THE INTERLEUKIN-2 RECEPTOR SUBUNIT EXPRESSION AND FUNCTION ON PERIPHERAL-BLOOD LYMPHOCYTES FROM HIV-INFECTED AND CONTROL PERSONS

The expression of interleukin-2 receptor (IL2R) was studied on circula ting lymphocytes from HIV-infected (HIV+) and control subjects, using chain-specific monoclonal antibodies and indirect immunofluorescence f low cytometry. The IL2R alpha chain expression was decreased on CD4 an d CD8 T cells from HIV+ persons compared to controls. Conversely, beta chain expression was enhanced on both T cell subsets from the patient s. IL2R-subunit levels were similar on natural killer cells from patie nts and controls. To evaluate the function of IL2R, we investigated to what extent IL2 could induce CD69, an early activation marker of lymp hocytes. A dose-dependent increase of CD69 expression was observed on T and NK cells from all subjects. The upregulation of CD69 was similar on CD4 T and NK cells from patients and controls, but was more pronou nced on CD8 T cells from HIV+ compared to HIV- subjects. Based on inhi bition studies, both the alpha and the beta chain contributed to the I L-2-induced CD69 expression on CD4 T cells, pointing to involvement of the high-affinity receptor. The early activation of CD8 T cells and N K cells was mainly dependent on the intermediate-affinity receptor. We conclude that significant changes in IL2R alpha and beta chain expres sion on circulating T cells occur after HIV infection, but that early activation through IL2 is preserved or enhanced, even in advanced stag es. (C) 1994 Academic Press, Inc.