Enhancement in immunity of tumor bearing mice by immunization against prostaglandin E2.

C57Bl/6 mice bearing a palpable Lewis lung carcinoma (LLC) were immunized against prostaglandin E2 (PGE2) in order to prevent the immune suppression typical of tumor bearers. Proliferation in response to concanavalin A (Con A) by normal spleen cells cultured in the presence of PGE2 or by spleen cells of LLC-bearing mice cultured with Con A alone was suppressed. However, the mitogenic response of spleen cells from PGE2 immunized LLC-bearing mice was only partially suppressed. The random migration of normal macrophages cultured in the presence of PGE2 or of macrophages from LLC-bearing mice cultured in medium alone was enhanced when compared to the random migration of normal macrophages cultured in the absence of PGE2. In contrast, the random migration of macrophages obtained from PGE2 immunized LLC-bearing mice was the same as that of normal macrophages cultured in the absence of PGE2.