scholarly journals Naturally processed viral peptides recognized by cytotoxic T lymphocytes on cells chronically infected by human immunodeficiency virus type 1.

1994 ◽  
Vol 180 (4) ◽  
pp. 1283-1293 ◽  
Author(s):  
T J Tsomides ◽  
A Aldovini ◽  
R P Johnson ◽  
B D Walker ◽  
R A Young ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Cell Lines ◽  
Cytotoxic T Lymphocytes ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Hiv 1

We have established long-term cultures of several cell lines stably and uniformly expressing human immunodeficiency virus type 1 (HIV-1) in order to (a) identify naturally processed HIV-1 peptides recognized by cytotoxic T lymphocytes (CTL) from HIV-1-seropositive individuals and (b) consider the hypothesis that naturally occurring epitope densities on HIV-infected cells may limit their lysis by CTL. Each of two A2-restricted CD8+ CTL specific for HIV-1 gag or reverse transcriptase (RT) recognized a single naturally processed HIV-1 peptide in trifluoroacetic acid (TFA) extracts of infected cells: gag 77-85 (SLYNTVATL) or RT 476-484 (ILKEPVHGV). Both processed peptides match the synthetic peptides that are optimally active in cytotoxicity assays and have the consensus motif described for A2-associated peptides. Their abundances were approximately 400 and approximately 12 molecules per infected Jurkat-A2 cell, respectively. Other synthetic HIV-1 peptides active at subnanomolar concentrations were not present in infected cells. Except for the antigen processing mutant line T2, HIV-infected HLA-A2+ cell lines were specifically lysed by both A2-restricted CTL, although infected Jurkat-A2 cells were lysed more poorly by RT-specific CTL than by gag-specific CTL, suggesting that low cell surface density of a natural peptide may limit the effectiveness of some HIV-specific CTL despite their vigorous activity against synthetic peptide-treated target cells.

scholarly journals Inhibition of Human Immunodeficiency Virus Type 1 Replication in Primary CD4+ T Lymphocytes, Monocytes, and Dendritic Cells by Cytotoxic T Lymphocytes

2000 ◽  
Vol 74 (14) ◽  
pp. 6695-6699 ◽  
Author(s):  
Michael E. Severino ◽  
Nikolaos V. Sipsas ◽  
Phuong Thi Nguyen ◽  
Spyros A. Kalams ◽  
Bruce D. Walker ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Dendritic Cells ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Inhibition ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT We demonstrate that human immunodeficiency virus type 1 (HIV-1)-specific CD8+ cytotoxic T lymphocytes (CTL) suppress HIV-1 replication in primary lymphocytes, monocytes, and dendritic cells individually. Viral inhibition is significantly diminished in lymphocyte-dendritic cell clusters, suggesting that these clusters in vivo could be sites where viral replication is more difficult to control by CTL.

scholarly journals Comparative clonal analysis of human immunodeficiency virus type 1 (HIV-1)-specific CD4+ and CD8+ cytolytic T lymphocytes isolated from seronegative humans immunized with candidate HIV-1 vaccines.

1992 ◽  
Vol 176 (6) ◽  
pp. 1531-1542 ◽  
Author(s):  
S A Hammond ◽  
R C Bollinger ◽  
P E Stanhope ◽  
T C Quinn ◽  
D Schwartz ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cytolytic T Lymphocytes ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Hiv 1

The lysis of infected host cells by virus-specific cytolytic T lymphocytes (CTL) is an important factor in host resistance to viral infection. An optimal vaccine against human immunodeficiency virus type 1 (HIV-1) would elicit virus-specific CTL as well as neutralizing antibodies. The induction by a vaccine of HIV-1-specific CD8+ CTL in humans has not been previously reported. In this study, CTL responses were evaluated in HIV-1-seronegative human volunteers participating in a phase I acquired immune deficiency syndrome (AIDS) vaccine trial involving a novel vaccine regimen. Volunteers received an initial immunization with a live recombinant vaccinia virus vector carrying the HIV-1 env gene and a subsequent boost with purified env protein. An exceptionally strong env-specific CTL response was detected in one of two vaccine recipients, while modest but significant env-specific CTL activity was present in the second vaccinee. Cloning of the responding CTL gave both CD4+ and CD8+ env-specific CTL clones, permitting a detailed comparison of critical functional properties of these two types of CTL. In particular, the potential antiviral effects of these CTL were evaluated in an in vitro system involving HIV-1 infection of cultures of normal autologous CD4+ lymphoblasts. At extremely low effector-to-target ratios, vaccine-induced CD8+ CTL clones lysed productively infected cells present within these cultures. When tested for lytic activity against target cells expressing the HIV-1 env gene, CD8+ CTL were 3-10-fold more active on a per cell basis than CD4+ CTL. However, when tested against autologous CD4+ lymphoblasts acutely infected with HIV-1, CD4+ clones lysed a much higher fraction of the target cell population than did CD8+ CTL. CD4+ CTL were shown to recognize not only the infected cells within these acutely infected cultures but also noninfected CD4+ T cells that had passively taken up gp120 shed from infected cells and/or free virions. These results were confirmed in studies in which CD4+ lymphoblasts were exposed to recombinant gp120 and used as targets for gp120-specific CD4+ and CD8+ CTL clones. gp120-pulsed, noninfected targets were lysed in an antigen-specific fashion by CD4+ but not CD8+ CTL clones. Taken together, these observations demonstrate that in an in vitro HIV-1 infection, sufficient amounts of gp120 antigen are produced and shed by infected cells to enable uptake by cells that are not yet infected, resulting in the lysis of these noninfected cells by gp120-specific, CD4+ CTL.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Silencing of both β-TrCP1 and HOS (β-TrCP2) Is Required To Suppress Human Immunodeficiency Virus Type 1 Vpu-Mediated CD4 Down-Modulation

