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Rausch D, Ruan X, Nandre R, Duan Q, Hashish E, Casey TA, Zhang W. Antibodies derived from a toxoid MEFA (multiepitope fusion antigen) show neutralizing activities against heat-labile toxin (LT), heat-stable toxins (STa, STb), and Shiga toxin 2e (Stx2e) of porcine enterotoxigenic Escherichia coli (ETEC). Vet Microbiol 2016; 202:79-89. [PMID: 26878972 PMCID: PMC7172483 DOI: 10.1016/j.vetmic.2016.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/22/2016] [Accepted: 02/04/2016] [Indexed: 11/18/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) strains are the main cause of diarrhea in pigs. Pig diarrhea especially post-weaning diarrhea remains one of the most important swine diseases. ETEC bacterial fimbriae including K88, F18, 987P, K99 and F41 promote bacterial attachment to intestinal epithelial cells and facilitate ETEC colonization in pig small intestine. ETEC enterotoxins including heat-labile toxin (LT) and heat-stable toxins type Ia (porcine-type STa) and type II (STb) stimulate fluid hyper-secretion, leading to watery diarrhea. Blocking bacteria colonization and/or neutralizing enterotoxicity of ETEC toxins are considered effective prevention against ETEC diarrhea. In this study, we applied the MEFA (multiepitope fusion antigen) strategy to create toxoid MEFAs that carried antigenic elements of ETEC toxins, and examined for broad antitoxin immunogenicity in a murine model. By embedding STa toxoid STaP12F (NTFYCCELCCNFACAGCY), a STb epitope (KKDLCEHY), and an epitope of Stx2e A subunit (QSYVSSLN) into the A1 peptide of a monomeric LT toxoid (LTR192G), two toxoid MEFAs, 'LTR192G-STb-Stx2e-STaP12F' and 'LTR192G-STb-Stx2e-3xSTaP12F' which carried three copies of STaP12F, were constructed. Mice intraperitoneally immunized with each toxoid MEFA developed IgG antibodies to all four toxins. Induced antibodies showed in vitro neutralizing activities against LT, STa, STb and Stx2e toxins. Moreover, suckling piglets born by a gilt immunized with 'LTR192G-STb-Stx2e-3xSTaP12F' were protected when challenged with ETEC strains, whereas piglets born by a control gilt developed diarrhea. Results from this study showed that the toxoid MEFA induced broadly antitoxin antibodies, and suggested potential application of the toxoid MEFA for developing a broad-spectrum vaccine against ETEC diarrhea in pigs.
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Affiliation(s)
- Dana Rausch
- The Center for Infectious Disease Research & Vaccinology/Veterinary & Biomedical Sciences Department, South Dakota State University, Brookings, SD 57006, USA
| | - Xiaosai Ruan
- The Center for Infectious Disease Research & Vaccinology/Veterinary & Biomedical Sciences Department, South Dakota State University, Brookings, SD 57006, USA; Kansas State University College of Veterinary Medicine, Diagnostic Medicine/Pathobiology Department, Manhattan, KS 66506, USA
| | - Rahul Nandre
- Kansas State University College of Veterinary Medicine, Diagnostic Medicine/Pathobiology Department, Manhattan, KS 66506, USA
| | - Qiangde Duan
- Kansas State University College of Veterinary Medicine, Diagnostic Medicine/Pathobiology Department, Manhattan, KS 66506, USA
| | - Emad Hashish
- The Center for Infectious Disease Research & Vaccinology/Veterinary & Biomedical Sciences Department, South Dakota State University, Brookings, SD 57006, USA
| | - Thomas A Casey
- National Animal Disease Center, Agricultural Research Service, USDA, Ames, IA 50010, USA
| | - Weiping Zhang
- The Center for Infectious Disease Research & Vaccinology/Veterinary & Biomedical Sciences Department, South Dakota State University, Brookings, SD 57006, USA; Kansas State University College of Veterinary Medicine, Diagnostic Medicine/Pathobiology Department, Manhattan, KS 66506, USA.
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