Title

Protection of Piglets Against Enteric Colibacillosis by Intranasal Immunization with K88ac (F4ac) Fimbriae and Heat Labile Enterotoxin of Escherichia coli

Document Type

Article

Publication Date

3-2013

Keywords

enterotoxigenic Escherichia coli, heat labile enterotoxin, intranasal vaccination, K88, F4, postweaning diarrhea, swine

Abstract

Enterotoxigenic Escherichia coli (ETEC) is an important diarrheal agent of young domestic animals. Currently, there are no commercially available non-living vaccines to protect weaned pigs from the disease and no major veterinary biologics company markets a postweaning ETEC vaccine of any kind. While efforts have been made to develop a non-living postweaning ETEC vaccine for pigs, studies have been limited to the assessment of immune responses to experimental immunogens. In the present study, we describe a reproducible gnotobiotic piglet model of post-weaning ETEC diarrhea and efficacy tests in that model of subunit vaccines consisting of K88 (F4) fimbriae and/or heat labile enterotoxin (LT) delivered by the intranasal route. We also report antibody responses to the vaccine antigens. Piglets vaccinated with both antigens mounted a substantial immune response with serum and cecal antibody titers to K88 antigen significantly greater than those of controls. Serum anti-LT antibody titers were also significantly greater than those of controls. Piglets vaccinated with both antigens remained healthy following challenge with ETEC. At least some pigs vaccinated with either antigen alone, and most of the control piglets developed dehydrating diarrhea and suffered significant weight loss. The results of this study suggest that an intranasal vaccine consisting of both antigens is highly protective against a vigorous experimental challenge of pigs with K88+ ETEC, while that against either antigen alone is not. The current study provides a system whereby various ETEC antigens and/or combinations of antigens can be tested in exploring strategies for the development of vaccines for ETEC.

Publication Title

Veterinary Microbiology

Volume

162

Issue

2-4

First Page

731

Last Page

739

DOI of Published Version

10.1016/j.vetmic.2012.09.025

Publisher

Elsevier

Rights

Copyright © 2012 Elsevier