In vitro activation of T lymphocytes from human immunodeficiency virus (HIV)-seropositive blood donors. I. Soluble interleukin 2 receptor (IL2R) production parallels cellular IL2R expression and DNA synthesis.

We investigated the relationship of soluble interleukin 2 receptor (sIL2R) production to cellular IL2R expression and DNA synthesis by mitogen-stimulated mononuclear cells from blood donors seropositive for human immunodeficiency virus (HIV). SIL2R was measured using an enzyme-linked immunosorbent assay which employed 2 anti-IL2R monoclonal antibodies recognizing distinct IL2R epitopes. Decreased phytohemagglutinin-induced DNA synthesis and cellular IL2R expression were accompanied by decreased levels of sIL2R in cell culture supernatants. Similar findings were observed for pokeweed mitogen-induced responses. There was no detectable spontaneous secretion of sIL2R into culture supernatants by unstimulated mononuclear cells from either HIV-seropositive or control seronegative donors. These findings indicate that the in vitro T-cell activation defects which characterize HIV infection include decreased sIL2R production, as well as decreased cellular IL2R expression and DNA synthesis. Further, they show that assessment of supernatant sIL2R levels can be used as a valid, reliable assay for T-cell activation.