Background and Aim: The bacterial superantigen staphylococcal enterotoxin B (SEB) is a potent inducer of anti - tumor immunity both in vitro and in vivo. In addition it is able to use as an adjuvant along with tumoral exosomes and antigens or design tumor - targeted superantigen.
Methods: The anti - tumor e ffect of SEB or biological structures containing SEB in mice with inoculated breast cancer cells (4T1) and fibrosarcoma (WEHI - 164) was examined by intravenous (IV) and sub - cutaneous injection and the sizes of the inoculated tumors, cytokine production, nec rosis, metastasis, survival time and CD4+/CD8+ T cell infiltration were determined.
Results: In the mice administered SEB a significant reduction (P < 0.05) of tumor size was observed in comparison with mice in control groups. Furthermore, in the mice admi nistered SEB showed significantly higher levels of IFN - gamma, IL - 2, TNF - α and CD4+/CD8+ T cell infiltration when compared with the other groups (P < 0.05). A significantly higher frequency of necrosis in tumor tissues was also observed in administered SEB group (P < 0.05).
Conclusion: Our present findings suggest that tumor cell death is caused by increased cytotoxic T - cell activity and cytokine levels in response to injection of SEB and that SEB may be a good option for use as a novel therapy in patients w ith breast cancer and fibrosarcoma.