD49d(low) but not in CD8(+)CD122(+)CD49d(high) cells, indicating that the regulatory cells in the CD8(+)CD122(+) population could be narrowed down to CD49d(low) cells. CD8(+)CD122(-) cells taken from lymphoproliferation (lpr) mice were resistant to regulation by normal CD122(+) Tregs. CD122(+) Tregs taken from generalized lymphoproliferative disease (gld) mice did not regulate wild-type CD8(+)CD122(-) cells, indicating that the regulation by CD122(+) Tregs is Fas/FasL-dependent. CD122(+) Tregs taken from IL-10-deficient mice could regulate CD8(+)CD122(-) cells as equally as wild-type CD122(+) Tregs both in vitro and in vivo. MHC class I-missing T cells were not regulated by CD122(+) Tregs in vitro. CD122(+) Tregs also regulated CD4(+) cells in a Fas/FasL-dependent manner in vitro. These results suggest an essential role of Fas/FasL as a terminal effector of the CD122(+) Tregs that kill activated T cells to maintain immune homeostasis.

  8. Blocking of PDL-1 interaction enhances primary and secondary CD8 T cell response to herpes simplex virus-1 infection.

    Directory of Open Access Journals (Sweden)

    Rudragouda Channappanavar

    Full Text Available The blocking of programmed death ligand-1 (PDL-1 has been shown to enhance virus-specific CD8 T cell function during chronic viral infections. Though, how PDL-1 blocking at the time of priming affects the quality of CD8 T cell response to acute infections is not well understood and remains controversial. This report demonstrates that the magnitude of the primary and secondary CD8 T cell responses to herpes simplex virus-1 (HSV-1 infection is subject to control by PDL-1. Our results showed that after footpad HSV-1 infection, PD-1 expression increases on immunodominant SSIEFARL peptide specific CD8 T cells. Additionally, post-infection, the level of PDL-1 expression also increases on CD11c+ dendritic cells. Intraperitoneal administration of anti-PDL-1 monoclonal antibody given one day prior to and three days after cutaneous HSV-1 infection, resulted in a marked increase in effector and memory CD8 T cell response to SSIEFARL peptide. This was shown by measuring the quantity and quality of SSIEFARL-specific CD8 T cells by making use of ex-vivo assays that determine antigen specific CD8 T cell function, such as intracellular cytokine assay, degranulation assay to measure cytotoxicity and viral clearance. Our results are discussed in terms of the beneficial effects of blocking PDL-1 interactions, while giving prophylactic vaccines, to generate a more effective CD8 T cell response to viral infection.

  9. TRAF2 regulates peripheral CD8(+) T-cell and NKT-cell homeostasis by modulating sensitivity to IL-15.

    Science.gov (United States)

    Villanueva, Jeanette E; Malle, Elisabeth K; Gardam, Sandra; Silveira, Pablo A; Zammit, Nathan W; Walters, Stacey N; Brink, Robert; Grey, Shane T

    2015-06-01

    In this study, a critical and novel role for TNF receptor (TNFR) associated factor 2 (TRAF2) is elucidated for peripheral CD8(+) T-cell and NKT-cell homeostasis. Mice deficient in TRAF2 only in their T cells (TRAF2TKO) show ∼40% reduction in effector memory and ∼50% reduction in naïve CD8(+) T-cell subsets. IL-15-dependent populations were reduced further, as TRAF2TKO mice displayed a marked ∼70% reduction in central memory CD8(+) CD44(hi) CD122(+) T cells and ∼80% decrease in NKT cells. TRAF2TKO CD8(+) CD44(hi) T cells exhibited impaired dose-dependent proliferation to exogenous IL-15. In contrast, TRAF2TKO CD8(+) T cells proliferated normally to anti-CD3 and TRAF2TKO CD8(+) CD44(hi) T cells exhibited normal proliferation to exogenous IL-2. TRAF2TKO CD8(+) T cells expressed normal levels of IL-15-associated receptors and possessed functional IL-15-mediated STAT5 phosphorylation, however TRAF2 deletion caused increased AKT activation. Loss of CD8(+) CD44(hi) CD122(+) and NKT cells was mechanistically linked to an inability to respond to IL-15. The reduced CD8(+) CD44(hi) CD122(+) T-cell and NKT-cell populations in TRAF2TKO mice were rescued in the presence of high dose IL-15 by IL-15/IL-15Rα complex administration. These studies demonstrate a critical role for TRAF2 in the maintenance of peripheral CD8(+) CD44(hi) CD122(+) T-cell and NKT-cell homeostasis by modulating sensitivity to T-cell intrinsic growth factors such as IL-15. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. T-bet and Eomes are differentially linked to the exhausted phenotype of CD8+ T cells in HIV infection.

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    Marcus Buggert

    2014-07-01

    Full Text Available CD8(+ T cell exhaustion represents a major hallmark of chronic HIV infection. Two key transcription factors governing CD8(+ T cell differentiation, T-bet and Eomesodermin (Eomes, have previously been shown in mice to differentially regulate T cell exhaustion in part through direct modulation of PD-1. Here, we examined the relationship between these transcription factors and the expression of several inhibitory receptors (PD-1, CD160, and 2B4, functional characteristics and memory differentiation of CD8(+ T cells in chronic and treated HIV infection. The expression of PD-1, CD160, and 2B4 on total CD8(+ T cells was elevated in chronically infected individuals and highly associated with a T-bet(dimEomes(hi expressional profile. Interestingly, both resting and activated HIV-specific CD8(+ T cells in chronic infection were almost exclusively T-bet(dimEomes(hi cells, while CMV-specific CD8(+ T cells displayed a balanced expression pattern of T-bet and Eomes. The T-bet(dimEomes(hi virus-specific CD8(+ T cells did not show features of terminal differentiation, but rather a transitional memory phenotype with poor polyfunctional (effector characteristics. The transitional and exhausted phenotype of HIV-specific CD8(+ T cells was longitudinally related to persistent Eomes expression after antiretroviral therapy (ART initiation. Strikingly, these characteristics remained stable up to 10 years after ART initiation. This study supports the concept that poor human viral-specific CD8(+ T cell functionality is due to an inverse expression balance between T-bet and Eomes, which is not reversed despite long-term viral control through ART. These results aid to explain the inability of HIV-specific CD8(+ T cells to control the viral replication post-ART cessation.

  11. Lower percentage of CD8+ T cells in peripheral blood of patients with sporotrichosis.

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    Zhu, Mingji; Xu, Yaqin; An, Lin; Jiang, Jinlan; Zhang, Xu; Jiang, Rihua

    2016-07-01

    To characterize the peripheral immunity and immunity response of patients with sporotrichosis, in this study we determined the lymphocyte subsets in the peripheral blood of Chinese patients with sporotrichosis. In this retrospective study, peripheral blood was collected from 69 sporotrichosis patients (37, fixed cutaneous form; 32 lymphocutaneous) and 66 healthy controls. Lymphocyte subsets were analyzed using flow cytometry. Compared to controls, the percentage of CD8+ T cells was lower in sporotrichosis patients. The percentage of CD8+ T cells in peripheral blood tended to become lower with disease duration and disease severity, although the difference was not statistically significant for either acute, subacute and chronic patients or fixed cutaneous and lymphocutaneous patients. Our data indicate that the decrease of CD8+ T cells in peripheral blood of patients with sporotrichosis is associated with disease severity, although the difference was not statistically significant for either duration or clinical forms of the disease. Combining antifungal agents and immunomodulators in patients with long disease duration and lymphocutaneous may be more beneficial than antifungal monotherapy. Copyright © 2016. Published by Elsevier Inc.

  12. Activated iNKT cells promote memory CD8+ T cell differentiation during viral infection.

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    Emma C Reilly

    Full Text Available α-Galactosylceramide (α-GalCer is the prototypical lipid ligand for invariant NKT cells. Recent studies have proposed that α-GalCer is an effective adjuvant in vaccination against a range of immune challenges, however its mechanism of action has not been completely elucidated. A variety of delivery methods have been examined including pulsing dendritic cells with α-GalCer to optimize the potential of α-GalCer. These methods are currently being used in a variety of clinical trials in patients with advanced cancer but cannot be used in the context of vaccine development against pathogens due to their complexity. Using a simple delivery method, we evaluated α-GalCer adjuvant properties, using the mouse model for cytomegalovirus (MCMV. We measured several key parameters of the immune response to MCMV, including inflammation, effector, and central memory CD8(+ T cell responses. We found that α-GalCer injection at the time of the infection decreases viral titers, alters the kinetics of the inflammatory response, and promotes both increased frequencies and numbers of virus-specific memory CD8(+ T cells. Overall, our data suggest that iNKT cell activation by α-GalCer promotes the development of long-term protective immunity through increased fitness of central memory CD8(+ T cells, as a consequence of reduced inflammation.

  13. Cooperation between Epstein-Barr virus immune evasion proteins spreads protection from CD8+ T cell recognition across all three phases of the lytic cycle.

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    Laura L Quinn

    2014-08-01

    Full Text Available CD8+ T cell responses to Epstein-Barr virus (EBV lytic cycle expressed antigens display a hierarchy of immunodominance, in which responses to epitopes of immediate-early (IE and some early (E antigens are more frequently observed than responses to epitopes of late (L expressed antigens. It has been proposed that this hierarchy, which correlates with the phase-specific efficiency of antigen presentation, may be due to the influence of viral immune-evasion genes. At least three EBV-encoded genes, BNLF2a, BGLF5 and BILF1, have the potential to inhibit processing and presentation of CD8+ T cell epitopes. Here we examined the relative contribution of these genes to modulation of CD8+ T cell recognition of EBV lytic antigens expressed at different phases of the replication cycle in EBV-transformed B-cells (LCLs which spontaneously reactivate lytic cycle. Selective shRNA-mediated knockdown of BNLF2a expression led to more efficient recognition of immediate-early (IE- and early (E-derived epitopes by CD8+ T cells, while knock down of BILF1 increased recognition of epitopes from E and late (L-expressed antigens. Contrary to what might have been predicted from previous ectopic expression studies in EBV-negative model cell lines, the shRNA-mediated inhibition of BGLF5 expression in LCLs showed only modest, if any, increase in recognition of epitopes expressed in any phase of lytic cycle. These data indicate that whilst BNLF2a interferes with antigen presentation with diminishing efficiency as lytic cycle progresses (IE>E>>L, interference by BILF1 increases with progression through lytic cycle (IEepitopes. Together, these data firstly indicate which potential immune-evasion functions are actually relevant in the context of lytic virus replication, and secondly identify lytic-cycle phase-specific effects that provide mechanistic

  14. Memory vs memory-like: The different facets of CD8+ T-cell memory in HCV infection.

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    Hofmann, Maike; Wieland, Dominik; Pircher, Hanspeter; Thimme, Robert

    2018-05-01

    Memory CD8 + T cells are essential in orchestrating protection from re-infection. Hallmarks of virus-specific memory CD8 + T cells are the capacity to mount recall responses with rapid induction of effector cell function and antigen-independent survival. Growing evidence reveals that even chronic infection does not preclude virus-specific CD8 + T-cell memory formation. However, whether this kind of CD8 + T-cell memory that is established during chronic infection is indeed functional and provides protection from re-infection is still unclear. Human chronic hepatitis C virus infection represents a unique model system to study virus-specific CD8 + T-cell memory formation during and after cessation of persisting antigen stimulation. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Characterization of CD4 and CD8 T Cell Responses in MuSK Myasthenia Gravis

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    Yi, JS; Guidon, A; Sparks, S; Osborne, R; Juel, VC; Massey, JM; Sanders, DB; Weinhold, KJ; Guptill, JT

    2014-01-01

    Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T-cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T-cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T-cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T-cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T-cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T-cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in Treg function or number. PMID:24378287

  16. alpha(4)beta(7) independent pathway for CD8(+) T cell-mediated intestinal immunity to rotavirus.

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    Kuklin, N A; Rott, L; Darling, J; Campbell, J J; Franco, M; Feng, N; Müller, W; Wagner, N; Altman, J; Butcher, E C; Greenberg, H B

    2000-12-01

    Rotavirus (RV), which replicates exclusively in cells of the small intestine, is the most important cause of severe diarrhea in young children worldwide. Using a mouse model, we show that expression of the intestinal homing integrin alpha(4)ss(7) is not essential for CD8(+) T cells to migrate to the intestine or provide immunity to RV. Mice deficient in ss7 expression (ss7(-/-)) and unable to express alpha(4)ss(7) integrin were found to clear RV as quickly as wild-type (wt) animals. Depletion of CD8(+) T cells in ss7(-/-) animals prolonged viral shedding, and transfer of immune ss7(-/-) CD8(+) T cells into chronically infected Rag-2-deficient mice resolved RV infection as efficiently as wt CD8(+) T cells. Paradoxically, alpha(4)ss(7)(hi) memory CD8(+) T cells purified from wt mice that had been orally immunized cleared RV more efficiently than alpha(4)ss(7)(low) CD8(+) T cells. We explained this apparent contradiction by demonstrating that expression of alpha(4)ss(7) on effector CD8(+) T cells depends upon the site of initial antigen exposure: oral immunization generates RV-specific CD8(+) T cells primarily of an alpha(4)ss(7)(hi) phenotype, but subcutaneous immunization yields both alpha(4)ss(7)(hi) and alpha(4)ss(7)(low) immune CD8(+) T cells with anti-RV effector capabilities. Thus, alpha(4)ss(7) facilitates normal intestinal immune trafficking to the gut, but it is not required for effective CD8(+) T cell immunity.

  17. Kinetics of Epstein-Barr virus load and virus-specific CD8+ T cells in acute infectious mononucleosis.

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    Hoshino, Yo; Nishikawa, Kazuo; Ito, Yoshinori; Kuzushima, Kiyotaka; Kimura, Hiroshi

    2011-03-01

    During the convalescent phase of acute infectious mononucleosis (AIM), Epstein-Barr virus (EBV) load shrinks rapidly in association with a rapid decline in the number of EBV-specific CD8(+) T cells. The actual contribution of EBV-specific CD8(+) T cells in reducing EBV load, however, is not known. To clarify the impact of EBV-specific CD8(+) T cells on the contraction of EBV load in AIM, we estimated half-lives of both EBV load and EBV-specific CD8(+) T cells. Blood was serially taken from five pediatric patients with AIM during the convalescent period, including the very early phase, and both EBV load and EBV-specific CD8(+) T cell numbers were assayed. EBV load declined rapidly (half-life 1.5 d) during the first 2 weeks after onset of symptoms. This half-life was seven-fold shorter than that reported for CD27(+) memory B cells. Subsequently, the EBV load declined much more slowly, with a half-life of 38.7 d. EBV-specific CD8(+) T cell numbers also declined concomitantly with the decrease in EBV load. The half-life of EBV-specific CD8(+) T cells during first 2 weeks was 2.9 d. The number of EBV-specific CD8(+) T cells and the rate of change of viral load correlated significantly (R(2) ≥ 0.8; p ≤ 0.02). The short half-life of EBV load, together with the strong correlation between the number of EBV-specific CD8(+) T cells and the rate of change of viral load indicates an active role for EBV-specific CD8(+) T cells in elimination of EBV in AIM. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. The ThPOK transcription factor differentially affects the development and function of self-specific CD8(+) T cells and regulatory CD4(+) T cells.

    Science.gov (United States)

    Twu, Yuh-Ching; Teh, Hung-Sia

    2014-03-01

    The zinc finger transcription factor ThPOK plays a crucial role in CD4 T-cell development and CD4/CD8 lineage decision. In ThPOK-deficient mice, developing T cells expressing MHC class II-restricted T-cell receptors are redirected into the CD8 T-cell lineage. In this study, we investigated whether the ThPOK transgene affected the development and function of two additional types of T cells, namely self-specific CD8 T cells and CD4(+) FoxP3(+) T regulatory cells. Self-specific CD8 T cells are characterized by high expression of CD44, CD122, Ly6C, 1B11 and proliferation in response to either IL-2 or IL-15. The ThPOK transgene converted these self-specific CD8 T cells into CD4 T cells. The converted CD4(+) T cells are no longer self-reactive, lose the characteristics of self-specific CD8 T cells, acquire the properties of conventional CD4 T cells and survive poorly in peripheral lymphoid organs. By contrast, the ThPOK transgene promoted the development of CD4(+) FoxP3(+) regulatory T cells resulting in an increased recovery of CD4(+) FoxP3(+) regulatory T cells that expressed higher transforming growth factor-β-dependent suppressor activity. These studies indicate that the ThPOK transcription factor differentially affects the development and function of self-specific CD8 T cells and CD4(+) FoxP3(+) regulatory T cells. © 2013 John Wiley & Sons Ltd.

  19. Characteristics of CD8+ T cell subsets in Chinese patients with chronic HIV infection during initial ART.

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    Jiao, Yanmei; Hua, Wei; Zhang, Tong; Zhang, Yonghong; Ji, Yunxia; Zhang, Hongwei; Wu, Hao

    2011-03-25

    CD8+ T cells may play an important role in protecting against HIV. However, the changes of CD8+ T cell subsets during early period of ART have not been fully studied. Twenty-one asymptomatic treatment-naive HIV-infected patients with CD4 T+ cells less than 350 cells/μl were enrolled in the study. Naïve, central memory(CM), effective memory(EM) and terminally differentiated effector (EMRA) CD8+ cell subsets and their activation and proliferation subsets were evaluated in blood samples collected at base line, and week 2, 4, 8 and 12 of ART. The total CD8+ T cells declined and the Naïve and CM subsets had a tendency of increase. Activation levels of all CD8+ T cell subsets except EMRA subset decreased after ART. However, proliferation levels of total CD8+ T cells, EMRA, EM and CM subsets increased at the first 4 weeks of ART, then decreased. Proliferation level of the naïve cells decreased after ART. The changes of CD8+ T cell subsets during initial ART are complex. Our results display a complete phenotypical picture of CD8+ cell subsets during initial ART and provide insights for understanding of immune status during ART.

  20. Characteristics of CD8+ T cell subsets in Chinese patients with chronic HIV infection during initial ART

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    Zhang Hongwei

    2011-03-01

    Full Text Available Abstract Background CD8+ T cells may play an important role in protecting against HIV. However, the changes of CD8+ T cell subsets during early period of ART have not been fully studied. Methods Twenty-one asymptomatic treatment-naive HIV-infected patients with CD4 T+ cells less than 350 cells/μl were enrolled in the study. Naïve, central memory(CM, effective memory(EM and terminally differentiated effector (EMRA CD8+ cell subsets and their activation and proliferation subsets were evaluated in blood samples collected at base line, and week 2, 4, 8 and 12 of ART. Results The total CD8+ T cells declined and the Naïve and CM subsets had a tendency of increase. Activation levels of all CD8+ T cell subsets except EMRA subset decreased after ART. However, proliferation levels of total CD8+ T cells, EMRA, EM and CM subsets increased at the first 4 weeks of ART, then decreased. Proliferation level of the naïve cells decreased after ART. Conclusion The changes of CD8+ T cell subsets during initial ART are complex. Our results display a complete phenotypical picture of CD8+ cell subsets during initial ART and provide insights for understanding of immune status during ART.

  1. Germline bias dictates cross-serotype reactivity in a common dengue-virus-specific CD8+ T cell response.

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    Culshaw, Abigail; Ladell, Kristin; Gras, Stephanie; McLaren, James E; Miners, Kelly L; Farenc, Carine; van den Heuvel, Heleen; Gostick, Emma; Dejnirattisai, Wanwisa; Wangteeraprasert, Apirath; Duangchinda, Thaneeya; Chotiyarnwong, Pojchong; Limpitikul, Wannee; Vasanawathana, Sirijitt; Malasit, Prida; Dong, Tao; Rossjohn, Jamie; Mongkolsapaya, Juthathip; Price, David A; Screaton, Gavin R

    2017-11-01

    Adaptive immune responses protect against infection with dengue virus (DENV), yet cross-reactivity with distinct serotypes can precipitate life-threatening clinical disease. We found that clonotypes expressing the T cell antigen receptor (TCR) β-chain variable region 11 (TRBV11-2) were 'preferentially' activated and mobilized within immunodominant human-leukocyte-antigen-(HLA)-A*11:01-restricted CD8 + T cell populations specific for variants of the nonstructural protein epitope NS3 133 that characterize the serotypes DENV1, DENV3 and DENV4. In contrast, the NS3 133 -DENV2-specific repertoire was largely devoid of such TCRs. Structural analysis of a representative TRBV11-2 + TCR demonstrated that cross-serotype reactivity was governed by unique interplay between the variable antigenic determinant and germline-encoded residues in the second β-chain complementarity-determining region (CDR2β). Extensive mutagenesis studies of three distinct TRBV11-2 + TCRs further confirmed that antigen recognition was dependent on key contacts between the serotype-defined peptide and discrete residues in the CDR2β loop. Collectively, these data reveal an innate-like mode of epitope recognition with potential implications for the outcome of sequential exposure to heterologous DENVs.

  2. CD8+ T Cells Mediate Female-Dominant IL-4 Production and Airway Inflammation in Allergic Asthma.

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    Chihiro Ito

    Full Text Available The prevalence and severity of bronchial asthma are higher in females than in males after puberty. Although antigen-specific CD8+ T cells play an important role in the development of asthma through their suppressive effect on cytokine production, the contribution of CD8+ T cells to sex differences in asthmatic responses remains unclear. In the present study, we investigated the sex-specific effect of CD8+ T cells in the suppression of asthma using an ovalbumin mouse model of asthma. The number of inflammatory cells in bronchoalveolar lavage (BAL fluid, lung type 2 T-helper cytokine levels, and interleukin-4 (IL-4 production by bronchial lymph node cells were significantly higher in female wild-type (WT mice compared with male mice, whereas no such sex differences were observed between male and female cd8α-disrupted mice. The adaptive transfer of male, but not female, CD8+ T cells reduced the number of inflammatory cells in the recovered BAL fluid of male recipient mice, while no such sex difference in the suppressive activity of CD8+ T cells was observed in female recipient mice. Male CD8+ T cells produced higher levels of IFN-γ than female CD8+ T cells did, and this trend was associated with reduced IL-4 production by male, but not female, CD4+ T cells. Interestingly, IFN-γ receptor expression on CD4+ T cells was significantly lower in female mice than in male mice. These results suggest that female-dominant asthmatic responses are orchestrated by the reduced production of IFN-γ by CD8+ T cells and the lower expression of IFN-γ receptor on CD4+ T cells in females compared with males.

  3. STAT3 Regulates Proliferation and Survival of CD8+ T Cells: Enhances Effector Responses to HSV-1 Infection, and Inhibits IL-10+ Regulatory CD8+ T Cells in Autoimmune Uveitis

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    Cheng-Rong Yu

    2013-01-01

    Full Text Available STAT3 regulates CD4+ T cell survival and differentiation. However, its effects on CD8+ T cells are not well understood. Here, we show that in comparison to WT CD8+ T cells, STAT3-deficient CD8+ T cells exhibit a preactivated memory-like phenotype, produce more IL-2, proliferate faster, and are more sensitive to activation-induced cell death (AICD. The enhanced proliferation and sensitivity to AICD correlated with downregulation of class-O forkhead transcription factors (FoxO1, FoxO3A, , , Bcl-2, OX-40, and upregulation of FasL, Bax, and Bad. We examined whether STAT3-deficient CD8+ T cells can mount effective response during herpes simplex virus (HSV-1 infection and experimental autoimmune uveitis (EAU. Compared to WT mice, HSV-1-infected STAT3-deficient mice (STAT3KO produced less IFN- and virus-specific KLRG-1+ CD8+ T cells. STAT3KO mice are also resistant to EAU and produced less IL-17-producing Tc17 cells. Resistance of STAT3KO to EAU correlated with marked expansion of IL-10-producing regulatory CD8+ T cells (CD8-Treg implicated in recovery from autoimmune encephalomyelitis. Thus, increases of IL-6-induced STAT3 activation observed during inflammation may inhibit expansion of CD8-Tregs, thereby impeding recovery from uveitis. These results suggest that STAT3 is a potential therapeutic target for upregulating CD8+ T cell-mediated responses to viruses and suggest the successful therapeutic targeting of STAT3 as treatment for uveitis, derived, in part, from promoting CD8-Treg expansion.

  4. CD8+ Tumor-Infiltrating T Cells Are Trapped in the Tumor-Dendritic Cell Network

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    Alexandre Boissonnas

    2013-01-01

    Full Text Available Chemotherapy enhances the antitumor adaptive immune T cell response, but the immunosuppressive tumor environment often dominates, resulting in cancer relapse. Antigen-presenting cells such as tumor-associated macrophages (TAMs and tumor dendritic cells (TuDCs are the main protagonists of tumor-infiltrating lymphocyte (TIL immuno-suppression. TAMs have been widely investigated and are associated with poor prognosis, but the immuno-suppressive activity of TuDCs is less well understood. We performed two-photon imaging of the tumor tissue to examine the spatiotemporal interactions between TILs and TuDCs after chemotherapy. In a strongly immuno-suppressive murine tumor model, cyclophosphamide-mediated chemotherapy transiently enhanced the antitumor activity of adoptively transferred ovalbumin-specific CD8+ T cell receptor transgenic T cells (OTI but barely affected TuDC compartment within the tumor. Time lapse imaging of living tumor tissue showed that TuDCs are organized as a mesh with dynamic interconnections. Once infiltrated into the tumor parenchyma, OTI T cells make antigen-specific and long-lasting contacts with TuDCs. Extensive analysis of TIL infiltration on histologic section revealed that after chemotherapy the majority of OTI T cells interact with TuDCs and that infiltration is restricted to TuDC-rich areas. We propose that the TuDC network exerts antigen-dependent unproductive retention that trap T cells and limit their antitumor effectiveness.

  5. Functional dichotomy between NKG2D and CD28-mediated co-stimulation in human CD8+ T cells.

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    Kamalakannan Rajasekaran

    2010-09-01

    Full Text Available Both CD28 and NKG2D can function as co-stimulatory receptors in human CD8+ T cells. However, their independent functional contributions in distinct CD8+ T cell subsets are not well understood. In this study, CD8+ T cells in human peripheral blood- and lung-derived lymphocytes were analyzed for CD28 and NKG2D expression and function. We found a higher level of CD28 expression in PBMC-derived naïve (CD45RA+CD27+ and memory (CD45RA-CD27+ CD8+ T cells (CD28Hi, while its expression was significantly lower in effector (CD45RA+CD27- CD8+ T cells (CD28Lo. Irrespective of the differences in the CD28 levels, NKG2D expression was comparable in all three CD8+ T cell subsets. CD28 and NKG2D expressions followed similar patterns in human lung-resident GILGFVFTL/HLA-A2-pentamer positive CD8+ T cells. Co-stimulation of CD28Lo effector T cells via NKG2D significantly increased IFN-γ and TNF-α levels. On the contrary, irrespective of its comparable levels, NKG2D-mediated co-stimulation failed to augment IFN-γ and TNF-α production in CD28Hi naïve/memory T cells. Additionally, CD28-mediated co-stimulation was obligatory for IL-2 generation and thereby its production was limited only to the CD28Hi naïve/memory subsets. MICA, a ligand for NKG2D was abundantly expressed in the tracheal epithelial cells, validating the use of NKG2D as the major co-stimulatory receptor by tissue-resident CD8+ effector T cells. Based on these findings, we conclude that NKG2D may provide an expanded level of co-stimulation to tissue-residing effector CD8+ T cells. Thus, incorporation of co-stimulation via NKG2D in addition to CD28 is essential to activate tumor or tissue-infiltrating effector CD8+ T cells. However, boosting a recall immune response via memory CD8+ T cells or vaccination to stimulate naïve CD8+ T cells would require CD28-mediated co-stimulation.

  6. Cognate antigen stimulation generates potent CD8+ inflammatory effector T cells.

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    Hsueh-Cheng eSung

    2013-12-01

    Full Text Available Inflammatory reactions are believed to be triggered by innate signals and have a major protective role by recruiting innate immunity cells, favoring lymphocyte activation and differentiation, and thus contributing to the sequestration and elimination of the injurious stimuli. Although certain lymphocyte types such as TH17 cells co-participate in inflammatory reactions, their generation from the naïve pool requires the pre-existence of an inflammatory milieu. In this context, inflammation is always regarded as beginning with an innate response that may be eventually perpetuated and amplified by certain lymphocyte types. In contrast, we here show that even in sterile immunizations or in MyD88 deficient mice, CD8 T cells produce a burst of pro-inflammatory cytokines and chemokines. These functions follow opposite rules to the classic CD8 effector functions since they are generated prior to cell expansion and decline before antigen elimination. As few as 56 CD8+ inflammatory effector cells in a lymph node can mobilize 107 cells in 24h, including lymphocytes, natural killer cells and several accessory cell types involved in inflammatory reactions. Thus, although inflammation modulates cognate responses, CD8 cognate responses also initiate local inflammatory reactions.

  7. Profiling the Targets of Protective CD8+ T Cell Responses to Infection

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    Joseph T. Bruder

    2017-12-01

    Full Text Available T cells are critical effectors of host immunity that target intracellular pathogens, such as the causative agents of HIV, tuberculosis, and malaria. The development of vaccines that induce effective cell-mediated immunity against such pathogens has proved challenging; for tuberculosis and malaria, many of the antigens targeted by protective T cells are not known. Here, we report a novel approach for screening large numbers of antigens as potential targets of T cells. Malaria provides an excellent model to test this antigen discovery platform because T cells are critical mediators of protection following immunization with live sporozoite vaccines and the specific antigen targets are unknown. We generated an adenovirus array by cloning 312 highly expressed pre-erythrocytic Plasmodium yoelii antigens into adenovirus vectors using high-throughput methodologies. The array was screened to identify antigen-specific CD8+ T cells induced by a live sporozoite vaccine regimen known to provide high levels of sterile protection mediated by CD8+ T cells. We identified 69 antigens that were targeted by CD8+ T cells induced by this vaccine regimen. The antigen that recalled the highest frequency of CD8+ T cells, PY02605, induced protective responses in mice, demonstrating proof of principle for this approach in identifying antigens for vaccine development.

