title: Characterization of antigenic determinants in ApxIIA exotoxin capable of inducing protective immunity to Actinobacillus pleuropneumoniae challenge.
abstract: Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia. Among the virulence factors of the pathogen, ApxIIA, a bacterial exotoxin, is expressed by many serotypes and presents a plausible target for vaccine development. We characterized the region within ApxIIA that induces a protective immune response against bacterial infection using mouse challenge model. Recombinant proteins spanning the length of ApxIIA were produced and antiserum to the full-length ApxIIA was induced in mice. This antiserum recognized fragments #2, #3 and #5 with high binding specificity, but showed poor recognition for fragments #1 and #4. Of the antisera induced in mice by injection of each fragments, only the antiserum to fragment #4 failed to efficiently recognize the full-length antigen, although the individual antisera recognized their cognate antigens with almost equal efficiency. The protective potency of the immunogenic proteins against a challenge injection of bacteria in vivo correlated well with the antibody titer. Fragment #5 induced the highest level of protective activity, comparable to that by the full-length protein. These results support the use of fragment #5 to produce a vaccine against A. pleuropneumoniae challenge, since the small antigen peptide is easier to handle than is the full-length protein and can be expressed efficiently in heterologous expression systems.
authors.affiliation: Department of Molecular Biology and the Institute for Molecular Biology and Genetics, Chonbuk National University, Korea.
authors.forename: Ki-Weon
authors.initials: KW
authors.lastname: Seo
authors.forename: Dong-Heon
authors.initials: DH
authors.lastname: Kim
authors.forename: Ah Hyun
authors.initials: AH
authors.lastname: Kim
authors.forename: Han-Sang
authors.initials: HS
authors.lastname: Yoo
authors.forename: Kyung-Yeol
authors.initials: KY
authors.lastname: Lee
authors.forename: Yong-Suk
authors.initials: YS
authors.lastname: Jang
mesh_terms: D000189:Actinobacillus Infections / Q000097:blood / Q000276:immunology* / Q000401:mortality / Q000517:prevention & control; D016977:Actinobacillus pleuropneumoniae / Q000276:immunology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D005098:Exotoxins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D006460:Hemolysin Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; C085361:ApxII toxin, bacteria; D001426:Bacterial Proteins; D005098:Exotoxins; D006460:Hemolysin Proteins; D011994:Recombinant Proteins