scholarly journals Long-Term Specific Immune Responses Induced in Humans by a Human Immunodeficiency Virus Type 1 Lipopeptide Vaccine: Characterization of CD8+-T-Cell Epitopes Recognized

2003 ◽  
Vol 77 (20) ◽  
pp. 11220-11231 ◽  
Author(s):  
Hanne Gahéry-Ségard ◽  
Gilles Pialoux ◽  
Suzanne Figueiredo ◽  
Céline Igéa ◽  
Mathieu Surenaud ◽  
...  
Keyword(s):  
Immune Response ◽  
Human Immunodeficiency Virus ◽  
T Cell ◽  
T Cell Responses ◽  
T Cell Epitopes ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT We studied the effect of booster injections and the long-term immune response after injections of an anti-human immunodeficiency virus type 1 (HIV-1) lipopeptide vaccine. This vaccine was injected alone or with QS21 adjuvant to 28 HIV-uninfected volunteers. One month later, after a fourth injection of the vaccine, B- and T-cell anti-HIV responses were detected in >85% of the vaccinated volunteers. One year after this injection, a long-term immune response was observed in >50% of the volunteers. At this point, a positive QS21 effect was observed only in the sustained B-cell and CD4+-T-cell responses. To better characterize the CD8+-T-cell response, we used a gamma interferon enzyme-linked immunospot method and a bank of 59 HIV-1 epitopes. For the six most common HLA molecules (HLA-A2, -A3, -A11, -A24, -B7 superfamily, and -B8), an average of 10 (range, 3 to 15) HIV-1 epitopes were tested. CD8+-T-cell responses were evaluated according to the HLA class I molecules of the volunteers. Each assessment was based on 18 HIV-1 epitopes in average. We showed that 31 HIV-1 epitopes elicited specific CD8+-T-cell responses after vaccination. The most frequently recognized peptides were Nef 68-76 (-B7), Nef 71-79 (-B7), Nef 84-92 (-A11), Nef 135-143 (-B7), Nef 136-145 (-A2), Nef 137-145 (-A2), Gag 259-267 (-B8), Gag 260-268 (-A2), Gag 267-274 (-A2), Gag 267-277 (-B7), and Gag 276-283 (A24). We found that CD8+-T-cell epitopes were induced at a higher number after a fourth injection (P < 0.05 compared to three injections), which indicates an increase in the breadth of HIV CD8+-T-cell epitope recognition after the boost.

scholarly journals Hierarchical Targeting of Subtype C Human Immunodeficiency Virus Type 1 Proteins by CD8+ T Cells: Correlation with Viral Load

2004 ◽  
Vol 78 (7) ◽  
pp. 3233-3243 ◽  
Author(s):  
Agatha Masemola ◽  
Tumelo Mashishi ◽  
Greg Khoury ◽  
Phineas Mohube ◽  
Pauline Mokgotho ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Load ◽  
T Cell ◽  
T Cell Responses ◽  
Subtype C ◽  
Viral Control ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT An understanding of the relationship between the breadth and magnitude of T-cell epitope responses and viral loads is important for the design of effective vaccines. For this study, we screened a cohort of 46 subtype C human immunodeficiency virus type 1 (HIV-1)-infected individuals for T-cell responses against a panel of peptides corresponding to the complete subtype C genome. We used a gamma interferon ELISPOT assay to explore the hypothesis that patterns of T-cell responses across the expressed HIV-1 genome correlate with viral control. The estimated median time from seroconversion to response for the cohort was 13 months, and the order of cumulative T-cell responses against HIV proteins was as follows: Nef > Gag > Pol > Env > Vif > Rev > Vpr > Tat > Vpu. Nef was the most intensely targeted protein, with 97.5% of the epitopes being clustered within 119 amino acids, constituting almost one-third of the responses across the expressed genome. The second most targeted region was p24, comprising 17% of the responses. There was no correlation between viral load and the breadth of responses, but there was a weak positive correlation (r = 0.297; P = 0.034) between viral load and the total magnitude of responses, implying that the magnitude of T-cell recognition did not contribute to viral control. When hierarchical patterns of recognition were correlated with the viral load, preferential targeting of Gag was significantly (r = 0.445; P = 0.0025) associated with viral control. These data suggest that preferential targeting of Gag epitopes, rather than the breadth or magnitude of the response across the genome, may be an important marker of immune efficacy. These data have significance for the design of vaccines and for interpretation of vaccine-induced responses.

scholarly journals Differential CD4+ versus CD8+ T-Cell Responses Elicited by Different Poxvirus-Based Human Immunodeficiency Virus Type 1 Vaccine Candidates Provide Comparable Efficacies in Primates

