Nonrandom association of cellular antigens with HTLV-III virions.

Retroviruses are known to incorporate cellular antigens as they bud from infected cells. To identify the cellular antigens that associate with the AIDS-retrovirus, we evaluated a preparation of HTLV-III antigens with a panel of monoclonal antibodies reactive with a variety of antigens expressed on the H9 T-cell line used to produce the virus. Only monoclonal antibodies that identified HLA class-II antigens, beta-2 microglobulin, and a single anti-HLA class-I antibody were reactive in an ELISA of solubilized HTLV-III virus. No reactivity was seen with 11 monoclonal antibodies to T-cell antigens or with five antibodies to determinants on HLA class-I A or B molecules. These data suggest that on H9 cells the association of budding HTLV-III virions with cellular antigens may be a nonrandom process in which some HLA antigens, particularly class-II antigens, are selectively incorporated into the viral envelope. It is possible that a selective association of HLA class II antigens with budding HTLV-III virions may also occur for T cells infected in vivo, and could have relevance for the pathogenesis of this virus.