Contribution of alpha interferon (alpha IFN) to HIV-induced immunosuppression.

In the present investigation we have shown that PBLs taken from HIV-positive patients suppressed T-cell proliferation when cultured for at least 12 days. When infected In vitro with HIV-1, these cells become suppressive after 6 days. PBLs collected from seronegative individuals turned out to be non-suppressive even after prolonged culturing. However, when infected in vitro with HIV they were found to be cytostatic also after 6 days. This anti-immune activity, related to HIV infection, is mediated, at least in part, by alpha IFN, since about 50% of this HIV associated activity could be quenched by alpha IFN antibodies. We also showed that this T-cell cytostasis is associated with CD8+ cells. In view of a possible use of suppressive cells for T-cell vaccination, we verified that such cellular functions were abolished by aldehyde treatment.