Macrophages Activated as Suspension Cultures with Lymphocyte Mediators Devoid of Antigen Become Cytotoxic for Tumor Cells

Abstract

Normal peritoneal exudate cells (PEC) were activated as suspension cultures either in mediator-rich supernatants from o-chlorobenzoyl-bovine γ-globulin (OCB-BGG) stimulated lymphocytes or in antigen-free Sephadex fractions from these supernatants. After 24 hr incubation the activated macrophages showed enhanced cytotoxicity for line 1 hepatoma and were inhibited in migration. The adherent cell fractions of PEC, recovered by trypsinization from monolayers and activated by this technique, were as cytotoxic as unfractionated PEC. Lymphocyte supernatants and antigen-free fractions of the supernatants induced comparable macrophage-mediated tumor cytotoxicity. Treatment of activated macrophages with trypsin did not alter their cytotoxic capacity.