  8. Clinical Control of HIV-1 by Cytotoxic T Cells Specific for Multiple Conserved Epitopes.

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    Murakoshi, Hayato; Akahoshi, Tomohiro; Koyanagi, Madoka; Chikata, Takayuki; Naruto, Takuya; Maruyama, Rie; Tamura, Yoshiko; Ishizuka, Naoki; Gatanaga, Hiroyuki; Oka, Shinichi; Takiguchi, Masafumi

    2015-05-01

    Identification and characterization of CD8(+) T cells effectively controlling HIV-1 variants are necessary for the development of AIDS vaccines and for studies of AIDS pathogenesis, although such CD8(+) T cells have been only partially identified. In this study, we sought to identify CD8(+) T cells controlling HIV-1 variants in 401 Japanese individuals chronically infected with HIV-1 subtype B, in which protective alleles HLA-B*57 and HLA-B*27 are very rare, by using comprehensive and exhaustive methods. We identified 13 epitope-specific CD8(+) T cells controlling HIV-1 in Japanese individuals, though 9 of these epitopes were not previously reported. The breadths of the T cell responses to the 13 epitopes were inversely associated with plasma viral load (P = 2.2 × 10(-11)) and positively associated with CD4 count (P = 1.2 × 10(-11)), indicating strong synergistic effects of these T cells on HIV-1 control in vivo. Nine of these epitopes were conserved among HIV-1 subtype B-infected individuals, whereas three out of four nonconserved epitopes were cross-recognized by the specific T cells. These findings indicate that these 12 epitopes are strong candidates for antigens for an AIDS vaccine. The present study highlighted a strategy to identify CD8(+) T cells controlling HIV-1 and demonstrated effective control of HIV-1 by those specific for 12 conserved or cross-reactive epitopes. HLA-B*27-restricted and HLA-B*57-restricted cytotoxic T lymphocytes (CTLs) play a key role in controlling HIV-1 in Caucasians and Africans, whereas it is unclear which CTLs control HIV-1 in Asian countries, where HLA-B*57 and HLA-B*27 are very rare. A recent study showed that HLA-B*67:01 and HLA-B*52:01-C*12:02 haplotypes were protective alleles in Japanese individuals, but it is unknown whether CTLs restricted by these alleles control HIV-1. In this study, we identified 13 CTLs controlling HIV-1 in Japan by using comprehensive and exhaustive methods. They included 5 HLA-B*52:01-restricted

  9. Characterization of the CD8+ T cell responses directed against respiratory syncytial virus during primary and secondary infection in C57BL/6 mice

    International Nuclear Information System (INIS)

    Lukens, Michael V.; Claassen, Erwin A.W.; Graaff, Patricia M.A. de; Dijk, Mariska E.A. van; Hoogerhout, Peter; Toebes, Mireille; Schumacher, Ton N.; Most, Robbert G. van der; Kimpen, Jan L.L.; Bleek, Grada M. van

    2006-01-01

    The BALB/c mouse model for human respiratory syncytial virus infection has contributed significantly to our understanding of the relative role for CD4 + and CD8 + T cells to immune protection and pathogenic immune responses. To enable comparison of RSV-specific T cell responses in different mouse strains and allow dissection of immune mechanisms by using transgenic and knockout mice that are mostly available on a C57BL/6 background, we characterized the specificity, level and functional capabilities of CD8 + T cells during primary and secondary responses in lung parenchyma, airways and spleens of C57BL/6 mice. During the primary response, epitopes were recognized originating from the matrix, fusion, nucleo- and attachment proteins, whereas the secondary response focused predominantly on the matrix epitope. C57BL/6 mice are less permissive for hRSV infection than BALB/c mice, yet we found CD8 + T cell responses in the lungs and bronchoalveolar lavage, comparable to the responses described for BALB/c mice

  10. How much of Virus-Specific CD8 T Cell Reactivity is Detected with a Peptide Pool when Compared to Individual Peptides?

    Directory of Open Access Journals (Sweden)

    Ramu A. Subbramanian

    2012-10-01

    Full Text Available Immune monitoring of T cell responses increasingly relies on the use of peptide pools. Peptides, when restricted by the same HLA allele, and presented from within the same peptide pool, can compete for HLA binding sites. What impact such competition has on functional T cell stimulation, however, is not clear. Using a model peptide pool that is comprised of 32 well-defined viral epitopes from Cytomegalovirus, Epstein-Barr virus, and Influenza viruses (CEF peptide pool, we assessed peptide competition in PBMC from 42 human subjects. The magnitude of the peptide pool-elicited CD8 T cell responses was a mean 79% and a median 77% of the sum of the CD8 T cell responses elicited by the individual peptides. Therefore, while the effect of peptide competition was evident, it was of a relatively minor magnitude. By studying the dose-response curves for individual CEF peptides, we show that several of these peptides are present in the CEF-pool at concentrations that are orders of magnitude in excess of what is needed for the activation threshold of the CD8 T cells. The presence of such T cells with very high functional avidity for the viral antigens can explain why the effect of peptide competition is relatively minor within the CEF-pool.

  11. Diet-induced obesity does not impact the generation and maintenance of primary memory CD8 T cells.

    Science.gov (United States)

    Khan, Shaniya H; Hemann, Emily A; Legge, Kevin L; Norian, Lyse A; Badovinac, Vladimir P

    2014-12-15

    The extent to which obesity compromises the differentiation and maintenance of protective memory CD8 T cell responses and renders obese individuals susceptible to infection remains unknown. In this study, we show that diet-induced obesity did not impact the maintenance of pre-existing memory CD8 T cells, including acquisition of a long-term memory phenotype (i.e., CD27(hi), CD62L(hi), KLRG1(lo)) and function (i.e., cytokine production, secondary expansion, and memory CD8 T cell-mediated protection). Additionally, obesity did not influence the differentiation and maintenance of newly evoked memory CD8 T cell responses in inbred and outbred hosts generated in response to different types of systemic (LCMV, L. monocytogenes) and/or localized (influenza virus) infections. Interestingly, the rate of naive-to-memory CD8 T cell differentiation after a peptide-coated dendritic cell immunization was similar in lean and obese hosts, suggesting that obesity-associated inflammation, unlike pathogen- or adjuvant-induced inflammation, did not influence the development of endogenous memory CD8 T cell responses. Therefore, our studies reveal that the obese environment does not influence the development or maintenance of memory CD8 T cell responses that are either primed before or after obesity is established, a surprising notion with important implications for future studies aiming to elucidate the role obesity plays in host susceptibility to infections. Copyright © 2014 by The American Association of Immunologists, Inc.

  12. The role of CD4 and CD8 T cells in human cutaneous leishmaniasis.

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    Claudia Ida Brodskyn

    2014-09-01

    Full Text Available Leishmaniasis, caused by infection with parasites of the Leishmania genus, affects millions of individuals worldwide. This disease displays distinct clinical manifestations ranging from self-healing skin lesions to severe tissue damage. The control of Leishmania infection is dependent on cellular immune mechanisms, and evidence has shown that CD4 and CD8 T lymphocytes play different roles in the outcome of leishmaniasis. Although the presence of CD4 T cells is important for controlling parasite growth, the results in the literature suggest that the inflammatory response elicited by these cells could contribute to the pathogenesis of lesions. However, recent studies on CD8 T lymphocytes show that these cells are mainly involved in tissue damage through cytotoxic mechanisms. In this review, we focus on the recent advances in the study of the human adaptive immunological response in the pathogenesis of tegumentary leishmaniasis.

  13. Vaginal type-II mucosa is an inductive site for primary CD8+ T-cell mucosal immunity

    Science.gov (United States)

    Wang, Yichuan; Sui, Yongjun; Kato, Shingo; Hogg, Alison E.; Steel, Jason C.; Morris, John C.; Berzofsky, Jay A.

    2014-01-01

    The structured lymphoid tissues are considered the only inductive sites where primary T cell immune responses occur. The naïve T cells in structured lymphoid tissues, once being primed by antigen -bearing dendritic cells, differentiate into memory T cells and traffic back to the mucosal sites through the bloodstream. Contrary to this belief, here we show that the vaginal type-II mucosa itself, despite lack of structured lymphoid tissues, can act as an inductive site during primary CD8+ T cell immune responses. We provide evidence that the vaginal mucosa supports both the local immune priming of naïve CD8+ T cells and the local expansion of antigen-specific CD8+ T cells, thereby demonstrating a different paradigm for primary mucosal T cell immune induction. PMID:25600442

  14. In vitro activation of CMV-specific human CD8ţ T cells by adenylate

    Czech Academy of Sciences Publication Activity Database

    Jelínek, J.; Adkins, Irena; Mikulková, Z.; Jagosová, J.; Pacasová, R.; Michličková, S.; Šebo, Peter; Michálek, J.

    2012-01-01

    Roč. 47, č. 2 (2012), s. 243-250 ISSN 0268-3369 R&D Projects: GA MŠk 2B06161; GA ČR GP310/09/P582 Institutional research plan: CEZ:AV0Z50200510 Keywords : T cells * antigenic peptide epitopes * CyaA toxoid Subject RIV: EE - Microbiology, Virology Impact factor: 3.541, year: 2012

  15. The contribution of Chlamydia-specific CD8T cells to upper genital tract pathology.

    Science.gov (United States)

    Vlcek, Kelly R; Li, Weidang; Manam, Srikanth; Zanotti, Brian; Nicholson, Bruce J; Ramsey, Kyle H; Murthy, Ashlesh K

    2016-02-01

    Genital chlamydial infections lead to severe upper reproductive tract pathology in a subset of untreated women. We demonstrated previously that tumor necrosis factor (TNF)-α-producing CD8(+) T cells contribute significantly to chlamydial upper genital tract pathology in female mice. In addition, we observed that minimal chlamydial oviduct pathology develops in OT-1 transgenic (OT-1) mice, wherein the CD8(+) T-cell repertoire is restricted to recognition of the ovalbumin peptide Ova(257-264), suggesting that non-Chlamydia-specific CD8(+) T cells may not be responsible for chlamydial pathogenesis. In the current study, we evaluated whether antigen-specific CD8(+) T cells mediate chlamydial pathology. Groups of wild-type (WT) C57BL/6J, OT-1 mice, and OT-1 mice replete with WT CD8(+) T cells (1 × 10(6) cells per mouse intravenously) were infected intravaginally with C. muridarum (5 × 10(4) IFU/mouse). Serum total anti-Chlamydia antibody and total splenic anti-Chlamydia interferon (IFN)-γ and TNF-α responses were comparable among the three groups of animals. However, Chlamydia-specific IFN-γ and TNF-α production from purified splenic CD8(+) T cells of OT-1 mice was minimal, whereas responses in OT-1 mice replete with WT CD8(+) T cells were comparable to those in WT animals. Vaginal chlamydial clearance was comparable between the three groups of mice. Importantly, the incidence and severity of oviduct and uterine horn pathology was significantly reduced in OT-1 mice but reverted to WT levels in OT-1 mice replete with WT CD8(+) T cells. Collectively, these results demonstrate that Chlamydia-specific CD8(+) T cells contribute significantly to upper genital tract pathology.

  16. Normalized Synergy Predicts That CD8 Co-Receptor Contribution to T Cell Receptor (TCR and pMHC Binding Decreases As TCR Affinity Increases in Human Viral-Specific T Cells

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    Chad M. Williams

    2017-07-01

    Full Text Available The discovery of naturally occurring T cell receptors (TCRs that confer specific, high-affinity recognition of pathogen and cancer-associated antigens remains a major goal in cellular immunotherapies. The contribution of the CD8 co-receptor to the interaction between the TCR and peptide-bound major histocompatibility complex (pMHC has previously been correlated with the activation and responsiveness of CD8+ T cells. However, these studies have been limited to model systems of genetically engineered hybridoma TCRs or transgenic mouse TCRs against either a single epitope or an array of altered peptide ligands. CD8 contribution in a native human antigen-specific T cell response remains elusive. Here, using Hepatitis C Virus-specific precursor CTLs spanning a large range of TCR affinities, we discovered that the functional responsiveness of any given TCR correlated with the contribution of CD8 to TCR/pMHC binding. Furthermore, we found that CD8 contribution to TCR/pMHC binding in the two-dimensional (2D system was more accurately reflected by normalized synergy (CD8 cooperation normalized by total TCR/pMHC bonds rather than synergy (total CD8 cooperation alone. While synergy showed an increasing trend with TCR affinity, normalized synergy was demonstrated to decrease with the increase of TCR affinity. Critically, normalized synergy was shown to correlate with CTL functionality and peptide sensitivity, corroborating three-dimensional (3D analysis of CD8 contribution with respect to TCR affinity. In addition, we identified TCRs that were independent of CD8 for TCR/pMHC binding. Our results resolve the current discrepancy between 2D and 3D analysis on CD8 contribution to TCR/pMHC binding, and demonstrate that naturally occurring high-affinity TCRs are more capable of CD8-independent interactions that yield greater functional responsiveness even with CD8 blocking. Taken together, our data suggest that addition of the normalized synergy parameter to our

  17. Highly differentiated, resting gn-specific memory CD8+ T cells persist years after infection by andes hantavirus.

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    Tobias Manigold

    2010-02-01

    Full Text Available In man, infection with South American Andes virus (ANDV causes hantavirus cardiopulmonary syndrome (HCPS. HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-gamma ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3(+CD8(+ T cells were specific for the single HLA-B*3501-restricted epitope Gn(465-473 years after the acute infection. Remarkably, Gn(465-473-specific cells readily secreted IFN-gamma, granzyme B and TNF-alpha but not IL-2 upon stimulation and showed a 'revertant' CD45RA(+CD27(-CD28(-CCR7(-CD127(- effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T

  18. CD8+ T-Cells Count in Acute Myocardial Infarction in HIV Disease in a Predominantly Male Cohort

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    Oluwatosin A. Badejo

    2015-01-01

    Full Text Available Human Immunodeficiency Virus- (HIV- infected persons have a higher risk for acute myocardial infarction (AMI than HIV-uninfected persons. Earlier studies suggest that HIV viral load, CD4+ T-cell count, and antiretroviral therapy are associated with cardiovascular disease (CVD risk. Whether CD8+ T-cell count is associated with CVD risk is not clear. We investigated the association between CD8+ T-cell count and incident AMI in a cohort of 73,398 people (of which 97.3% were men enrolled in the U.S. Veterans Aging Cohort Study-Virtual Cohort (VACS-VC. Compared to uninfected people, HIV-infected people with high baseline CD8+ T-cell counts (>1065 cells/mm3 had increased AMI risk (adjusted HR=1.82, P<0.001, 95% CI: 1.46 to 2.28. There was evidence that the effect of CD8+ T-cell tertiles on AMI risk differed by CD4+ T-cell level: compared to uninfected people, HIV-infected people with CD4+ T-cell counts ≥200 cells/mm3 had increased AMI risk with high CD8+ T-cell count, while those with CD4+ T-cell counts <200 cells/mm3 had increased AMI risk with low CD8+ T-cell count. CD8+ T-cell counts may add additional AMI risk stratification information beyond that provided by CD4+ T-cell counts alone.

  19. Tumor rejection induced by CD70-mediated quantitative and qualitative effects on effector CD8+ T cell formation

    NARCIS (Netherlands)

    Arens, Ramon; Schepers, Koen; Nolte, Martijn A.; van Oosterwijk, Michiel F.; van Lier, René A. W.; Schumacher, Ton N. M.; van Oers, Marinus H. J.

    2004-01-01

    In vivo priming of antigen-specific CD8+ T cells results in their expansion and differentiation into effector T cells followed by contraction into a memory T cell population that can be maintained for life. Recent evidence suggests that after initial antigenic stimulation, the magnitude and kinetics

  20. Cytotoxic potential of decidual NK cells and CD8+ T cells awakened by infections.

    Science.gov (United States)

    Crespo, Ângela C; van der Zwan, Anita; Ramalho-Santos, João; Strominger, Jack L; Tilburgs, Tamara

    2017-02-01

    To establish a healthy pregnancy the maternal immune system must tolerate fetal allo-antigens, yet remain competent to respond to infections. The ability of decidual NK cells (dNK) to promote migration of fetal extravillous trophoblasts (EVT) and placental growth as well as the capacity of EVT to promote immune tolerance are topics of high interest and extensive research. However, the problem of how dNK and decidual CD8+ T cells (CD8+ dT) provide immunity to infections of the placenta and the mechanisms that regulate their cytolytic function has thus far largely been ignored. Fetal EVT are the most invasive cells of the placenta and directly interact with maternal decidual immune cells at this maternal-fetal interface. Besides the expression of non-polymorphic HLA-E and HLA-G molecules that are associated with immune tolerance, EVT also express highly polymorphic HLA-C molecules that can serve as targets for maternal dNK and CD8+ dT responses. HLA-C expression by EVT has a dual role as the main molecule to which immune tolerance needs to be established and as the only molecule that can present pathogen-derived peptides and provide protective immunity when EVT are infected. The focus of this review is to address the regulation of cytotoxicity of dNK and CD8+ dT, which is essential for maternal-fetal immune tolerance as well as recent evidence that both cell types can provide immunity to infections at the maternal-fetal interface. A particular emphasis is given to the role of HLA-C expressed by EVT and its capacity to elicit dNK and CD8+ dT responses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. CD8+ T Cells Mediate Female-Dominant IL-4 Production and Airway Inflammation in Allergic Asthma

    OpenAIRE

    Ito, Chihiro; Okuyama-Dobashi, Kaori; Miyasaka, Tomomitsu; Masuda, Chiaki; Sato, Miki; Kawano, Tasuku; Ohkawara, Yuichi; Kikuchi, Toshiaki; Takayanagi, Motoaki; Ohno, Isao

    2015-01-01

    The prevalence and severity of bronchial asthma are higher in females than in males after puberty. Although antigen-specific CD8+ T cells play an important role in the development of asthma through their suppressive effect on cytokine production, the contribution of CD8+ T cells to sex differences in asthmatic responses remains unclear. In the present study, we investigated the sex-specific effect of CD8+ T cells in the suppression of asthma using an ovalbumin mouse model of asthma. The numbe...

  2. Decreased Expression of T-Cell Costimulatory Molecule CD28 on CD4 and CD8 T Cells of Mexican Patients with Pulmonary Tuberculosis

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    German Bernal-Fernandez

    2010-01-01

    Full Text Available Patients with tuberculosis frequently develop anergy, a state of T-cell hyporesponsiveness in which defective T-cell costimulation could be a factor. To know if the expression of T-cell costimulatory molecules was altered in tuberculosis, we analyzed the peripheral blood T-cell phenotype of 23 Mexican patients with pulmonary tuberculosis. There was severe CD4 (P<.001 and CD8 (P<.01 lymphopenia and upregulation of costimulatory molecule CD30 on CD4 and CD8 T cells (P<.05; this increase was higher in relapsing tuberculosis. The main finding was severe downregulation of the major costimulatory molecule CD28 on both CD8 and CD4 T cells (P<.001. Depletion of the CD4/CD28 subset, a hitherto undescribed finding, is relevant because CD4 T cells constitute the main arm of the cell-mediated antimycobacterial immune response.

  3. Antigen and Memory CD8 T Cells: Were They Both Right?

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    Epelman Slava

    2007-06-01

    Full Text Available Picture yourself as a researcher in immunology. To begin your project, you ask a question: Do CD8 T cells require antigen to maintain a memory response? This question is of prime importance to numerous medical fields. In chronologic order, you digest the literature, but unfortunately, you hit a major stumbling block in the 1990s. The crux of the problem is that which so often happens in science: two well-recognized, capable groups emerge with diametrically opposed conclusions, leaving you pondering which set of wellcontrolled data to believe. Fortunately, years later, a surprising group of articles sheds light on this mystery and subtly reconciles these two positions.

  4. Qualitative and quantitative analysis of adenovirus type 5 vector-induced memory CD8 T cells

    DEFF Research Database (Denmark)

    Steffensen, Maria Abildgaard; Holst, Peter Johannes; Steengaard, Sanne Skovvang

    2013-01-01

    infection with lymphocytic choriomeningitis virus. We found that localized immunization with intermediate doses of Ad vector induce a moderate number of functional CD8 T cells, which qualitatively match those found in LCMV-infected mice. Numbers of these cells may be efficiently increased by additional...... adenoviral boosting and, importantly, the generated secondary memory cells cannot be qualitatively differentiated from those induced by primary infection with replicating virus. Quantitatively, DNA priming prior to Ad-vaccination will lead to even higher numbers of memory cells. In this case, the vaccination...

  5. Alpha 4 integrin directs virus-activated CD8+ T cells to sites of infection

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Andersson, E C; Scheynius, A

    1995-01-01

    This article examines the role of VLA-4 in directing lymphocytes to sites of viral infection using the murine lymphocytic choriomeningitis virus infection (LCMV) as the model system. This virus by itself induces little or no inflammation, but in most mouse/virus strain combinations a potent T cell...... response is induced, which is associated with marked CD8+ cell-mediated inflammation. Two expressions of LCMV-induced inflammation were studied: meningitis induced by intracerebral infection and adoptive transfer of virus-specific delayed-type hypersensitivity. Our previous studies have shown that LCMV...

  6. HIV-specific cytotoxic T lymphocyte precursors exist in a CD28-CD8+ T cell subset and increase with loss of CD4 T cells.

    Science.gov (United States)

    Lewis, D E; Yang, L; Luo, W; Wang, X; Rodgers, J R

    1999-06-18

    To determine whether the CD28-CD8+ T cells that develop during HIV infection contain HIV-specific cytotoxic precursor cells. CD8 subpopulations from six asymptomatic HIV-positive adults, with varying degrees of CD4 T cell loss, were sorted by flow cytometry and HIV-specific precursor cytotoxic T lymphocyte frequencies were measured. Three populations of CD8 T cells were tested: CD28+CD5-- T cells, CD28-CD57+ T cells (thought to be memory cells) and CD28-CD57- T cells (function unknown). Sorted CD8 subsets were stimulated with antigen presenting cells expressing HIV-1 Gag/Pol molecules. Cytotoxic T cell assays on Gag/Pol expressing 51Cr-labeled Epstein-Barr virus transformed autologous B cells lines or control targets were performed after 2 weeks. Specific lysis and precursor frequencies were calculated. Both CD28 positive and CD28-CD57+ populations contained appreciable numbers of precursors (9-1720 per 10(6) CD8+ T cells). However, the CD28-CD57- population had fewer precursors in five out of six people studied. More CD28 positive HIV-specific cytotoxic T lymphocyte precursors were found in patients with CD4:CD8 ratios > 1, whereas more CD28-CD57+ precursors were found in patients whose CD4:CD8 ratios were < 1 (r2, 0.68). Memory HIV-specific precursor cytotoxic T lymphocytes are found in both CD28 positive and CD28-CD8+ cells, however, a CD28-CD57- subpopulation had fewer. Because CD28-CD57+ cells are antigen-driven with limited diversity, the loss of CD28 on CD8 T cells during disease progression may reduce the response to new HIV mutations; this requires further testing.

  7. Is a Human CD8 T-Cell Vaccine Possible, and if So, What Would It Take? CD8 T-Cell Vaccines: To B or Not to B?

    Science.gov (United States)

    Beura, Lalit K; Jameson, Stephen C; Masopust, David

    2017-12-18

    Although CD8 T-cell vaccines do not have the record of success of humoral-mediated vaccines, they do not receive the same degree of effort. Many diseases, including malaria, tuberculosis, and acquired immune deficiency syndrome (AIDS) have not yielded to vaccines, and intrinsic barriers may impede approaches limited solely to generating antibodies. Moreover, population growth and modernization are driving an increased pace of new emerging global health threats (human immunodeficiency virus [HIV] is a recent example), which will create unpredictable challenges for vaccinologists. Vaccine-elicited CD8 T cells may contribute to protective modalities, although their development will require a more thorough understanding of CD8 T-cell biology, practices for manufacturing and delivering CD8 T-cell-eliciting vectors that have acceptable safety profiles, and, ultimately, the political will and faith of those that make vaccine research funding decisions. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  8. CD8 apoptosis may be a predictor of T cell number normalization after immune reconstitution in HIV

    Directory of Open Access Journals (Sweden)

    Martinez Maria L

    2007-01-01

    Full Text Available Abstract Background As part of the Houston Vanguard study, a subset of 10 patients randomized to receive IL-2 therapy were compared to 4 patients randomized to not receive IL-2, for markers of T cell activation and death during the first three cycles of IL-2. All patients were treated with combination antiretroviral therapy (ART and were virally suppressed. The purpose of the study was to examine the role of CD8+ T cell death in responses to ART and IL-2 therapy. Methods Lymphocytes were examined at Day 0, 5 and 30 days during three cycles of IL-2 therapy. CD25, CD38, HLA-DR expression and annexin (cell death were examined on CD4 and CD8 subpopulations. Follow up studies examined CD4 levels and CD4:CD8 reconstitution after 6 years using both univariant and multivariate analyses. Results Human lymphocytes responded to IL-2 therapy by upregulation of CD25 on CD4+ T cells, leading to an increase in CD4 cell counts. CD8+ T cells did not increase CD25 expression, but upregulated activation antigens (CD38 and DR and had increased death. At baseline, 7 of the 14 patients had high CD8+ T cell apoptosis (mean 17.0% ± 6.0. We did an exploratory analysis of immune status after six years, and found that baseline CD8+ T cell apoptosis was correlated with CD4 cell count gain beginning two years post enrollment. Patients with low levels of CD8+ T cell apoptosis at baseline (mean 2.2% ± 2.1 had significantly higher CD4 cell counts and more normalized CD4:CD8 ratios than patients with high CD8+ T cell apoptosis (mean CD4 cell counts 1,209 ± 164 vs 754 ± 320 cells/mm3; CD4:CD8 ratios 1.55 vs. 0.70, respectively. Conclusion We postulate that CD8+ T cell apoptosis may reflect inherent activation status, which continues in some patients even though viral replication is suppressed which influences the ability of CD4+ T cells to rebound. Levels of CD8+ T cell apoptosis may therefore be an independent predictor of immune status, which should be shown in a

  9. CD8 apoptosis may be a predictor of T cell number normalization after immune reconstitution in HIV

    Science.gov (United States)

    Lewis, Dorothy E; Gross, Kimber L; Diez, Martine M; Martinez, Maria L; Lukefahr, Helen N; Kozinetz, Claudia A; Arduino, Roberto C

    2007-01-01

    Background As part of the Houston Vanguard study, a subset of 10 patients randomized to receive IL-2 therapy were compared to 4 patients randomized to not receive IL-2, for markers of T cell activation and death during the first three cycles of IL-2. All patients were treated with combination antiretroviral therapy (ART) and were virally suppressed. The purpose of the study was to examine the role of CD8+ T cell death in responses to ART and IL-2 therapy. Methods Lymphocytes were examined at Day 0, 5 and 30 days during three cycles of IL-2 therapy. CD25, CD38, HLA-DR expression and annexin (cell death) were examined on CD4 and CD8 subpopulations. Follow up studies examined CD4 levels and CD4:CD8 reconstitution after 6 years using both univariant and multivariate analyses. Results Human lymphocytes responded to IL-2 therapy by upregulation of CD25 on CD4+ T cells, leading to an increase in CD4 cell counts. CD8+ T cells did not increase CD25 expression, but upregulated activation antigens (CD38 and DR) and had increased death. At baseline, 7 of the 14 patients had high CD8+ T cell apoptosis (mean 17.0% ± 6.0). We did an exploratory analysis of immune status after six years, and found that baseline CD8+ T cell apoptosis was correlated with CD4 cell count gain beginning two years post enrollment. Patients with low levels of CD8+ T cell apoptosis at baseline (mean 2.2% ± 2.1) had significantly higher CD4 cell counts and more normalized CD4:CD8 ratios than patients with high CD8+ T cell apoptosis (mean CD4 cell counts 1,209 ± 164 vs 754 ± 320 cells/mm3; CD4:CD8 ratios 1.55 vs. 0.70, respectively). Conclusion We postulate that CD8+ T cell apoptosis may reflect inherent activation status, which continues in some patients even though viral replication is suppressed which influences the ability of CD4+ T cells to rebound. Levels of CD8+ T cell apoptosis may therefore be an independent predictor of immune status, which should be shown in a prospective study. PMID:17263884

  10. IL-4 and IL-13 mediated down-regulation of CD8 expression levels can dampen anti-viral CD8T cell avidity following HIV-1 recombinant pox viral vaccination.

    Science.gov (United States)

    Wijesundara, Danushka K; Jackson, Ronald J; Tscharke, David C; Ranasinghe, Charani

    2013-09-23

    We have shown that mucosal HIV-1 recombinant pox viral vaccination can induce high, avidity HIV-specific CD8(+) T cells with reduced interleukin (IL)-4 and IL-13 expression compared to, systemic vaccine delivery. In the current study how these cytokines act to regulate anti-viral CD8(+) T, cell avidity following HIV-1 recombinant pox viral prime-boost vaccination was investigated. Out of a panel of T cell avidity markers tested, only CD8 expression levels were found to be enhanced on, KdGag197-205 (HIV)-specific CD8(+) T cells obtained from IL-13(-/-), IL-4(-/-) and signal transducer and, activator of transcription of 6 (STAT6)(-/-) mice compared to wild-type (WT) controls following, vaccination. Elevated CD8 expression levels in this instance also correlated with polyfunctionality, (interferon (IFN)-γ, tumour necorsis factor (TNF)-α and IL-2 production) and the avidity of HIVspecific CD8(+) T cells. Furthermore, mucosal vaccination and vaccination with the novel adjuvanted IL-13 inhibitor (i.e. IL-13Rα2) vaccines significantly enhanced CD8 expression levels on HIV-specific CD8(+), T cells, which correlated with avidity. Using anti-CD8 antibodies that blocked CD8 availability on CD8(+), T cells, it was established that CD8 played an important role in increasing HIV-specific CD8(+) T cell avidity and polyfunctionality in IL-4(-/-), IL-13(-/-) and STAT6(-/-) mice compared to WT controls, following vaccination. Collectively, our data demonstrate that IL-4 and IL-13 dampen CD8 expression levels on anti-viral CD8(+) T cells, which can down-regulate anti-viral CD8(+) T cell avidity and, polyfunctionality following HIV-1 recombinant pox viral vaccination. These findings can be exploited to, design more efficacious vaccines not only against HIV-1, but many chronic infections where high, avidity CD8(+) T cells help protection. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. High affinity soluble ILT2 receptor: a potent inhibitor of CD8(+) T cell activation.

    Science.gov (United States)

    Moysey, Ruth K; Li, Yi; Paston, Samantha J; Baston, Emma E; Sami, Malkit S; Cameron, Brian J; Gavarret, Jessie; Todorov, Penio; Vuidepot, Annelise; Dunn, Steven M; Pumphrey, Nicholas J; Adams, Katherine J; Yuan, Fang; Dennis, Rebecca E; Sutton, Deborah H; Johnson, Andy D; Brewer, Joanna E; Ashfield, Rebecca; Lissin, Nikolai M; Jakobsen, Bent K

    2010-12-01

    Using directed mutagenesis and phage display on a soluble fragment of the human immunoglobulin super-family receptor ILT2 (synonyms: LIR1, MIR7, CD85j), we have selected a range of mutants with binding affinities enhanced by up to 168,000-fold towards the conserved region of major histocompatibility complex (MHC) class I molecules. Produced in a dimeric form, either by chemical cross-linking with bivalent polyethylene glycol (PEG) derivatives or as a genetic fusion with human IgG Fc-fragment, the mutants exhibited a further increase in ligand-binding strength due to the avidity effect, with resident half-times (t(1/2)) on the surface of MHC I-positive cells of many hours. The novel compounds antagonized the interaction of CD8 co-receptor with MHC I in vitro without affecting the peptide-specific binding of T-cell receptors (TCRs). In both cytokine-release assays and cell-killing experiments the engineered receptors inhibited the activation of CD8(+) cytotoxic T lymphocytes (CTLs) in the presence of their target cells, with subnanomolar potency and in a dose-dependent manner. As a selective inhibitor of CD8(+) CTL responses, the engineered high affinity ILT2 receptor presents a new tool for studying the activation mechanism of different subsets of CTLs and could have potential for the development of novel autoimmunity therapies.

