IMMUNIZATION WITH NANOPARTICLED CHITOSAN CONTAINING OF RECOMBINANT EIT AND STX2B ANTIGENS AGAINST E. COLI O157:H7 IN ANIMAL MODEL

Background and Aim: E. coli O157:H7 is an infectious zoonotic pathogen causing human hemolytic uremic syndrome (HUS) with renal failure that can be deadly dangerous. Here two important virulence nanoparticulate recombinant proteins with chitosan, (the rEIT (ESPA, Intimin, Tir) and rStx2B the nontoxic sticky part of Shiga toxin2 B subunit monomers were mixed together and used as nanovaccine candidate.Methods:Synthetic pET28-genes with eit and stx2B were transformed into E. coli BL21 (DE3) separately for Expression of rEIT and rStx2B recombinant proteins. These antigens were purified and confirmed with Western blotting. Female- five- weeks old BALB/c mice immunized. The specific Immune responses were measured by ELISA. In challenging tests different groups of immunized mice were infected orally with E.coli O157:H7.Results:Higher titers of serum and feces anti rEIT and rStx2B IgG , IgA were achieved after the last immunization proses in all of the groups.. The reduction in the number of colonies was observed for all the immunized groups for over two weeks. After preincubation of EHEC with antisera the lowest E. coli counts adhering to monolayer Caco-2 cells were in binding inhibition assay. All the vaccinated groups were challenged with lethal dose of Stx2. More than 66% of immunized mice with these vaccines were survived and protected against toxi .Conclusion:The results showed these recombinant nanovaccine candidates induced strong humoral and mucosal immune responses and greatly reduced signs and symptoms of E.coli O157:H7 infections.

Keywords:

E. coli O157:H7 , EIT , Stx2B , Nanovaccine , immunization