The association of two recombinant proteinases of a feline strain of Porphyromonas gingivalis with periodontal disease in cats.
Serum from 40 domestic cats with various grades of periodontal disease was used to probe two recombinant functional proteinases from feline strain VPB 3457 of Porphyromonas gingivalis expressed in E. coli. One recombinant proteinase (VPB 2856) was constructed using polymerase chain reaction and had 91% DNA identity with the prtC collagenase gene of the human type strain of P. gingivalis, while the other proteinase (VPB 2814) was isolated from a size selected genomic library and had an amino-terminal sequence with no significant identity with deposited sequences. Thirteen of 40 cats showed a serum antibody response to VPB 2856 using Western immunoblot detection. All the 13 cats had an overall periodontal grade of 3 or greater and greater than 1.68x10(5) cfu P. gingivalis at the canine and premolar periodontium sample sites. Fourteen of 40 cats showed a serum antibody response to VPB 2814. Thirteen of these 14 cats had an overall periodontal grade of 3 or greater. Regression analysis of overall periodontal grade against the serum antibody response showed significant positive relationships for both VPB 2856 (r2 = 0.351; p<0.001) and VPB 2814 (r2 = 0.247; p<0.001). Regression analysis of the total colony forming units of feline strain P. gingivalis against the grade of serum antibody response showed a positive relationship for both VPB 2856 (r2 = 0.662; p<0.001) and VPB 2814 (r2 = 0.531; p<0.001). These data provide strong evidence that the recombinant proteinases of feline P. gingivalis expressed in E. coli clones VPB 2856 and VPB 2814 are associated with periodontal disease in cats.