LACK OF EVIDENCE FOR A SUPERANTIGEN IN LYMPHOCYTES FROM HIV-DISCORDANT MONOZYGOTIC TWINS

Objective: An HIV-associated superantigen (SAg) has been hypothesized. Here we test whether an SAg is functionally detectable in peripheral blood mononuclear cells (PBMC) from monozygotic twins discordant for H IV infection. Design and methods: The Vbeta selective T-cell depletion found in minor lymphocyte stimulation (Mls)-positive mice is caused b y an SAg encoded by the mouse mammary tumour virus. Mls is a locus who se gene product stimulates a mixed lymphocyte reaction (MLR) in mice s trains identical at the major histocompatibility complex locus. If an SAg is present in PBMC and/or sorted CD4+ cells from one HIV-infected monozygotic twin, it would stimulate PBMC from the corresponding healt hy monozygotic twin in an MLR. In addition, if an SAg causes Vbeta-sel ective T-cell depletion in AIDS patients, a differential proliferation to a panel of staphylococcal enterotoxins (SE) of T lymphocytes from healthy and HIV-infected monozygotic twins should become measurable. R esults: No positive MLR or significant differences in the SE-driven pr oliferation between the healthy and the HIV-infected twins were observ ed. Conclusions: Our results suggest that PBMC from the two HIV-infect ed twins do not express a functionally detectable SAg.