Influence of the human T-lymphotropic virus/lymphadenopathy-associated virus on functions of human lymphocytes: evidence for immunosuppressive effects and polyclonal B-cell activation by banded viral preparations.

The etiologic agent for the acquired immunodeficiency syndrome (AIDS) is now firmly established as the retrovirus termed the human T-lymphotropic virus type III (HTLV-III) or the lymphadenopathy-associated virus, LAV. The disease is characterized by profound and progressive loss of immunity, but molecular evidence indicates that only a few cells in peripheral blood are being productively infected with this virus. In the present study we have investigated a disrupted HTLV-III viral preparation for biologic effects on normal lymphoid cells. Relatively dilute concentrations of this preparation were found to stimulate immunoglobulin secretion by peripheral blood lymphocytes; at the same dosages, the preparation was inhibitory for the B-cell differentiation responses that are induced with other known polyclonal B-cell activators, pokeweed mitogen, Staphylococcus aureus, and Epstein-Barr virus. This preparation was also inhibitory at high concentrations for T-lymphocyte proliferative responses to phytomitogens and antigens and resulted in a reduced expression of Tac antigen on phytohemagglutinin-activated lymphocytes. Paradoxically, incubation of lymphocytes of certain healthy donors with the HTLV-III preparation alone resulted in increased expression of Tac and Leu-12 antigens. These findings show that a disrupted preparation of HTLV-III virus can mimic many of the immunologic abnormalities present in patients with HTLV-III infection. Nonviable viral proteins may be responsible for some of the immunologic perturbations that occur in HTLV-III-infected states.