Surface phenotype of nonadherent peritoneal cells effecting cell-mediated cytotoxicity in vitro for allogeneic and syngeneic murine sarcoma cells.

The participation of B cells in cell-mediated cytotoxicity (CMC) for allogeneic and syngeneic murine sarcoma cells induced with 3-methylcholanthrene was investigated. Primed nonadherent peritoneal cells (NAPC) were treated with antisera against lymphocyte surface antigens and complement, and residual CMC activity was measured with the [3H]proline microassay. The antisera (anti-PC.1 and various anti-Ig sera) used for this purpose were highly reactive with B cells according to established serologic criteria. Elimination of cells that carried PC.1 or Ig on their surface did not diminish CMC of NAPC for allogeneic or syngeneic tumor cells. Exposure of cytotoxic NAPC to various anti-Ig antisera (without complement) before and during the CMC assay did not inhibit CMC either. We conclude that under these conditions CMC is not mediated by B cells, nor is it dependent on their presence. In addition, our findings do not implicate any of the usual classes and types of Ig covered by the Ig antisera used in this study as constituting specific receptors on the effector T cells of CMC.