Immunization with Porphyromonas Gingivalis Cysteine Protease : Effects on Experimental Gingivitis and Ligature-Induced Periodontitis in Macaca Fascicularis

Targeting specific bacterial virulence factors such as proteases for immunization may hold the key to limiting or preventing loss of attachment and alveolar bone in periodontal disease. This study was undertaken to examine the clinical, microbiological and immunological responses following active immunization with a purified 120 kDa Porphyromonas gingivitis cysteine protease (porphypain-2) in the nonhuman primate (Nhp) Macaca fascicularis (cynomolgus monkey). 4 Nhp were immunized with 100ug of porphypain-2 antigen at baseline, 2 and 4 weeks. A 'non-immunized' control group of 4 Nhp received placebo injections. The animals were subjected to a 4 week experimental gingivitis phase initiated by soft diet, followed by a 13 week ligature-induced periodontitis phase. Mandibular left 'test' teeth (3-5, 3-6, 3-7) in each animal received silk ligatures to initiate periodontitis, with mandibular right teeth (4-5, 4-6, 4-7) in each animal serving as a non-ligated intra-animal control. Clinical, radiographic, microbiologic and immunologic data were gathered and analyzed using the student t-test and nonparametric rank analyses. An ELISA demonstrated that immunization elicited an elevated and specific IgG response to both whole cell P. gingivalis (36-fold) and to porphypain-2 (194- fold). This antibody response in immunized Nhp remained significantly elevated versus baseline (P < 0.0001) and the control group (P < 0.00001) throughout the study. Checkerboard DNA probe analysis of 16 subgingival plaque species from ligated sextants demonstrated that 25% more gram-negative anaerobic species became significantly elevated from baseline and at earlier timepoints in the control group than in the immunized group. Immunization did not suppress the emergence of P. gingivalis.Air Force Inst of Tech Wright-Patterson AFB OH is the author of 'Immunization with Porphyromonas Gingivalis Cysteine Protease : Effects on Experimental Gingivitis and Ligature-Induced Periodontitis in Macaca Fascicularis', published 1997 under ISBN 9781423567516 and ISBN 142356751X.