title: Immunogenic characterization of outer membrane porins OmpC and OmpF of porcine extraintestinal pathogenic Escherichia coli.
abstract: Extraintestinal pathogenic Escherichia coli (ExPEC) is an important pathogen that can cause systemic infections in a broad spectrum of mammals and birds. To date, commercial vaccines against ExPEC infections in pigs are rare and antibiotic resistance has become a serious clinical problem. Identification of protective antigens is helpful for developing potentially effective vaccines. In this study, two outer membrane porins, OmpC and OmpF, of porcine ExPEC were cloned and expressed to investigate their immunogenicity. Intraperitoneal immunization of mice with the purified recombinant proteins OmpC and OmpF stimulated strong immunoglobulin G (IgG) antibody responses. Both IgG1 and IgG2a subclasses were induced, with a predominance of IgG1 production. After challenge with 2.5 × 10(7) CFU (5 × LD50 ) of the highly virulent ExPEC strain PCN033, 62.5% and 87.5% protection was observed in mice immunized with OmpC and OmpF, respectively. In addition, both anti-OmpC and anti-OmpF sera can mediate complement-dependent opsonophagocytosis. Phylogenetic analysis showed that the ompC gene was ubiquitously present in all E. coli strains, whereas the ompF gene was mutated in certain strains. Furthermore, the selection analysis indicated that gene ompC may be subject to strong immune pressure. Our results demonstrated that OmpC is a promising vaccine target against ExPEC infections in swine.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
authors.forename: Canying
authors.initials: C
authors.lastname: Liu
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Chen
authors.forename: Chen
authors.initials: C
authors.lastname: Tan
authors.forename: Wugang
authors.initials: W
authors.lastname: Liu
authors.forename: Zhuofei
authors.initials: Z
authors.lastname: Xu
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
authors.forename: Huanchun
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D003001:Cloning, Molecular; D016000:Cluster Analysis; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000276:immunology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control* / Q000662:veterinary; D022361:Escherichia coli Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D015870:Gene Expression; D007074:Immunoglobulin G / Q000097:blood; D007274:Injections, Intraperitoneal; D051379:Mice; D010802:Phylogeny; D018272:Porins / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology; D014611:Vaccination / Q000379:methods
chemical_list: D000907:Antibodies, Bacterial; D022361:Escherichia coli Vaccines; D007074:Immunoglobulin G; C113724:OmpC protein; C109237:OmpF protein; D018272:Porins; D011994:Recombinant Proteins