CONICET | Buscador de Institutos y Recursos Humanos

In previous studies we have shown that the protein moiety of Omp19 from Brucella spp.(Omp19S) as adjuvant induces CD4+ T cell responses. In this study, we evaluate the adjuvant capacity on CD8+ T cell responses using chicken ovoalbumin (OVA) as an antigen model. C57BL/6 mice were adoptively transferred with CFSE- labeled OT-1 T cells, which recognize a class I epitope of OVA. One day later they were immunized s.c. with OVA coadministered with: Omp19S, Omp19SPK (digested with Proteinase K), LPS or PBS. Immunization with Omp19S as adjuvant induced greater OT-I cell proliferation (CFSE dilution) than immunization with OVA without adjuvant or OVA+Omp19SPK, and similar to the control LPS group. Moreover, the percentage of OVA-specific IFN-g producing CD8+ T cells was significantly enhanced in the OVA+Omp19S (0.73%) than in the OVA group (0.14%). Whereas immunization with OVA+Omp19SPK failed to induce IFN-g producing CD8+ T cells, confirming that the adjuvant capacity resides in the protein. In conclusion, we demonstrate that Omp19S co administered adjuvant facilitates antigen cross-presentation and induces IFN-g producing CD8+ T cells.