Preservation of protective effects of hyperimmune anti-Stx2 bovine colostrum against EHEC O157:H7 pathogenicity after pasteurization and spray-drying procedures.

DIAZ VERGARA LADISLAO; SODERO SONIA; AMARAL MARÍA MARTA; MONTENEGRO MARIANA; CATALDI ANGEL; KIM ANDREA; BERNAL ALAN MAURO; LESPINARD ALEJANDRO; PALERMO MARINA S; IBARRA CRISTINA; GARIMANO NICOLÁS; BADIM EMILIANO; GONZALEZ DIEGO; PORPORATTO CARINA; LARZABAL MARIANO; SACERDOTI FLAVIA

Congreso; Reunión de las Sociedades de Biociencias; 2020

SAIC, SAI, SAFIS

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 is a major etiologic agent responsible for bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Shiga toxin (Stx) is the main virulence factor of EHEC and the main responsible for the onset of HUS. Although many efforts have been made to develop an effectivetreatment for Stx-mediated HUS, a specific therapy has not been found yet. It is well known that human consumption of bovine colostrum has therapeutic effects against several gastrointestinal infections, as it contains a range of peptides and proteins (including antibodies) with antimicrobial and endotoxin-neutralizing effects. Consistent with these findings, we have previously demonstrated that colostrum from Stx type 2 (Stx2)-immunized pregnant cows effectively prevents Stx2 cytotoxicity and EHEC O157:H7 pathogenicity. This study evaluated different pasteurization (72°C for 15 s vs 60°C for 60 min) and spray drying paramenters (Inlet temperature 110°C vs 120°C and outlet temperature lower or higher than 55°C) in order to optimize the preservation of the protective properties of hyperimmune colostrum (HIC-Stx2) against Stx2 after processing.Characterization of neutralizing properties of colostrum were assayed in vitro and in vivo. Our results showed that pasteurization at 60°C for 60 min, combined with spray-drying at inlet and outlet temperatures of 120°C and >55°C, respectively, showed the highest yield and lowest humidity on final samples (p<0.05). Reconstituted HIC-Stx2 colostrum after processing under optimized conditions preserved specific IgG quantity and effectively neutralized Stx2 cytotoxicity on Vero cells. Furthermore, this pasteurized/dehydratedand reconstituted HIC-Stx2 preserved the protective properties against EHEC infection in a weaned mice model. In this regard we propose that hyperimmune bovine colostrum has the potential to be administered to patients with the aim of protecting children againstEHEC infection.