Subcutaneous delivery of a bacterial protease inhibitor in a vaccine formulation increases the half life of Ag inside DCs and enhances immune responses

CORIA L, IBAÑEZ A, PASQUEVICH K, CARAVAJAL M, BERGUER P, BRUNO L, RISSO G, GONZALEZ COBIELLO PL, FRANK FM, CASSATARO J.

Mar del Plata

Congreso; LXII REUNIÓN ANUAL Sociedad Argentina de Inmunología; 2014

Sociedad Argentina de Inmunología

Previous results demonstrated that a Brucella spp. protein (Bp) is a broad spectrum protease inhibitor as it can inhibit proteases present in the stomach and gut (mostly serine proteases) and also lysosomal proteases (cysteine proteases). Moreover, subcutaneous co-administration of Bp as adjuvant and ovalbumin (OVA) as model antigen (Ag) induces OVA specific IFN-γ producing CD8+T cells and cytotoxic T cells in mice. In this work we characterized the mechanism of inhibition of Bp on cysteine proteases using a specific fluorogenic substrate for cathepsin L. We have found that Bp has a competitive mechanism of inhibition of cathepsin L with an inhibition constant in the µM range. We also found that Bp increases the amount of the co-administered Ag inside Lamp2+ compartments in dendritic cells (DCs) by confocal microscopy (P