Abstract
Herein, we tested the ability of IL-12 to enhance protection induced by recombinant Sm14 (rSm14). Mice immunization with three doses of 25
μg of rSm14 was able to induce 25% of protection in mice against challenge. However, co-administration of exogenous IL-12 enhanced protective immunity engendered by rSm14 from 25 to 42.2%. Higher levels of IgG2a and TNF-α were observed in mice immunized with rSm14 plus IL-12 compared to animals vaccinated with rSm14 alone. Regarding other cytokines, significant amounts of IFN-γ were measured in splenocyte culture supernatants of rSm14/IL-12 or rSm14 vaccinated mice and no IL-4 was detected. In an attempt to determine the role of IFN-γ and TNF-α in IL-12 induced immunity, IFN-γ and TNFR-p55 knockout mice were immunized with rSm14/IL-12 and no protection was achieved. Therefore, protection induced by rSm14/IL-12 was shown to be dependent on endogenous IFN-γ and TNF-α. Although, rSm14 immunization induced partial protection, reduction of hepatic granuloma area was only observed when IL-12 was co-administered.