Abstract
CD4+CD8dim T cells represent a minor subset of the total CD3+ T cell population in peripheral blood. Although transient and persistent expansions of these cells have been reported in both healthy and diseased individuals, the functional properties of the CD4+CD8dim population are largely unknown. In this study, we examined antigen-specific cytokine and proliferative responses of the CD4+CD8dim subset. In whole blood cultures stimulated with the viral antigens HCMV and HIV-1, a significant fraction of the CD4+CD8dim subset exhibited cytokine expression and proliferation in response to antigen activation. Typically, the CD4+CD8dim population contained two- to eightfold higher frequencies of antigen-specific cytokine producing cells than the CD4+CD8- population. Phenotypic analysis of the cytokine expressing CD4+CD8dim population indicated that these cells are memory T cells, with a high frequency of this population expressing the cytotoxic markers CD56 and perforin. Furthermore, the CD4+CD8dim cytokine responses to CMV were shown to be MHC class II dependent. Significantly, purified CD4+CD8dim T cells were found to possess higher CMV-specific cytotoxic activity than purified CD4+CD8- T cells in a standard 51Cr-release CTL assay. Thus, CD4+CD8dim T cells appear to be MHC class II dependent, are capable of cytolytic effector activity, and are highly enriched within the CD4+ cell populations specific for HCMV and HIV-1.
Original language | English (US) |
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Pages (from-to) | 2512-2520 |
Number of pages | 9 |
Journal | European Journal of Immunology |
Volume | 31 |
Issue number | 8 |
DOIs | |
State | Published - 2001 |
Keywords
- Antigen-specific
- CTL
- Cytokine
- Flow cytometry
- Proliferation
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology