Strain specificity of cell-mediated cytotoxic responses specific for the human immunodeficiency virus type 1 (HIV-1) envelope protein in seropositive donors: HIV-1Lai is more commonly recognized than HIV-1MN.

ABSTRACT

Cell-mediated cytotoxic (CMC) responses were measured in a group of human immunodeficiency virus type 1 (HIV-1)-seropositive donors against target cells expressing the envelope protein of either the HIV-1 strain Lai or strain MN. In primary CMC assays using freshly isolated peripheral blood mononuclear cells, seropositive individuals more commonly had CMC responses against HIV-1Lai than HIV-1MN. Moreover, each of the responders to HIV-1MN envelope also had primary CMC responses against HIV-1Lai 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 populations 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 capable of recognizing the V3 loop of HIV-1MN but rarely that of HIV-1Lai.