Attenuated Salmonella as adjuvant in cancer vaccines

VENDRELL A; DI SCIULLO P; GRAVISACO MJ; COLMAN E; RIZZO N; MONGINI C; WALDNER C

Tandil, Argentina

Congreso; XL Reunión Anual de la Sociedad Argentina de Farmacología Experimental; 2008

Sociedad Argentina de Farmacología Experimental

The role of innate immunity in stimulating adaptive immune responses is the basis of the action of adjuvants which are useful in clinical vaccines by promoting nonspecific proinflammatory response to elicit specific host defense. Based on previous studies that demonstrated the ability of Salmonella to elicit an inflammatory Th1 response when it is inoculated by mucosal route, we propose to study the use of an attenuated Salmonella strain as an adjuvant in cancer vaccines to stimulate the innate and modulate the adaptive immune response against tumors. Two times at seven days intervals BALB/c mice were immunized via the orogastric route with 2x10e9 UFC of CVD915 or PBS (control) using a gavage tube needle, and simultaneously, 1x10e6 irradiated LBC tumor cells (LBCi) or PBS were inoculated by intraperitoneal (i.p) injection. Seven days after the second immunization, all groups of animals were challenged i.p with wild-type LBC cells. Mice immunized with bacteria simultaneously with LBCi display a significant increase in the medium survival time respect to PBS-treated mice (p<0.05, Log rank test). Our findings suggest that immunization with Salmonella in combination with irradiated tumor cells could be a useful strategy for prophylactic vaccination that merits further studies to prove its potential in cancer vaccines.