2006 ◽  
Vol 81 (3) ◽  
pp. 1502-1505 ◽  
Author(s):  
Christophe Butticaz ◽  
Olivier Michielin ◽  
Josiane Wyniger ◽  
Amalio Telenti ◽  
Sylvia Rothenberger
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Lines ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
The Individual ◽  
Endoplasmic Reticula ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) Vpu protein interacts with CD4 within the endoplasmic reticula of infected cells and targets CD4 for degradation through interaction with β-TrCP1. Mammals possess a homologue of β-TrCP1, HOS, which is also named β-TrCP2. We show by coimmunoprecipitation experiments that β-TrCP2 binds Vpu and is able to induce CD4 down-modulation as efficiently as β-TrCP1. In two different cell lines, HeLa CD4+ and Jurkat, Vpu-mediated CD4 down-modulation could not be reversed through the individual silencing of endogenous β-TrCP1 or β-TrCP2 but instead required the two genes to be silenced simultaneously.

scholarly journals Differential Impairment of Lytic and Cytokine Functions in Senescent Human Immunodeficiency Virus Type 1-Specific Cytotoxic T Lymphocytes

2003 ◽  
Vol 77 (5) ◽  
pp. 3077-3083 ◽  
Author(s):  
Mirabelle Dagarag ◽  
Hwee Ng ◽  
Rachel Lubong ◽  
Rita B. Effros ◽  
Otto O. Yang
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Antigenic Specificity ◽  
Immunodeficiency Virus ◽  
The Impact ◽  
Hiv 1

ABSTRACT Telomere length is abnormally short in the CD8+ T-cell compartment of human immunodeficiency virus type 1 (HIV-1)-infected persons, likely because of chronic cell turnover. Although clonal exhaustion of CD8+ cytotoxic T lymphocytes (CTL) has been proposed as a mechanism for loss of antigen-specific responses, the functional consequences of exhaustion are poorly understood. Here we used telomerase transduction to evaluate the impact of senescence on CTL effector functions. Constitutive expression of telomerase in an HIV-1-specific CTL clone results in enhanced proliferative capacity, in agreement with prior studies of other human cell types. Whereas the CTL remain phenotypically normal in terms of antigenic specificity and requirements for proliferation, their cytolytic and antiviral capabilities are superior to those of control CTL. In contrast, their ability to produce gamma interferon and RANTES is essentially unchanged. The selective enhancement of cytolytic function in memory CTL by ectopic telomerase expression implies that loss of this function (but not cytokine production) is a specific consequence of replicative senescence. These data suggest a unifying mechanism for the in vivo observations that telomere lengths are shortened in the CD8+ cells of HIV-1-infected persons and that HIV-1-specific CTL are deficient in perforin. Telomerase transduction could therefore be a tool with which to explore a potential therapeutic approach to an important pathophysiologic process of immune dysfunction in chronic viral infection.

scholarly journals Virus-Specific Cytotoxic T Lymphocytes in Human Immunodeficiency Virus Type 1-Infected Chimpanzees

1999 ◽  
Vol 73 (8) ◽  
pp. 7065-7069 ◽  
Author(s):  
Sampa Santra ◽  
Patricia N. Fultz ◽  
Norman L. Letvin
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mononuclear Cells ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Chimpanzees have been important in studies of human immunodeficiency virus type 1 (HIV-1) pathogenesis and in evaluation of HIV-1 candidate vaccines. However, little information is available about HIV-1-specific cytotoxic T lymphocytes (CTL) in these animals. In the present study, in vitro stimulation of peripheral blood mononuclear cells (PBMC) from infected chimpanzees with HIV-1 Gag peptides was shown to be a sensitive, reproducible method of expanding HIV-1-specific CD8+ effector CTL. Of interest, PBMC from two chimpanzees had CTL activity against Gag epitopes also recognized by major histocompatibility complex class I-restricted CTL from HIV-1-infected humans. The use of peptide stimulation will help to clarify the role of CTL in vaccine-mediated protection and HIV-1 disease progression in this important animal model.

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