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High-level HIV-1 viremia suppresses viral antigen-specific CD4(+) T cell proliferation.

ABSTRACT: In chronic viral infections of humans and experimental animals, virus-specific CD4(+) T cell function is believed to be critical for induction and maintenance of host immunity that mediates effective restriction of viral replication. Because in vitro proliferation of HIV-specific memory CD4(+) T cells is only rarely demonstrable in HIV-infected individuals, it is presumed that HIV-specific CD4(+) T cells are killed upon encountering the virus, and maintenance of CD4(+) T cell responses in some patients causes the restriction of virus replication. In this study, proliferative responses were absent in patients with poorly restricted virus replication although HIV-specific CD4(+) T cells capable of producing IFN-gamma were detected. In a separate cohort, interruption of antiretroviral therapy resulted in the rapid and complete abrogation of virus-specific proliferation although HIV-1-specific CD4(+) T cells were present. HIV-specific proliferation returned when therapy was resumed and virus replication was controlled. Further, HIV-specific CD4(+) T cells of viremic patients could be induced to proliferate in response to HIV antigens when costimulation was provided by anti-CD28 antibody in vitro. Thus, HIV-1-specific CD4(+) T cells persist but remain poorly responsive (produce IFN-gamma but do not proliferate) in viremic patients. Unrestricted virus replication causes diminished proliferation of virus-specific CD4(+) T cells. Suppression of proliferation of HIV-specific CD4(+) T cells in the context of high levels of antigen may be a mechanism by which HIV or other persistently replicating viruses limit the precursor frequency of virus-specific CD4(+) T cells and disrupt the development of effective virus-specific immune responses.

SUBMITTER: McNeil AC

PROVIDER: S-EPMC61135 | biostudies-literature | 2001 Nov

REPOSITORIES: biostudies-literature

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High-level HIV-1 viremia suppresses viral antigen-specific CD4(+) T cell proliferation.

McNeil A C AC Shupert W L WL Iyasere C A CA Hallahan C W CW Mican J A JA Davey R T RT Connors M M

Proceedings of the National Academy of Sciences of the United States of America 20011101 24

In chronic viral infections of humans and experimental animals, virus-specific CD4(+) T cell function is believed to be critical for induction and maintenance of host immunity that mediates effective restriction of viral replication. Because in vitro proliferation of HIV-specific memory CD4(+) T cells is only rarely demonstrable in HIV-infected individuals, it is presumed that HIV-specific CD4(+) T cells are killed upon encountering the virus, and maintenance of CD4(+) T cell responses in some p ...[more]

PMID: 11717444

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Project description:UnlabelledCD4+ 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.ImportanceThe 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 important for our understanding of HIV immunopathology.

Project description:CD8+ and CD4+ T cells from HIV infected patients with HIV-RNA viremia of >50 copies/ml and CD8+ and CD4+ T cells from healthy controls were isolated by negative selection (Miltenyi Biotech, Auburn, CA). Cell sorting of the CD4 and CD8 T cell subsets were performed based on surface staining of CD3+CD8+ or CD3+CD4+ and na ve CD45RA+CD27+CD127highHLA-DRlow, and CD3+CD8+ or CD3+CD4+ and memory CD45RA-CD27+CD127highHLA-DRlow. Sorted cell populations were spun down and stored as dry pellets at -80M-BM-0C. Samples analyzed by transcript levels of genes related to cytokine signaling were determined by the JAK/STAT Signaling Pathway microarray. CD8+ and CD4+ T cells from HIV infected patients with HIV-RNA viremia of >50 copies/ml and CD8+ and CD4+ T cells from healthy controls were isolated by negative selection (Miltenyi Biotech, Auburn, CA). Cell sorting of the CD4 and CD8 T cell subsets were performed based on surface staining of CD3+CD8+ or CD3+CD4+ and naM-CM-/ve CD45RA+CD27+CD127highHLA-DRlow, and CD3+CD8+ or CD3+CD4+ and memory CD45RA-CD27+CD127highHLA-DRlow. Sorted cell populations were spun down and stored as dry pellets at -80M-BM-0C. Samples analyzed by transcript levels of genes related to cytokine signaling were determined by the JAK/STAT Signaling Pathway microarray (http://www.sabiosciences.com/rt_pcr_product/HTML/PAHS-039A.html, SABiosciences Frederick, MD). Briefly, total RNA was harvested from each individual T cell subset from each patient or healthy control and contaminating DNA was digested with DNase. Messenger RNA was converted to cDNA and loaded onto PCR array plates for quantitative real-time PCR. Quantification of transcript levels was determined by normalizing to 5 housekeeping genes from each individual sample. Relative gene expression levels for each subset were averaged and compared between cell populations from the patient group and healthy controls. Because of the multiple comparisons only p values M-bM-^IM-$ 0.01 were considered significant.

Dataset Information

High-level HIV-1 viremia suppresses viral antigen-specific CD4(+) T cell proliferation.

Publications

High-level HIV-1 viremia suppresses viral antigen-specific CD4(+) T cell proliferation.

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