Soluble factors inhibitory for T-cell-dependent immune responses in patients with the acquired immune deficiency syndrome and its prodromes.

Supernatants from PBMC obtained from certain patients with AIDS or its prodrome were capable of depressing pokeweed mitogen-driven immunoglobulin production and the proliferative response of T cells to specific antigen. These soluble suppressor factors (SSF) were present in uniquely high concentrations, and were the product of an interaction of T lymphocytes with adherent cells. T-cell independent functions were not modified by soluble suppressor factors. Restoration of immunoglobulin synthesis in SSF-treated cultures was realized by addition of reducing agents such as 2-mercaptoethanol, suggesting inhibitory mechanisms possibly related to that of Con A-induced soluble immune response suppression, and perhaps offering clues to clinically applicable substances capable of modifying such responses. A relationship between SSF-AIDS and a human retrovirus LAV/HTLV III, linked etiologically to AIDS and its prodromes, is suggested by studies of SSF-like substances released by human T-T cell hybridomas derived from LAV+ patients.