Decreased T-cell proliferative response to common environmental antigens could be an indicator of early human immunodeficiency virus-mediated lymphocyte lesions.

To evaluate CD4+/CD29+ cells and their responses to different antigens in polar stages of human immunodeficiency virus (HIV) infection, we studied 26 HIV-seropositive carriers (SPCs) and 15 patients with AIDS simultaneously with 20 healthy volunteers (HVs) and 10 seronegative homosexual and bisexual men (SNH). CD3, CD4, CD29, and CD45RA phenotypes were analyzed by two-color flow cytometry. Significant depletion of CD4+ T cells and both memory (CD4+/CD29+) and naive (CD4+/CD45RA+) T-cell subsets was found among SPCs and AIDS patients compared with the numbers of such cells in the HV and SNH groups. Responses to optimal doses of Candida albicans, streptokinase, and tetanus toxoid were explored in peripheral blood mononuclear cells and CD4(+)- and CD4+/CD29(+)-enriched cell populations. In SPCs, the response to C. albicans in peripheral blood mononuclear cells showed a statistically significant diminution compared with the response of HVs (15,308 versus 35,951 cpm). In addition, a significantly reduced response to streptokinase was evident only when cell preparations were CD4+/CD29+ enriched (3,048 versus 10,367 cpm). Furthermore, the SPC group comprised seven responders to at least one antigen and seven nonresponders to any of the selected specific antigens. Absence of a response in these latter patients was independent of the absolute counts of memory and naive T-cell populations. The response to tetanus toxoid, although diminished in SPCs, was not significantly different from that in controls. Our results suggest that defective responses to common environmental antigens, unrelated to the absolute number of CD4+/CD29+ cells, is probably an early indicator of an HIV-induced lymphocyte lesion.