Mechanism of the local antitumor action of inflammation.

Some but not all tumor cells are killed in the environment of a delayed hypersensitivity reaction (DHSR) induced by antigens unrelated to the tumor. Of the several cytotoxic components, cellular and humoral, which are present at the site of a DHSR, a lymphokine released by the interaction of specific antigen with immune T cells-presumptively lymphotoxin-was shown to be responsible for the antitumor action of DHSR. The same mechanism may account for the failure of some tumor cells to grow when inoculated in admixture with BCG.