Abstract: Superantigens, including Staphylococcal enterotoxins streptococcal pyrogenic exotoxins (SpE's), biologically active fragments and homologues thereof and fission proteins of the native superantigens, homologues and fragments, are useful agents for killing tumor cells, enhancing antitumor immunity and for treating tumors in a tumor-bearing subject. In particular, a subject having a tumor is treated with a tumoricidally effective amount of a superantigen, such as a SE or SpE, or a biologically active homologue thereof, fusion protein thereof or a fusion protein of the homologue. These agents stimulate T cells, leading to increased antitumor immunity and killing of tumor cells.

Abstract: Staphylococcal enterotoxins obtained by secretion from Staphylococcus aureus, by expression of enterotoxins in other bacteria or cells, or by chemical mutagenic treatment of Staphlococcus aureus strains are used in treatment of cancer as tumoricidal agents. Enterotoxins A, B, C, D, E and toxic shock toxin (TSST-1) can be administered via simple intravenous injection or in the form of adjuvants such as pluronic triblock copolymers. Enterotoxins may also be used ex-vivo to induce mitogenesis, enlarge and enrich a tumoricidal T-cell population. Streptococcus pyrogenic exotoxins which have structural and functional homology to the enterotoxins, are also useful in tumoricidal treatment. Chemically derivatized enterotoxins as well as synthetic or genetically prepared polypeptides having structural homology to the native enterotoxins are also useful in this application.