  12. 1Protein Energy Malnutrition Impairs Homeostatic Proliferation of Memory CD8 T cells

    Science.gov (United States)

    Iyer, Smita S.; Chatraw, Janel Hart; Tan, Wendy G.; Wherry, E. John; Becker, Todd C.; Ahmed, Rafi; Kapasi, Zoher F.

    2011-01-01

    Nutrition is a critical but poorly understood determinant of immunity. There is abundant epidemiological evidence linking protein malnutrition to impaired vaccine efficacy and increased susceptibility to infections; yet, the role of dietary protein in immune memory homeostasis remains poorly understood. Here we show that protein energy malnutrition (PEM) induced in mice by low-protein (LP) feeding has a detrimental impact on CD8 memory. Relative to adequate-protein (AP) fed controls, LP feeding in lymphocytic choriomeningitis virus (LCMV) immune mice resulted in a 2-fold decrease in LCMV-specific CD8 memory T cells. Adoptive transfer of memory cells, labeled with a division tracking dye, from AP mice into naive LP or AP mice demonstrated that PEM caused profound defects in homeostatic proliferation. Remarkably, this defect occurred despite the lymphopenic environment in LP hosts. While antigen-specific memory cells in LP and AP hosts were phenotypically similar, memory cells in LP hosts were markedly less-responsive to poly(I:C)-induced acute proliferative signals. Furthermore, upon recall, memory cells in LP hosts displayed reduced proliferation and protection from challenge with LCMV-clone 13 resulting in impaired viral clearance in the liver. The findings show a metabolic requirement of dietary protein in sustaining functional CD8 memory and suggest that interventions to optimize dietary protein intake may improve vaccine efficacy in malnourished individuals. PMID:22116826

  13. Protein energy malnutrition impairs homeostatic proliferation of memory CD8 T cells.

    Science.gov (United States)

    Iyer, Smita S; Chatraw, Janel Hart; Tan, Wendy G; Wherry, E John; Becker, Todd C; Ahmed, Rafi; Kapasi, Zoher F

    2012-01-01

    Nutrition is a critical but poorly understood determinant of immunity. There is abundant epidemiological evidence linking protein malnutrition to impaired vaccine efficacy and increased susceptibility to infections; yet, the role of dietary protein in immune memory homeostasis remains poorly understood. In this study, we show that protein-energy malnutrition induced in mice by low-protein (LP) feeding has a detrimental impact on CD8 memory. Relative to adequate protein (AP)-fed controls, LP feeding in lymphocytic choriomeningitis virus (LCMV)-immune mice resulted in a 2-fold decrease in LCMV-specific CD8 memory T cells. Adoptive transfer of memory cells, labeled with a division tracking dye, from AP mice into naive LP or AP mice demonstrated that protein-energy malnutrition caused profound defects in homeostatic proliferation. Remarkably, this defect occurred despite the lymphopenic environment in LP hosts. Whereas Ag-specific memory cells in LP and AP hosts were phenotypically similar, memory cells in LP hosts were markedly less responsive to polyinosinic-polycytidylic acid-induced acute proliferative signals. Furthermore, upon recall, memory cells in LP hosts displayed reduced proliferation and protection from challenge with LCMV-clone 13, resulting in impaired viral clearance in the liver. The findings show a metabolic requirement of dietary protein in sustaining functional CD8 memory and suggest that interventions to optimize dietary protein intake may improve vaccine efficacy in malnourished individuals.

  14. HBV-specific CD4+ cytotoxic T cells in hepatocellular carcinoma are less cytolytic toward tumor cells and suppress CD8+ T cell-mediated antitumor immunity.

    Science.gov (United States)

    Meng, Fanzhi; Zhen, Shoumei; Song, Bin

    2017-08-01

    In East Asia and sub-Saharan Africa, chronic infection is the main cause of the development of hepatocellular carcinoma, an aggressive cancer with low survival rate. Cytotoxic T cell-based immunotherapy is a promising treatment strategy. Here, we investigated the possibility of using HBV-specific CD4 + cytotoxic T cells to eliminate tumor cells. The naturally occurring HBV-specific cytotoxic CD4 + and CD8 + T cells were identified by HBV peptide pool stimulation. We found that in HBV-induced hepatocellular carcinoma patients, the HBV-specific cytotoxic CD4 + T cells and cytotoxic CD8 + T cells were present at similar numbers. But compared to the CD8 + cytotoxic T cells, the CD4 + cytotoxic T cells secreted less cytolytic factors granzyme A (GzmA) and granzyme B (GzmB), and were less effective at eliminating tumor cells. In addition, despite being able to secrete cytolytic factors, CD4 + T cells suppressed the cytotoxicity mediated by CD8 + T cells, even when CD4 + CD25 + regulator T cells were absent. Interestingly, we found that interleukin 10 (IL-10)-secreting Tr1 cells were enriched in the cytotoxic CD4 + T cells. Neutralization of IL-10 abrogated the suppression of CD8 + T cells by CD4 + CD25 - T cells. Neither the frequency nor the absolute number of HBV-specific CD4 + cytotoxic T cells were correlated with the clinical outcome of advanced stage hepatocellular carcinoma patients. Together, this study demonstrated that in HBV-related hepatocellular carcinoma, CD4 + T cell-mediated cytotoxicity was present naturally in the host and had the potential to exert antitumor immunity, but its capacity was limited and was associated with immunoregulatory properties. © 2017 APMIS. Published by John Wiley & Sons Ltd.

  15. Aging Converts Innate B1a Cells into Potent CD8+ T Cell Inducers.

    Science.gov (United States)

    Lee-Chang, Catalina; Bodogai, Monica; Moritoh, Kanako; Chen, Xin; Wersto, Robert; Sen, Ranjan; Young, Howard A; Croft, Michael; Ferrucci, Luigi; Biragyn, Arya

    2016-04-15

    B cell dysregulation in aging is thought to mostly occur in conventional B2 cells without affecting innate B1 cells. Elderly humans and mice also accumulate 4-1BBL(+)MHC class-I(Hi)CD86(Hi)B cells of unknown origin. In this article, we report that these cells, termed 4BL cells, are activated murine and possibly human B1a cells. The activation is mediated by aging human monocytes and murine peritoneal macrophages. They induce expression and activation of 4-1BBL and IFN-γR1 on B1a cells to subsequently upregulate membrane TNF-α and CD86. As a result, activated B1a/4BL cells induce expression of granzyme B in CD8(+)T cells by targeting TNFR2 via membrane TNF-α and providing costimulation with CD86. Thus, for the first time, to our knowledge, these results indicate that aging affects the function of B1a cells. Upon aging, these cells lose their tumor-supporting activity and become inducers of potentially antitumor and autoimmune CD8(+)T cells. Copyright © 2016 by The American Association of Immunologists, Inc.

  16. Cholesterol negatively regulates IL-9-producing CD8+ T cell differentiation and antitumor activity.

    Science.gov (United States)

    Ma, Xingzhe; Bi, Enguang; Huang, Chunjian; Lu, Yong; Xue, Gang; Guo, Xing; Wang, Aibo; Yang, Maojie; Qian, Jianfei; Dong, Chen; Yi, Qing

    2018-05-09

    CD8 + T cells can be polarized into IL-9-secreting (Tc9) cells. We previously showed that adoptive therapy using tumor-specific Tc9 cells generated stronger antitumor responses in mouse melanoma than classical Tc1 cells. To understand why Tc9 cells exert stronger antitumor responses, we used gene profiling to compare Tc9 and Tc1 cells. Tc9 cells expressed different levels of cholesterol synthesis and efflux genes and possessed significantly lower cholesterol content than Tc1 cells. Unique to Tc9, but not other CD8 + or CD4 + T cell subsets, manipulating cholesterol content in polarizing Tc9 cells significantly affected IL-9 expression and Tc9 differentiation and antitumor response in vivo. Mechanistic studies showed that IL-9 was indispensable for Tc9 cell persistence and antitumor effects, and cholesterol or its derivatives inhibited IL-9 expression by activating liver X receptors (LXRs), leading to LXR Sumoylation and reduced p65 binding to Il9 promoter. Our study identifies cholesterol as a critical regulator of Tc9 cell differentiation and function. © 2018 Ma et al.

  17. CXCR5-Dependent Entry of CD8 T Cells into Rhesus Macaque B-Cell Follicles Achieved through T-Cell Engineering.

    Science.gov (United States)

    Ayala, Victor I; Deleage, Claire; Trivett, Matthew T; Jain, Sumiti; Coren, Lori V; Breed, Matthew W; Kramer, Joshua A; Thomas, James A; Estes, Jacob D; Lifson, Jeffrey D; Ott, David E

    2017-06-01

    Follicular helper CD4 T cells, T FH , residing in B-cell follicles within secondary lymphoid tissues, are readily infected by AIDS viruses and are a major source of persistent virus despite relative control of viral replication. This persistence is due at least in part to a relative exclusion of effective antiviral CD8 T cells from B-cell follicles. To determine whether CD8 T cells could be engineered to enter B-cell follicles, we genetically modified unselected CD8 T cells to express CXC chemokine receptor 5 (CXCR5), the chemokine receptor implicated in cellular entry into B-cell follicles. Engineered CD8 T cells expressing human CXCR5 (CD8 hCXCR5 ) exhibited ligand-specific signaling and chemotaxis in vitro Six infected rhesus macaques were infused with differentially fluorescent dye-labeled autologous CD8 hCXCR5 and untransduced CD8 T cells and necropsied 48 h later. Flow cytometry of both spleen and lymph node samples revealed higher frequencies of CD8 hCXCR5 than untransduced cells, consistent with preferential trafficking to B-cell follicle-containing tissues. Confocal fluorescence microscopy of thin-sectioned lymphoid tissues demonstrated strong preferential localization of CD8 hCXCR5 T cells within B-cell follicles with only rare cells in extrafollicular locations. CD8 hCXCR5 T cells were present throughout the follicles with some observed near infected T FH In contrast, untransduced CD8 T cells were found in the extrafollicular T-cell zone. Our ability to direct localization of unselected CD8 T cells into B-cell follicles using CXCR5 expression provides a strategy to place highly effective virus-specific CD8 T cells into these AIDS virus sanctuaries and potentially suppress residual viral replication. IMPORTANCE AIDS virus persistence in individuals under effective drug therapy or those who spontaneously control viremia remains an obstacle to definitive treatment. Infected follicular helper CD4 T cells, T FH , present inside B-cell follicles represent a

  18. Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein–Barr virus associated nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Fogg, Mark; Murphy, John R.; Lorch, Jochen; Posner, Marshall; Wang, Fred

    2013-01-01

    Epstein–Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients. - Highlights: • Viral proteins are tumor antigens in Epstein–Barr virus associated Nasopharyngeal Carcinoma. • CD8+ T cell responses against EBV proteins EBNA-1 and LMP2 are suppressed in NPC patients. • T regulatory cells are responsible for suppressing EBV immunity in NPC patients. • Depletion of Tregs with Ontak can rescue EBV-specific CD8+ T cell responses in NPC patients. • This clinically approved drug may be effective for enhancing anti-tumor immunity in NPC patients

  19. Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein–Barr virus associated nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Fogg, Mark [Department of Medicine, Brigham and Women' s Hospital (United States); Murphy, John R. [Departments of Medicine and Microbiology, Boston University School of Medicine, Boston, MA 02118 (United States); Lorch, Jochen; Posner, Marshall [Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115 (United States); Wang, Fred, E-mail: fwang@research.bwh.harvard.edu [Department of Medicine, Brigham and Women' s Hospital (United States); Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 (United States)

    2013-07-05

    Epstein–Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients. - Highlights: • Viral proteins are tumor antigens in Epstein–Barr virus associated Nasopharyngeal Carcinoma. • CD8+ T cell responses against EBV proteins EBNA-1 and LMP2 are suppressed in NPC patients. • T regulatory cells are responsible for suppressing EBV immunity in NPC patients. • Depletion of Tregs with Ontak can rescue EBV-specific CD8+ T cell responses in NPC patients. • This clinically approved drug may be effective for enhancing anti-tumor immunity in NPC patients.

  20. Autoreactive effector/memory CD4+ and CD8+ T cells infiltrating grafted and endogenous islets in diabetic NOD mice exhibit similar T cell receptor usage.

    Directory of Open Access Journals (Sweden)

    Ramiro Diz

    Full Text Available Islet transplantation provides a "cure" for type 1 diabetes but is limited in part by recurrent autoimmunity mediated by β cell-specific CD4(+ and CD8(+ T cells. Insight into the T cell receptor (TCR repertoire of effector T cells driving recurrent autoimmunity would aid the development of immunotherapies to prevent islet graft rejection. Accordingly, we used a multi-parameter flow cytometry strategy to assess the TCR variable β (Vβ chain repertoires of T cell subsets involved in autoimmune-mediated rejection of islet grafts in diabetic NOD mouse recipients. Naïve CD4(+ and CD8(+ T cells exhibited a diverse TCR repertoire, which was similar in all tissues examined in NOD recipients including the pancreas and islet grafts. On the other hand, the effector/memory CD8(+ T cell repertoire in the islet graft was dominated by one to four TCR Vβ chains, and specific TCR Vβ chain usage varied from recipient to recipient. Similarly, islet graft- infiltrating effector/memory CD4(+ T cells expressed a limited number of prevalent TCR Vβ chains, although generally TCR repertoire diversity was increased compared to effector/memory CD8(+ T cells. Strikingly, the majority of NOD recipients showed an increase in TCR Vβ12-bearing effector/memory CD4(+ T cells in the islet graft, most of which were proliferating, indicating clonal expansion. Importantly, TCR Vβ usage by effector/memory CD4(+ and CD8(+ T cells infiltrating the islet graft exhibited greater similarity to the repertoire found in the pancreas as opposed to the draining renal lymph node, pancreatic lymph node, or spleen. Together these results demonstrate that effector/memory CD4(+ and CD8(+ T cells mediating autoimmune rejection of islet grafts are characterized by restricted TCR Vβ chain usage, and are similar to T cells that drive destruction of the endogenous islets.

  1. miRNA profiling of naive, effector and memory CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Haoquan Wu

    Full Text Available microRNAs have recently emerged as master regulators of gene expression during development and cell differentiation. Although profound changes in gene expression also occur during antigen-induced T cell differentiation, the role of miRNAs in the process is not known. We compared the miRNA expression profiles between antigen-specific naïve, effector and memory CD8+ T cells using 3 different methods--small RNA cloning, miRNA microarray analysis and real-time PCR. Although many miRNAs were expressed in all the T cell subsets, the frequency of 7 miRNAs (miR-16, miR-21, miR-142-3p, miR-142-5p, miR-150, miR-15b and let-7f alone accounted for approximately 60% of all miRNAs, and their expression was several fold higher than the other expressed miRNAs. Global downregulation of miRNAs (including 6/7 dominantly expressed miRNAs was observed in effector T cells compared to naïve cells and the miRNA expression levels tended to come back up in memory T cells. However, a few miRNAs, notably miR-21 were higher in effector and memory T cells compared to naïve T cells. These results suggest that concomitant with profound changes in gene expression, miRNA profile also changes dynamically during T cell differentiation. Sequence analysis of the cloned mature miRNAs revealed an extensive degree of end polymorphism. While 3'end polymorphisms dominated, heterogeneity at both ends, resembling drosha/dicer processing shift was also seen in miR-142, suggesting a possible novel mechanism to generate new miRNA and/or to diversify miRNA target selection. Overall, our results suggest that dynamic changes in the expression of miRNAs may be important for the regulation of gene expression during antigen-induced T cell differentiation. Our study also suggests possible novel mechanisms for miRNA biogenesis and function.

  2. Cognate CD4 T-cell licensing of dendritic cells heralds anti-CMV CD8 T-cell immunity after human allogeneic umbilical cord blood transplantation

    NARCIS (Netherlands)

    Flinsenberg, T W H; Spel, Lotte; Jansen, M; Koning, D; de Haar, C; Plantinga, M; Scholman, R; van Loenen, M M; Nierkens, S; Boon, L; van Baarle, D; Heemskerk, M H M; Boelens, J J; Boes, M

    2014-01-01

    Reactivation of human cytomegalovirus (CMV) is hazardous to patients undergoing allogeneic cord-blood transplantation (CBT), lowering survival rates by approximately 25%. While antiviral treatment ameliorates viremia, complete viral control requires CD8(+) T-cell-driven immunity. Mouse studies

  3. Profound protection against respiratory challenge with a lethal H7N7 influenza A virus by increasing the magnitude of CD8(+) T-cell memory

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Doherty, P C; Branum, K C

    2000-01-01

    The recall of CD8(+) T-cell memory established by infecting H-2(b) mice with an H1N1 influenza A virus provided a measure of protection against an extremely virulent H7N7 virus. The numbers of CD8(+) effector and memory T cells specific for the shared, immunodominant D(b)NP(366) epitope were...... greatly increased subsequent to the H7N7 challenge, and though lung titers remained as high as those in naive controls for 5 days or more, the virus was cleared more rapidly. Expanding the CD8(+) memory T-cell pool (10%) by sequential priming with two different influenza A viruses (H3N2-->H1N1......) gave much better protection. Though the H7N7 virus initially grew to equivalent titers in the lungs of naive and double-primed mice, the replicative phase was substantially controlled within 3 days. This tertiary H7N7 challenge caused little increase in the magnitude of the CD8(+) D(b)NP(366)(+) T...

  4. Emergence of CD4+ and CD8+ Polyfunctional T Cell Responses Against Immunodominant Lytic and Latent EBV Antigens in Children With Primary EBV Infection

    Directory of Open Access Journals (Sweden)

    Janice K. P. Lam

    2018-03-01

    Full Text Available Long term carriers were shown to generate robust polyfunctional T cell (PFC responses against lytic and latent antigens of Epstein-Barr virus (EBV. However, the time of emergence of PFC responses against EBV antigens, pattern of immunodominance and difference between CD4+ and CD8+ T cell responses during various stages of EBV infection are not clearly understood. A longitudinal study was performed to assess the development of antigen-specific PFC responses in children diagnosed to have primary symptomatic (infectious mononucleosis [IM] and asymptomatic (AS EBV infection. Evaluation of IFN-γ secreting CD8+ T cell responses upon stimulation by HLA class I-specific peptides of EBV lytic and latent proteins by ELISPOT assay followed by assessment of CD4+ and CD8+ PFC responses upon stimulation by a panel of overlapping EBV peptides for co-expression of IFN-γ, TNF-α, IL-2, perforin and CD107a by flow cytometry were performed. Cytotoxicity of T cells against autologous lymphoblastoid cell lines (LCLs as well as EBV loads in PBMC and plasma were also determined. Both IM and AS patients had elevated PBMC and plasma viral loads which declined steadily during a 12-month period from the time of diagnosis whilst decrease in the magnitude of CD8+ T cell responses toward EBV lytic peptides in contrast to increase toward latent peptides was shown with no significant difference between those of IM and AS patients. Both lytic and latent antigen-specific CD4+ and CD8+ T cells demonstrated polyfunctionality (defined as greater or equal to three functions concurrent with enhanced cytotoxicity against autologous LCLs and steady decrease in plasma and PBMC viral loads over time. Immunodominant peptides derived from BZLF1, BRLF1, BMLF1 and EBNA3A-C proteins induced the highest proportion of CD8+ as well as CD4+ PFC responses. Diverse functional subtypes of both CD4+ and CD8+ PFCs were shown to emerge at 6–12 months. In conclusion, EBV antigen-specific CD4+ and CD

  5. A molecular threshold for effector CD8(+) T cell differentiation controlled by transcription factors Blimp-1 and T-bet.

    Science.gov (United States)

    Xin, Annie; Masson, Frederick; Liao, Yang; Preston, Simon; Guan, Tianxia; Gloury, Renee; Olshansky, Moshe; Lin, Jian-Xin; Li, Peng; Speed, Terence P; Smyth, Gordon K; Ernst, Matthias; Leonard, Warren J; Pellegrini, Marc; Kaech, Susan M; Nutt, Stephen L; Shi, Wei; Belz, Gabrielle T; Kallies, Axel

    2016-04-01

    T cell responses are guided by cytokines that induce transcriptional regulators, which ultimately control differentiation of effector and memory T cells. However, it is unknown how the activities of these molecular regulators are coordinated and integrated during the differentiation process. Using genetic approaches and transcriptional profiling of antigen-specific CD8(+) T cells, we reveal a common program of effector differentiation that is regulated by IL-2 and IL-12 signaling and the combined activities of the transcriptional regulators Blimp-1 and T-bet. The loss of both T-bet and Blimp-1 leads to abrogated cytotoxic function and ectopic IL-17 production in CD8(+) T cells. Overall, our data reveal two major overlapping pathways of effector differentiation governed by the availability of Blimp-1 and T-bet and suggest a model for cytokine-induced transcriptional changes that combine, quantitatively and qualitatively, to promote robust effector CD8(+) T cell differentiation.

  6. Tissue-Resident Memory CD8+ T Cells: From Phenotype to Function

    Directory of Open Access Journals (Sweden)

    David J. Topham

    2018-03-01

    Full Text Available Tissue-resident memory CD8+ T cells are an important first line of defense from infection in peripheral non-lymphoid tissues, such as the mucosal tissues of the respiratory, digestive, and urogenital tracts. This memory T cell subset is established late during resolution of primary infection of those tissues, has a distinct genetic signature, and is often defined by the cell surface expression of CD69, CD103, CD49a, and CD44 in both mouse and human studies. The stimuli that program or imprint the unique gene expression and cell surface phenotypes on TRM are beginning to be defined, but much work remains to be done. It is not clear, for example, when and where the TRM precursors receive these signals, and there is evidence that supports imprinting in both the lymph node and the peripheral tissue sites. In most studies, expression of CD49a, CD103, and CD69 on T cells in the tissues appears relatively late in the response, suggesting there are precise environmental cues that are not present at the height of the acute response. CD49a and CD103 are not merely biomarkers of TRM, they confer substrate specificities for cell adhesion to collagen and E-cadherin, respectively. Yet, little attention has been paid to how expression affects the positioning of TRM in the peripheral tissues. CD103 and CD49a are not mutually exclusive, and not always co-expressed, although whether they can compensate for one another is unknown. In fact, they may define different subsets of TRM in certain tissues. For instance, while CD49a+CD8+ memory T cells can be found in almost all peripheral tissues, CD103 appears to be more restricted. In this review, we discuss the evidence for how these hallmarks of TRM affect positioning of T cells in peripheral sites, how CD49a and CD103 differ in expression and function, and why they are important for immune protection conferred by TRM in mucosal tissues such as the respiratory tract.

  7. Engagement of NKG2D on bystander memory CD8 T cells promotes increased immunopathology following Leishmania major infection.

    Directory of Open Access Journals (Sweden)

    Erika J Crosby

    2014-02-01

    Full Text Available One of the hallmarks of adaptive immunity is the development of a long-term pathogen specific memory response. While persistent memory T cells certainly impact the immune response during a secondary challenge, their role in unrelated infections is less clear. To address this issue, we utilized lymphocytic choriomeningitis virus (LCMV and Listeria monocytogenes immune mice to investigate whether bystander memory T cells influence Leishmania major infection. Despite similar parasite burdens, LCMV and Listeria immune mice exhibited a significant increase in leishmanial lesion size compared to mice infected with L. major alone. This increased lesion size was due to a severe inflammatory response, consisting not only of monocytes and neutrophils, but also significantly more CD8 T cells. Many of the CD8 T cells were LCMV specific and expressed gzmB and NKG2D, but unexpectedly expressed very little IFN-γ. Moreover, if CD8 T cells were depleted in LCMV immune mice prior to challenge with L. major, the increase in lesion size was lost. Strikingly, treating with NKG2D blocking antibodies abrogated the increased immunopathology observed in LCMV immune mice, showing that NKG2D engagement on LCMV specific memory CD8 T cells was required for the observed phenotype. These results indicate that bystander memory CD8 T cells can participate in an unrelated immune response and induce immunopathology through an NKG2D dependent mechanism without providing increased protection.

  8. The chromatin accessibility signature of human immune aging stems from CD8+ T cells.

    Science.gov (United States)

    Ucar, Duygu; Márquez, Eladio J; Chung, Cheng-Han; Marches, Radu; Rossi, Robert J; Uyar, Asli; Wu, Te-Chia; George, Joshy; Stitzel, Michael L; Palucka, A Karolina; Kuchel, George A; Banchereau, Jacques

    2017-10-02

    Aging is linked to deficiencies in immune responses and increased systemic inflammation. To unravel the regulatory programs behind these changes, we applied systems immunology approaches and profiled chromatin accessibility and the transcriptome in PBMCs and purified monocytes, B cells, and T cells. Analysis of samples from 77 young and elderly donors revealed a novel and robust aging signature in PBMCs, with simultaneous systematic chromatin closing at promoters and enhancers associated with T cell signaling and a potentially stochastic chromatin opening mostly found at quiescent and repressed sites. Combined analyses of chromatin accessibility and the transcriptome uncovered immune molecules activated/inactivated with aging and identified the silencing of the IL7R gene and the IL-7 signaling pathway genes as potential biomarkers. This signature is borne by memory CD8 + T cells, which exhibited an aging-related loss in binding of NF-κB and STAT factors. Thus, our study provides a unique and comprehensive approach to identifying candidate biomarkers and provides mechanistic insights into aging-associated immunodeficiency. © 2017 Ucar et al.

  9. Induction of influenza-specific local CD8 T-cells in the respiratory tract after aerosol delivery of vaccine antigen or virus in the Babraham inbred pig

    Science.gov (United States)

    Morgan, Sophie B.; Attaf, Meriem; Szomolay, Barbara; Miles, John J.; Townsend, Alain; Bailey, Mick; Charleston, Bryan; Tchilian, Elma

    2018-01-01

    There is increasing evidence that induction of local immune responses is a key component of effective vaccines. For respiratory pathogens, for example tuberculosis and influenza, aerosol delivery is being actively explored as a method to administer vaccine antigens. Current animal models used to study respiratory pathogens suffer from anatomical disparity with humans. The pig is a natural and important host of influenza viruses and is physiologically more comparable to humans than other animal models in terms of size, respiratory tract biology and volume. It may also be an important vector in the birds to human infection cycle. A major drawback of the current pig model is the inability to analyze antigen-specific CD8+ T-cell responses, which are critical to respiratory immunity. Here we address this knowledge gap using an established in-bred pig model with a high degree of genetic identity between individuals, including the MHC (Swine Leukocyte Antigen (SLA)) locus. We developed a toolset that included long-term in vitro pig T-cell culture and cloning and identification of novel immunodominant influenza-derived T-cell epitopes. We also generated structures of the two SLA class I molecules found in these animals presenting the immunodominant epitopes. These structures allowed definition of the primary anchor points for epitopes in the SLA binding groove and established SLA binding motifs that were used to successfully predict other influenza-derived peptide sequences capable of stimulating T-cells. Peptide-SLA tetramers were constructed and used to track influenza-specific T-cells ex vivo in blood, the lungs and draining lymph nodes. Aerosol immunization with attenuated single cycle influenza viruses (S-FLU) induced large numbers of CD8+ T-cells specific for conserved NP peptides in the respiratory tract. Collectively, these data substantially increase the utility of pigs as an effective model for studying protective local cellular immunity against respiratory

  10. Viral sequestration of antigen subverts cross presentation to CD8(+ T cells.

    Directory of Open Access Journals (Sweden)

    Eric F Tewalt

    2009-05-01

    Full Text Available Virus-specific CD8(+ T cells (T(CD8+ are initially triggered by peptide-MHC Class I complexes on the surface of professional antigen presenting cells (pAPC. Peptide-MHC complexes are produced by two spatially distinct pathways during virus infection. Endogenous antigens synthesized within virus-infected pAPC are presented via the direct-presentation pathway. Many viruses have developed strategies to subvert direct presentation. When direct presentation is blocked, the cross-presentation pathway, in which antigen is transferred from virus-infected cells to uninfected pAPC, is thought to compensate and allow the generation of effector T(CD8+. Direct presentation of vaccinia virus (VACV antigens driven by late promoters does not occur, as an abortive infection of pAPC prevents production of these late antigens. This lack of direct presentation results in a greatly diminished or ablated T(CD8+ response to late antigens. We demonstrate that late poxvirus antigens do not enter the cross-presentation pathway, even when identical antigens driven by early promoters access this pathway efficiently. The mechanism mediating this novel means of viral modulation of antigen presentation involves the sequestration of late antigens within virus factories. Early antigens and cellular antigens are cross-presented from virus-infected cells, as are late antigens that are targeted to compartments outside of the virus factories. This virus-mediated blockade specifically targets the cross-presentation pathway, since late antigen that is not cross-presented efficiently enters the MHC Class II presentation pathway. These data are the first to describe an evasion mechanism employed by pathogens to prevent entry into the cross-presentation pathway. In the absence of direct presentation, this evasion mechanism leads to a complete ablation of the T(CD8+ response and a potential replicative advantage for the virus. Such mechanisms of viral modulation of antigen presentation

  11. Characterization of CD8+ T-Cell Responses in the Peripheral Blood and Skin Injection Sites of Melanoma Patients Treated with mRNA Electroporated Autologous Dendritic Cells (TriMixDC-MEL

    Directory of Open Access Journals (Sweden)

    Daphné Benteyn

    2013-01-01

    Full Text Available Treatment of melanoma patients with mRNA electroporated dendritic cells (TriMixDC-MEL stimulates T-cell responses against the presented tumor-associated antigens (TAAs. In the current clinical trials, melanoma patients with systemic metastases are treated, requiring priming and/or expansion of preexisting TAA-specific T cells that are able to migrate to both the skin and internal organs. We monitored the presence of TAA-specific CD8+ T cells infiltrating the skin at sites of intradermal TriMixDC-MEL injection (SKILs and within the circulation of melanoma patients treated in two clinical trials. In 10 out of fourteen (71% patients screened, CD8+ T cells recognizing any of the four TAA presented by TriMixDC-MEL cellular vaccine were found in both compartments. In total, 30 TAA-specific T-cell responses were detected among the SKILs and 29 among peripheral blood T cells, of which 24 in common. A detailed characterization of the antigen specificity of CD8+ T-cell populations in four patients indicates that the majority of the epitopes detected were only recognized by CD8+ T cells derived from either skin biopsies or peripheral blood, indicating that some compartmentalization occurs after TriMix-DC therapy. To conclude, functional TAA-specific CD8+ T cells distribute both to the skin and peripheral blood of patients after TriMixDC-MEL therapy.

  12. Characterization of CD8+ T-cell responses in the peripheral blood and skin injection sites of melanoma patients treated with mRNA electroporated autologous dendritic cells (TriMixDC-MEL).

