BRUCELLA ABORTUS U-OMP19 IMPROVES THE IMMUNE RESPONSE AND PROTECTIVE CAPACITY OF ENTEROTOXIGENIC ESCHERICHIA COLI (ETEC) ANTIGENS

FRANCO LUIS MARTINEZ; CORIA, LORENA M.; LAURA BRUNO; KARINA ALEJANDRA PASQUEVICH; DARRIBA, MARÍA L.; CARABAJAL, MARIANELA V.; TIM VICKERS; JAMES FLECKENSTEIN; JULIANA CASSATARO

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017; 2017

Sociedades Biocientíficas. Sociedad Argentina de Inmunología.

Enterotoxigenic E. coli (ETEC) is the most common cause of bacterial diarrhea both among children in developing countries and in travelers to these regions. Both naturally acquired infection and oral-mucosal vaccination against ETEC enterotoxins, colonization factors or adhesins can induce protective immunity. EtpA, an extracellular ETEC adhesin, is a novel antigen (Ag) with immunogenic and protective capacity found recently. We propose to use a bacterial protease inhibitor, U-Omp19 from Brucella abortus, as platform to deliver antigens in oral formulations against infectious diseases since this protein can protect antigens (Ags) from digestion and it can also trigger and direct the type of immune responses. Thus in this work our aim was to investigate the effect of U-Omp19 co-delivery on EtpA immunogenicity and protective efficacy. To this end inbread BALB/c and outbread CD1 mice were orally immunized with i) saline ii) EtpA iii) EtpA+Omp19 iv) EtpA+dmLT or v) EtpA+dmLT+Omp19. Different doses of EtpA were studied alone or plus adjuvants. Fecal and serum anti-EtpA and anti-LT antibodies (Abs) were evaluated by ELISA. Cellular immune responses or the protective capacity of formulations against oral challenge with ETEC H10407 were also evaluated. Results obtained indicated that U-Omp19 co-delivery increased mucosal anti-EtpA or anti-LT Abs (IgA in fecal extracts) and induced EtpA-specific IgA and IgG producing memory B cells in bone marrows. U-Omp19 improved Ag-specific IFN-γ and IL-17 response in spleens (P