A Salmonella vaccine as an antitumor therapy

VENDRELL A; GRAVISACO M; RODRIGUEZ C; HERSCHLIK L; MONGINI C; WALDNER C

Congreso; 14th International Congress of Immunology; 2010

The International Society of Immunology

We have previously demonstrated the anticancer properties of an attenuated Salmonella Typhi vaccine strain against an aggressive mammary adenocarcinoma murine model. The aim of this study is to evaluate the immunotherapeutic efficacy of Salmonella for the treatment of established tumors of different histological origin (T cell Lymphoma). To this end, mice bearing a subcutaneous tumor were immunized twice with S. Typhi, by injection into the tumor and in the draining lymph node areas. Our results showed that Salmonella was able to significantly reduce the tumor growth as early as 5 days after the first treatment; the mean tumor volume of the bacteria-treated mice is about 30% of the mean volume of control ones (p<0.01). The reduction in tumor volume correlated with a decrease in the average weight of the tumors [0.35 g (treated) vs 0.83 g (control), p<0.01].  Moreover, this treatment resulted in a significant increase in survival time compared with controls (p<0.05). Salmonella immunization induced T and B lymphocyte expansion in tumor draining lymph nodes 7 days after the treatment (p<0.05). The results observed in Nude mice suggest that T cells could be involved in the increase of survival time, whereas tumor reduction seems to be T cell independent. Our results illustrate the potential usefulness of S. Typhi as a therapy against highly malignant tumors able to induce host antitumor effect to control tumor growth. This bacteria therapy represents a novel approach that could be used in the treatment of different cancers