Submitted to: American Society of Microbiologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 4, 2000
Publication Date: N/A
Previous sequence analysis of the prn gene from Bordetella pertussis and B. bronchiseptica revealed 2 regions encoding amino acid repeats. Region 1, immediately adjacent to an RGD motif shown to function in attachment to eukaryotic cells, contains the repeat GGXXPn. Region 2, roughly 900 bp 3' of region 1, encodes a reiterated PQPn motif. Analysis of several hundred strains of B. pertussis demonstrated heterogeneity in the number of repeat in region 1 between vaccine strains and clinical isolates. No variation in the number of repeats in region 2 was noted for any strain. The published sequence of B. bronchiseptica prn, derived from a canine isolate, contains 3 GGXXP and 7 PQP repeats. The goal of the present study was to determine whether there is variation in these repeats among swine atrophic rhinitis vaccine strains and B. bronchiseptica isolates obtained from pigs with respiratory disease. Southern blotting revealed RFLPs associated with genomic DNA restriction fragments derived from region 1, as well as those from region 2, of several strains. Subsequent sequence analysis demonstrated the number of GGXXP repeats varied from 3 to 4, while 6 to 8 PQP repeats were present in the strains examined. The sequence coding for the RGD triplet was conserved in all strains. This is the first time variation in the PQP region has been documented in Bordetella. The pertactin variants associated with field isolates are unique from those of vaccine strains. These results imply that vaccine strains may not be antigenically identical to disease-causing field strains, perhaps reducing the efficacy of atrophic rhinitis vaccines.