Properties of peritoneal exudate lymphocytes that mediate tuberculin delayed-type hypersensitivity and anti-tuberculosis immunity. I. The effect of cytotoxic agents.

Acute peritoneal exudates were raised in rats that had been immunized by BCG, in order to draw into the peritoneal cavity sensitized immunoblasts. The peritoneal exudate cells (PEC) were harvested 24 h after exudate induction. The ability of these cells to confer tuberculin delayed-type hypersensitivity (DTH) and anti-tuberculosis immunity upon syngeneic recipients was examined after treatment with various cytotoxic agents. The transfer of DTH and immunity was entirely unaffected by in vitro exposure of PEC to high specific activity [3H]-thymidine, 5-bromodeoxyuridine or a low dose of mitomycin C. agents that adversely affect DNA-synthetic cells. Treatment of immunized rats with vinblastine reduced the number of PEC, but the cells were able to transfer DTH and immunity. In vitro exposure of PEC to vinblastine ablated the transfer of DTH but spared immunity. A moderate dose of mitomycin C suppressed immunity but not DTH; but a high dose abolished both expressions of cell-mediated immunity. The transfer of immunity was highly susceptible to ionizing radiation whereas DTH was resistant. These results suggest that the lymphocytes mediating DTH and anti-tuberculosis immunity are not actively replicating cells.