    Science.gov (United States)

    Benteyn, Daphné; Van Nuffel, An M T; Wilgenhof, Sofie; Corthals, Jurgen; Heirman, Carlo; Neyns, Bart; Thielemans, Kris; Bonehill, Aude

    2013-01-01

    Treatment of melanoma patients with mRNA electroporated dendritic cells (TriMixDC-MEL) stimulates T-cell responses against the presented tumor-associated antigens (TAAs). In the current clinical trials, melanoma patients with systemic metastases are treated, requiring priming and/or expansion of preexisting TAA-specific T cells that are able to migrate to both the skin and internal organs. We monitored the presence of TAA-specific CD8(+) T cells infiltrating the skin at sites of intradermal TriMixDC-MEL injection (SKILs) and within the circulation of melanoma patients treated in two clinical trials. In 10 out of fourteen (71%) patients screened, CD8(+) T cells recognizing any of the four TAA presented by TriMixDC-MEL cellular vaccine were found in both compartments. In total, 30 TAA-specific T-cell responses were detected among the SKILs and 29 among peripheral blood T cells, of which 24 in common. A detailed characterization of the antigen specificity of CD8(+) T-cell populations in four patients indicates that the majority of the epitopes detected were only recognized by CD8(+) T cells derived from either skin biopsies or peripheral blood, indicating that some compartmentalization occurs after TriMix-DC therapy. To conclude, functional TAA-specific CD8(+) T cells distribute both to the skin and peripheral blood of patients after TriMixDC-MEL therapy.

  13. Lymphocytic choriomeningitis virus infection is associated with long-standing perturbation of LFA-1 expression on CD8+ T cells

    DEFF Research Database (Denmark)

    Andersson, E C; Christensen, Jan Pravsgaard; Scheynius, A

    1995-01-01

    activation and expansion which was demonstrated not to depend on CD4+ T cells or their products. Cell sorting experiments defined virus-specific CTL to be included in this population (LFA-1hiMEL-14lo), but since about 80% of splenic CD8+ T cells have a changed phenotype, extensive bystander activation must...

  14. Diminished primary and secondary influenza virus-specific CD8(+) T-cell responses in CD4-depleted Ig(-/-) mice

    DEFF Research Database (Denmark)

    Riberdy, J M; Christensen, Jan Pravsgaard; Branum, K

    2000-01-01

    Optimal expansion of influenza virus nucleoprotein (D(b)NP(366))-specific CD8(+) T cells following respiratory challenge of naive Ig(-/-) microMT mice was found to require CD4(+) T-cell help, and this effect was also observed in primed animals. Absence of the CD4(+) population was consistently...

  15. Recent Advances in Targeting CD8 T-Cell Immunity for More Effective Cancer Immunotherapy

    Directory of Open Access Journals (Sweden)

    Aurélie Durgeau

    2018-01-01

    Full Text Available Recent advances in cancer treatment have emerged from new immunotherapies targeting T-cell inhibitory receptors, including cytotoxic T-lymphocyte associated antigen (CTLA-4 and programmed cell death (PD-1. In this context, anti-CTLA-4 and anti-PD-1 monoclonal antibodies have demonstrated survival benefits in numerous cancers, including melanoma and non-small-cell lung carcinoma. PD-1-expressing CD8+ T lymphocytes appear to play a major role in the response to these immune checkpoint inhibitors (ICI. Cytotoxic T lymphocytes (CTL eliminate malignant cells through recognition by the T-cell receptor (TCR of specific antigenic peptides presented on the surface of cancer cells by major histocompatibility complex class I/beta-2-microglobulin complexes, and through killing of target cells, mainly by releasing the content of secretory lysosomes containing perforin and granzyme B. T-cell adhesion molecules and, in particular, lymphocyte-function-associated antigen-1 and CD103 integrins, and their cognate ligands, respectively, intercellular adhesion molecule 1 and E-cadherin, on target cells, are involved in strengthening the interaction between CTL and tumor cells. Tumor-specific CTL have been isolated from tumor-infiltrating lymphocytes and peripheral blood lymphocytes (PBL of patients with varied cancers. TCRβ-chain gene usage indicated that CTL identified in vitro selectively expanded in vivo at the tumor site compared to autologous PBL. Moreover, functional studies indicated that these CTL mediate human leukocyte antigen class I-restricted cytotoxic activity toward autologous tumor cells. Several of them recognize truly tumor-specific antigens encoded by mutated genes, also known as neoantigens, which likely play a key role in antitumor CD8 T-cell immunity. Accordingly, it has been shown that the presence of T lymphocytes directed toward tumor neoantigens is associated with patient response to immunotherapies, including ICI, adoptive cell transfer

  16. Multiscale Modeling of the Early CD8 T-Cell Immune Response in Lymph Nodes: An Integrative Study

    Directory of Open Access Journals (Sweden)

    Sotiris A. Prokopiou

    2014-09-01

    Full Text Available CD8 T-cells are critical  in controlling infection by intracellular  pathogens. Upon encountering antigen presenting cells, T-cell receptor activation promotes the differentiation of naïve CD8 T-cells into strongly proliferating  activated and effector stages. We propose a 2D-multiscale computational model to study the maturation of CD8 T-cells in a lymph node controlled by their molecular profile. A novel molecular pathway is presented and converted into an ordinary differential  equation model, coupled with a cellular Potts model to describe cell-cell interactions. Key molecular  players such as activated IL2 receptor and Tbet levels  control the differentiation  from naïve into activated and effector stages, respectively,  while caspases and Fas-Fas ligand interactions control cell apoptosis.  Coupling  this molecular model to the cellular scale successfully  reproduces  qualitatively the evolution of total CD8 T-cell counts observed in mice lymph node, between Day 3 and 5.5 post-infection. Furthermore, this model allows us to make testable predictions  of the evolution of the different CD8 T-cell stages.

  17. Interference with Intraepithelial TNF-α Signaling Inhibits CD8+ T-Cell-Mediated Lung Injury in Influenza Infection

    OpenAIRE

    Srikiatkhachorn, Anon; Chintapalli, Jyothi; Liu, Jun; Jamaluddin, Mohammad; Harrod, Kevin S.; Whitsett, Jeffrey A.; Enelow, Richard I.; Ramana, Chilakamarti V.

    2010-01-01

    CD8+ T-cell-mediated pulmonary immunopathology in respiratory virus infection is mediated in large part by antigen-specific TNF-α expression by antiviral effector T cells, which results in epithelial chemokine expression and inflammatory infiltration of the lung. To further define the signaling events leading to lung epithelial chemokine production in response to CD8+ T-cell antigen recognition, we expressed the adenoviral 14.7K protein, a putative inhibitor of TNF-α signaling, in the distal ...

  18. In vivo proliferation of naïve and memory influenza-specific CD8(+) T cells

    DEFF Research Database (Denmark)

    Flynn, K J; Riberdy, J M; Christensen, Jan Pravsgaard

    1999-01-01

    days. The greatly expanded population of CD8(+)NPP(+) memory T cells in the lymphoid tissue of secondarily challenged mice declines progressively in mean prevalence over the ensuing 100 days, despite the fact that at least some of these lymphocytes continue to cycle. The recall of cell......The virus-specific CD8(+) T cell response has been analyzed through the development, effector, and recovery phases of primary and secondary influenza pneumonia. Apparently, most, if not all, memory T cells expressing clonotypic receptors that bind a tetrameric complex of influenza nucleoprotein (NP......)(366-374) peptide+H-2D(b) (NPP) are induced to divide during the course of this localized respiratory infection. The replicative phase of the recall response ends about the time that virus can no longer be recovered from the lung, whereas some primary CD8(+)NPP(+) T cells may proliferate for a few more...

  19. Estradiol-induced vaginal mucus inhibits antigen penetration and CD8(+) T cell priming in response to intravaginal immunization.

    Science.gov (United States)

    Seavey, Matthew M; Mosmann, Tim R

    2009-04-14

    Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8(+) T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APCs) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8(+) T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8(+) T cell priming after insemination or vaginal vaccination.

  20. Estradiol-induced vaginal mucus inhibits antigen penetration and CD8+ T cell priming in response to intravaginal immunization

    Science.gov (United States)

    Seavey, Matthew M.; Mosmann, Tim R.

    2010-01-01

    Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8+ T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APC) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8+ T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8+ T cell priming after insemination or vaginal vaccination. PMID:19428849

  1. Virus-induced polyclonal T cell activation is followed by apoptosis: partitioning of CD8+ T cells based on alpha 4 integrin expression

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Röpke, C; Thomsen, Allan Randrup

    1996-01-01

    that LCMV-induced activation of T cells is followed by apoptosis of many of the activated cells. Those CD8+VLA-4hi cells which do persist in LCMV immune mice are more sensitive to treatment with the cell-cycle-specific drug hydroxyurea than are phenotypically naive T cells. Our results therefore indicate...

  2. Abundance of early functional HIV-specific CD8+ T cells does not predict AIDS-free survival time.

    Directory of Open Access Journals (Sweden)

    Ingrid M M Schellens

    Full Text Available BACKGROUND: T-cell immunity is thought to play an important role in controlling HIV infection, and is a main target for HIV vaccine development. HIV-specific central memory CD8(+ and CD4(+ T cells producing IFNgamma and IL-2 have been associated with control of viremia and are therefore hypothesized to be truly protective and determine subsequent clinical outcome. However, the cause-effect relationship between HIV-specific cellular immunity and disease progression is unknown. We investigated in a large prospective cohort study involving 96 individuals of the Amsterdam Cohort Studies with a known date of seroconversion whether the presence of cytokine-producing HIV-specific CD8(+ T cells early in infection was associated with AIDS-free survival time. METHODS AND FINDINGS: The number and percentage of IFNgamma and IL-2 producing CD8(+ T cells was measured after in vitro stimulation with an overlapping Gag-peptide pool in T cells sampled approximately one year after seroconversion. Kaplan-Meier survival analysis and Cox proportional hazard models showed that frequencies of cytokine-producing Gag-specific CD8(+ T cells (IFNgamma, IL-2 or both shortly after seroconversion were neither associated with time to AIDS nor with the rate of CD4(+ T-cell decline. CONCLUSIONS: These data show that high numbers of functional HIV-specific CD8(+ T cells can be found early in HIV infection, irrespective of subsequent clinical outcome. The fact that both progressors and long-term non-progressors have abundant T cell immunity of the specificity associated with low viral load shortly after seroconversion suggests that the more rapid loss of T cell immunity observed in progressors may be a consequence rather than a cause of disease progression.

  3. CD19 CAR-T cells of defined CD4+:CD8+ composition in adult B cell ALL patients.

    Science.gov (United States)

    Turtle, Cameron J; Hanafi, Laïla-Aïcha; Berger, Carolina; Gooley, Theodore A; Cherian, Sindhu; Hudecek, Michael; Sommermeyer, Daniel; Melville, Katherine; Pender, Barbara; Budiarto, Tanya M; Robinson, Emily; Steevens, Natalia N; Chaney, Colette; Soma, Lorinda; Chen, Xueyan; Yeung, Cecilia; Wood, Brent; Li, Daniel; Cao, Jianhong; Heimfeld, Shelly; Jensen, Michael C; Riddell, Stanley R; Maloney, David G

    2016-06-01

    T cells that have been modified to express a CD19-specific chimeric antigen receptor (CAR) have antitumor activity in B cell malignancies; however, identification of the factors that determine toxicity and efficacy of these T cells has been challenging in prior studies in which phenotypically heterogeneous CAR-T cell products were prepared from unselected T cells. We conducted a clinical trial to evaluate CD19 CAR-T cells that were manufactured from defined CD4+ and CD8+ T cell subsets and administered in a defined CD4+:CD8+ composition to adults with B cell acute lymphoblastic leukemia after lymphodepletion chemotherapy. The defined composition product was remarkably potent, as 27 of 29 patients (93%) achieved BM remission, as determined by flow cytometry. We established that high CAR-T cell doses and tumor burden increase the risks of severe cytokine release syndrome and neurotoxicity. Moreover, we identified serum biomarkers that allow testing of early intervention strategies in patients at the highest risk of toxicity. Risk-stratified CAR-T cell dosing based on BM disease burden decreased toxicity. CD8+ T cell-mediated anti-CAR transgene product immune responses developed after CAR-T cell infusion in some patients, limited CAR-T cell persistence, and increased relapse risk. Addition of fludarabine to the lymphodepletion regimen improved CAR-T cell persistence and disease-free survival. Immunotherapy with a CAR-T cell product of defined composition enabled identification of factors that correlated with CAR-T cell expansion, persistence, and toxicity and facilitated design of lymphodepletion and CAR-T cell dosing strategies that mitigated toxicity and improved disease-free survival. ClinicalTrials.gov NCT01865617. R01-CA136551; Life Science Development Fund; Juno Therapeutics; Bezos Family Foundation.

  4. Increased numbers of CD4+ and CD8+ T cells in lesional skin of cats with allergic dermatitis.

    Science.gov (United States)

    Roosje, P J; van Kooten, P J; Thepen, T; Bihari, I C; Rutten, V P; Koeman, J P; Willemse, T

    1998-07-01

    The aim of this study was to characterize T cells in the skin of cats with an allergic dermatitis histologically compatible with atopic dermatitis, since T cells play an important role in the pathogenesis of atopic dermatitis in humans. We observed a significantly greater number of T cells in lesional skin of domestic short-haired cats with allergic dermatitis (n = 10; median age 5.8 years) than in the skin of healthy control animals (n = 10; median age 5.0 years). In the skin of the healthy control animals, one or two CD4+ cells and no CD8+ cells were found. A predominant increase of CD4+ T cells and a CD4+/CD8+ ratio (mean +/- SD: 3.9 +/- 2.0) was found in the lesional skin of 10 cats with allergic dermatitis. The CD4+/CD8+ cell ratio in the skin of healthy control animals could not be determined because of the absence of CD8+ cells. The CD4+/CD8+ cell ratio in the peripheral blood of 10 cats with allergic dermatitis (mean +/- SD: 1.9 +/- 0.4) did not differ significantly from that in 10 healthy control animals (2.2 +/- 0.4). The CD4+/CD8+ cell ratio and predominance of CD4+ T cells in the lesional skin of cats with allergic dermatitis is comparable to that found in atopic dermatitis in humans. In addition, the observed increase of CD4+ T cells in the nonlesional skin of cats with allergic dermatitis compared to the skin of healthy cats is similar to what is seen in humans. Cytokines produced by T cells and antigen-specific T cells are important mediators in the inflammatory cascade resulting in atopic dermatitis in humans. This study is a first step to investigate their role in feline allergic dermatitis.

  5. High epitope expression levels increase competition between T cells.

    Directory of Open Access Journals (Sweden)

    Almut Scherer

    2006-08-01

    Full Text Available Both theoretical predictions and experimental findings suggest that T cell populations can compete with each other. There is some debate on whether T cells compete for aspecific stimuli, such as access to the surface on antigen-presenting cells (APCs or for specific stimuli, such as their cognate epitope ligand. We have developed an individual-based computer simulation model to study T cell competition. Our model shows that the expression level of foreign epitopes per APC determines whether T cell competition is mainly for specific or aspecific stimuli. Under low epitope expression, competition is mainly for the specific epitope stimuli, and, hence, different epitope-specific T cell populations coexist readily. However, if epitope expression levels are high, aspecific competition becomes more important. Such between-specificity competition can lead to competitive exclusion between different epitope-specific T cell populations. Our model allows us to delineate the circumstances that facilitate coexistence of T cells of different epitope specificity. Understanding mechanisms of T cell coexistence has important practical implications for immune therapies that require a broad immune response.

  6. Bioinformatics Tools for the Prediction of T-Cell Epitopes

    DEFF Research Database (Denmark)

    Andreatta, Massimo; Nielsen, Morten

    2018-01-01

    T-cell responses are activated by specific peptides, called epitopes, presented on the cell surface by MHC molecules. Binding of peptides to the MHC is the most selective step in T-cell antigen presentation and therefore an essential factor in the selection of potential epitopes. Several in-vitro...

  7. Pre-existing vector immunity does not prevent replication deficient adenovirus from inducing efficient CD8 T-cell memory and recall responses.

    Directory of Open Access Journals (Sweden)

    Maria Abildgaard Steffensen

    Full Text Available Adenoviral vectors have shown a great potential for vaccine development due to their inherent ability to induce potent and protective CD8 T-cell responses. However, a critical issue regarding the use of these vectors is the existence of inhibitory immunity against the most commonly used Ad5 vector in a large part of the human population. We have recently developed an improved adenoviral vaccine vector system in which the vector expresses the transgene tethered to the MHC class II associated invariant chain (Ii. To further evaluate the potential of this system, the concept of pre-existing inhibitory immunity to adenoviral vectors was revisited to investigate whether the inhibition previously seen with the Ad5 vector also applied to the optimized vector system. We found this to be the case, and antibodies dominated as the mechanism underlying inhibitory vector immunity. However, presence of CD8 T cells directed against epitopes in the adenoviral vector seemed to correlate with repression of the induced response in re-vaccinated B-cell deficient mice. More importantly, despite a repressed primary effector CD8 T-cell response in Ad5-immune animals subjected to vaccination, memory T cells were generated that provided the foundation for an efficient recall response and protection upon subsequent viral challenge. Furthermore, the transgene specific response could be efficiently boosted by homologous re-immunization. Taken together, these studies indicate that adenoviral vectors can be used to induce efficient CD8 T-cell memory even in individuals with pre-existing vector immunity.

  8. Deficient CD4+ T cell priming and regression of CD8+ T cell functionality in virus-infected mice lacking a normal B cell compartment

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Kauffmann, Susanne Ørding; Thomsen, Allan Randrup

    2003-01-01

    of virus-specific CD4(+) T cells was markedly impaired in B(-/-) mice infected with either virus strain. Thus, our results indicate that B cells play an important role in antiviral immunity not only as Ab producers, but also in promoting an optimal and sustained T cell response. The T cell defects......In this study, we investigate the state of T cell-mediated immunity in B cell-deficient (B(-/-)) mice infected with two strains of lymphocytic choriomeningitis virus known to differ markedly in their capacity to persist. In B(-/-) C57BL mice infected with the more persisting virus, virus......-specific CD8(+) T cells are initially generated that are qualitatively similar to those in wild-type mice. However, although cell numbers are well sustained over time, the capacity to produce cytokines is rapidly impaired. In similarly infected B(-/-) BALB/c mice, virus-specific CD8(+) T cells are completely...

  9. CD19 CAR–T cells of defined CD4+:CD8+ composition in adult B cell ALL patients

    Science.gov (United States)

    Turtle, Cameron J.; Hanafi, Laïla-Aïcha; Berger, Carolina; Gooley, Theodore A.; Cherian, Sindhu; Hudecek, Michael; Sommermeyer, Daniel; Melville, Katherine; Pender, Barbara; Budiarto, Tanya M.; Robinson, Emily; Steevens, Natalia N.; Chaney, Colette; Soma, Lorinda; Chen, Xueyan; Li, Daniel; Cao, Jianhong; Heimfeld, Shelly; Jensen, Michael C.; Riddell, Stanley R.; Maloney, David G.

    2016-01-01

    BACKGROUND. T cells that have been modified to express a CD19-specific chimeric antigen receptor (CAR) have antitumor activity in B cell malignancies; however, identification of the factors that determine toxicity and efficacy of these T cells has been challenging in prior studies in which phenotypically heterogeneous CAR–T cell products were prepared from unselected T cells. METHODS. We conducted a clinical trial to evaluate CD19 CAR–T cells that were manufactured from defined CD4+ and CD8+ T cell subsets and administered in a defined CD4+:CD8+ composition to adults with B cell acute lymphoblastic leukemia after lymphodepletion chemotherapy. RESULTS. The defined composition product was remarkably potent, as 27 of 29 patients (93%) achieved BM remission, as determined by flow cytometry. We established that high CAR–T cell doses and tumor burden increase the risks of severe cytokine release syndrome and neurotoxicity. Moreover, we identified serum biomarkers that allow testing of early intervention strategies in patients at the highest risk of toxicity. Risk-stratified CAR–T cell dosing based on BM disease burden decreased toxicity. CD8+ T cell–mediated anti-CAR transgene product immune responses developed after CAR–T cell infusion in some patients, limited CAR–T cell persistence, and increased relapse risk. Addition of fludarabine to the lymphodepletion regimen improved CAR–T cell persistence and disease-free survival. CONCLUSION. Immunotherapy with a CAR–T cell product of defined composition enabled identification of factors that correlated with CAR–T cell expansion, persistence, and toxicity and facilitated design of lymphodepletion and CAR–T cell dosing strategies that mitigated toxicity and improved disease-free survival. TRIAL REGISTRATION. ClinicalTrials.gov NCT01865617. FUNDING. R01-CA136551; Life Science Development Fund; Juno Therapeutics; Bezos Family Foundation. PMID:27111235

  10. Priming of CD8 T Cells by Adenoviral Vectors Is Critically Dependent on B7 and Dendritic Cells but Only Partially Dependent on CD28 Ligation on CD8 T Cells

    DEFF Research Database (Denmark)

    Nielsen, Karen N; Steffensen, Maria A; Christensen, Jan P

    2014-01-01

    expression resulted in a delayed primary response, whereas memory CD8 T cells generated in CD28-deficient mice appeared almost normal in terms of both phenotype and effector cytokine profile, but they exhibited a significantly reduced proliferative capacity upon secondary challenge while retaining immediate...... in vivo effector capabilities: in vivo cytotoxicity and short-term in vivo protective capacity. Overall, our data point to an absolute requirement for professional APCs and the expression of the costimulatory molecules CD80/86 for efficient CD8 T cell priming by adenoviral vectors. Additionally, our......Adenoviral vectors have long been forerunners in the development of effective CD8 T cell-based vaccines; therefore, it is imperative that we understand the factors controlling the induction of robust and long-lasting transgene-specific immune responses by these vectors. In this study, we...

  11. Splenectomy alters distribution and turnover but not numbers or protective capacity of de novo generated memory CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Marie eKim

    2014-11-01

    Full Text Available The spleen is a highly compartmentalized lymphoid organ that allows for efficient antigen presentation and activation of immune responses. Additionally, the spleen itself functions to remove senescent red blood cells, filter bacteria, and sequester platelets. Splenectomy, commonly performed after blunt force trauma or splenomegaly, has been shown to increase risk of certain bacterial and parasitic infections years after removal of the spleen. Although previous studies report defects in memory B cells and IgM titers in splenectomized patients, the effect of splenectomy on CD8 T cell responses and memory CD8 T cell function remains ill defined. Using TCR-transgenic P14 cells, we demonstrate that homeostatic proliferation and representation of pathogen-specific memory CD8 T cells in the blood are enhanced in splenectomized compared to sham surgery mice. Surprisingly, despite the enhanced turnover, splenectomized mice displayed no changes in total memory CD8 T cell numbers nor impaired protection against lethal dose challenge with Listeria monocytogenes. Thus, our data suggest that memory CD8 T cell maintenance and function remain intact in the absence of the spleen.

  12. NS1 specific CD8+ T-cells with effector function and TRBV11 dominance in a patient with parvovirus B19 associated inflammatory cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Mathias Streitz

    Full Text Available BACKGROUND: Parvovirus B19 (B19V is the most commonly detected virus in endomyocardial biopsies (EMBs from patients with inflammatory cardiomyopathy (DCMi. Despite the importance of T-cells in antiviral defense, little is known about the role of B19V specific T-cells in this entity. METHODOLOGY AND PRINCIPAL FINDINGS: An exceptionally high B19V viral load in EMBs (115,091 viral copies/mug nucleic acids, peripheral blood mononuclear cells (PBMCs and serum was measured in a DCMi patient at initial presentation, suggesting B19V viremia. The B19V viral load in EMBs had decreased substantially 6 and 12 months afterwards, and was not traceable in PBMCs and the serum at these times. Using pools of overlapping peptides spanning the whole B19V proteome, strong CD8(+ T-cell responses were elicited to the 10-amino-acid peptides SALKLAIYKA (19.7% of all CD8(+ cells and QSALKLAIYK (10% and additional weaker responses to GLCPHCINVG (0.71% and LLHTDFEQVM (0.06%. Real-time RT-PCR of IFNgamma secretion-assay-enriched T-cells responding to the peptides, SALKLAIYKA and GLCPHCINVG, revealed a disproportionately high T-cell receptor Vbeta (TRBV 11 expression in this population. Furthermore, dominant expression of type-1 (IFNgamma, IL2, IL27 and T-bet and of cytotoxic T-cell markers (Perforin and Granzyme B was found, whereas gene expression indicating type-2 (IL4, GATA3 and regulatory T-cells (FoxP3 was low. CONCLUSIONS: Our results indicate that B19V Ag-specific CD8(+ T-cells with effector function are involved in B19V associated DCMi. In particular, a dominant role of TRBV11 and type-1/CTL effector cells in the T-cell mediated antiviral immune response is suggested. The persistence of B19V in the endomyocardium is a likely antigen source for the maintenance of CD8(+ T-cell responses to the identified epitopes.

  13. Therapeutic limitations in tumor-specific CD8+ memory T cell engraftment

    International Nuclear Information System (INIS)

    Bathe, Oliver F; Dalyot-Herman, Nava; Malek, Thomas R

    2003-01-01

    Adoptive immunotherapy with cytotoxic T lymphocytes (CTL) represents an alternative approach to treating solid tumors. Ideally, this would confer long-term protection against tumor. We previously demonstrated that in vitro-generated tumor-specific CTL from the ovalbumin (OVA)-specific OT-I T cell receptor transgenic mouse persisted long after adoptive transfer as memory T cells. When recipient mice were challenged with the OVA-expressing E.G7 thymoma, tumor growth was delayed and sometimes prevented. The reasons for therapeutic failures were not clear. OT-I CTL were adoptively transferred to C57BL/6 mice 21 – 28 days prior to tumor challenge. At this time, the donor cells had the phenotypical and functional characteristics of memory CD8+ T cells. Recipients which developed tumor despite adoptive immunotherapy were analyzed to evaluate the reason(s) for therapeutic failure. Dose-response studies demonstrated that the degree of tumor protection was directly proportional to the number of OT-I CTL adoptively transferred. At a low dose of OT-I CTL, therapeutic failure was attributed to insufficient numbers of OT-I T cells that persisted in vivo, rather than mechanisms that actively suppressed or anergized the OT-I T cells. In recipients of high numbers of OT-I CTL, the E.G7 tumor that developed was shown to be resistant to fresh OT-I CTL when examined ex vivo. Furthermore, these same tumor cells no longer secreted a detectable level of OVA. In this case, resistance to immunotherapy was secondary to selection of clones of E.G7 that expressed a lower level of tumor antigen. Memory engraftment with tumor-specific CTL provides long-term protection against tumor. However, there are several limitations to this immunotherapeutic strategy, especially when targeting a single antigen. This study illustrates the importance of administering large numbers of effectors to engraft sufficiently efficacious immunologic memory. It also demonstrates the importance of targeting several

  14. Transfer of allogeneic CD4+ T cells rescues CD8+ T cells in anti-PD-L1–resistant tumors leading to tumor eradication

    Science.gov (United States)

    Arina, Ainhoa; Karrison, Theodore; Galka, Eva; Schreiber, Karin; Weichselbaum, Ralph R.; Schreiber, Hans

    2017-01-01

    Adoptively transferred CD8+ T cells can stabilize the size of solid tumors over long periods of time by exclusively recognizing antigen cross-presented on tumor stroma. However, these tumors eventually escape T cell–mediated growth control. The aim of this study was to eradicate such persistent cancers. In our model, the SIYRYYGL antigen is expressed by cancer cells that lack the MHC-I molecule Kb needed for direct presentation, but the antigen is picked up and cross-presented by tumor stroma. A single injection of antigen-specific 2C CD8+ T cells caused long-term inhibition of tumor growth, but without further intervention, tumors started to progress after approximately 3 months. Escape was associated with reduced numbers of circulating 2C cells. Tumor-infiltrating 2C cells produced significantly less TNFα and expressed more of the “exhaustion” markers PD-1 and Tim-3 than T cells from lymphoid organs. High-dose local ionizing radiation, depletion of myeloid-derived suppressor cells, infusions of additional 2C cells, and antibodies blocking PD-L1 did not prevent tumor escape. In contrast, adoptive transfer of allogeneic CD4+ T cells restored the numbers of circulating Ag-specific CD8+ T cells and their intratumoral function, resulting in tumor eradication. These CD4+ T cells had no antitumor effects in the absence of CD8+ T cells and recognized the alloantigen cross-presented on tumor stroma. CD4+ T cells might also be effective in cancer patients when PD1/PD-L1 blockade does not rescue intratumoral CD8+ T-cell function and tumors persist. PMID:28077434

  15. Sequential activation of CD8+ T cells in the draining lymph nodes in response to pulmonary virus infection.

    Science.gov (United States)

    Yoon, Heesik; Legge, Kevin L; Sung, Sun-sang J; Braciale, Thomas J

    2007-07-01

    We have used a TCR-transgenic CD8+ T cell adoptive transfer model to examine the tempo of T cell activation and proliferation in the draining lymph nodes (DLN) in response to respiratory virus infection. The T cell response in the DLN differed for mice infected with different type A influenza strains with the onset of T cell activation/proliferation to the A/JAPAN virus infection preceding the A/PR8 response by 12-24 h. This difference in T cell activation/proliferation correlated with the tempo of accelerated respiratory DC (RDC) migration from the infected lungs to the DLN in response to influenza virus infection, with the migrant RDC responding to the A/JAPAN infection exhibiting a more rapid accumulation in the lymph nodes (i.e., peak migration for A/JAPAN at 18 h, A/PR8 at 24-36 h). Furthermore, in vivo administration of blocking anti-CD62L Ab at various time points before/after infection revealed that the virus-specific CD8+ T cells entered the DLN and activated in a sequential "conveyor belt"-like fashion. These results indicate that the tempo of CD8+ T cell activation/proliferation after viral infection is dependent on the tempo of RDC migration to the DLN and that T cell activation occurs in an ordered sequential fashion.

  16. Activated human neonatal CD8+ T cells are subject to immunomodulation by direct TLR2 or TLR5 stimulation.

    LENUS (Irish Health Repository)

    McCarron, Mark

    2012-02-01

    In conditions of optimal priming, the neonate possesses competency to mount quantitatively adult-like responses. Vaccine formulations containing sufficiently potent adjuvants may overcome the neonate\\'s natural tendency for immunosuppression and provoke a similarly robust immune response. TLR expression on T cells represents the possibility of directly enhancing T cell immunity. We examined the ex vivo responsiveness of highly purified human cord blood-derived CD8(+) T cells to direct TLR ligation by a repertoire of TLR agonists. In concert with TCR stimulation, only Pam(3)Cys (palmitoyl-3-Cys-Ser-(Lys)(4)) and flagellin monomers significantly enhanced proliferation, CD25(+) expression, IL-2, IFN-gamma, TNF-alpha, and intracellular granzyme B expression. TLR2 and TLR5 mRNA was detected in the CD8(+) T cells. Blocking studies confirmed that the increase in IFN-gamma production was by the direct triggering of surface TLR2 or TLR5. The simultaneous exposure of CD8(+) T cells to both TLR agonists had an additive effect on IFN-gamma production. These data suggest that a combination of the two TLR ligands would be a potent T cell adjuvant. This may represent a new approach to TLR agonist-based adjuvant design for future human neonatal vaccination strategies requiring a CD8(+) component.

