Antigenic content of an in vitro cellular immunity reactive cell surface extract of Raji cells.

Antigenic content of a Raji cell surface extract (TS) was studied by sequential abosrption of rabbit antiserum to this extract with different cells. Anti-TS was first allowed to react exhaustively with human blood cells followed by HeLa cells and human diploid fibroblasts. The residual reactivity was studied by stepwise absorption with an EBV-negative B lymphoblastoid cell line, BJAB, and then with B1--19, a clone derived from EBV transformed BJAB cells. These processes delineated three kinds of reactivities in anti-TS having specificities for antigens on B blasts, EBV-determined cell surface antigen(s) and antigens that are exclusive to Raji cells, respectively. These results are compatible with the heterogeneous protein content of TS and with the results of our earlier in vitro cell-mediated immunity studies using a similar preparation of Raji cell TS.