title: Comparative sequence analysis of Bordetella bronchiseptica pertactin gene (prn) repeat region variants in swine vaccines and field isolates.
abstract: The product of the Bordetella bronchiseptica pertactin gene, prn, has been implicated as an adhesin and a protective immunogen in swine. Recent studies demonstrate prn sequence heterogeneity in swine isolates and vaccine strains within and surrounding the region 1 amino acid repeat GGXXP(n) and the region 2 amino acid repeat PQP(n). However, only a few isolates have been evaluated. Allelic variation between vaccine strains and field isolates may affect vaccine efficacy, since region 2 is known to encode an immunodominant protective epitope. In the present study, the DNA and predicted amino acid sequences of the pertactin repeat regions from a collection of 81 recent swine field isolates and 5 vaccine strains from the United States were determined. Two region 1 variants and four region 2 variants, one of which has not been previously reported, were identified, comprising four pertactin types. Four vaccines are derived from strains with a region 1 variant identical to that found in the majority of field isolates. However, only two vaccines possess the most commonly identified sequence in region 2, while two others contain a variant found in only one other swine isolate. Ribotype analysis demonstrated that although vaccines containing the novel region 2 variant fall within the same major cluster as other common swine ribotypes, they are less closely related. No relationship was observed between pertactin type and ribotype.
authors.affiliation: Respiratory Diseases of Livestock Research Unit, USDA/Agricultural Research Service/National Animal Disease Center, P.O. Box 70, Ames, IA 50010, USA. kregiste@nadc.ars.usda.gov
authors.forename: Karen B
authors.initials: KB
authors.lastname: Register
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics*; D000818:Animals; D001885:Bordetella Infections / Q000382:microbiology / Q000662:veterinary*; D016950:Bordetella bronchiseptica / Q000145:classification / Q000235:genetics*; D010567:Pertussis Vaccine / Q000235:genetics* / Q000276:immunology; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics*; D021521:Ribotyping; D017421:Sequence Analysis; D013552:Swine; D010566:Virulence Factors, Bordetella
chemical_list: D018829:Adhesins, Bacterial; D010567:Pertussis Vaccine; D010566:Virulence Factors, Bordetella