  17. T Cell Epitope Immunotherapy Induces a CD4+ T Cell Population with Regulatory Activity

    Directory of Open Access Journals (Sweden)

    Verhoef Adrienne

    2005-01-01

    Full Text Available Background Synthetic peptides, representing CD4+ T cell epitopes, derived from the primary sequence of allergen molecules have been used to down-regulate allergic inflammation in sensitised individuals. Treatment of allergic diseases with peptides may offer substantial advantages over treatment with native allergen molecules because of the reduced potential for cross-linking IgE bound to the surface of mast cells and basophils. Methods and Findings In this study we address the mechanism of action of peptide immunotherapy (PIT in cat-allergic, asthmatic patients. Cell-division-tracking dyes, cell-mixing experiments, surface phenotyping, and cytokine measurements were used to investigate immunomodulation in peripheral blood mononuclear cells (PBMCs after therapy. Proliferative responses of PBMCs to allergen extract were significantly reduced after PIT. This was associated with modified cytokine profiles generally characterised by an increase in interleukin-10 and a decrease in interleukin-5 production. CD4+ cells isolated after PIT were able to actively suppress allergen-specific proliferative responses of pretreatment CD4neg PBMCs in co-culture experiments. PIT was associated with a significant increase in surface expression of CD5 on both CD4+ and CD8+ PBMCs. Conclusion This study provides evidence for the induction of a population of CD4+ T cells with suppressor/regulatory activity following PIT. Furthermore, up-regulation of cell surface levels of CD5 may contribute to reduced reactivity to allergen.

  18. Increased CD8+ T cell response to Epstein-Barr virus lytic antigens in the active phase of multiple sclerosis.

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    Daniela F Angelini

    Full Text Available It has long been known that multiple sclerosis (MS is associated with an increased Epstein-Barr virus (EBV seroprevalence and high immune reactivity to EBV and that infectious mononucleosis increases MS risk. This evidence led to postulate that EBV infection plays a role in MS etiopathogenesis, although the mechanisms are debated. This study was designed to assess the prevalence and magnitude of CD8+ T-cell responses to EBV latent (EBNA-3A, LMP-2A and lytic (BZLF-1, BMLF-1 antigens in relapsing-remitting MS patients (n = 113 and healthy donors (HD (n = 43 and to investigate whether the EBV-specific CD8+ T cell response correlates with disease activity, as defined by clinical evaluation and gadolinium-enhanced magnetic resonance imaging. Using HLA class I pentamers, lytic antigen-specific CD8+ T cell responses were detected in fewer untreated inactive MS patients than in active MS patients and HD while the frequency of CD8+ T cells specific for EBV lytic and latent antigens was higher in active and inactive MS patients, respectively. In contrast, the CD8+ T cell response to cytomegalovirus did not differ between HD and MS patients, irrespective of the disease phase. Marked differences in the prevalence of EBV-specific CD8+ T cell responses were observed in patients treated with interferon-β and natalizumab, two licensed drugs for relapsing-remitting MS. Longitudinal studies revealed expansion of CD8+ T cells specific for EBV lytic antigens during active disease in untreated MS patients but not in relapse-free, natalizumab-treated patients. Analysis of post-mortem MS brain samples showed expression of the EBV lytic protein BZLF-1 and interactions between cytotoxic CD8+ T cells and EBV lytically infected plasma cells in inflammatory white matter lesions and meninges. We therefore propose that inability to control EBV infection during inactive MS could set the stage for intracerebral viral reactivation and disease relapse.

  19. Low intraprostatic DHT promotes the infiltration of CD8+ T cells in BPH tissues via modulation of CCL5 secretion.

    Science.gov (United States)

    Fan, Yu; Hu, Shuai; Liu, Jie; Xiao, Fei; Li, Xin; Yu, Wei; Cui, Yun; Sun, Mengkui; Lv, Tianjing; He, Qun; Jin, Jie

    2014-01-01

    Clinical studies suggested thatandrogen might be associated with infiltrating T cells in prostate of benign prostatic hyperplasia (BPH) patients, but detail of T-cell subset and mechanism still remained unclear. The present study tested the hypothesis that intraprostatic 5 α -dihydrotestosterone (DHT) exerts effects on T cells recruitment by BPH epithelial cells. Prostate tissues from 64 cases of BPH patients after transurethral resection of prostate (TURP) were divided into 2 groups: (1) no medication history; (2) administration of 5 α -reductase type II inhibitor-finasteride 5 mg daily for at least 6 months before surgery. Group 2 presented significantly higher CD8+ T cells infiltration than group 1, but no changes in CD4+ T cells (immunohistochemistry and flow cytometry). In vitro study more CD8+ T cell migrated to the prostate tissue lysates from group 2 and BPH-1 cells in low DHT condition. Transcription of chemokine (C-C motif) Ligand 5 (CCL5) mRNA in BPH-1 cells and chemokine (C-C motif) receptor 5 (CCR5) mRNA in CD8+ T cells were upregulated in low DHT condition (q-PCR). CCL5 expression was also identified to be higher in group 2 prostate tissues by IHC. This study suggested that intraprostatic DHT may participate in regulating inflammatory response which was induced by human prostatic epithelial cell, via modulating CCL5 secretion.

  20. Low Intraprostatic DHT Promotes the Infiltration of CD8+ T Cells in BPH Tissues via Modulation of CCL5 Secretion

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    Yu Fan

    2014-01-01

    Full Text Available Clinical studies suggested thatandrogen might be associated with infiltrating T cells in prostate of benign prostatic hyperplasia (BPH patients, but detail of T-cell subset and mechanism still remained unclear. The present study tested the hypothesis that intraprostatic 5α-dihydrotestosterone (DHT exerts effects on T cells recruitment by BPH epithelial cells. Prostate tissues from 64 cases of BPH patients after transurethral resection of prostate (TURP were divided into 2 groups: (1 no medication history; (2 administration of 5α-reductase type II inhibitor-finasteride 5 mg daily for at least 6 months before surgery. Group 2 presented significantly higher CD8+ T cells infiltration than group 1, but no changes in CD4+ T cells (immunohistochemistry and flow cytometry. In vitro study more CD8+ T cell migrated to the prostate tissue lysates from group 2 and BPH-1 cells in low DHT condition. Transcription of chemokine (C-C motif Ligand 5 (CCL5 mRNA in BPH-1 cells and chemokine (C-C motif receptor 5 (CCR5 mRNA in CD8+ T cells were upregulated in low DHT condition (q-PCR. CCL5 expression was also identified to be higher in group 2 prostate tissues by IHC. This study suggested that intraprostatic DHT may participate in regulating inflammatory response which was induced by human prostatic epithelial cell, via modulating CCL5 secretion.

  1. Rapid selection of escape mutants by the first CD8 T cell responses in acute HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette Tina Marie [Los Alamos National Laboratory

    2008-01-01

    The recent failure of a vaccine that primes T cell responses to control primary HIV-1 infection has raised doubts about the role of CD8+ T cells in early HIV-1 infection. We studied four patients who were identified shortly after HIV-1 infection and before seroconversion. In each patient there was very rapid selection of multiple HIV-1 escape mutants in the transmitted virus by CD8 T cells, including examples of complete fixation of non-synonymous substitutions within 2 weeks. Sequencing by single genome amplification suggested that the high rate of virus replication in acute infection gave a selective advantage to virus molecules that contained simultaneous and gained sequential T cell escape mutations. These observations show that whilst early HIV-1 specific CD8 T cells can act against virus, rapid escape means that these T cell responses are unlikely to benefit the patient and may in part explain why current HIV-1 T cell vaccines may not be protective.

  2. Inhibitory receptor expression depends more dominantly on differentiation and activation than exhaustion of human CD8 T cells

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    Amandine eLegat

    2013-12-01

    Full Text Available Under conditions of chronic antigen stimulation, such as persistent viral infection and cancer, CD8 T cells may diminish effector function, which has been termed exhaustion. Expression of inhibitory Receptors (iRs is often regarded as a hallmark of exhaustion. Here we studied the expression of eight different iRs by CD8 T cells of healthy humans, including CTLA-4, PD1, TIM3, LAG3, 2B4, BTLA, CD160 and KLRG-1. We show that many iRs are expressed upon activation, and with progressive differentiation to effector cells, even in absence of long-term (chronic antigenic stimulation. In particular, we evaluated the direct relationship between iR expression and functionality in CD8 T cells by using anti-CD3 and anti-CD28 stimulation to stimulate all cells and differentiation subsets. We observed a striking upregulation of certain iRs following the cytokine production wave, in agreement with the notion that iRs function as a negative feedback mechanism. Intriguingly, we found no major impairment of cytokine production in cells positive for a broad array of iRs, as previously shown for PD1 in healthy donors. Rather, the expression of the various iRs strongly correlated with T cell differentiation or activation states, or both. Furthermore, we analyzed CD8 T cells from lymph nodes (LNs of melanoma patients. Interestingly, we found altered iR expression and lower cytokine production by T cells from metastatic LNs, but also from non-metastatic LNs, likely due to mechanisms which are not related to exhaustion. Together, our data shows that expression of iRs per se does not mark dysfunctional cells, but is rather tightly linked to activation and differentiation. This study highlights the importance of considering the status of activation and differentiation for the study and the clinical monitoring of CD8 T cells.

  3. Complementarity-Determining Region 3 Size Spectratypes of T Cell Receptor β Chains in CD8+ T Cells following Antiviral Treatment of Chronic Hepatitis B▿

    Science.gov (United States)

    Ma, Shi-Wu; Li, Yong-Yin; Zhang, Guang-Wen; Huang, Xuan; Sun, Jian; Li, Chris; Abbott, William G. H.; Hou, Jin-Lin

    2011-01-01

    An increased CD8+ T cell response to hepatitis B virus (HBV) peptides occurs between 12 and 24 weeks after starting antiviral therapy for chronic hepatitis B. It is not known whether these cells have antiviral function. The aim of this study was to determine whether clonal expansions of CD8+ T cells at these time points predict the virological response to therapy. Peripheral blood CD8+ T cells were obtained from 20 patients treated with lamivudine or telbivudine for chronic hepatitis B at baseline, 12 weeks, and 24 weeks. The CDR3 spectratype of each T cell receptor (TCR) β chain variable region (Vβ) gene family was analyzed, and the changes in the numbers of Vβ families with clonal expansions were compared in subjects with (n = 12) and without (n = 8) a virological response (52 week HBV DNA < 300 copies/ml). The number of CD8+ TCR Vβ families with clonal expansions at 12 weeks relative to baseline (median [10th to 90th percentile], +2.5 [0 to +7] versus +1 [0 to +2], P = 0.03) and at 24 weeks relative to 12 weeks (+1 [0 to +2] versus −1 [−3 to +4], P = 0.006) was higher in subjects with a virological response versus subjects without a virological response, as were interleukin-2 (IL-2) but not IL-21 mRNA levels in peripheral blood mononuclear cells. The duration of new expansions at 12 weeks was higher (P < 0.0001) in responders. Increased numbers of CD8+ T cell expansions after antiviral therapy are associated with a virological response to treatment. These CD8+ T cells are a potential target for a therapeutic vaccine for chronic hepatitis B. PMID:21098256

  4. CXCR5+ CD8+ T Cells Indirectly Offer B Cell Help and Are Inversely Correlated with Viral Load in Chronic Hepatitis B Infection.

    Science.gov (United States)

    Jiang, Hang; Li, Linhai; Han, Jiang; Sun, Zhiwei; Rong, Yihui; Jin, Yun

    2017-04-01

    Treatment options for chronic hepatitis B (CHB) infection are extremely limited. CXCR5 + CD8 + T cell is a novel cell subtype and could possess strong cytotoxic properties in HIV infection. In this study, we investigated the role of CXCR5 + CD8 + T cells in CHB patients. Compared to healthy individuals, both CHB patients and hepatitis B virus (HBV)-infected hepatocellular carcinoma patients presented significant upregulation of CXCR5 + CD8 + T cells in peripheral blood, in which CXCR5 + CD8 + T cells were negatively correlated with the frequency of CXCR5 + CD4 + T cells in CHB patients. After PMA+ionomycin stimulation, CXCR5 + CD8 + T cells from CHB patients presented significantly higher transcription level of interferon gamma (IFN-γ), interleukin 10 (IL-10), and IL-21, as well as higher IL-10 and IL-21 protein secretion, than CXCR5 - CD8 + T cells. Unlike CXCR5 + CD4 + T cells, when incubated with naive CD19 + CD27 - B cells, CXCR5 + CD8 + T cells alone did not upregulate IgM, IgG, and IgA secretion. However, addition of CXCR5 + CD8 + T cells in B cell-CXCR5 + CD4 + T cell coculture significantly increased the levels of secreted IgG and IgA, demonstrating that CXCR5 + CD8 + T cell could indirectly offer B cell help. Furthermore, high frequencies of CXCR5 + CD8 + T cells tended to associate with low HBV DNA load, and the frequency of CXCR5 + CD8 + T cells was negatively correlated with alanine aminotransferase (ALT) level. Together, these results suggested that CXCR5 + CD8 + T cells were involved in the antiviral immune responses in CHB and could potentially serve as a therapeutic candidate.

  5. Decreased numbers of CD4+ naive and effector memory T cells, and CD8+ naïve T cells, are associated with trichloroethylene exposure

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    H Dean eHosgood

    2012-01-01

    Full Text Available Trichloroethylene (TCE is a volatile chlorinated organic compound that is commonly used as a solvent for lipophilic compounds. Although recognized as an animal carcinogen, TCE’s carcinogenic potential in humans is still uncertain. We have carried out a cross-sectional study of 80 workers exposed to TCE and 96 unexposed controls matched on age and sex in Guangdong, China to study TCE’s early biologic effects. We previously reported that the total lymphocyte count and each of the major lymphocyte subsets (i.e., CD4+ T cells, CD8+ T cells, natural killer (NK cells, and B cells were decreased in TCE-exposed workers compared to controls, suggesting a selective effect on lymphoid progenitors and/or lymphocyte survival. To explore which T lymphocyte subsets are affected, we investigated the effect of TCE exposure on the numbers of CD4+ naïve and memory T cells, CD8+ naïve and memory T cells, and regulatory T cells by FACS analysis. Linear regression of each subset was used to test for differences between exposed workers and controls adjusting for potential confounders. We observed that CD4+ and CD8+ naïve T cell counts were about 8% (p = 0.056 and 17% (p = 0.0002 lower, respectively, among exposed workers. CD4+ effector memory T cell counts were decreased by about 20% among TCE exposed workers compared to controls (p = 0.001. The selective targeting of TCE on CD8+ naïve and possibly CD4+ naive T cells, and CD4+ effector memory T cells, provide further insights into the immunosuppression-related response of human immune cells upon TCE exposure.

  6. Co-administration of α-GalCer analog and TLR4 agonist induces robust CD8+ T-cell responses to PyCS protein and WT-1 antigen and activates memory-like effector NKT cells

    OpenAIRE

    Coelho-dos-Reis, Jordana G.; Huang, Jing; Tsao, Tiffany; Pereira, Felipe V.; Funakoshi, Ryota; Nakajima, Hiroko; Sugiyama, Haruo; Tsuji, Moriya

    2016-01-01

    In the present study, the combined adjuvant effect of 7DW8-5, a potent α-GalCer-analog, and monophosphoryl lipid A (MPLA), a TLR4 agonist, on the induction of vaccine-induced CD8+ T-cell responses and protective immunity was evaluated. Mice were immunized with peptides corresponding to the CD8+ T-cell epitopes of a malaria antigen, a circumsporozoite protein of Plasmodium yoelii, and a tumor antigen, a Wilms Tumor antigen-1 (WT-1), together with 7DW8-5 and MPLA, as an adjuvant. These immuniza...

  7. Role of alveolar epithelial Early growth response-1 (Egr-1) in CD8+ T Cell mediated Lung Injury

    OpenAIRE

    Ramana, Chilakamarti V.; Cheng, Guang-Shing; Kumar, Aseem; Kwon, Hyung- Joo; Enelow, Richard I.

    2009-01-01

    Influenza infection of the distal airways results in severe lung injury, a considerable portion of which is immunopathologic and attributable to the host responses. We have used a mouse model to specifically investigate the role of antiviral CD8+ T cells in this injury, and have found that the critical effector molecule is TNF-α expressed by the T cells upon antigen recognition. Interestingly, the immunopathology which ensues is characterized by significant accumulation of host inflammatory c...

  8. Evidence from Human and Animal Studies: Pathological Roles of CD8(+) T Cells in Autoimmune Peripheral Neuropathies.

    Science.gov (United States)

    Yang, Mu; Peyret, Corentin; Shi, Xiang Qun; Siron, Nicolas; Jang, Jeong Ho; Wu, Sonia; Fournier, Sylvie; Zhang, Ji

    2015-01-01

    Autoimmune peripheral neuropathies such as Guillain-Barre Syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) affect millions of people worldwide. Despite significant advances in understanding the pathology, the molecular and cellular mechanisms of immune-mediated neuropathies remain elusive. T lymphocytes definitely play an important role in disease pathogenesis and CD4(+) T cells have been the main area of research for decades. This is partly due to the fact that the most frequent animal model to study autoimmune peripheral neuropathy is experimental allergic neuritis (EAN). As it is induced commonly by immunization with peripheral nerve proteins, EAN is driven mainly by CD4(+) T cells. However, similarly to what has been reported for patients suffering from multiple sclerosis, a significant body of evidence indicates that CD8(+) T cells may play a pathogenic role in GBS and CIDP disease development and/or progression. Here, we summarize clinical studies pertaining to the presence and potential role of CD8(+) T cells in autoimmune peripheral neuropathies. We also discuss the findings from our most recent studies using a transgenic mouse line (L31 mice) in which the T cell co-stimulator molecule B7.2 (CD86) is constitutively expressed in antigen presenting cells of the nervous tissues. L31 mice spontaneously develop peripheral neuropathy, and CD8(+) T cells are found accumulating in peripheral nerves of symptomatic animals. Interestingly, depletion of CD4(+) T cells accelerates disease onset and increases disease prevalence. Finally, we point out some unanswered questions for future research to dissect the critical roles of CD8(+) T cells in autoimmune peripheral neuropathies.

  9. Evidence from Human and Animal Studies: Pathological Roles of CD8+ T Cells in Autoimmune Peripheral Neuropathies

    Science.gov (United States)

    Yang, Mu; Peyret, Corentin; Shi, Xiang Qun; Siron, Nicolas; Jang, Jeong Ho; Wu, Sonia; Fournier, Sylvie; Zhang, Ji

    2015-01-01

    Autoimmune peripheral neuropathies such as Guillain-Barre Syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) affect millions of people worldwide. Despite significant advances in understanding the pathology, the molecular and cellular mechanisms of immune-mediated neuropathies remain elusive. T lymphocytes definitely play an important role in disease pathogenesis and CD4+ T cells have been the main area of research for decades. This is partly due to the fact that the most frequent animal model to study autoimmune peripheral neuropathy is experimental allergic neuritis (EAN). As it is induced commonly by immunization with peripheral nerve proteins, EAN is driven mainly by CD4+ T cells. However, similarly to what has been reported for patients suffering from multiple sclerosis, a significant body of evidence indicates that CD8+ T cells may play a pathogenic role in GBS and CIDP disease development and/or progression. Here, we summarize clinical studies pertaining to the presence and potential role of CD8+ T cells in autoimmune peripheral neuropathies. We also discuss the findings from our most recent studies using a transgenic mouse line (L31 mice) in which the T cell co-stimulator molecule B7.2 (CD86) is constitutively expressed in antigen presenting cells of the nervous tissues. L31 mice spontaneously develop peripheral neuropathy, and CD8+ T cells are found accumulating in peripheral nerves of symptomatic animals. Interestingly, depletion of CD4+ T cells accelerates disease onset and increases disease prevalence. Finally, we point out some unanswered questions for future research to dissect the critical roles of CD8+ T cells in autoimmune peripheral neuropathies. PMID:26528293

  10. CD8+ T Cells Induce Fatal Brainstem Pathology during Cerebral Malaria via Luminal Antigen-Specific Engagement of Brain Vasculature.

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    Phillip A Swanson

    2016-12-01

    Full Text Available Cerebral malaria (CM is a severe complication of Plasmodium falciparum infection that results in thousands of deaths each year, mostly in African children. The in vivo mechanisms underlying this fatal condition are not entirely understood. Using the animal model of experimental cerebral malaria (ECM, we sought mechanistic insights into the pathogenesis of CM. Fatal disease was associated with alterations in tight junction proteins, vascular breakdown in the meninges / parenchyma, edema, and ultimately neuronal cell death in the brainstem, which is consistent with cerebral herniation as a cause of death. At the peak of ECM, we revealed using intravital two-photon microscopy that myelomonocytic cells and parasite-specific CD8+ T cells associated primarily with the luminal surface of CNS blood vessels. Myelomonocytic cells participated in the removal of parasitized red blood cells (pRBCs from cerebral blood vessels, but were not required for the disease. Interestingly, the majority of disease-inducing parasite-specific CD8+ T cells interacted with the lumen of brain vascular endothelial cells (ECs, where they were observed surveying, dividing, and arresting in a cognate peptide-MHC I dependent manner. These activities were critically dependent on IFN-γ, which was responsible for activating cerebrovascular ECs to upregulate adhesion and antigen-presenting molecules. Importantly, parasite-specific CD8+ T cell interactions with cerebral vessels were impaired in chimeric mice rendered unable to present EC antigens on MHC I, and these mice were in turn resistant to fatal brainstem pathology. Moreover, anti-adhesion molecule (LFA-1 / VLA-4 therapy prevented fatal disease by rapidly displacing luminal CD8+ T cells from cerebrovascular ECs without affecting extravascular T cells. These in vivo data demonstrate that parasite-specific CD8+ T cell-induced fatal vascular breakdown and subsequent neuronal death during ECM is associated with luminal, antigen

  11. A novel intracellular pool of LFA-1 is critical for asymmetric CD8+ T cell activation and differentiation.

    Science.gov (United States)

    Capece, Tara; Walling, Brandon L; Lim, Kihong; Kim, Kyun-Do; Bae, Seyeon; Chung, Hung-Li; Topham, David J; Kim, Minsoo

    2017-11-06

    The integrin lymphocyte function-associated antigen 1 (LFA-1; CD11a/CD18) is a key T cell adhesion receptor that mediates stable interactions with antigen-presenting cell (APC), as well as chemokine-mediated migration. Using our newly generated CD11a-mYFP knock-in mice, we discovered that naive CD8 + T cells reserve a significant intracellular pool of LFA-1 in the uropod during migration. Intracellular LFA-1 quickly translocated to the cell surface with antigenic stimulus. Importantly, the redistribution of intracellular LFA-1 at the contact with APC was maintained during cell division and led to an unequal inheritance of LFA-1 in divided T cells. The daughter CD8 + T cells with disparate LFA-1 expression showed different patterns of migration on ICAM-1, APC interactions, and tissue retention, as well as altered effector functions. In addition, we identified Rab27 as an important regulator of the intracellular LFA-1 translocation. Collectively, our data demonstrate that an intracellular pool of LFA-1 in naive CD8 + T cells plays a key role in T cell activation and differentiation. © 2017 Capece et al.

  12. De novo alloreactive memory CD8+ T cells develop following allogeneic challenge when CNI immunosuppression is delayed.

    Science.gov (United States)

    Hart-Matyas, M; Gareau, A J; Hirsch, G M; Lee, T D G

    2015-01-01

    Allospecific memory T cells are a recognized threat to the maintenance of solid-organ transplants. Limited information exists regarding the development of alloreactive memory T cells when post-transplant immunosuppression is present. The clinical practice of delaying calcineurin inhibitor (CNI) initiation post-transplant may permit the development of a de novo allospecific memory population. We investigated the development of de novo allospecific memory CD8+ T cells following the introduction of CNI immunosuppression in a murine model using allogeneic cell priming. Recipient mice alloprimed with splenocytes from fully mismatched donors received cyclosporine (CyA), initiated at 0, 2, 6, or 10days post-prime. Splenocytes from recipients were analyzed by flow cytometry or enzyme-linked immunosorbent assay for evidence of memory cell formation. Memory and effector CD8+ T cell development was prevented when CyA was initiated at 0day or 2days post-prime (p0.05). Delaying CyA up to 6days or later post-prime permits the development of functional de novo allospecific memory CD8+ T cells. The development of this potentially detrimental T cell population in patients could be prevented by starting CNI immunosuppression early post-transplant. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Altered development of NKT cells, γδ T cells, CD8 T cells and NK cells in a PLZF deficient patient.

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    Maggie Eidson

    Full Text Available In mice, the transcription factor, PLZF, controls the development of effector functions in invariant NKT cells and a subset of NKT cell-like, γδ T cells. Here, we show that in human lymphocytes, in addition to invariant NKT cells, PLZF was also expressed in a large percentage of CD8+ and CD4+ T cells. Furthermore, PLZF was also found to be expressed in all γδ T cells and in all NK cells. Importantly, we show that in a donor lacking functional PLZF, all of these various lymphocyte populations were altered. Therefore, in contrast to mice, PLZF appears to control the development and/or function of a wide variety of human lymphocytes that represent more than 10% of the total PBMCs. Interestingly, the PLZF-expressing CD8+ T cell population was found to be expanded in the peripheral blood of patients with metastatic melanoma but was greatly diminished in patients with autoimmune disease.

  14. Interferon-β therapy reduces CD4+ and CD8+ T-cell reactivity in multiple sclerosis

    NARCIS (Netherlands)

    Zafranskaya, M.; Oschmann, P.; Engel, R.; Weishaupt, A.; Noort, J.M. van; Jomaa, H.; Eberl, M.

    2007-01-01

    Therapy with interferon-β (IFN-β) has well-established clinical effects in multiple sclerosis (MS), albeit the immunomodulatory mechanisms are not fully understood. We assessed the prevalence and functional capacity of CD4+ and CD8+ T cells in healthy donors, and in untreated and IFN-β-treated MS

  15. Adoptive transfer of EBV specific CD8+ T cell clones can transiently control EBV infection in humanized mice.

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    Olga Antsiferova

    2014-08-01

    Full Text Available Epstein Barr virus (EBV infection expands CD8+ T cells specific for lytic antigens to high frequencies during symptomatic primary infection, and maintains these at significant numbers during persistence. Despite this, the protective function of these lytic EBV antigen-specific cytotoxic CD8+ T cells remains unclear. Here we demonstrate that lytic EBV replication does not significantly contribute to virus-induced B cell proliferation in vitro and in vivo in a mouse model with reconstituted human immune system components (huNSG mice. However, we report a trend to reduction of EBV-induced lymphoproliferation outside of lymphoid organs upon diminished lytic replication. Moreover, we could demonstrate that CD8+ T cells against the lytic EBV antigen BMLF1 can eliminate lytically replicating EBV-transformed B cells from lymphoblastoid cell lines (LCLs and in vivo, thereby transiently controlling high viremia after adoptive transfer into EBV infected huNSG mice. These findings suggest a protective function for lytic EBV antigen-specific CD8+ T cells against EBV infection and against virus-associated tumors in extra-lymphoid organs. These specificities should be explored for EBV-specific vaccine development.

  16. Prolonged antigen presentation is required for optimal CD8+ T cell responses against malaria liver stage parasites.

    Directory of Open Access Journals (Sweden)

    Ian A Cockburn

    2010-05-01

    Full Text Available Immunization with irradiated sporozoites is currently the most effective vaccination strategy against liver stages of malaria parasites, yet the mechanisms underpinning the success of this approach are unknown. Here we show that the complete development of protective CD8+ T cell responses requires prolonged antigen presentation. Using TCR transgenic cells specific for the malaria circumsporozoite protein, a leading vaccine candidate, we found that sporozoite antigen persists for over 8 weeks after immunization--a remarkable finding since irradiated sporozoites are incapable of replication and do not differentiate beyond early liver stages. Persisting antigen was detected in lymphoid organs and depends on the presence of CD11c+ cells. Prolonged antigen presentation enhanced the magnitude of the CD8+ T cell response in a number of ways. Firstly, reducing the time primed CD8+ T cells were exposed to antigen in vivo severely reduced the final size of the developing memory population. Secondly, fully developed memory cells expanded in previously immunized mice but not when transferred to naïve animals. Finally, persisting antigen was able to prime naïve cells, including recent thymic emigrants, to become functional effector cells capable of eliminating parasites in the liver. Together these data show that the optimal development of protective CD8+ T cell immunity against malaria liver stages is dependent upon the prolonged presentation of sporozoite-derived antigen.

  17. Polyfunctional analysis of Gag and Nef specific CD8+ T-cell responses in HIV-1 infected Indian individuals.

    Science.gov (United States)

    Mendiratta, Sanjay; Vajpayee, Madhu; Mojumdar, Kamalika; Chauhan, Neeraj K; Sreenivas, Vishnubhatla

    2011-02-01

    Polyfunctional CD8+ T-cells have been described as most competent in controlling viral replication. We studied the impact of antigen persistence on the polyfunctional immune responses of CD8+ T-lymphocytes to HIV Gag and Nef peptides and polyclonal stimuli in 40 ART naïve HIV infected individuals and analyzed the alterations in T-cell functionality in early and late stages of infection. Significantly elevated level of global response and polyfunctional profile of CD8+ T-cells were observed to polyclonal stimulation, than HIV specific antigens in chronically infected individuals. However no key differences were observed in CD8+ T-cell functional profile in any of the 15 unique subsets for Gag and Nef specific antigens. The subjects in early stage of infection (defined as a gap of 6 months or less between seroconversion and enrolment and with no apparent clinical symptoms) had a higher degree of response functionality (4+ or 3+ different functions simultaneously) than in the late stage infection (defined as time duration since seroconversion greater than 6 months). The data suggest that persistence of antigen during chronic infection leads to functional impairment of HIV specific responses. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Reprogramming tumor-infiltrating dendritic cells for CD103+CD8+ mucosal T cell differentiation and breast cancer rejection

    Science.gov (United States)

    Wu, Te-Chia; Xu, Kangling; Banchereau, Romain; Marches, Florentina; Yu, Chun I; Martinek, Jan; Anguiano, Esperanza; Pedroza-Gonzalez, Alexander; Snipes, G. Jackson; O’Shaughnessy, Joyce; Nishimura, Stephen; Liu, Yong-Jun; Pascual, Virginia; Banchereau, Jacques; Oh, Sangkon; Palucka, Karolina

    2014-01-01

    Our studies showed that tumor-infiltrating dendritic cells (DC) in breast cancer drive inflammatory T helper 2 (iTh2) cells and protumor inflammation. Here we show that intratumoral delivery of the β-glucan curdlan, a ligand of dectin-1, blocks the generation of iTh2 cells, and prevents breast cancer progression in vivo. Curdlan reprograms tumor-infiltrating DC via the ligation of dectin-1, enabling the DC to become resistant to cancer-derived thymic stromal lymphopoietin (TSLP), to produce IL12p70, and to favor the generation of T helper 1 (Th1) cells. DC activated via dectin-1, but not those activated with TLR-7/8 ligand or poly IC, induce CD8+ T cells to express CD103 (αE integrin), a ligand for cancer cells E-cadherin. Generation of these mucosal CD8+ T cells is regulated by DC-derived integrin αvβ8 and TGF-β activation in a dectin-1-dependent fashion. These CD103+CD8+ mucosal T cells accumulate in the tumors thereby increasing cancer necrosis and inhibiting cancer progression in vivo in a humanized mouse model of breast cancer. Importantly, CD103+CD8+ mucosal T cells elicited by reprogrammed DC can reject established cancer. Thus, reprogramming tumor-infiltrating DC represents a new strategy for cancer rejection. PMID:24795361

  19. iNKT cells suppress the CD8+ T cell response to a murine Burkitt's-like B cell lymphoma.

