STRAIN SPECIFICITY OF CELL-MEDIATED CYTOTOXIC RESPONSES SPECIFIC FOR THE HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1) ENVELOPE PROTEIN IN SEROPOSITIVE DONORS - HIV-1(LAI) IS MORE COMMONLY RECOGNIZED THAN HIV-1(MN)

Cell-mediated cytotoxic (CMC) responses were measured in a group of hu man immunodeficiency virus type 1 (HIV-1)-seropositive donors against target cells expressing the envelope protein of either the HIV-1 strai n Lai or strain MN. In primary CMC assays using freshly isolated perip heral blood mononuclear cells, seropositive individuals more commonly had CMC responses against HIV-1(Lai) than HIV-1(MN). Moreover, each of the responders to HIV-1(MN) envelope also had primary CMC responses a gainst HIV-1(Lai) envelope. Cytotoxic T cells generated by nonspecific in vitro stimulation recognized both strains at a similar frequency. These results may indicate the existence of multiple effector populati ons or that the cellular immune response is directed at regions of the envelope outside the V3 loop. By contrast, serologic studies done on similar populations have shown that most persons have antibodies capab le of recognizing the V3 loop of HIV-1(MN) but rarely that of HIV-1(La i).