2008 ◽  
Vol 82 (6) ◽  
pp. 2975-2988 ◽  
Author(s):  
Petra Mooij ◽  
Sunita S. Balla-Jhagjhoorsingh ◽  
Gerrit Koopman ◽  
Niels Beenhakker ◽  
Patricia van Haaften ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Immune Responses ◽  
Vaccinia Virus ◽  
T Cell Responses ◽  
Vaccine Candidates ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Poxvirus vectors have proven to be highly effective for boosting immune responses in diverse vaccine settings. Recent reports reveal marked differences in the gene expression of human dendritic cells infected with two leading poxvirus-based human immunodeficiency virus (HIV) vaccine candidates, New York vaccinia virus (NYVAC) and modified vaccinia virus Ankara (MVA). To understand how complex genomic changes in these two vaccine vectors translate into antigen-specific systemic immune responses, we undertook a head-to-head vaccine immunogenicity and efficacy study in the pathogenic HIV type 1 (HIV-1) model of AIDS in Indian rhesus macaques. Differences in the immune responses in outbred animals were not distinguished by enzyme-linked immunospot assays, but differences were distinguished by multiparameter fluorescence-activated cell sorter analysis, revealing a difference between the number of animals with both CD4+ and CD8+ T-cell responses to vaccine inserts (MVA) and those that elicit a dominant CD4+ T-cell response (NYVAC). Remarkably, vector-induced differences in CD4+/CD8+ T-cell immune responses persisted for more than a year after challenge and even accompanied antigenic modulation throughout the control of chronic infection. Importantly, strong preexposure HIV-1/simian immunodeficiency virus-specific CD4+ T-cell responses did not prove deleterious with respect to accelerated disease progression. In contrast, in this setting, animals with strong vaccine-induced polyfunctional CD4+ T-cell responses showed efficacies similar to those with stronger CD8+ T-cell responses.

scholarly journals Magnitude of Functional CD8+ T-Cell Responses to the Gag Protein of Human Immunodeficiency Virus Type 1 Correlates Inversely with Viral Load in Plasma

2002 ◽  
Vol 76 (5) ◽  
pp. 2298-2305 ◽  
Author(s):  
Bradley H. Edwards ◽  
Anju Bansal ◽  
Steffanie Sabbaj ◽  
Janna Bakari ◽  
Mark J. Mulligan ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Load ◽  
T Cell ◽  
Disease Progression ◽  
T Cell Responses ◽  
Cell Responses ◽  
Cell Counts ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The importance of CD8+ T-cell responses in the control of human immunodeficiency virus type 1 (HIV-1) infection has been demonstrated, yet few studies have been able to correlate these responses with markers of HIV-1 disease progression. This study measured cell-mediated immune responses using peripheral blood mononuclear cells (PBMC) obtained from 27 patients with chronic HIV-1 infection, the majority of whom were off antiretroviral therapy. The ELISPOT assay was used to detect gamma interferon-secreting PBMC after stimulation with overlapping HIV-1 peptides spanning the Gag, Pol, Env, and Nef proteins in addition to the baculovirus-derived p24 and gp160 proteins. All volunteers had responses to at least one HIV-1-specific peptide. All but one of the subjects (96%) responded to the Gag peptide pool, and 86% responded to the Pol and/or Nef peptide pools. The magnitude and the breadth of T-cell responses directed to either the Gag or p24 peptide pools correlated inversely with viral load in plasma (r = −0.60, P < 0.001 and r = −0.52, P < 0.005, respectively) and directly with absolute CD4+ T-cell counts (r = 0.54, P < 0.01 and r = 0.39, P < 0.05, respectively) using the Spearman rank correlation test. Responses to the Pol and integrase peptide pools also correlated with absolute CD4+ T-cell counts (r = 0.45, P < 0.05 and r = 0.49, P < 0.01, respectively). No correlation with markers of disease progression was seen with specific T-cell responses directed toward the Env or Nef peptides. These data serve as strong evidence that major histocompatibility complex class I presentation of Gag peptides is an essential feature for any HIV-1 vaccine designed to elicit optimal CD8+ T-cell responses.

scholarly journals De Novo Generation of Escape Variant-Specific CD8+ T-Cell Responses following Cytotoxic T-Lymphocyte Escape in Chronic Human Immunodeficiency Virus Type 1 Infection