    Directory of Open Access Journals (Sweden)

    Ryan L Bjordahl

    Full Text Available The T cell response to B cell lymphomas differs from the majority of solid tumors in that the malignant cells themselves are derived from B lymphocytes, key players in immune response. B cell lymphomas are therefore well situated to manipulate their surrounding microenvironment to enhance tumor growth and minimize anti-tumor T cell responses. We analyzed the effect of T cells on the growth of a transplantable B cell lymphoma and found that iNKT cells suppressed the anti-tumor CD8(+ T cell response. Lymphoma cells transplanted into syngeneic wild type (WT mice or Jalpha18(-/- mice that specifically lack iNKT cells grew initially at the same rate, but only the mice lacking iNKT cells were able to reject the lymphoma. This effect was due to the enhanced activity of tumor-specific CD8(+ T cells in the absence of iNKT cells, and could be partially reversed by reconstitution of iNKT cells in Jalpha 18(-/- mice. Treatment of tumor-bearing WT mice with alpha -galactosyl ceramide, an activating ligand for iNKT cells, reduced the number of tumor-specific CD8(+ T cells. In contrast, lymphoma growth in CD1d1(-/- mice that lack both iNKT and type II NKT cells was similar to that in WT mice, suggesting that type II NKT cells are required for full activation of the anti-tumor immune response. This study reveals a tumor-promoting role for iNKT cells and suggests their capacity to inhibit the CD8(+ T cell response to B cell lymphoma by opposing the effects of type II NKT cells.

  20. Effector/memory CD8+ T cells synergize with co-stimulation competent macrophages to trigger autoimmune peripheral neuropathy.

    Science.gov (United States)

    Yang, Mu; Shi, Xiang Qun; Peyret, Corentin; Oladiran, Oladayo; Wu, Sonia; Chambon, Julien; Fournier, Sylvie; Zhang, Ji

    2018-04-05

    Autoimmune peripheral neuropathy (APN) such as Guillain Barre Syndrome (GBS) is a debilitating illness and sometimes life threatening. The molecular and cellular mechanisms remain elusive but exposure to environmental factors including viral/bacterial infection and injury is highly associated with disease incidence. We demonstrated previously that both male and female B7.2 (CD86) transgenic L31 and L31/CD4KO mice develop spontaneous APN. Here we further reveal that CD8 + T cells in these mice exhibit an effector/memory phenotype, which bears a resemblance to the CD8 + T cell response following persistent cytomegalovirus (CMV) infection in humans and mice, whilst CMV has been considered as one of the most relevant pathogens in APN development. These activated, peripheral myelin Ag specific CD8 + T cells are required for the disease initiation. While an injury to a peripheral nerve results in Wallerian degeneration in control littermates, the same injury accelerates the development of APN in other non-injured nerves of L31 mice which have a predisposed inflammatory background consisting of effector/memory CD8 + T (CD8 + T EM ) cells. However, CD8 + T EM cells alone are not sufficient. A certain threshold of B7.2 expression on nerve macrophages is an additional requisite. Our findings reveal that indeed, the synergism between CD8 + T EM cells and co-stimulation competent macrophages is crucial in inducing autoimmune-mediated peripheral neuropathy. The identification of decisive molecular/cellular players connecting environmental triggers and the occurrence of APN provides opportunities to prevent disease onset, reduce relapses and develop new therapeutic strategies. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  1. SAP is required for the development of innate phenotype in H2-M3-restricted CD8+ T cells1

    Science.gov (United States)

    Bediako, Yaw; Bian, Yao; Zhang, Hong; Cho, Hoonsik; Stein, Paul L.; Wang, Chyung-Ru

    2012-01-01

    H2-M3-restricted T cells have a pre-activated surface phenotype, rapidly expand and produce cytokines upon stimulation and as such, are classified as innate T cells. Unlike most innate T cells, M3-restricted T cells also express CD8αβ co-receptors and a diverse TCR repertoire: hallmarks of conventional MHC Ia-restricted CD8+ T cells. Although iNKT cells are also innate lymphocytes, they are selected exclusively on hematopoietic cells (HC), while M3-restricted T cells can be selected on either hematopoietic or thymic epithelial cells (TEC). Moreover, their phenotypes differ depending on what cells mediate their selection. Though there is a clear correlation between selection on HC and development of innate phenotype, the underlying mechanism remains unclear. SAP is required for the development of iNKT cells and mediates signals from SLAM receptors that are exclusively expressed on HC. Based on their dual selection pathway, M3-restricted T cells present a unique model for studying the development of innate T cell phenotype. Using both polyclonal and transgenic mouse models we demonstrate that while M3-restricted T cells are capable of developing in the absence of SAP, SAP is required for HC-mediated selection, development of pre-activated phenotype and heightened effector functions of M3-restricted T cells. These findings are significant because they directly demonstrate the need for SAP in HC-mediated acquisition of innate T cell phenotype and suggest that due to their SAP-dependent HC-mediated selection, M3-restricted T cells develop a pre-activated phenotype and an intrinsic ability to proliferate faster upon stimulation, allowing for an important role in the early response to infection. PMID:23041566

  2. Cytomegalovirus (CMV) Epitope-Specific CD4+ T Cells Are Inflated in HIV+ CMV+ Subjects.

    Science.gov (United States)

    Abana, Chike O; Pilkinton, Mark A; Gaudieri, Silvana; Chopra, Abha; McDonnell, Wyatt J; Wanjalla, Celestine; Barnett, Louise; Gangula, Rama; Hager, Cindy; Jung, Dae K; Engelhardt, Brian G; Jagasia, Madan H; Klenerman, Paul; Phillips, Elizabeth J; Koelle, David M; Kalams, Spyros A; Mallal, Simon A

    2017-11-01

    Select CMV epitopes drive life-long CD8 + T cell memory inflation, but the extent of CD4 memory inflation is poorly studied. CD4 + T cells specific for human CMV (HCMV) are elevated in HIV + HCMV + subjects. To determine whether HCMV epitope-specific CD4 + T cell memory inflation occurs during HIV infection, we used HLA-DR7 (DRB1*07:01) tetramers loaded with the glycoprotein B DYSNTHSTRYV (DYS) epitope to characterize circulating CD4 + T cells in coinfected HLA-DR7 + long-term nonprogressor HIV subjects with undetectable HCMV plasma viremia. DYS-specific CD4 + T cells were inflated among these HIV + subjects compared with those from an HIV - HCMV + HLA-DR7 + cohort or with HLA-DR7-restricted CD4 + T cells from the HIV-coinfected cohort that were specific for epitopes of HCMV phosphoprotein-65, tetanus toxoid precursor, EBV nuclear Ag 2, or HIV gag protein. Inflated DYS-specific CD4 + T cells consisted of effector memory or effector memory-RA + subsets with restricted TCRβ usage and nearly monoclonal CDR3 containing novel conserved amino acids. Expression of this near-monoclonal TCR in a Jurkat cell-transfection system validated fine DYS specificity. Inflated cells were polyfunctional, not senescent, and displayed high ex vivo levels of granzyme B, CX 3 CR1, CD38, or HLA-DR but less often coexpressed CD38 + and HLA-DR + The inflation mechanism did not involve apoptosis suppression, increased proliferation, or HIV gag cross-reactivity. Instead, the findings suggest that intermittent or chronic expression of epitopes, such as DYS, drive inflation of activated CD4 + T cells that home to endothelial cells and have the potential to mediate cytotoxicity and vascular disease. Copyright © 2017 by The American Association of Immunologists, Inc.

  3. Acetylation of the Cd8 Locus by KAT6A Determines Memory T Cell Diversity

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    Dane M. Newman

    2016-09-01

    Full Text Available How functionally diverse populations of pathogen-specific killer T cells are generated during an immune response remains unclear. Here, we propose that fine-tuning of CD8αβ co-receptor levels via histone acetylation plays a role in lineage fate. We show that lysine acetyltransferase 6A (KAT6A is responsible for maintaining permissive Cd8 gene transcription and enabling robust effector responses during infection. KAT6A-deficient CD8+ T cells downregulated surface CD8 co-receptor expression during clonal expansion, a finding linked to reduced Cd8α transcripts and histone-H3 lysine 9 acetylation of the Cd8 locus. Loss of CD8 expression in KAT6A-deficient T cells correlated with reduced TCR signaling intensity and accelerated contraction of the effector-like memory compartment, whereas the long-lived memory compartment appeared unaffected, a result phenocopied by the removal of the Cd8 E8I enhancer element. These findings suggest a direct role of CD8αβ co-receptor expression and histone acetylation in shaping functional diversity within the cytotoxic T cell pool.

  4. Hyper-IL-15 suppresses metastatic and autochthonous liver cancer by promoting tumour-specific CD8+ T cell responses.

    Science.gov (United States)

    Cheng, Liang; Du, Xuexiang; Wang, Zheng; Ju, Jianqi; Jia, Mingming; Huang, Qibin; Xing, Qiao; Xu, Meng; Tan, Yi; Liu, Mingyue; Du, Peishuang; Su, Lishan; Wang, Shengdian

    2014-12-01

    Liver cancer has a very dismal prognosis due to lack of effective therapy. Here, we studied the therapeutic effects of hyper-interleukin15 (hyper-IL-15), which is composed of IL-15 and the sushi domain of the IL-15 receptor α chain, on metastatic and autochthonous liver cancers. Liver metastatic tumour models were established by intraportally injecting syngeneic mice with murine CT26 colon carcinoma cells or B16-OVA melanoma cells. Primary hepatocellular carcinoma (HCC) was induced by diethylnitrosamine (DEN). A hydrodynamics-based gene delivery method was used to achieve sustained hyper-IL-15 expression in the liver. Liver gene delivery of hyper-IL-15 robustly expanded CD8(+) T and NK cells, leading to a long-term (more than 40 days) accumulation of CD8(+) T cells in vivo, especially in the liver. Hyper-IL-15 treatment exerted remarkable therapeutic effects on well-established liver metastatic tumours and even on DEN-induced autochthonous HCC, and these effects were abolished by depletion of CD8(+) T cells but not NK cells. Hyper-IL-15 triggered IL-12 and interferon-γ production and reduced the expression of co-inhibitory molecules on dendritic cells in the liver. Adoptive transfer of T cell receptor (TCR) transgenic OT-1 cells showed that hyper-IL-15 preferentially expanded tumour-specific CD8(+) T cells and promoted their interferon-γ synthesis and cytotoxicity. Liver delivery of hyper-IL-15 provides an effective therapy against well-established metastatic and autochthonous liver cancers in mouse models by preferentially expanding tumour-specific CD8(+) T cells and promoting their anti-tumour effects. Copyright © 2014 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  5. Deep Surveying of the Transcriptional and Alternative Splicing Signatures for Decidual CD8+ T Cells at the First Trimester of Human Healthy Pregnancy

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    Weihong Zeng

    2018-05-01

    Full Text Available Decidual CD8+ (dCD8 T cells have been proposed to play important roles in immune protection against the invading pathogens and in tolerance toward the growing semi-allogeneic fetus during early pregnancy. However, their phenotypic and functional characteristics remain poorly defined. Here, we performed the first analysis of the transcriptional and alternative splicing (AS signatures for human first-trimester dCD8 T cells using high-throughput mRNA sequencing. Our data revealed that dCD8 T cells have distinct transcriptional and AS landscapes when compared with their autologous peripheral blood CD8+ (pCD8 T counterparts. Furthermore, human dCD8 T cells were observed to contain CD8-Treg and effector-memory T-cell subsets, and display enhanced functionality in terms of degranulation and cytokine production on a per-cell basis. Additionally, we have identified the novel splice junctions that use a high ratio of the non-canonical splicing motif GC-AG and found that AS is not a major contributor to the gene expression-level changes between paired pCD8 and dCD8 T cells. Together, our findings not only provide a comprehensive framework of the transcriptional and AS landscapes but also reveal the functional feature of human dCD8 T cells, which are of great importance in understanding the biology of these cells and the physiology of human healthy pregnancy.

  6. High frequency of cytolytic 21-Hydroxylase specific CD8+ T cells in autoimmune Addison’s disease patients1

    Science.gov (United States)

    Dawoodji, Amina; Chen, Ji-Li; Shepherd, Dawn; Dalin, Frida; Tarlton, Andrea; Alimohammadi, Mohammad; Penna-Martinez, Marissa; Meyer, Gesine; Mitchell, Anna L; Gan, Earn H; Bratland, Eirik; Bensing, Sophie; Husebye, Eystein; Pearce, Simon H.; Badenhoop, Klaus; Kämpe, Olle; Cerundolo, Vincenzo

    2016-01-01

    The mechanisms behind the destruction of the adrenal glands in autoimmune Addison’s disease remain unclear. Autoantibodies against steroid 21-hydroxylase, an intracellular key enzyme of the adrenal cortex, are found in over 90% of patients, but these autoantibodies are not thought to mediate the disease. Here we demonstrate highly frequent 21-hydroxylase specific T cells detectable in 20 patients with Addison’s disease. Using overlapping 18aa peptides spanning the full length of 21-hydroxylase, we identified immunodominant CD8+ and CD4+ T cell responses in a large proportion of Addison’s patients both ex-vivo and after in-vitro culture of peripheral blood lymphocytes up to 20 years after diagnosis. In a large proportion of patients, CD8+ 21-hydroxylase specific T cells and CD4+ 21-hydroxylase specific T cells were very abundant and detectable in ex-vivo assays. HLA class-I tetramer-guided isolation of 21-hydroxylase specific CD8+ T cells showed their ability to lyse 21-hydroxylase positive target cells, consistent with a potential mechanism for disease pathogenesis. These data indicate strong cytotoxic T lymphocyte responses to 21-hydroxylase often occur in-vivo, and that reactive cytotoxic T lymphocytes have substantial proliferative and cytolytic potential. These results have implications for earlier diagnosis of adrenal failure and ultimately a potential target for therapeutic intervention and induction of immunity against adrenal cortex cancer. PMID:25063864

  7. High conservation level of CD8(+) T cell immunogenic regions within an unusual H1N2 human influenza variant.

    Science.gov (United States)

    Komadina, Naomi; Quiñones-Parra, Sergio M; Kedzierska, Katherine; McCaw, James M; Kelso, Anne; Leder, Karin; McVernon, Jodie

    2016-10-01

    Current seasonal influenza vaccines require regular updates due to antigenic drift causing loss of effectiveness and therefore providing little or no protection against novel influenza A subtypes. Next generation vaccines capable of eliciting CD8(+) T cell (CTL) mediated cross-protective immunity may offer a long-term alternative strategy. However, measuring pre- and existing levels of CTL cross-protection in humans is confounded by differences in infection histories across individuals. During 2000-2003, H1N2 viruses circulated persistently in the human population for the first time and we hypothesized that the viral nucleoprotein (NP) contained novel CTL epitopes that may have contributed to the survival of the viruses. This study describes the immunogenic NP peptides of H1N1, H2N2, and H3N2 influenza viruses isolated from humans over the past century, 1918-2003, by comparing this historical dataset to reference NP peptides from H1N2 that circulated in humans during 2000-2003. Observed peptides sequences ranged from highly conserved (15%) to highly variable (12%), with variation unrelated to reported immunodominance. No unique NP peptides which were exclusive to the H1N2 viruses were noted. However, the virus had inherited the NP from a recently emerged H3N2 variant containing novel peptides, which may have assisted its persistence. Any advantage due to this novelty was subsequently lost with emergence of a newer H3N2 variant in 2003. Our approach has potential to provide insight into the population context in which influenza viruses emerge, and may help to inform immunogenic peptide selection for CTL-inducing influenza vaccines. J. Med. Virol. 88:1725-1732, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Incomplete Memories: The Natural Suppression of Tissue-Resident Memory CD8 T Cells in the Lung

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    Katie L. Reagin

    2018-01-01

    Full Text Available The yearly, cyclic impact of viruses like influenza on human health and the economy is due to the high rates of mutation of traditional antibody targets, which negate any preexisting humoral immunity. However, the seasonality of influenza infections can equally be attributed to an absent or defective memory CD8 T cell response since the epitopes recognized by these cells are derived from essential virus proteins that mutate infrequently. Experiments in mouse models show that protection from heterologous influenza infection is temporally limited and conferred by a population of tissue-resident memory (TRM cells residing in the lung and lung airways. TRM are elicited by a diverse set of pathogens penetrating mucosal barriers and broadly identified by extravascular staining and expression of the activation and adhesion molecules CD69 and CD103. Interestingly, lung TRM fail to express these molecules, which could limit tissue retention, resulting in airway expulsion or death with concomitant loss of heterologous protection. Here, we make the case that respiratory infections uniquely evoke a form of natural immunosuppression whereby specific cytokines and cell–cell interactions negatively impact memory cell programming and differentiation. Respiratory memory is not only short-lived but most of the memory cells in the lung parenchyma may not be bona fide TRM. Given the quantity of microbes humans inhale over a lifetime, limiting cellular residence could be a mechanism employed by the respiratory tract to preserve organismal vitality. Therefore, successful efforts to improve respiratory immunity must carefully and selectively breach these inherent tissue barriers.

  9. Enumeration of CD4 and CD8 T-cells in HIV infection in Zimbabwe using a manual immunocytochemical method

    DEFF Research Database (Denmark)

    Gomo, E; Ndhlovu, P; Vennervald, B J

    2001-01-01

    OBJECTIVES: To enumerate CD4 and CD8 T-cells using the simple and cheap immuno-alkaline phosphatase (IA) method and to compare it with flow cytometry (FC); and to study the effects of duration of sample storage on the IA method results. DESIGN: Method comparison study. SETTING: Blair Research...... Laboratory, Harare, Zimbabwe. SUBJECTS: 41 HIV positive and 11 HIV negative men and women from Harare participating in HIV studies at Blair Research Laboratory, Zimbabwe. MAIN OUTCOME MEASURES: CD4 and CD8 T-cell counts by FC and the IA method. RESULTS: The IA method and FC were highly correlated for CD4...... counts (Spearman rs = 0.91), CD4 percentage (rs = 0.84), CD8 count (rs = 0.83), CD8 percentage (rs = 0.96) and CD4/CD8 ratio (rs = 0.89). However, CD4 cell counts and percentage measured by the IA method were (mean difference +/- SE) 133 +/- 24 cells/microL [corrected] and 6.7 +/- 1.1% higher than those...

  10. HTLV-1 specific CD8+ T cell function augmented by blockade of 2B4/CD48 interaction in HTLV-1 infection.

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    Chibueze Chioma Ezinne

    Full Text Available CD8+ T cell response is important in the response to viral infections; this response though is regulated by inhibitory receptors. Expression of inhibitory receptors has been positively correlated with CD8+ T cell exhaustion; the consequent effect of simultaneous blockade of these inhibitory receptors on CD8+ T cell response in viral infections have been studied, however, the role of individual blockade of receptor-ligand pair is unclear. 2B4/CD48 interaction is involved in CD8+T cell regulation, its signal transducer SAP (signaling lymphocyte activation molecule (SLAM-associated protein is required for stimulatory function of 2B4/CD244 on lymphocytes hence, we analyzed 2B4/CD244 (natural killer cell receptor and SAP (signaling lymphocyte activation molecule(SLAM-associated protein on total CD8+ and HTLV-1 specific CD8+T cells in HTLV-1 infection and the effect of blockade of interaction with ligand CD48 on HTLV-1 specific CD8+ T cell function. We observed a high expression of 2B4/CD244 on CD8+ T cells relative to uninfected and further upregulation on HTLV-1 specific CD8+ T cells. 2B4+ CD8+ T cells exhibited more of an effector and terminally differentiated memory phenotype. Blockade of 2B4/CD48 interaction resulted in improvement in function via perforin expression and degranulation as measured by CD107a surface mobilization on HTLV-1 specific CD8+ T cells. In the light of these findings, we thus propose an inhibitory role for 2B4/CD48 interaction on CD8+T cell function.

  11. Exposure of Human CD8+ T Cells to Type-2 Cytokines Impairs Division and Differentiation and Induces Limited Polarization

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    Annette Fox

    2018-05-01

    Full Text Available Effector CD8+ T cells generally produce type-1 cytokines and mediators of the perforin/granzyme cytolytic pathway, yet type-2-polarized CD8+ cells (Tc2 are detected in type-2 (T2 cytokine-driven diseases such as asthma. It is unclear whether T2 cytokine exposure during activation is sufficient to polarize human CD8+ T cells. To address this question, a protocol was developed for high-efficiency activation of human CD8+ T cells in which purified single cells or populations were stimulated with plate-bound anti-CD3 and anti-CD11a mAb for up to 8 days in T2 polarizing or neutral conditions, before functional analysis. Activation of CD8+ naïve T cells (TN in T2 compared with neutral conditions decreased the size of single-cell clones, although early division kinetics were equivalent, indicating an effect on overall division number. Activation of TN in T2 conditions followed by brief anti-CD3 mAb restimulation favored expression of T2 cytokines, GATA3 and Eomes, and lowered expression of type-1 cytokines, Prf1, Gzmb, T-BET, and Prdm1. However, IL-4 was only weakly expressed, and PMA and ionomycin restimulation favored IFN-γ over IL-4 expression. Activation of TN in T2 compared with neutral conditions prevented downregulation of costimulatory (CD27, CD28 and lymph-node homing receptors (CCR7 and CD95 acquisition, which typically occur during differentiation into effector phenotypes. CD3 was rapidly and substantially induced after activation in neutral, but not T2 conditions, potentially contributing to greater division and differentiation in neutral conditions. CD8+ central memory T cells (TCM were less able to enter division upon reactivation in T2 compared with neutral conditions, and were more refractory to modulating IFN-γ and IL-4 production than CD8+ TN. In summary, while activation of TN in T2 conditions can generate T2 cytokine-biased cells, IL-4 expression is weak, T2 bias is lost upon strong restimulation, differentiation, and division

  12. Cis-acting pathways selectively enforce the non-immunogenicity of shed placental antigen for maternal CD8 T cells.

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    Chin-Siean Tay

    Full Text Available Maternal immune tolerance towards the fetus and placenta is thought to be established in part by pathways that attenuate T cell priming to antigens released from the placenta into maternal blood. These pathways remain largely undefined and their existence, at face value, seems incompatible with a mother's need to maintain a functional immune system during pregnancy. A particular conundrum is evident if we consider that maternal antigen presenting cells, activated in order to prime T cells to pathogen-derived antigens, would also have the capacity to prime T cells to co-ingested placental antigens. Here, we address this paradox using a transgenic system in which placental membranes are tagged with a strong surrogate antigen (ovalbumin. We find that although a remarkably large quantity of acellular ovalbumin-containing placental material is released into maternal blood, splenic CD8 T cells in pregnant mice bearing unmanipulated T cell repertoires are not primed to ovalbumin even if the mice are intravenously injected with adjuvants. This failure was largely independent of regulatory T cells, and instead was linked to the intrinsic characteristics of the released material that rendered it selectively non-immunogenic, potentially by sequestering it from CD8α(+ dendritic cells. The release of ovalbumin-containing placental material into maternal blood thus had no discernable impact on CD8 T cell priming to soluble ovalbumin injected intravenously during pregnancy, nor did it induce long-term tolerance to ovalbumin. Together, these results outline a major pathway governing the maternal immune response to the placenta, and suggest how tolerance to placental antigens can be maintained systemically without being detrimental to host defense.

  13. Cis-Acting Pathways Selectively Enforce the Non-Immunogenicity of Shed Placental Antigen for Maternal CD8 T Cells

    Science.gov (United States)

    Tay, Chin-Siean; Tagliani, Elisa; Collins, Mary K.; Erlebacher, Adrian

    2013-01-01

    Maternal immune tolerance towards the fetus and placenta is thought to be established in part by pathways that attenuate T cell priming to antigens released from the placenta into maternal blood. These pathways remain largely undefined and their existence, at face value, seems incompatible with a mother's need to maintain a functional immune system during pregnancy. A particular conundrum is evident if we consider that maternal antigen presenting cells, activated in order to prime T cells to pathogen-derived antigens, would also have the capacity to prime T cells to co-ingested placental antigens. Here, we address this paradox using a transgenic system in which placental membranes are tagged with a strong surrogate antigen (ovalbumin). We find that although a remarkably large quantity of acellular ovalbumin-containing placental material is released into maternal blood, splenic CD8 T cells in pregnant mice bearing unmanipulated T cell repertoires are not primed to ovalbumin even if the mice are intravenously injected with adjuvants. This failure was largely independent of regulatory T cells, and instead was linked to the intrinsic characteristics of the released material that rendered it selectively non-immunogenic, potentially by sequestering it from CD8α+ dendritic cells. The release of ovalbumin-containing placental material into maternal blood thus had no discernable impact on CD8 T cell priming to soluble ovalbumin injected intravenously during pregnancy, nor did it induce long-term tolerance to ovalbumin. Together, these results outline a major pathway governing the maternal immune response to the placenta, and suggest how tolerance to placental antigens can be maintained systemically without being detrimental to host defense. PMID:24391885

  14. Live Imaging of Influenza Infection of the Trachea Reveals Dynamic Regulation of CD8+ T Cell Motility by Antigen.

    Science.gov (United States)

    Lambert Emo, Kris; Hyun, Young-Min; Reilly, Emma; Barilla, Christopher; Gerber, Scott; Fowell, Deborah; Kim, Minsoo; Topham, David J

    2016-09-01

    During a primary influenza infection, cytotoxic CD8+ T cells need to infiltrate the infected airways and engage virus-infected epithelial cells. The factors that regulate T cell motility in the infected airway tissue are not well known. To more precisely study T cell infiltration of the airways, we developed an experimental model system using the trachea as a site where live imaging can be performed. CD8+ T cell motility was dynamic with marked changes in motility on different days of the infection. In particular, significant changes in average cell velocity and confinement were evident on days 8-10 during which the T cells abruptly but transiently increase velocity on day 9. Experiments to distinguish whether infection itself or antigen affect motility revealed that it is antigen, not active infection per se that likely affects these changes as blockade of peptide/MHC resulted in increased velocity. These observations demonstrate that influenza tracheitis provides a robust experimental foundation to study molecular regulation of T cell motility during acute virus infection.

  15. Live Imaging of Influenza Infection of the Trachea Reveals Dynamic Regulation of CD8+ T Cell Motility by Antigen.

    Directory of Open Access Journals (Sweden)

    Kris Lambert Emo

    2016-09-01

    Full Text Available During a primary influenza infection, cytotoxic CD8+ T cells need to infiltrate the infected airways and engage virus-infected epithelial cells. The factors that regulate T cell motility in the infected airway tissue are not well known. To more precisely study T cell infiltration of the airways, we developed an experimental model system using the trachea as a site where live imaging can be performed. CD8+ T cell motility was dynamic with marked changes in motility on different days of the infection. In particular, significant changes in average cell velocity and confinement were evident on days 8-10 during which the T cells abruptly but transiently increase velocity on day 9. Experiments to distinguish whether infection itself or antigen affect motility revealed that it is antigen, not active infection per se that likely affects these changes as blockade of peptide/MHC resulted in increased velocity. These observations demonstrate that influenza tracheitis provides a robust experimental foundation to study molecular regulation of T cell motility during acute virus infection.

  16. The Cish SH2 domain is essential for PLC-γ1 regulation in TCR stimulated CD8+ T cells.

    Science.gov (United States)

    Guittard, Geoffrey; Dios-Esponera, Ana; Palmer, Douglas C; Akpan, Itoro; Barr, Valarie A; Manna, Asit; Restifo, Nicholas P; Samelson, Lawrence E

    2018-03-28

    Cish, participates within a multi-molecular E3 ubiquitin ligase complex, which ubiquitinates target proteins. It has an inhibitory effect on T cell activation mediated by PLC-γ1 regulation, and it functions as a potent checkpoint in CD8 + T cell tumor immunotherapy. To study the structural and functional relationships between Cish and PLC-γ1 during CD8 + T cell activation, we tested mutants of the Cish-SH2 (R107K) and D/BC (L222Q, C226Q) domains. We confirmed that Cish-SH2-specific binding was essential for PLC-γ1 ubiquitination and degradation. This domain was essential for the Cish-mediated inhibition of Ca 2+ release upon TCR stimulation. No effect on inhibition of cytokine release was observed with SH2 or D/BC mutants, although the absence of Cish led to an increased release of IFN-γ and TNF-α. Using imaging we showed that Cish was expressed mostly in the cytoplasm and we did not see any Cish clustering at the plasma membrane upon stimulation. We conclude that the Cish-SH2 domain is essential for PLC-γ1 regulation in TCR-stimulated CD8 + T cells.

  17. High frequency of cytolytic 21-hydroxylase-specific CD8+ T cells in autoimmune Addison's disease patients.

    Science.gov (United States)

    Dawoodji, Amina; Chen, Ji-Li; Shepherd, Dawn; Dalin, Frida; Tarlton, Andrea; Alimohammadi, Mohammad; Penna-Martinez, Marissa; Meyer, Gesine; Mitchell, Anna L; Gan, Earn H; Bratland, Eirik; Bensing, Sophie; Husebye, Eystein S; Pearce, Simon H; Badenhoop, Klaus; Kämpe, Olle; Cerundolo, Vincenzo

    2014-09-01

    The mechanisms behind destruction of the adrenal glands in autoimmune Addison's disease remain unclear. Autoantibodies against steroid 21-hydroxylase, an intracellular key enzyme of the adrenal cortex, are found in >90% of patients, but these autoantibodies are not thought to mediate the disease. In this article, we demonstrate highly frequent 21-hydroxylase-specific T cells detectable in 20 patients with Addison's disease. Using overlapping 18-aa peptides spanning the full length of 21-hydroxylase, we identified immunodominant CD8(+) and CD4(+) T cell responses in a large proportion of Addison's patients both ex vivo and after in vitro culture of PBLs ≤20 y after diagnosis. In a large proportion of patients, CD8(+) and CD4(+) 21-hydroxylase-specific T cells were very abundant and detectable in ex vivo assays. HLA class I tetramer-guided isolation of 21-hydroxylase-specific CD8(+) T cells showed their ability to lyse 21-hydroxylase-positive target cells, consistent with a potential mechanism for disease pathogenesis. These data indicate that strong CTL responses to 21-hydroxylase often occur in vivo, and that reactive CTLs have substantial proliferative and cytolytic potential. These results have implications for earlier diagnosis of adrenal failure and ultimately a potential target for therapeutic intervention and induction of immunity against adrenal cortex cancer. Copyright © 2014 by The American Association of Immunologists, Inc.

