Staphylococcal Enterotoxin B Attenuates the Tumorigenic Properties of Texosomes as a Candidate forBreast Cancer Immunotherapy

Exosomes, as an acellular vehicles, could be used for cancer immunotherapy owning to theirimmune inducing properties. A novel bipartite structure made up exosomes andstaphylococcal enterotoxin B (SEB) showed cytostatic impacts on various types of tumorcells in vitro. It is suggested that it can be a proper candidate in tumor immunotherapy. In thecurrent study, we perposed to evaluate its antitumor immune responses in a murine tumormodel. Materials&Methods: SEB was anchored onto isolated exosomes from breast tumorcells ( named the exosome/SEB) and was administered for immunization of mice beforebeing challenged with 4T1 cells. Tumor size, survival time, necrosis, metastasis rate, and thelevel of Il-2, IL-4, IL-17, IL-12, TNF-α and IFN-γ were assessed. Results: Immunization of themice with the exosome/SEB gave rise the stimulation index of lymphocytes significantlycompared with the PBS (p<0.01). Additionally, the release of TNF-α, IL-2 and IFN-γsignificantly augmented from purified splenocytes of the mice immunized by theexosome/SEB, in comparison PBS (p<0.05). In contrast, The IL-17 and IFN- γ levelsignificantly decreased after the exosome/SEB immunization (p<0.05). In tumor tissues, nosignificant differences were seen in the level of IL-12, IL-4 and TNF-α between theexosome/SEB immunized group and negative control group. Although the exosome/SEBimmunization relatively prolonged the survival of the mice, it showed no inhibitory effect ontumor size. Pathologic manifestations viewed the significant increase of necrosis afterimmunization with the exosome/SEB compared to the negative control group (p<0.01).Conclusion: Overall, our data suggest that the presence of SEB attenuates the tumorigenesisupsets of exosome and enhance the antitumor immunity.

کلیدواژه ها:

Exosome ، Breast Cancer ، Staphylococcal Entorotoxin B ، Immunotherapy ، Exosome Display