2005 ◽  
Vol 79 (20) ◽  
pp. 12952-12960 ◽  
Author(s):  
Todd M. Allen ◽  
Xu G. Yu ◽  
Elizabeth T. Kalife ◽  
Laura L. Reyor ◽  
Mathias Lichterfeld ◽  
...  
Keyword(s):  
T Cell ◽  
De Novo ◽  
Cytotoxic T Lymphocyte ◽  
T Cell Responses ◽  
T Cell Epitopes ◽  
Wild Type ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) evades CD8+ T-cell responses through mutations within targeted epitopes, but little is known regarding its ability to generate de novo CD8+ T-cell responses to such mutants. Here we examined gamma interferon-positive, HIV-1-specific CD8+ T-cell responses and autologous viral sequences in an HIV-1-infected individual for more than 6 years following acute infection. Fourteen optimal HIV-1 T-cell epitopes were targeted by CD8+ T cells, four of which underwent mutation associated with dramatic loss of the original CD8+ response. However, following the G357S escape in the HLA-A11-restricted Gag349-359 epitope and the decline of wild-type-specific CD8+ T-cell responses, a novel CD8+ T-cell response equal in magnitude to the original response was generated against the variant epitope. CD8+ T cells targeting the variant epitope did not exhibit cross-reactivity against the wild-type epitope but rather utilized a distinct T-cell receptor Vβ repertoire. Additional studies of chronically HIV-1-infected individuals expressing HLA-A11 demonstrated that the majority of the subjects targeted the G357S escape variant of the Gag349-359 epitope, while the wild-type consensus sequence was significantly less frequently recognized. These data demonstrate that de novo responses against escape variants of CD8+ T-cell epitopes can be generated in chronic HIV-1 infection and provide the rationale for developing vaccines to induce CD8+ T-cell responses directed against both the wild-type and variant forms of CD8 epitopes to prevent the emergence of cytotoxic T-lymphocyte escape variants.

scholarly journals Reduced Hepatitis B Virus (HBV)-Specific CD4+ T-Cell Responses in Human Immunodeficiency Virus Type 1-HBV-Coinfected Individuals Receiving HBV-Active Antiretroviral Therapy

2005 ◽  
Vol 79 (5) ◽  
pp. 3038-3051 ◽  
Author(s):  
J. Judy Chang ◽  
Fiona Wightman ◽  
Angeline Bartholomeusz ◽  
Anna Ayres ◽  
Stephen J. Kent ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Hepatitis B Virus ◽  
T Cell ◽  
T Cell Responses ◽  
Cell Responses ◽  
B Virus ◽  
Immunodeficiency Virus ◽  
Chronic Hbv ◽  
Hiv 1

ABSTRACT Functional hepatitis B virus (HBV)-specific T cells are significantly diminished in individuals chronically infected with HBV compared to individuals with self-limiting HBV infection or those on anti-HBV therapy. In individuals infected with human immunodeficiency virus type 1 (HIV-1), coinfection with HBV is associated with an increased risk of worsening liver function following antiviral therapy and of more rapid HBV disease progression. Total HBV-specific T-cell responses in subjects with diverse genetic backgrounds were characterized by using a library of 15-mer peptides overlapping by 11 amino acids and spanning all HBV proteins. The magnitude and breadth of CD4+ and CD8+ T-cell responses to HBV in peripheral blood were examined by flow cytometry to detect gamma interferon production following stimulation with HBV peptide pools. Chronic HBV carriers (n = 34) were studied, including individuals never treated for HBV infection (n = 7), HBV-infected individuals receiving anti-HBV therapy (n = 13), and HIV-1-HBV-coinfected individuals receiving anti-HBV therapy (n = 14). CD4+ and CD8+ HBV-specific T-cell responses were more frequently detected and the CD8+ T-cell responses were of greater magnitude and breadth in subjects on anti-HBV treatment than in untreated chronic HBV carriers. There was a significant inverse correlation between detection of a HBV-specific T-cell response and HBV viral load. HBV-specific CD4+ and CD8+ T-cell responses were significantly (fivefold) reduced compared with HIV-specific responses. Although, the frequency and breadth of HBV-specific CD8+ T-cell responses were comparable in the monoinfected and HIV-1-HBV-coinfected groups, HBV-specific CD4+ T-cell responses were significantly reduced in HIV-1-HBV-coinfected individuals. Therefore, HIV-1 infection has a significant and specific effect on HBV-specific T-cell immunity.

scholarly journals Low Immune Activation despite High Levels of Pathogenic Human Immunodeficiency Virus Type 1 Results in Long-Term Asymptomatic Disease

2007 ◽  
Vol 81 (16) ◽  
pp. 8838-8842 ◽  
Author(s):  
Shailesh K. Choudhary ◽  
Nienke Vrisekoop ◽  
Christine A. Jansen ◽  
Sigrid A. Otto ◽  
Hanneke Schuitemaker ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Load ◽  
T Cell ◽  
Immune Activation ◽  
T Cell Responses ◽  
Viral Loads ◽  
Cell Responses ◽  
Immunodeficiency Virus