  18. CD8 T cells primed in the gut-associated lymphoid tissue induce immune-mediated cholangitis in mice.

    Science.gov (United States)

    Seidel, Daniel; Eickmeier, Ira; Kühl, Anja A; Hamann, Alf; Loddenkemper, Christoph; Schott, Eckart

    2014-02-01

    The pathogenesis of primary sclerosing cholangitis (PSC) remains poorly understood. Since PSC predominantly occurs in patients with inflammatory bowel disease, autoimmunity triggered by activated T cells migrating from the gut to the liver is a possible mechanism. We hypothesized that T cells primed in the gut-associated lymphoid tissue (GALT) by a specific antigen migrate to the liver and cause cholangitis when they recognize the same antigen on cholangiocytes. We induced ovalbumin-dependent colitis in mice that express ovalbumin in biliary epithelia (ASBT-OVA mice) and crossed ASBT-OVA mice with mice that express ovalbumin in enterocytes (iFABP-OVA mice). We analyzed T-cell activation in the GALT and crossreactivity to the same antigen in the liver as well as the effects of colitis per se on antigen-presentation and T-cell activation in the liver. Intrarectal application of ovalbumin followed by transfer of CD8 OT-I T cells led to antigen-dependent colitis. CD8 T cells primed in the GALT acquired effector function and the capability to migrate to the liver, where they caused cholangitis in a strictly antigen-dependent manner. Likewise, cholangitis developed in mice expressing ovalbumin simultaneously in biliary epithelia and enterocytes after transfer of OT-I T cells. Dextran sodium sulfate colitis led to increased levels of inflammatory cytokines in the portal venous blood, induced activation of resident liver dendritic cells, and promoted the induction of T-cell-dependent cholangitis. Our data strengthen the notion that immune-mediated cholangitis is caused by T cells primed in the GALT and provide the first link between colitis and cholangitis in an antigen-dependent mouse model. © 2013 by the American Association for the Study of Liver Diseases.

  19. The role of natural killer T cells in dendritic cell licensing, cross-priming and memory CD8+ T cell generation

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    Catherine eGottschalk

    2015-07-01

    Full Text Available New vaccination strategies focus on achieving CD8+ T cell (CTL immunity rather than on induction of protective antibody responses. While the requirement of CD4+ T (Th cell help in dendritic cell (DC activation and licensing, and in CTL memory induction has been described in several disease models, CTL responses may occur in a Th cell help independent manner. Natural Killer T cells (NKT cells can substitute for Th cell help and license DC as well. NKT cells produce a broad spectrum of Th1 and Th2 cytokines, thereby inducing a similar set of costimulatory molecules and cytokines in DC. This form of licensing differs from Th cell help by inducing other chemokines: while Th cell licensed DC produce CCR5 ligands, NKT cell-licensed DC produce CCL17 which attracts CCR4+ CD8+ T cells for subsequent activation. It has recently been shown that iNKT cells do not only enhance immune responses against bacterial pathogens or parasites, but also play a role in viral infections. The inclusion of NKT cell ligands in Influenza virus vaccines enhanced memory CTL generation and protective immunity in a mouse model. This review will focus on the role of iNKT cells in the cross-talk with cross-priming DC and memory CD8+ T cell formation.

  20. Regulatory CD8{sup +} T cells induced by exposure to all-trans retinoic acid and TGF-{beta} suppress autoimmune diabetes

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    Kishi, Minoru [Department of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan); Yasuda, Hisafumi, E-mail: yasuda@med.kobe-u.ac.jp [Department of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan); Abe, Yasuhisa; Sasaki, Hirotomo; Shimizu, Mami; Arai, Takashi; Okumachi, Yasuyo; Moriyama, Hiroaki; Hara, Kenta; Yokono, Koichi; Nagata, Masao [Department of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)

    2010-03-26

    Antigen-specific regulatory CD4{sup +} T cells have been described but there are few reports on regulatory CD8{sup +} T cells. We generated islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)-specific regulatory CD8{sup +} T cells from 8.3-NOD transgenic mice. CD8{sup +} T cells from 8.3-NOD splenocytes were cultured with IGRP, splenic dendritic cells (SpDCs), TGF-{beta}, and all-trans retinoic acid (ATRA) for 5 days. CD8{sup +} T cells cultured with either IGRP alone or IGRP and SpDCs in the absence of TGF-{beta} and ATRA had low Foxp3{sup +} expression (1.7 {+-} 0.9% and 3.2 {+-} 4.5%, respectively). In contrast, CD8{sup +} T cells induced by exposure to IGRP, SpDCs, TGF-{beta}, and ATRA showed the highest expression of Foxp3{sup +} in IGRP-reactive CD8{sup +} T cells (36.1 {+-} 10.6%), which was approximately 40-fold increase compared with that before induction culture. CD25 expression on CD8{sup +} T cells cultured with IGRP, SpDCs, TGF-{beta}, and ATRA was only 7.42%, whereas CD103 expression was greater than 90%. These CD8{sup +} T cells suppressed the proliferation of diabetogenic CD8{sup +} T cells from 8.3-NOD splenocytes in vitro and completely prevented diabetes onset in NOD-scid mice in cotransfer experiments with diabetogenic splenocytes from NOD mice in vivo. Here we show that exposure to ATRA and TGF-{beta} induces CD8{sup +}Foxp3{sup +} T cells ex vivo, which suppress diabetogenic T cells in vitro and in vivo.

  1. Decreased memory B cells and increased CD8 memory T cells in blood of breastfed children: the generation R study.

    Science.gov (United States)

    Jansen, Michelle A E; van den Heuvel, Diana; van Zelm, Menno C; Jaddoe, Vincent W V; Hofman, Albert; de Jongste, Johan C; Hooijkaas, Herbert; Moll, Henriette A

    2015-01-01

    Breastfeeding provides a protective effect against infectious diseases in infancy. Still, immunological evidence for enhanced adaptive immunity in breastfed children remains inconclusive. To determine whether breastfeeding affects B- and T-cell memory in the first years of life. We performed immunophenotypic analysis on blood samples within a population-based prospective cohort study. Participants included children at 6 months (n=258), 14 months (n=166), 25 months (n=112) and 6 years of age (n=332) with both data on breastfeeding and blood lymphocytes. Total B- and T-cell numbers and their memory subsets were determined with 6-color flow cytometry. Mothers completed questionnaires on breastfeeding when their children were aged 2, 6, and 12 months. Multiple linear regression models with adjustments for potential confounders were performed. Per month continuation of breastfeeding, a 3% (95% CI -6, -1) decrease in CD27+IgM+, a 2% (95 CI % -5, -1) decrease in CD27+IgA+ and a 2% (95% CI -4, -1) decrease in CD27-IgG+ memory B cell numbers were observed at 6 months of age. CD8 T-cell numbers at 6 months of age were 20% (95% CI 3, 37) higher in breastfed than in non-breastfed infants. This was mainly found for central memory CD8 T cells and associated with exposure to breast milk, rather than duration. The same trend was observed at 14 months, but associations disappeared at older ages. Longer breastfeeding is associated with increased CD8 T-cell memory, but not B-cell memory numbers in the first 6 months of life. This transient skewing towards T cell memory might contribute to the protective effect against infectious diseases in infancy.

  2. Decreased memory B cells and increased CD8 memory T cells in blood of breastfed children: the generation R study.

    Directory of Open Access Journals (Sweden)

    Michelle A E Jansen

    Full Text Available Breastfeeding provides a protective effect against infectious diseases in infancy. Still, immunological evidence for enhanced adaptive immunity in breastfed children remains inconclusive.To determine whether breastfeeding affects B- and T-cell memory in the first years of life.We performed immunophenotypic analysis on blood samples within a population-based prospective cohort study. Participants included children at 6 months (n=258, 14 months (n=166, 25 months (n=112 and 6 years of age (n=332 with both data on breastfeeding and blood lymphocytes. Total B- and T-cell numbers and their memory subsets were determined with 6-color flow cytometry. Mothers completed questionnaires on breastfeeding when their children were aged 2, 6, and 12 months. Multiple linear regression models with adjustments for potential confounders were performed.Per month continuation of breastfeeding, a 3% (95% CI -6, -1 decrease in CD27+IgM+, a 2% (95 CI % -5, -1 decrease in CD27+IgA+ and a 2% (95% CI -4, -1 decrease in CD27-IgG+ memory B cell numbers were observed at 6 months of age. CD8 T-cell numbers at 6 months of age were 20% (95% CI 3, 37 higher in breastfed than in non-breastfed infants. This was mainly found for central memory CD8 T cells and associated with exposure to breast milk, rather than duration. The same trend was observed at 14 months, but associations disappeared at older ages.Longer breastfeeding is associated with increased CD8 T-cell memory, but not B-cell memory numbers in the first 6 months of life. This transient skewing towards T cell memory might contribute to the protective effect against infectious diseases in infancy.

  3. Pleural mesothelial cells promote expansion of IL-17-producing CD8+ T cells in tuberculous pleural effusion.

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    Li, X; Zhou, Q; Yang, W B; Xiong, X Z; Du, R H; Zhang, J C

    2013-05-01

    IL-17-producing CD8(+) T lymphocytes (Tc17 cells) have recently been detected in many cancers and autoimmune diseases. However, the possible implication of Tc17 cells in tuberculous pleural effusion remains unclarified. In this study, distribution and phenotypic features of Tc17 cells in both tuberculous pleural effusion (TPE) and peripheral blood from patients with tuberculosis were determined. The effects of proinflammatory cytokines and local accessory cells (pleural mesothelial cells) on Tc17 cell expansion were also explored. We found that TPE contained more Tc17 cells than the blood. Compared with IFN-γ-producing CD8(+) T cells, Tc17 cells displayed higher expression of chemokine receptors (CCRs) and lower expression of cytotoxic molecules. In particularly, Tc17 cells in TPE exhibited high expression levels of CCR6, which could migrate in response to CCL20. Furthermore, IL-1β, IL-6, IL-23, or their various combinations could promote Tc17 cell expansion from CD8(+) T cells, whereas the proliferative response of Tc17 cells to above cytokines was lower than that of Th17 cells. Pleural mesothelial cells (PMCs) were able to stimulate Tc17 cell expansion via cell contact in an IL-1β/IL-6/IL-23 independent fashion. Thus this study demonstrates that Tc17 cells marks a subset of non-cytotoxic, CCR6(+) CD8(+) T lymphocytes with low proliferative capacity. The overrepresentation of Tc17 cells in TPE may be due to Tc17 cell expansion stimulated by pleural proinflammatory cytokines and to recruitment of Tc17 cells from peripheral blood. Additionally, PMCs may promote the production of IL-17 by CD8(+) T cells at sites of TPE via cell-cell interactions.

  4. Serial Assessment of Immune Status by Circulating CD8+ Effector T Cell Frequencies for Posttransplant Infectious Complications

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    Shinji Uemoto

    2008-01-01

    Full Text Available To clarify the role of CD8+ effector T cells for infectious complications, 92 recipients were classified according to the hierarchical clustering of preoperative CD8+CD45 isoforms: Group I was naive, Group II was effector memory, and Group III was effector (E T cell-dominant. The posttransplant infection rates progressively increased from 29% in Group I to 64.3% in Group III recipients. The posttransplant immune status was compared with the pretransplant status, based on the measure (% difference and its graphical form (scatter plot. In Groups I and II, both approaches showed a strong upward deviation from pretransplant status upon posttransplant infection, indicating an enhanced clearance of pathogens. In Group III, in contrast, both approaches showed a clear downward deviation from preoperative status, indicating deficient cytotoxicity. The % E difference and scatter plot can be used as a useful indicator of a posttransplant infectious complication.

  5. Theileria parva antigens recognized by CD8+ T cells show varying degrees of diversity in buffalo-derived infected cell lines.

    Science.gov (United States)

    Sitt, Tatjana; Pelle, Roger; Chepkwony, Maurine; Morrison, W Ivan; Toye, Philip

    2018-05-06

    The extent of sequence diversity among the genes encoding 10 antigens (Tp1-10) known to be recognized by CD8+ T lymphocytes from cattle immune to Theileria parva was analysed. The sequences were derived from parasites in 23 buffalo-derived cell lines, three cattle-derived isolates and one cloned cell line obtained from a buffalo-derived stabilate. The results revealed substantial variation among the antigens through sequence diversity. The greatest nucleotide and amino acid diversity were observed in Tp1, Tp2 and Tp9. Tp5 and Tp7 showed the least amount of allelic diversity, and Tp5, Tp6 and Tp7 had the lowest levels of protein diversity. Tp6 was the most conserved protein; only a single non-synonymous substitution was found in all obtained sequences. The ratio of non-synonymous: synonymous substitutions varied from 0.84 (Tp1) to 0.04 (Tp6). Apart from Tp2 and Tp9, we observed no variation in the other defined CD8+ T cell epitopes (Tp4, 5, 7 and 8), indicating that epitope variation is not a universal feature of T. parva antigens. In addition to providing markers that can be used to examine the diversity in T. parva populations, the results highlight the potential for using conserved antigens to develop vaccines that provide broad protection against T. parva.

  6. Elimination of self-reactive CD8+, but not CD4+, T cells by a peripheral immune mechanism

    International Nuclear Information System (INIS)

    Rammensee, H.G.; Huegin, D.

    1990-01-01

    Unirradiated (BALB/c X B6)F1 recipients of lymphocytes from either parent or (B6 X DBA/2)F2 recipients of DBA/2 parental lymphocytes specifically remove the function of donor-derived F1-reactive CTL from the spleen, since such cells could not be recovered 1 week after injection. However, donor-derived CTL specific for third-party antigens, as well as donor-derived F1-reactive CD4+ T cells could be recovered. In contrast, CTL in spleens from recipients sublethally irradiated prior to injections consisted predominantly of F1-reactive CTL in all strain combinations tested. Athymic BALB/c nude mice grafted with fetal thymus of B6 develop a T cell compartment tolerant of BALB/c and B6, like (BALB/c X B6)F1 animals. However, unlike the F1 mice, the thymus-grafted nude mice were not able to eliminate B6-reactive lymphocytes after injection of normal BALB/c spleen cells. Our data indicate the existence of a peripheral immune mechanism capable of selectively eliminating self-reactive CD8+ CTL, but not CD4+, T cells. This mechanism requires self antigen expressed on radiosensitive cells. The presence of T cells tolerant to self antigen by thymic negative selection is not sufficient and perhaps not required. Most likely, this mechanism is involved in the relative resistance to lethal GVHR mediated by parental CD8+ T cells in parent-into-F1 situations

  7. A defect in KCa3.1 channel activity limits the ability of CD8+ T cells from cancer patients to infiltrate an adenosine-rich microenvironment.

    Science.gov (United States)

    Chimote, Ameet A; Balajthy, Andras; Arnold, Michael J; Newton, Hannah S; Hajdu, Peter; Qualtieri, Julianne; Wise-Draper, Trisha; Conforti, Laura

    2018-04-24

    The limited ability of cytotoxic T cells to infiltrate solid tumors hampers immune surveillance and the efficacy of immunotherapies in cancer. Adenosine accumulates in solid tumors and inhibits tumor-specific T cells. Adenosine inhibits T cell motility through the A 2A receptor (A 2A R) and suppression of KCa3.1 channels. We conducted three-dimensional chemotaxis experiments to elucidate the effect of adenosine on the migration of peripheral blood CD8 + T cells from head and neck squamous cell carcinoma (HNSCC) patients. The chemotaxis of HNSCC CD8 + T cells was reduced in the presence of adenosine, and the effect was greater on HNSCC CD8 + T cells than on healthy donor (HD) CD8 + T cells. This response correlated with the inability of CD8 + T cells to infiltrate tumors. The effect of adenosine was mimicked by an A 2A R agonist and prevented by an A 2A R antagonist. We found no differences in A 2A R expression, 3',5'-cyclic adenosine monophosphate abundance, or protein kinase A type 1 activity between HNSCC and HD CD8 + T cells. We instead detected a decrease in KCa3.1 channel activity, but not expression, in HNSCC CD8 + T cells. Activation of KCa3.1 channels by 1-EBIO restored the ability of HNSCC CD8 + T cells to chemotax in the presence of adenosine. Our data highlight the mechanism underlying the increased sensitivity of HNSCC CD8 + T cells to adenosine and the potential therapeutic benefit of KCa3.1 channel activators, which could increase infiltration of these T cells into tumors. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  8. Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity

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    II Kim Jae

    2010-10-01

    Full Text Available Abstract Background Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through in vitro and in vivo studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism. Methods In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB. Proliferation assay based on [3H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8+ T cell was compared by JAM test. Results Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight and histological analysis of the lung metastasis (gross analysis and histological staining. Reduced expression of Cox-2 (mRNA and protein from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8+ T cells by increasing the proliferation capacity and their cytolytic activity. Conclusions Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8+ T cells.

  9. Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity.

    Science.gov (United States)

    Lee, Choong-Gu; Kwon, Ho-Keun; Ryu, Jae Ha; Kang, Sung Jin; Im, Chang-Rok; Ii Kim, Jae; Im, Sin-Hyeog

    2010-10-20

    Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through in vitro and in vivo studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism. In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB). Proliferation assay based on [3H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8+ T cell was compared by JAM test. Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight) and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight) and histological analysis of the lung metastasis (gross analysis and histological staining). Reduced expression of Cox-2 (mRNA and protein) from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8+ T cells by increasing the proliferation capacity and their cytolytic activity. Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8+ T cells.

  10. miR-150-Mediated Foxo1 Regulation Programs CD8+ T Cell Differentiation.

    Science.gov (United States)

    Ban, Young Ho; Oh, Se-Chan; Seo, Sang-Hwan; Kim, Seok-Min; Choi, In-Pyo; Greenberg, Philip D; Chang, Jun; Kim, Tae-Don; Ha, Sang-Jun

    2017-09-12

    MicroRNA (miR)-150 is a developmental regulator of several immune-cell types, but its role in CD8 + T cells is largely unexplored. Here, we show that miR-150 regulates the generation of memory CD8 + T cells. After acute virus infection, miR-150 knockout (KO) mice exhibited an accelerated differentiation of CD8 + T cells into memory cells and improved production of effector cytokines. Additionally, miR-150 KO CD8 + T cells displayed an enhanced recall response and improved protection against infections with another virus and bacteria. We found that forkhead box O1 (Foxo1) and T cell-specific transcription factor 1 (TCF1) are upregulated during the early activation phase in miR-150 KO CD8 + T cells and that miR-150 directly targets and suppresses Foxo1. These results suggest that miR-150-mediated suppression of Foxo1 regulates the balance between effector and memory cell differentiation, which might aid in the development of improved vaccines and T cell therapeutics. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Inflammatory impact of IFN-γ in CD8+ T cell-mediated lung injury is mediated by both Stat1-dependent and -independent pathways

    Science.gov (United States)

    Ramana, Chilakamarti V.; DeBerge, Matthew P.; Kumar, Aseem; Alia, Christopher S.; Durbin, Joan E.

    2015-01-01

    Influenza infection results in considerable pulmonary pathology, a significant component of which is mediated by CD8+ T cell effector functions. To isolate the specific contribution of CD8+ T cells to lung immunopathology, we utilized a nonviral murine model in which alveolar epithelial cells express an influenza antigen and injury is initiated by adoptive transfer of influenza-specific CD8+ T cells. We report that IFN-γ production by adoptively transferred influenza-specific CD8+ T cells is a significant contributor to acute lung injury following influenza antigen recognition, in isolation from its impact on viral clearance. CD8+ T cell production of IFN-γ enhanced lung epithelial cell expression of chemokines and the subsequent recruitment of inflammatory cells into the airways. Surprisingly, Stat1 deficiency in the adoptive-transfer recipients exacerbated the lung injury that was mediated by the transferred influenza-specific CD8+ T cells but was still dependent on IFN-γ production by these cells. Loss of Stat1 resulted in sustained activation of Stat3 signaling, dysregulated chemokine expression, and increased infiltration of the airways by inflammatory cells. Taken together, these data identify important roles for IFN-γ signaling and Stat1-independent IFN-γ signaling in regulating CD8+ T cell-mediated acute lung injury. This is the first study to demonstrate an anti-inflammatory effect of Stat1 on CD8+ T cell-mediated lung immunopathology without the complication of differences in viral load. PMID:25617378

  12. Circulating CD8+CD28- suppressor T cells tied to poorer prognosis among metastatic breast cancer patients receiving adoptive T-cell therapy: A cohort study.

    Science.gov (United States)

    Song, Qingkun; Ren, Jun; Zhou, Xinna; Wang, Xiaoli; Song, Guohong; Hobeika, Amy; Yuan, Yanhua; Lyerly, Herbert Kim

    2018-01-01

    This study aimed to determine the prognostic value of circulating CD8 + CD28 - T lymphocytes among breast cancer patients treated with adoptive T-lymphocyte immunotherapy after chemotherapy. Two hundred and thirty-two breast cancer patients underwent adoptive T-cell immunotherapy. Circulating CD8 + CD28 - proportion was measured by flow cytometry. Median proportion of CD8 + CD28 - was 24.2% and set as the categorical cutoff value for further analysis. The median survival was estimated by Kaplan-Meier curve, with difference detection and hazard ratio estimation by log-rank test and Cox hazard proportion regression model. With adoptive T-cell therapy, patients with higher CD8 + CD28 - levels experienced median progression-free and overall survival of 7.1 months and 26.9 months, respectively-significantly shorter than patients with lower levels (11.8 and 36.2 months). CD8 + CD28 - proportion >24.2% demonstrated a hazard ratio (HR) of 2.06 (95% confidence interval [CI] 1.31-3.12) for progression and an HR of 1.97 (95% CI 1.06-3.67) for death. Among patients who had received previous first-line chemotherapy, CD8 + CD28 - proportion >24.2% demonstrated an HR of 2.66 (95% CI 1.45-4.88) for progression. Among patients exposed to previous second-line or higher chemotherapy, CD8 + CD28 - proportion >24.2% demonstrated a 486% higher risk for death (HR = 5.86, 95% CI 1.77-19.39). A 1% increase in suppressive T cells was associated with a 5% increased risk of death. Elevated peripheral blood CD8 + CD28 - was associated with poorer prognosis for metastatic breast cancer, especially for higher risk of progression among patients with first-line chemotherapy and higher risk of death among patients with more than second-line chemotherapy. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  13. Generalized Liver- and Blood-Derived CD8+ T-Cell Impairment in Response to Cytokines in Chronic Hepatitis C Virus Infection.

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    Stephanie C Burke Schinkel

    Full Text Available Generalized CD8+ T-cell impairment in chronic hepatitis C virus (HCV infection and the contribution of liver-infiltrating CD8+ T-cells to the immunopathogenesis of this infection remain poorly understood. It is hypothesized that this impairment is partially due to reduced CD8+ T-cell activity in response to cytokines such as IL-7, particularly within the liver. To investigate this, the phenotype and cytokine responsiveness of blood- and liver-derived CD8+ T-cells from healthy controls and individuals with HCV infection were compared. In blood, IL-7 receptor α (CD127 expression on bulk CD8+ T-cells in HCV infection was no different than controls yet was lower on central memory T-cells, and there were fewer naïve cells. IL-7-induced signalling through phosphorylated STAT5 was lower in HCV infection than in controls, and differed between CD8+ T-cell subsets. Production of Bcl-2 following IL-7 stimulation was also lower in HCV infection and inversely related to the degree of liver fibrosis. In liver-derived CD8+ T-cells, STAT5 activation could not be increased with cytokine stimulation and basal Bcl-2 levels of liver-derived CD8+ T-cells were lower than blood-derived counterparts in HCV infection. Therefore, generalized CD8+ T-cell impairment in HCV infection is characterized, in part, by impaired IL-7-mediated signalling and survival, independent of CD127 expression. This impairment is more pronounced in the liver and may be associated with an increased potential for apoptosis. This generalized CD8+ T-cell impairment represents an important immune dysfunction in chronic HCV infection that may alter patient health.

  14. Hesperidin Inhibits Inflammatory Response Induced by Aeromonas hydrophila Infection and Alters CD4+/CD8+ T Cell Ratio

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    Abdelaziz S. A. Abuelsaad

    2014-01-01

    Full Text Available Background. Aeromonas hydrophila is an opportunistic bacterial pathogen that is associated with a number of human diseases. Hesperidin (HES has been reported to exert antioxidant and anti-inflammatory activities. Objectives. The aim of this study was to investigate the potential effect of HES treatment on inflammatory response induced by A. hydrophila infection in murine. Methods. A. hydrophila-infected mice were treated with HES at 250 mg/kg b.wt./week for 4 consecutive weeks. Phagocytosis, reactive oxygen species production, CD4+/CD8+ T cell ratio, and CD14 expression on intestinal infiltrating monocytes were evaluated. The expression of E-selectin and intercellular adhesion molecule 1 on stimulated HUVECs and RAW macrophage was evaluated. Results. Percentage of CD4+ T cells in the intestinal tissues of infected treated mice was highly significantly increased; however, phagocytic index, ROS production, CD8+ T cells percentage, and CD14 expression on monocytes were significantly reduced. On the other hand, HES significantly inhibited A-LPS- and A-ECP-induced E-selectin and ICAM-1 expression on HUVECs and ICAM-1 expression on RAW macrophage. Conclusion. Present data indicated that HES has a potential role in the suppression of inflammatory response induced by A. hydrophila toxins through downmodulation of ROS production and CD14 and adhesion molecules expression, as well as increase of CD4+/CD8+ cell ratio.

  15. Effective collaboration between marginal metallophilic macrophages and CD8+ dendritic cells in the generation of cytotoxic T cells

    Science.gov (United States)

    Backer, Ronald; Schwandt, Timo; Greuter, Mascha; Oosting, Marije; Jüngerkes, Frank; Tüting, Thomas; Boon, Louis; O’Toole, Tom; Kraal, Georg; Limmer, Andreas; den Haan, Joke M. M.

    2009-01-01

    The spleen is the lymphoid organ that induces immune responses toward blood-borne pathogens. Specialized macrophages in the splenic marginal zone are strategically positioned to phagocytose pathogens and cell debris, but are not known to play a role in the activation of T-cell responses. Here we demonstrate that splenic marginal metallophilic macrophages (MMM) are essential for cross-presentation of blood-borne antigens by splenic dendritic cells (DCs). Our data demonstrate that antigens targeted to MMM as well as blood-borne adenoviruses are efficiently captured by MMM and exclusively transferred to splenic CD8+ DCs for cross-presentation and for the activation of cytotoxic T lymphocytes. Depletion of macrophages in the marginal zone prevents cytotoxic T-lymphocyte activation by CD8+ DCs after antibody targeting or adenovirus infection. Moreover, we show that tumor antigen targeting to MMM is very effective as antitumor immunotherapy. Our studies point to an important role for splenic MMM in the initial steps of CD8+ T-cell immunity by capturing and concentrating blood-borne antigens and the transfer to cross-presenting DCs which can be used to design vaccination strategies to induce antitumor cytotoxic T-cell immunity. PMID:20018690

  16. Clinical, immunological and treatment-related factors associated with normalised CD4+/CD8+ T-cell ratio: effect of naïve and memory T-cell subsets.

    LENUS (Irish Health Repository)

    Tinago, Willard

    2014-01-01

    Although effective antiretroviral therapy(ART) increases CD4+ T-cell count, responses to ART vary considerably and only a minority of patients normalise their CD4+\\/CD8+ ratio. Although retention of naïve CD4+ T-cells is thought to predict better immune responses, relationships between CD4+ and CD8+ T-cell subsets and CD4+\\/CD8+ ratio have not been well described.

  17. IL-12-mediated STAT4 signaling and TCR signal strength cooperate in the induction of CD40L in human and mouse CD8+ T cells.

    Science.gov (United States)

    Stark, Regina; Hartung, Anett; Zehn, Dietmar; Frentsch, Marco; Thiel, Andreas

    2013-06-01

    CD40L is one of the key molecules bridging the activation of specific T cells and the maturation of professional and nonprofessional antigen-presenting cells including B cells. CD4(+) T cells have been regarded as the major T-cell subset that expresses CD40L upon cognate activation; however, we demonstrate here that a putative CD8(+) helper T-cell subset expressing CD40L is induced in human and murine CD8(+) T cells in vitro and in mice immunized with antigen-pulsed dendritic cells. IL-12 and STAT4-mediated signaling was the major instructive cytokine signal boosting the ability of CD8(+) T cells to express CD40L both in vitro and in vivo. Additionally, TCR signaling strength modulated CD40L expression in CD8(+) T cells after primary differentiation in vitro as well as in vivo. The induction of CD40L in CD8(+) T cells regulated by IL-12 and TCR signaling may enable CD8(+) T cells to respond autonomously of CD4(+) T cells. Thus, we propose that under proinflammatory conditions, a self-sustaining positive feedback loop could facilitate the efficient priming of T cells stimulated by high affinity peptide displaying APCs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Dynamic analysis of CD127 expression on memory CD8 T cells from patients with chronic hepatitis B during telbivudine treatment

    Directory of Open Access Journals (Sweden)

    Lv Guocai

    2010-08-01

    Full Text Available Abstract Background Accumulating evidence supports the theory that expression of CD127 on CD8 T cells during the process of antiviral immune response indicates a subset of effect CD8 T cells that successfully develop into fully protective memory. CD8 T cells expression of CD127 may be used as a predictor to evaluate disease status in chronic viral infection. The aim of this study was to investigate the CD127 expression level on different subsets of CD8 T cell and explore the relationship between CD127 expression on CD8 memory T cells and serum hepatitis B virus (HBV DNA and hepatitis B e antigen (HBeAg levels in patients with chronic hepatitis B (CHB. We also aimed to investigate the CD127 expression pattern on CD8 memory T cells of CHB patients who were treated with Telbivudine. Methods/Results Twenty HBeAg-positive CHB patients were selected and treated with telbivudine 600 mg/day for 48 weeks. The memory CD8 T cells were characterized by expression of CD45RA and CD27 markers. CD127 expression on the CD8 T-cell surface was measured by four-colour flow cytometry. Our results showed that CD127 expression on memory CD8 T cells was reduced in CHB patients. There was a strong negative correlation between CD127 expression on memory CD8 T cells and serum HBV DNA and HBeAg levels in CHB patients. Moreover, successful antiviral therapy increased CD127 expression on CD8 memory T cells as well as on HBV-specific CD8 T cells in CHB patients. Conclusion These results suggest that diminished CD127 expression on CD8 memory T cells of CHB patients is a potential mechanism explaining cellular immune function impairment in CHB infection, and that CD127 expression on CD8 memory T cells is a useful indicator for evaluating the effects of anti-HBV therapy.

  19. Low CD4/CD8 T-cell ratio associated with inflammatory arthropathy in human T-cell leukemia virus type I Tax transgenic mice.

