Production of egg yolk immunoglobulin (IgY) against recombinant chimeric protein CfaB-EtpA-LtB (CEL), and evaluation of its specificity and neutralization efficacy against Enterotoxigenic Escherichia coli (ETEC)

Background and Aim : Enterotoxigenic Escherichia coli (ETEC) strains are the most common cause of diarrhea among children and travelers in developing countries. Colonization factors (CFs) and enterotoxins are the major virulence factors in ETEC pathogenesis and hence can be considered as vaccine candidates. Passive immunotherapy through oral administration of chicken egg yolk antibodies (IgY) is applied as a new alternative strategy for the prophylaxis and treatment of diarrhea caused by ETEC. In the present study, we evaluated the protective efficacy of specific egg yolk antibody (IgY) produced against recombinant chimeric protein CfaB-EtpA-LtB (CEL).Methods : Recombinant chimeric protein (CEL) was expressed in E. coli BL۲۱ (DE۳) after IPTG induction, purified through a Ni-NTA affinity chromatography column, and confirmed through SDS-PAGE and western blotting. Hens were immunized intramuscularly with purified recombinant protein thrice with two-week intervals. IgY was purified through a water dilution method, using NaCl precipitation and its purity was analyzed by SDS-PAGE. The activity and specificity of the produced IgY antibody were examined by indirect ELISA. The protective effect of produced IgY against LT toxin was also investigated on the Y-۱ cell line.Results : The produced IgY showed specific binding activity to the chimeric protein in indirect ELISA, and a significant difference was observed between test and control IgY groups. Anti-chimeric CEL IgY in a concentration of ۷۰۰ μg/mL was able to reduce LtB cytotoxic effects on Y-۱ cells.Conclusion : The obtained immunoglobulin could effectively act in passive immunotherapy against ETEC-induced diarrhea infection.

کلیدواژه ها:

ETEC ، Diarrhea ، Enterotoxin ، Egg yolk immunoglobulins (IgY) ، Recombinant protein