OMP16 coadministered as a mucosal adjuvant induces a Th1 immune response

A. E. IBAÑEZ, L. M. CORIA, K. A. PASQUEVICH, G. H. GIAMBARTOLOMEI, J. CASSATARO

Viña del Mar, Chile.

Congreso; 9th Latin American Congress of Immunology; 2009

Previous results demonstrated that the protein moiety of the Brucella Omp16 lipoprotein (Omp16S) administered by the oral route has self-adjuvanting properties. This prompts us to study its mucosal adjuvant capacity using as a model antigen ovalbumin (OVA) by two different mucosal routes: oral and nasal. For this purpose mice were immunized orally with OVA, Omp16S+OVA, or choleric toxin (CT)+OVA. By flow cytometry we determined that the percentage of CD8+ T cells expressing alpha4beta7 integrin increased in mesenteric lymph nodes from Omp16S+OVA (4.53%) and CT+OVA (16.43%) in comparison with OVA (1.64%) immunized group. We also observed a significant (P<0.01) delayed type hypersensitivity (DTH) response to OVA injection in Omp16S+OVA and CT+OVA while OVA group did not. Similarly, splenocytes from mice immunized intranasally with Omp16S+OVA or CT+OVA secreted IFN- but not IL-4 in response to OVA stimulation in vitro. By flow cytometry we determined that the percentage of CD4+ and CD8+ T ells producing intracellular IFN- increased in Omp16S+OVA (0.97%; 1.08%) in comparison with CT+OVA (0.28%; 0.22%) and OVA (0.23%; 0.47%). In conclusion, Omp16S as mucosal adjuvant induce the migration of CD8+ T cells to gastrointestinal mucosa. ,