ABSTRACT Long-term asymptomatic human immunodeficiency virus (HIV)-infected individuals (LTA) usually have low viral load and low immune activation. To discern whether viral load or immune activation is dominant in determining progression to AIDS, we studied three exceptional LTA with high viral loads. HIV type 1 isolates from these LTA were as pathogenic as viruses from progressors in organ culture. Despite high viral loads, these LTA had low levels of proliferating and activated T cells compared to progressors, like other LTA. In contrast to those in progressors, HIV-specific CD4+ T-cell responses in these LTA were maintained. Thus, low immune activation despite a high viral load preserved HIV-specific T-cell responses and resulted in a long-term asymptomatic phenotype.

scholarly journals Multiepitopic B- and T-Cell Responses Induced in Humans by a Human Immunodeficiency Virus Type 1 Lipopeptide Vaccine

2000 ◽  
Vol 74 (4) ◽  
pp. 1694-1703 ◽  
Author(s):  
Hanne Gahéry-Ségard ◽  
Gilles Pialoux ◽  
Bénédicte Charmeteau ◽  
Sandrine Sermet ◽  
Hubert Poncelet ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Gag Proteins ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT We have attempted to develop an anti-human immunodeficiency virus (HIV) lipopeptide vaccine with several HIV-specific long peptides modified by C-terminal addition of a single palmitoyl chain. A mixture of six lipopeptides derived from regulatory or structural HIV-1 proteins (Nef, Gag, and Env) was prepared. A phase I study was conducted to evaluate immunogenicity and tolerance in lipopeptide vaccination of HIV-1-seronegative volunteers given three injections of either 100, 250, or 500 μg of each lipopeptide, with or without immunoadjuvant (QS21). This report analyzes in detail B- and T-cell responses induced by vaccination. The lipopeptide vaccine elicited strong and multiepitopic B- and T-cell responses. Vaccinated subjects produced specific immunoglobulin G antibodies that recognized the Nef and Gag proteins. After the third injection, helper CD4+-T-cell responses as well as specific cytotoxic CD8+ T cells were also obtained. These CD8+ T cells were able to recognize naturally processed viral proteins. Finally, specific gamma interferon-secreting CD8+ T cells were also detected ex vivo.

scholarly journals Detection of Antibody-Dependent Complement-Mediated Inactivation of both Autologous and Heterologous Virus in Primary Human Immunodeficiency Virus Type 1 Infection

2005 ◽  
Vol 79 (5) ◽  
pp. 2823-2830 ◽  
Author(s):  
Marlén M. I. Aasa-Chapman ◽  
Sophie Holuigue ◽  
Keith Aubin ◽  
MaiLee Wong ◽  
Nicola A. Jones ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
T Cell Responses ◽  
Igg Antibodies ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Specific CD8 T-cell responses to human immunodeficiency virus type 1 (HIV-1) are induced in primary infection and make an important contribution to the control of early viral replication. The importance of neutralizing antibodies in containing primary viremia is questioned because they usually arise much later. Nevertheless antienvelope antibodies develop simultaneously with, or even before, peak viremia. We determined whether such antibodies might control viremia by complement-mediated inactivation (CMI). In each of seven patients studied, antibodies capable of CMI appeared at or shortly after the peak in viremia, concomitantly with detection of virus-specific T-cell responses. The CMI was effective on both autologous and heterologous HIV-1 isolates. Activation of the classical pathway and direct viral lysis were at least partly responsible. Since immunoglobulin G (IgG)-antibodies triggered the CMI, specific memory B cells could also be induced by vaccination. Thus, consideration should be given to vaccination strategies that induce IgG antibodies capable of CMI.

scholarly journals Proliferative Capacity of Epitope-Specific CD8 T-Cell Responses Is Inversely Related to Viral Load in Chronic Human Immunodeficiency Virus Type 1 Infection

2006 ◽  
Vol 81 (1) ◽  
pp. 434-438 ◽  
Author(s):  
Cheryl L. Day ◽  
Photini Kiepiela ◽  
Alasdair J. Leslie ◽  
Mary van der Stok ◽  
Kriebashne Nair ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Load ◽  
T Cell ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Epitopes ◽  
Viral Control ◽  
Cell Responses ◽  
Immunodeficiency Virus

ABSTRACT The relationship between the function of human immunodeficiency virus (HIV)-specific CD8 T-cell responses and viral load has not been defined. In this study, we used a panel of major histocompatibility complex class I tetramers to examine responses to frequently targeted CD8 T-cell epitopes in a large cohort of antiretroviral-therapy-naïve HIV type 1 clade C virus-infected persons in KwaZulu Natal, South Africa. In terms of effector functions of proliferation, cytokine production, and degranulation, only proliferation showed a significant correlation with viral load. This robust inverse relationship provides an important functional correlate of viral control relevant to both vaccine design and evaluation.

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