Genetic fusions of heat-labile toxoid (LT) and heat-stable toxin b (STb) of porcine enterotoxigenic Escherichia coli elicit protective anti-LT and anti-STb antibodies.
Enterotoxigenic Escherichia coli (ETEC)-associated diarrhea causes a substantial economic loss to swine producers worldwide. The majority of ETEC strains causing porcine diarrhea, especially postweaning diarrhea (PWD), produce heat-labile toxin (LT) and heat-stable toxin b (STb). LT is commonly used in vaccine development, but STb has not been included because of its poor immunogenicity. As a virulence factor in porcine diarrhea, STb needs to be included as an antigen for development of broad-spectrum vaccines. In this study, we used an LT toxoid (LT(R192G) [hereafter, LT(192)]) derived from porcine ETEC to carry a mature STb peptide for LT(192)-STb fusions to enhance STb immunogenicity for potential vaccine application. Anti-LT and anti-STb antibodies were detected in immunized rabbits and pigs. In addition, when challenged with an STb-positive ETEC strain, all 10 suckling piglets borne by immunized gilts remained healthy, whereas 7 out 9 piglets borne by unimmunized gilts developed moderate diarrhea. This study indicates that the LT(192)-STb fusion enhanced anti-STb immunogenicity and suggests the LT(192)-STb fusion antigen can be used in future vaccine development against porcine ETEC diarrhea.
Zhang
Weiping
W
The Center for Infectious Disease Research & Vaccinology, Department, Veterinary & Biomedical Sciences, South Dakota State University, Brookings, SD 57006, USA. weiping.zhang@sdstate.edu
Francis
David H
DH
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000992:Antitoxins / Q000097:blood; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology*; D003967:Diarrhea / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics / Q000276:immunology*; D004768:Enterotoxins / Q000235:genetics / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology*; D022361:Escherichia coli Vaccines / Q000276:immunology*; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000517:prevention & control*; D014121:Toxoids / Q000235:genetics / Q000276:immunology
D000907:Antibodies, Bacterial; D000992:Antitoxins; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D022361:Escherichia coli Vaccines; D011993:Recombinant Fusion Proteins; D014121:Toxoids; C034151:heat stable toxin (E coli); C027538:heat-labile enterotoxin, E coli