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    Takeo Ohsugi

    Full Text Available BACKGROUND: Human T-cell leukemia virus type I (HTLV-1 can cause an aggressive malignancy known as adult T-cell leukemia/lymphoma (ATL as well as inflammatory diseases such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. A transgenic mouse that expresses HTLV-1 Tax also develops T-cell leukemia/lymphoma and an inflammatory arthropathy that resembles rheumatoid arthritis. The aim of this study was to identify the primary T-cell subsets involved in the development of arthropathy in Tax transgenic mice. PRINCIPAL FINDINGS: By 24 months of age, Tax transgenic mice developed severe arthropathy with a cumulative incidence of 22.8%. The pathological findings of arthropathy in Tax transgenic mice were similar to those seen in human rheumatoid arthritis or mouse models of rheumatoid arthritis, with synovial proliferation and a positive rheumatoid factor. Before the onset of spontaneous arthropathy, young and old Tax transgenic mice were not sensitive to collagen and did not develop arthritis after immunization with type II collagen. The arthropathic Tax transgenic mice showed a significantly decreased proportion of splenic CD4(+ T cells, whereas the proportion of splenic CD8(+ T cells was increased. Regulatory T cells (CD4(+CD25(+Foxp3(+ were significantly decreased and CD8(+ T cells that expressed the chemokine receptor CCR4 (CD8(+CCR4(+ were significantly increased in arthropathic Tax transgenic mice. The expression of tax mRNA was strong in the spleen and joints of arthropathic mice, with a 40-fold increase compared with healthy transgenic mice. CONCLUSIONS: Our findings reveal that Tax transgenic mice develop rheumatoid-like arthritis with proliferating synovial cells in the joints; however, the proportion of different splenic T-cell subsets in these mice was completely different from other commonly used animal models of rheumatoid arthritis. The crucial T-cell subsets in arthropathic Tax transgenic mice appear to resemble

  20. Severity of Acute Infectious Mononucleosis Correlates with Cross-Reactive Influenza CD8 T-Cell Receptor Repertoires.

    Science.gov (United States)

    Aslan, Nuray; Watkin, Levi B; Gil, Anna; Mishra, Rabinarayan; Clark, Fransenio G; Welsh, Raymond M; Ghersi, Dario; Luzuriaga, Katherine; Selin, Liisa K

    2017-12-05

    Fifty years after the discovery of Epstein-Barr virus (EBV), it remains unclear how primary infection with this virus leads to massive CD8 T-cell expansion and acute infectious mononucleosis (AIM) in young adults. AIM can vary greatly in severity, from a mild transient influenza-like illness to a prolonged severe syndrome. We questioned whether expansion of a unique HLA-A2.01-restricted, cross-reactive CD8 T-cell response between influenza virus A-M1 58 (IAV-M1) and EBV BMLF1 280 (EBV-BM) could modulate the immune response to EBV and play a role in determining the severity of AIM in 32 college students. Only ex vivo total IAV-M1 and IAV-M1+EBV-BM cross-reactive tetramer + frequencies directly correlated with AIM severity and were predictive of severe disease. Expansion of specific cross-reactive memory IAV-M1 T-cell receptor (TCR) Vβ repertoires correlated with levels of disease severity. There were unique profiles of qualitatively different functional responses in the cross-reactive and EBV-specific CD8 T-cell responses in each of the three groups studied, severe-AIM patients, mild-AIM patients, and seropositive persistently EBV-infected healthy donors, that may result from differences in TCR repertoire use. IAV-M1 tetramer + cells were functionally cross-reactive in short-term cultures, were associated with the highest disease severity in AIM, and displayed enhanced production of gamma interferon, a cytokine that greatly amplifies immune responses, thus frequently contributing to induction of immunopathology. Altogether, these data link heterologous immunity via CD8 T-cell cross-reactivity to CD8 T-cell repertoire selection, function, and resultant disease severity in a common and important human infection. In particular, it highlights for the first time a direct link between the TCR repertoire with pathogenesis and the diversity of outcomes upon pathogen encounter. IMPORTANCE The pathogenic impact of immune responses that by chance cross-react to unrelated

  1. TCR down-regulation controls virus-specific CD8+ T cell responses

    DEFF Research Database (Denmark)

    Bonefeld, Charlotte Menné; Haks, Mariëlle; Nielsen, Bodil

    2008-01-01

    in mice with a mutated CD3gamma di-leucine-based motif. The CD3gamma mutation did not impair early TCR signaling, nor did it compromise recruitment or proliferation of virus-specific T cells, but it increased the apoptosis rate of the activated T cells by increasing down-regulation of the antiapoptotic...

  2. IL-6 trans-Signaling-Dependent Rapid Development of Cytotoxic CD8+ T Cell Function

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    Jan P. Böttcher

    2014-09-01

    Full Text Available Immune control of infections with viruses or intracellular bacteria relies on cytotoxic CD8+ T cells that use granzyme B (GzmB for elimination of infected cells. During inflammation, mature antigen-presenting dendritic cells instruct naive T cells within lymphoid organs to develop into effector T cells. Here, we report a mechanistically distinct and more rapid process of effector T cell development occurring within 18 hr. Such rapid acquisition of effector T cell function occurred through cross-presenting liver sinusoidal endothelial cells (LSECs in the absence of innate immune stimulation and known costimulatory signaling. Rather, interleukin-6 (IL-6 trans-signaling was required and sufficient for rapid induction of GzmB expression in CD8+ T cells. Such LSEC-stimulated GzmB-expressing CD8+ T cells further responded to inflammatory cytokines, eliciting increased and protracted effector functions. Our findings identify a role for IL-6 trans-signaling in rapid generation of effector function in CD8+ T cells that may be beneficial for vaccination strategies.

  3. Genome-wide expression profiling analysis to identify key genes in the anti-HIV mechanism of CD4+ and CD8+ T cells.

    Science.gov (United States)

    Gao, Lijie; Wang, Yunqi; Li, Yi; Dong, Ya; Yang, Aimin; Zhang, Jie; Li, Fengying; Zhang, Rongqiang

    2018-07-01

    Comprehensive bioinformatics analyses were performed to explore the key biomarkers in response to HIV infection of CD4 + and CD8 + T cells. The numbers of CD4 + and CD8 + T cells of HIV infected individuals were analyzed and the GEO database (GSE6740) was screened for differentially expressed genes (DEGs) in HIV infected CD4 + and CD8 + T cells. Gene Ontology enrichment, KEGG pathway analyses, and protein-protein interaction (PPI) network were performed to identify the key pathway and core proteins in anti-HIV virus process of CD4 + and CD8 + T cells. Finally, we analyzed the expressions of key proteins in HIV-infected T cells (GSE6740 dataset) and peripheral blood mononuclear cells(PBMCs) (GSE511 dataset). 1) CD4 + T cells counts and ratio of CD4 + /CD8 + T cells decreased while CD8 + T cells counts increased in HIV positive individuals; 2) 517 DEGs were found in HIV infected CD4 + and CD8 + T cells at acute and chronic stage with the criterial of P-value T cells. The main biological processes of the DEGs were response to virus and defense response to virus. At chronic stage, ISG15 protein, in conjunction with IFN-1 pathway might play key roles in anti-HIV responses of CD4 + T cells; and 4) The expression of ISG15 increased in both T cells and PBMCs after HIV infection. Gene expression profile of CD4 + and CD8 + T cells changed significantly in HIV infection, in which ISG15 gene may play a central role in activating the natural antiviral process of immune cells. © 2018 Wiley Periodicals, Inc.

  4. Role of alveolar epithelial Early growth response-1 (Egr-1) in CD8+ T Cell mediated Lung Injury

    Science.gov (United States)

    Ramana, Chilakamarti V.; Cheng, Guang-Shing; Kumar, Aseem; Kwon, Hyung- Joo; Enelow, Richard I.

    2009-01-01

    Influenza infection of the distal airways results in severe lung injury, a considerable portion of which is immunopathologic and attributable to the host responses. We have used a mouse model to specifically investigate the role of antiviral CD8+ T cells in this injury, and have found that the critical effector molecule is TNF-α expressed by the T cells upon antigen recognition. Interestingly, the immunopathology which ensues is characterized by significant accumulation of host inflammatory cells, recruited by chemokines expressed by the target alveolar epithelial cells. In this study we analyzed the mechanisms involved in the induction of epithelial chemokine expression triggered by antigen-specific CD8+ T cell recognition, and demonstrate that the Early growth response-1 (Egr-1) transcription factor is rapidly induced in epithelial cells, both in vitro and ex vivo, and that this is a critical regulator of a host of inflammatory chemokines. Genetic deficiency of Egr-1 significantly abrogates both the chemokine expression and the immunopathologic injury associated with T cell recognition, and it directly regulates transcriptional activity of a model CXC chemokine, MIP-2. We further demonstrate that Egr-1 induction is triggered by TNF-α– dependent ERK activation, and inhibition of this pathway ablates Egr-1 expression. These findings suggest that Egr-1 may represent an important target in mitigating the immunopathology of severe influenza infection. PMID:19786304

  5. Role of alveolar epithelial early growth response-1 (Egr-1) in CD8+ T cell-mediated lung injury.

    Science.gov (United States)

    Ramana, Chilakamarti V; Cheng, Guang-Shing; Kumar, Aseem; Kwon, Hyung-Joo; Enelow, Richard I

    2009-12-01

    Influenza infection of the distal airways results in severe lung injury, a considerable portion of which is immunopathologic and attributable to the host responses. We have used a mouse model to specifically investigate the role of antiviral CD8(+) T cells in this injury, and have found that the critical effector molecule is TNF-alpha expressed by the T cells upon antigen recognition. Interestingly, the immunopathology which ensues is characterized by significant accumulation of host inflammatory cells, recruited by chemokines expressed by the target alveolar epithelial cells. In this study we analyzed the mechanisms involved in the induction of epithelial chemokine expression triggered by antigen-specific CD8(+) T cell recognition, and demonstrate that the early growth response-1 (Egr-1) transcription factor is rapidly induced in epithelial cells, both in vitro and ex vivo, and that this is a critical regulator of a host of inflammatory chemokines. Genetic deficiency of Egr-1 significantly abrogates both the chemokine expression and the immunopathologic injury associated with T cell recognition, and it directly regulates transcriptional activity of a model CXC chemokine, MIP-2. We further demonstrate that Egr-1 induction is triggered by TNF-alpha-dependent ERK activation, and inhibition of this pathway ablates Egr-1 expression. These findings suggest that Egr-1 may represent an important target in mitigating the immunopathology of severe influenza infection.

  6. Investigating the Consequences of Interference between Multiple CD8+ T Cell Escape Mutations in Early HIV Infection.

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    Victor Garcia

    2016-02-01

    Full Text Available During early human immunodeficiency virus (HIV infection multiple CD8+ T cell responses are elicited almost simultaneously. These responses exert strong selective pressures on different parts of HIV's genome, and select for mutations that escape recognition and are thus beneficial to the virus. Some studies reveal that the later these escape mutations emerge, the more slowly they go to fixation. This pattern of escape rate decrease(ERD can arise by distinct mechanisms. In particular, in large populations with high beneficial mutation rates interference among different escape strains--an effect that can emerge in evolution with asexual reproduction and results in delayed fixation times of beneficial mutations compared to sexual reproduction--could significantly impact the escape rates of mutations. In this paper, we investigated how interference between these concurrent escape mutations affects their escape rates in systems with multiple epitopes, and whether it could be a source of the ERD pattern. To address these issues, we developed a multilocus Wright-Fisher model of HIV dynamics with selection, mutation and recombination, serving as a null-model for interference. We also derived an interference-free null model assuming initial neutral evolution before immune response elicitation. We found that interference between several equally selectively advantageous mutations can generate the observed ERD pattern. We also found that the number of loci, as well as recombination rates substantially affect ERD. These effects can be explained by the underexponential decline of escape rates over time. Lastly, we found that the observed ERD pattern in HIV infected individuals is consistent with both independent, interference-free mutations as well as interference effects. Our results confirm that interference effects should be considered when analyzing HIV escape mutations. The challenge in estimating escape rates and mutation-associated selective

  7. Opposing effects of CXCR3 and CCR5 deficiency on CD8+ T cell-mediated inflammation in the central nervous system of virus-infected mice

    DEFF Research Database (Denmark)

    de Lemos, Carina; Christensen, Jeanette Erbo; Nansen, Anneline

    2005-01-01

    and therefore protect mice against the otherwise fatal CD8+ T cell-mediated immune attack. Contrary to expectations, the accumulation of mononuclear cells in cerebrospinal fluid was only slightly delayed compared with mice with normal expression of both receptors. Even more surprising, CXCR3/CCR5 double-deficient......T cells play a key role in the control of viral infection in the CNS but may also contribute to immune-mediated cell damage. To study the redundancy of the chemokine receptors CXCR3 and CCR5 in regulating virus-induced CD8+ T cell-mediated inflammation in the brain, CXCR3/CCR5 double-deficient mice...... mice were more susceptible to intracerebral infection than CXCR3-deficient mice. Analysis of effector T cell generation revealed an accelerated antiviral CD8+ T cell response in CXCR3/CCR5 double-deficient mice. Furthermore, while the accumulation of CD8+ T cells in the neural parenchyma...

  8. Therapeutic Vaccination Using Cationic Liposome-Adjuvanted HIV Type 1 Peptides Representing HLA-Supertype-Restricted Subdominant T Cell Epitopes

    DEFF Research Database (Denmark)

    Román, Victor Raúl Gómez; Jensen, Kristoffer Jarlov; Jensen, Sanne Skov

    2013-01-01

    We have designed a therapeutic HIV-1 vaccine concept based on peptides together with the adjuvant CAF01. Peptides represented 15 HLA-supertype-restricted subdominant and conserved CD8 T cell epitopes and three CD4 T-helper cell epitopes. In this phase I clinical trial, safety and immunogenicity...... were assessed in untreated HIV-1-infected individuals in Guinea-Bissau, West Africa. Twenty-three HIV-1-infected individuals were randomized to receive placebo (n=5) or vaccine (n=18). Safety was appraised by clinical follow-up combined with monitoring of biochemistry, hematology, CD4 T cell counts......, and HIV-1 viral loads. T cell immunogenicity was monitored longitudinally by interferon (IFN)-γ ELISpot. New vaccine-specific T cell responses were induced in 6/14 vaccinees for whom ELISpot data were valid. CD4 T cell counts and viral loads were stable. The study shows that therapeutic immunization...

  9. Characterization of T cell clones from chagasic patients: predominance of CD8 surface phenotype in clones from patients with pathology

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    Washington R. Cuna

    1995-08-01

    Full Text Available Human Chagas' disease, caused by the protozoan Trypanosoma cruzi, is associated with pathological processes whose mechanisms are not known. To address this question, T cell lines were developed from chronic chagasic patients peripheral blood mononuclear cells (PBMC and cloned. These T cell clones (TCC were analyzed phenotypically with monoclonal antibodies by the use of a fluorescence microscope. The surface phenotype of the TCC from the asymptomatic patient were predominantly CD4 positive (86%. On the contrary, the surface phenotype CD8 was predominant in the TCC from the patients suffering from cardiomegaly with right bundle branch block (83%, bradycardia with megacolon (75 % and bradycardia (75%. Future studies will be developed in order to identify the antigens eliciting these T cell subpopulations.

  10. Bystander hyperactivation of preimmune CD8+ T cells in chronic HCV patients.

    OpenAIRE

    Alanio , Cécile; Nicoli , Francesco; Sultanik , Philippe; Flecken , Tobias; Perot , Brieuc; Duffy , Darragh; Bianchi , Elisabetta; Lim , Annick; Clave , Emmanuel; van Buuren , Marit M; Schnuriger , Aurélie; Johnsson , Kerstin; Boussier , Jeremy; Garbarg-Chenon , Antoine; Bousquet , Laurence

    2015-01-01

    eLife digest Long-lasting or ?chronic? infections massively perturb the immune system as a way to favor their own growth. In particular, they can stop T cells ? a subtype of immune cells that help to destroy viruses ? from working well. For example, HIV and hepatitis C viruses can overwork T cells and cause them to die. This can make individuals vulnerable to other infections. In healthy people, T cells that have participated in the fight against particular infections continue to live to prov...

  11. CD8 T Cell Sensory Adaptation Dependent on TCR Avidity for Self-Antigens

    DEFF Research Database (Denmark)

    Marquez, M.-E.; Ellmeier, W.; Sanchez-Guajardo, Vanesa Maria

    2005-01-01

    dephosphorylation of linker for activation of T cells and ERK upon activation. Normal TCR levels and cytokine production were restored by culturing cells in the absence of TCR/spMHC interaction, demonstrating dynamic tuning of peripheral T cell responses. The effect of avidity for self-ligand(s) on this sensory...... ZAP-YEEI cells were enhanced. Our data provide support for central and peripheral sensory T cell adaptation induced as a function of TCR avidity for self-ligands and signaling level. This may contribute to buffer excessive autoreactivity while optimizing TCR repertoire usage....

  12. Analysis of adenovirus-induced immunity to infection with Listeria monocytogenes: Fading protection coincides with declining CD8 T cell numbers and phenotypic changes.

    Science.gov (United States)

    Jahn, Marie Louise; Steffensen, Maria Abildgaard; Christensen, Jan Pravsgaard; Thomsen, Allan Randrup

    2018-05-11

    Defining correlates of T cell mediated protection is important in order to accelerate the development of efficient T cell based vaccines conferring long-term immunity. Extensive studies have provided important insight regarding the characteristics and functional properties of the effector and memory CD8 T cells induced by viral vector based vaccines. However, long-term protection has been difficult to achieve with T cell inducing vaccines, and the determinants underlying this loss in protection over time are still not fully defined. In this study we analyzed different parameters of the CD8 T cell response as a function of time after vaccination with a human serotype 5 adenovector expressing the glycoprotein (GP) of LCMV tethered to the MHC class II-associated invariant chain. Using this vector we have previously found that CD8 T cells mediate protection from challenge with GP-expressing Listeria monocytogenes at 60 days post vaccination, but only little protection after further 60 days, and we now confirm this observation. A comparison of vaccine-primed CD8 T cells early and late after vaccination revealed a minor decline in the overall numbers of antigen specific memory CD8 T cells during this interval. More importantly, we also observed phenotypic changes over time with a distinct decline in the frequency and number of KLRG1 + CD8 T cells, and, notably, adoptive transfer studies confirmed that memory CD8 T cells expressing KLRG1 are central to protection from systemic L. monocytogenes infection. Together these findings imply that multiple factors including changes in memory T cell numbers and phenotypic composition over time influence the longevity of CD8 T-cell mediated protection. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Perforin and Fas in murine gammaherpesvirus-specific CD8(+) T cell control and morbidity

    DEFF Research Database (Denmark)

    Topham, D J; Cardin, R C; Christensen, Jan Pravsgaard

    2001-01-01

    resulted in a failure of most animals to drive the virus into latency, although lytic virus in the lung was reduced by approximately 1000-fold from its peak. Second, the absence of either perforin or Fas alone had no impact on the ability to reduce titres of lytic virus in the lung. Further neutralization...... of IFN-gamma in CD4-depleted P(+/+), P(-/-) or Fas(-/-) mice had no effect. To define the requirements for Fas or perforin more clearly, two sets of chimeric mice were constructed differing in perforin expression by the T cells, and Fas on infected epithelial cells or lymphocytes. Animals with P(-/-) T...... cells and a Fas(-/-) lung failed to limit the shedding of infectious virus, regardless of whether CD4 T cells were present. In addition, we noted that having P(-/-) T cells in irradiated Fas(+/+) hosts caused a lethal disease that was not apparent in the non-chimeric (unirradiated) P(-/-) (Fas...

  14. Associations of HLA-A, HLA-B and HLA-C Alleles Frequency with Prevalence of Herpes Simplex Virus Infections and Diseases Across Global Populations: Implication for the Development of an Universal CD8+ T-Cell Epitope-Based Vaccine

    Science.gov (United States)

    Samandary, Sarah; Kridane-Miledi, Hédia; Sandoval, Jacqueline S.; Choudhury, Zareen; Langa-Vives, Francina; Spencer, Doran; Chentoufi, Aziz A.; Lemonnier, François A.; BenMohamed, Lbachir

    2014-01-01

    A significant portion of the world’s population is infected with herpes simplex virus type 1 and/or type 2 (HSV-1 and/or HSV-2), that cause a wide range of diseases including genital herpes, oro-facial herpes, and the potentially blinding ocular herpes. While the global prevalence and distribution of HSV-1 and HSV-2 infections cannot be exactly established, the general trends indicate that: (i) HSV-1 infections are much more prevalent globally than HSV-2; (ii) Over half billion people worldwide are infected with HSV-2; (iii) the sub-Saharan African populations account for a disproportionate burden of genital herpes infections and diseases; (iv) the dramatic differences in the prevalence of herpes infections between regions of the world appear to be associated with differences in the frequencies of human leukocyte antigen (HLA) alleles. The present report: (i) analyzes the prevalence of HSV-1 and HSV-2 infections across various regions of the world; (ii) analyzes potential associations of common HLA-A, HLA-B and HLA-C alleles with the prevalence of HSV-1 and HSV-2 infections in the Caucasoid, Oriental, Hispanic and Black major populations; and (iii) discusses how our recently developed HLA-A, HLA-B, and HLA-C transgenic/H-2 class I null mice will help validate HLA/herpes prevalence associations. Overall, high prevalence of herpes infection and disease appears to be associated with high frequency of HLA-A*24, HLA-B*27, HLA-B*53 and HLA-B*58 alleles. In contrast, low prevalence of herpes infection and disease appears to be associated with high frequency of HLA-B*44 allele. The finding will aid in developing a T-cell epitope-based universal herpes vaccine and immunotherapy. PMID:24798939

  15. mTOR Complex Signaling through the SEMA4A-Plexin B2 Axis Is Required for Optimal Activation and Differentiation of CD8+ T Cells.

    Science.gov (United States)

    Ito, Daisuke; Nojima, Satoshi; Nishide, Masayuki; Okuno, Tatsusada; Takamatsu, Hyota; Kang, Sujin; Kimura, Tetsuya; Yoshida, Yuji; Morimoto, Keiko; Maeda, Yohei; Hosokawa, Takashi; Toyofuku, Toshihiko; Ohshima, Jun; Kamimura, Daisuke; Yamamoto, Masahiro; Murakami, Masaaki; Morii, Eiichi; Rakugi, Hiromi; Isaka, Yoshitaka; Kumanogoh, Atsushi

    2015-08-01

    Mammalian target of rapamycin (mTOR) plays crucial roles in activation and differentiation of diverse types of immune cells. Although several lines of evidence have demonstrated the importance of mTOR-mediated signals in CD4(+) T cell responses, the involvement of mTOR in CD8(+) T cell responses is not fully understood. In this study, we show that a class IV semaphorin, SEMA4A, regulates CD8(+) T cell activation and differentiation through activation of mTOR complex (mTORC) 1. SEMA4A(-/-) CD8(+) T cells exhibited impairments in production of IFN-γ and TNF-α and induction of the effector molecules granzyme B, perforin, and FAS-L. Upon infection with OVA-expressing Listeria monocytogenes, pathogen-specific effector CD8(+) T cell responses were significantly impaired in SEMA4A(-/-) mice. Furthermore, SEMA4A(-/-) CD8(+) T cells exhibited reduced mTORC1 activity and elevated mTORC2 activity, suggesting that SEMA4A is required for optimal activation of mTORC1 in CD8(+) T cells. IFN-γ production and mTORC1 activity in SEMA4A(-/-) CD8(+) T cells were restored by administration of recombinant Sema4A protein. In addition, we show that plexin B2 is a functional receptor of SEMA4A in CD8(+) T cells. Collectively, these results not only demonstrate the role of SEMA4A in CD8(+) T cells, but also reveal a novel link between a semaphorin and mTOR signaling. Copyright © 2015 by The American Association of Immunologists, Inc.

  16. Mathematical modeling of ultradeep sequencing data reveals that acute CD8+ T-lymphocyte responses exert strong selective pressure in simian immunodeficiency virus-infected macaques but still fail to clear founder epitope sequences.

    Science.gov (United States)

    Love, Tanzy M T; Thurston, Sally W; Keefer, Michael C; Dewhurst, Stephen; Lee, Ha Youn

    2010-06-01

    The prominent role of antiviral cytotoxic CD8(+) T-lymphocytes (CD8-TL) in containing the acute viremia of human and simian immunodeficiency viruses (HIV-1 and SIV) has rationalized the development of T-cell-based vaccines. However, the presence of escape mutations in the acute stage of infection has raised a concern that accelerated escape from vaccine-induced CD8-TL responses might undermine vaccine efficacy. We reanalyzed previously published data of 101,822 viral genomes of three CD8-TL epitopes, Nef(103-111)RM9 (RM9), Tat(28-35)SL8 (SL8), and Gag(181-189)CM9 (CM9), sampled by ultradeep pyrosequencing from eight macaques. Multiple epitope variants appeared during the resolution of acute viremia, followed by the predominance of a single mutant epitope. By fitting a mathematical model, we estimated the first acute escape rate as 0.36 day(-1) within escape-prone epitopes, RM9 and SL8, and the chronic escape rate as 0.014 day(-1) within the CM9 epitope. Our estimate of SIV acute escape rates was found to be comparable to very early HIV-1 escape rates. The timing of the first escape was more highly correlated with the timing of the peak CD8-TL response than with the magnitude of the CD8-TL response. The transmitted epitope decayed more than 400 times faster during the acute viral decline stage than predicted by a neutral evolution model. However, the founder epitope persisted as a minor population even at the viral set point; in contrast, the majority of acute escape epitopes were completely cleared. Our results suggest that a reservoir of SIV infection is preferentially formed by virus with the transmitted epitope.

  17. The CXC Chemokine Receptor 3 Inhibits Autoimmune Cholangitis via CD8+ T Cells but Promotes Colitis via CD4+ T Cells

    Directory of Open Access Journals (Sweden)

    Qing-Zhi Liu

    2018-05-01

    Full Text Available CXC chemokine receptor 3 (CXCR3, a receptor for the C-X-C motif chemokines (CXCL CXCL9, CXCL10, and CXCL11, which not only plays a role in chemotaxis but also regulates differentiation and development of memory and effector T cell populations. Herein, we explored the function of CXCR3 in the modulation of different organ-specific autoimmune diseases in interleukin (IL-2 receptor deficiency (CD25−/− mice, a murine model for both cholangitis and colitis. We observed higher levels of CXCL9 and CXCL10 in the liver and colon and higher expression of CXCR3 on T cells of the CD25−/− mice compared with control animals. Deletion of CXCR3 resulted in enhanced liver inflammation but alleviated colitis. These changes in liver and colon pathology after CXCR3 deletion were associated with increased numbers of hepatic CD4+ and CD8+ T cells, in particular effector memory CD8+ T cells, as well as decreased T cells in mesenteric lymph nodes and colon lamina propria. In addition, increased interferon-γ response and decreased IL-17A response was observed in both liver and colon after CXCR3 deletion. CXCR3 modulated the functions of T cells involved in different autoimmune diseases, whereas the consequence of such modulation was organ-specific regarding to their effects on disease severity. Our findings emphasize the importance of extra caution in immunotherapy for organ-specific autoimmune diseases, as therapeutic interventions aiming at a target such as CXCR3 for certain disease could result in adverse effects in an unrelated organ.

  18. Curtailed T-cell activation curbs effector differentiation and generates CD8+ T cells with a naturally-occurring memory stem cell phenotype.

    Science.gov (United States)

    Zanon, Veronica; Pilipow, Karolina; Scamardella, Eloise; De Paoli, Federica; De Simone, Gabriele; Price, David A; Martinez Usatorre, Amaia; Romero, Pedro; Mavilio, Domenico; Roberto, Alessandra; Lugli, Enrico

    2017-09-01

    Human T memory stem (T SCM ) cells with superior persistence capacity and effector functions are emerging as important players in the maintenance of long-lived T-cell memory and are thus considered an attractive population to be used in adoptive transfer-based immunotherapy of cancer. However, the molecular signals regulating their generation remain poorly defined. Here we show that curtailed T-cell receptor stimulation curbs human effector CD8 + T-cell differentiation and allows the generation of CD45RO - CD45RA + CCR7 + CD27 + CD95 + -phenotype cells from highly purified naïve T-cell precursors, resembling naturally-occurring human T SCM . These cells proliferate extensively in vitro and in vivo, express low amounts of effector-associated genes and transcription factors and undergo considerable self-renewal in response to IL-15 while retaining effector differentiation potential. Such a phenotype is associated with a lower number of mitochondria compared to highly-activated effector T cells committed to terminal differentiation. These results shed light on the molecular signals that are required to generate long-lived memory T cells with potential application in adoptive cell transfer immunotherapy. © 2017 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co.KGaA, Weinheim.

  19. CD4+ Primary T Cells Expressing HCV-Core Protein Upregulate Foxp3 and IL-10, Suppressing CD4 and CD8 T Cells

    Science.gov (United States)

    Aguado, Enrique; Garcia-Cozar, Francisco

    2014-01-01

    Adaptive T cell responses are critical for controlling HCV infection. While there is clinical evidence of a relevant role for regulatory T cells in chronic HCV-infected patients, based on their increased number and function; mechanisms underlying such a phenomena are still poorly understood. Accumulating evidence suggests that proteins from Hepatitis C virus can suppress host immune responses. We and others have shown that HCV is present in CD4+ lymphocytes from chronically infected patients and that HCV-core protein induces a state of unresponsiveness in the CD4+ tumor cell line Jurkat. Here we show that CD4+ primary T cells lentivirally transduced with HCV-core, not only acquire an anergic phenotype but also inhibit IL-2 production and proliferation of bystander CD4+ or CD8+ T cells in response to anti-CD3 plus anti-CD28 stimulation. Core-transduced CD4+ T cells show a phenotype characterized by an increased basal secretion of the regulatory cytokine IL-10, a decreased IFN-γ production upon stimulation, as well as expression of regulatory T cell markers, CTLA-4, and Foxp3. A significant induction of CD4+CD25+CD127lowPD-1highTIM-3high regulatory T cells with an exhausted phenotype was also observed. Moreover, CCR7 expression decreased in HCV-core expressing CD4+ T cells explaining their sequestration in inflamed tissues such as the infected liver. This work provides a new perspective on de novo generation of regulatory CD4+ T cells in the periphery, induced by the expression of a single viral protein. PMID:24465502

  20. CD4+ primary T cells expressing HCV-core protein upregulate Foxp3 and IL-10, suppressing CD4 and CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Cecilia Fernandez-Ponce

    Full Text Available Adaptive T cell responses are critical for controlling HCV infection. While there is clinical evidence of a relevant role for regulatory T cells in chronic HCV-infected patients, based on their increased number and function; mechanisms underlying such a phenomena are still poorly understood. Accumulating evidence suggests that proteins from Hepatitis C virus can suppress host immune responses. We and others have shown that HCV is present in CD4+ lymphocytes from chronically infected patients and that HCV-core protein induces a state of unresponsiveness in the CD4+ tumor cell line Jurkat. Here we show that CD4+ primary T cells lentivirally transduced with HCV-core, not only acquire an anergic phenotype but also inhibit IL-2 production and proliferation of bystander CD4+ or CD8+ T cells in response to anti-CD3 plus anti-CD28 stimulation. Core-transduced CD4+ T cells show a phenotype characterized by an increased basal secretion of the regulatory cytokine IL-10, a decreased IFN-γ production upon stimulation, as well as expression of regulatory T cell markers, CTLA-4, and Foxp3. A significant induction of CD4+CD25+CD127(lowPD-1(highTIM-3(high regulatory T cells with an exhausted phenotype was also observed. Moreover, CCR7 expression decreased in HCV-core expressing CD4+ T cells explaining their sequestration in inflamed tissues such as the infected liver. This work provides a new perspective on de novo generation of regulatory CD4+ T cells in the periphery, induced by the expression of a single viral protein.

  1. Genome-wide RNA profiling of long-lasting stem cell-like memory CD8 T cells induced by Yellow Fever vaccination in humans

    Directory of Open Access Journals (Sweden)

    Silvia A. Fuertes Marraco

    2015-09-01

    Full Text Available The live-attenuated Yellow Fever (YF vaccine YF-17D induces a broad and polyfunctional CD8 T cell response in humans. Recently, we identified a po