ANTIBODIES TO HUMAN AND NONHUMAN PRIMATE CELLULAR AND CULTURE-MEDIUM COMPONENTS IN MACAQUES VACCINATED WITH THE SIMIAN IMMUNODEFICIENCY VIRUS

Inactivated simian immunodeficiency virus (SIV) grown in a human T-cel l line induces protection from infection by the virus in macaques. How ever, observations that immunization with uninfected human T cells or with SIV-1 prepared in human T cells can also induce protection, has r aised the possibility that protective antigens could be of human cellu lar origin. Sera from animals immunized with fixed infected and uninfe cted human T cells, as well as from animals immunized with partially p urified cell-free SIV have been examined for their ability to bind to human and macaque peripheral blood mononuclear cells (PBMC) and to com ponents present in fetal calf serum (FCS) in which the cells were grow n. Analysis by how cytometry suggests that antibodies to human cell su rface antigens can be elicited with both inactivated SIV grown in huma n T cells and by uninfected T cells. There was a significant associati on between the presence of anti-cell antibodies and protection from in fection. However, anti-cell surface antibodies were not detected with macaque mononuclear cells by how cytometry or by immunoprecipitation, unless these cells were first treated with FCS or activated by a mitog en. Immunoprecipitation of resting human PBMC with sera from immunized animals suggests the presence of antibodies to class I heavy and ligh t chains [beta(2)-microglobulin (beta(2)m)] and to bovine beta(2)m, wh ich may originate in FCS used to grow the cell line. Antibodies to CD4 were also found in sera from animals immunized with SIV grown in huma n T cells. We suggest that human cellular components augmented by FCS elicit anti-class I heavy chain, beta(2)m, CD3 and FCS antibodies whic h may be responsible for protection against SIV infection in macaques.