title: A multiepitope fusion antigen elicits neutralizing antibodies against enterotoxigenic Escherichia coli and homologous bovine viral diarrhea virus in vitro.
abstract: Diarrhea is one of the most important bovine diseases. Enterotoxigenic Escherichia coli (ETEC) and bovine viral diarrhea virus (BVDV) are the major causes of diarrhea in calves and cattle. ETEC expressing K99 (F5) fimbriae and heat-stable type Ia (STa) toxin are the leading bacteria causing calf diarrhea, and BVDV causes diarrhea and other clinical illnesses in cattle of all ages. It is reported that maternal immunization with K99 fimbrial antigens provides passive protection to calves against K99 fimbrial ETEC and that BVDV major structural protein E2 elicits antibodies neutralizing against BVDV viral infection. Vaccines inducing anti-K99 and anti-STa immunity would protect calves more effectively against ETEC diarrhea, and those also inducing anti-E2 neutralizing antibodies would protect calves and cattle against diarrhea caused by both ETEC and BVDV. In this study, we used the ETEC K99 major subunit FanC as a backbone, genetically embedded the STa toxoid STaP12F and the most-antigenic B-cell epitope and T-cell epitope predicted from the BVDV E2 glycoprotein into FanC for the multivalent antigen FanC-STa-E2, and examined immunogenicity of this multivalent antigen to assess vaccine potential against bovine diarrhea. Mice intraperitoneally (i.p.) immunized with this multivalent antigen developed anti-K99, anti-STa, and anti-BVDV antibodies. Moreover, elicited antibodies showed neutralization activities, as they inhibited adherence of K99 fimbrial E. coli, neutralized STa toxin, and prevented homologous BVDV viral infection in vitro. Results from this study suggest that this multiepitope fusion antigen can potentially be developed as a vaccine for broad protection against bovine diarrhea and that the multiepitope fusion strategy may be generally applied for multivalent vaccine development against heterogeneous pathogens.
authors.affiliation: Veterinary & Biomedical Sciences Department, The Center for Infectious Disease Research & Vaccinology, South Dakota State University, Brookings, South Dakota, USA.
authors.forename: Emad A
authors.initials: EA
authors.lastname: Hashish
authors.forename: Chengxian
authors.initials: C
authors.lastname: Zhang
authors.forename: Xiaosai
authors.initials: X
authors.lastname: Ruan
authors.forename: David E
authors.initials: DE
authors.lastname: Knudsen
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Chase
authors.forename: Richard E
authors.initials: RE
authors.lastname: Isaacson
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Zhou
authors.forename: Weiping
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D057134:Antibodies, Neutralizing / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology; D030241:Diarrhea Virus 1, Bovine Viral / Q000276:immunology*; D030242:Diarrhea Virus 2, Bovine Viral / Q000276:immunology*; D054307:Enterotoxigenic Escherichia coli / Q000276:immunology*; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D022361:Escherichia coli Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D000942:Antigens, Bacterial; D000956:Antigens, Viral; D000939:Epitopes; D022361:Escherichia coli Vaccines; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014765:Viral Vaccines