Direct cell-mediated cytotoxicity in experimental allergic encephalomyelitis.

Splenocytes from guinea pigs with experimental allergic encephalomyelitis were assayed in a short-term 51Cr release assay for cytolytic activity against target cells coated with myelin basic protein. The basic protein was attached to target cells via a concanavalin A bridge which had been complexed to the basic protein with glutaraldehyde. Cytolytic activity was detected in symptomatic animals and the activity could be boosted by culture in vitro with additional basic protein. Histone was used as a control antigen.

Chemical enhancement of tumor immunogenicity.

C57BL/6 spleen cells immunized in vitro against syngeneic methylcholanthrene-induced sarcoma cells(MC-1 cells) modified with various chemical reagents show cytotoxic activity against unmodified MC-1 cells in a short-term 51Cr release assay, whereas unmodified MC-1 cells are nonimmunogenic. The effector cells cross-react widely with many other fibroblastic and epithelioid tumors, even those that are not H-2 matched, as well as with some nonneoplastic cells. Priming mice in vivo with a hapten leads to enhanced anti-tumor cytotoxicity developed by spleen cells from these mice immunized in vitro against tumor cells modified with the same hapten. Cytotoxic activity is largely, but not completely, removed by treatment with anti-theta serum and C. The existence of suppressor cells that can inhibit an anti-tumor response is demonstrasted in in vitro immunizations of mixtures of spleen cells from normal mice and mice primed with mitomyhcin-treated tumor cells, the latter suppressing the former.