Influences of related retroviruses on lymphocyte functions.

The human immunodeficiency virus (HIV-1) is known to be profoundly immunosuppressive [Spickett and Dalgleish (1988) Clin. Exp. Immunol. 71, 1]. In this communication, we have studied the influences of HIV-1 (BH10), HIV-2 (LAV-2) and STLV-3 on B and T cells from healthy volunteers. B lymphocytes were found to differentiate into immunoglobulin secreting cells in response to stimulation by proteins of HIV-1 and LAV-2, but not by STLV-3. This response was obtained at protein concentrations of 0.05-0.005 micrograms/ml and was T cell dependent. IgM secretion was induced only by HIV-1 in the EBV-transformed B cell line SKW 6.4. At higher concentrations all three retroviral preparations had inhibitory influences on functions of B as well as T lymphocytes. B cell differentiation was maximally inhibited by HIV-1 and LAV-2 when these proteins were added concurrently to cultures with the polyclonal B cell activators pokeweed mitogen or Epstein-Barr virus. Tetanus antigen-specific T cell lymphoproliferation was inhibited by all retroviral proteins. These findings suggest that related retroviruses differ in their capacity to influence normal immune responses.