A BRUCELLA MEMBRANE PROTEIN IMPROVES THE INMUNOGENICITY OF THE CO-ADMINISTERED ANTIGEN BY INCREASING ITS HALF LIFE IN ENDOSOMAL COMPARTMENTS

LORENA M. CORIA; MARIA VICTORIA DELPINO; ANDRES E. IBAÑEZ; LAURA BRUNO; GABRIELA RISSO; PAULA BARRIONUEVO; GUILLERMO H. GIAMBARTOLOMEI; JULIANA CASSATARO

Campos do Jordao

Congreso; XXXVII Congress of the Brazilian Immunology Society; 2012

Sociedad Brasilera de Inmunologia

Introduction: In previous studies we have shown that a protein from Brucella spp. (Bp) co-administered as adjuvant increases antigen (Ag) cross-presentation by dendritic cells (DCs) and induces IFN-producing CD8+ and cytotoxic T cells. We also found that this protein has significant sequence homology with protease inhibitors from other bacteria, therefore we hypothesized that it would inhibit lysosomal proteases activities in endosomal compartments increasing the half life of the co-administered Ag thus increasing its immunogenicity. Methods and results: We analyzed the biological activity of Bp against cysteine and aspartyl proteases (cathepsins) that constitute a subset of endocytic proteases using a fluorometric assay kit (Enzcheck) which contains casein as substrate. We found that Bp inhibited partially the activity of cathepsin D, L, C, and B (p