A Chimeric protein of CFA/I, CS6 subunits and LTB/STa toxoid could protect immunized mice against enterotoxigenic Escherichia coli

Abstract Enterotoxigenic Escherichia Coli (ETEC) strains are the most common bacteria causing diarrhea in children in developing countries and travelers to these areas. Colonization factors (CFs) and enterotoxins are the main virulence determinants in ETEC pathogenesis. Heterogeneity of CFs commonly considered as the bottleneck to achieve an effective vaccine. On the other hand, it is believed that a broad spectrum protection against ETEC would be available when the anti‐CF and anti‐enterotoxin immunity were induced simultaneously. Here, the fusion antigen strategy was used to construct a quadrivalent recombinant protein called 3CL composed of CfaB, structural subunit of CFA/I and CS6 structural subunits, LTB and STa toxoid of ETEC and thereafter its anti‐CF and antitoxin immunogenicity was checked. For a high‐level expression, the 3CL gene was synthesized using E. coli codon bias. The immunization was conducted in mice with purified recombinant 3CL. Immunized mice developed antibodies which could detect each recombinant subunit in addition to native CS6 protein and also protect the mice against ETEC challenge. Moreover, the sera from immunized mice also neutralized STa toxin in the suckling mouse assay. The results revealed that 3CL can induce anti‐CF and neutralizing antitoxin antibodies along with introducing CFA/I as a platform for epitope insertion.
Source: Microbiology and Immunology - Category: Microbiology Authors: Tags: Original Article Source Type: research