Immunization with Porphyromonas (Bacteroides) gingivalis fimbriae protects against periodontal destruction

Abstract

Adhesive fimbriae from Porphyromonas gingivalis are cell surface structures which may be important in the virulence of this oral pathogen and thus may serve as a critical or target antigen. Immunization with highly purified 43-kDa fimbrial protein protected against periodontal tissue destruction when tested in the P. gingivalis-infected gnotobiotic rat model. A similarly highly purified 75-kDa cell surface component did not provide protection. Heat-killed whole-cell and sonicated cell surface extracts which contain the 43-kDa protein as well as the 75-kDa component were protective also. This study indicates that the fimbrial protein may serve as a model for the development of effective vaccines against periodontitis, a major human oral disease. * Corresponding author. cultured on modified 5% sheep blood agar (Trypticase soy agar base supplemented with 0.5% yeast extract, 5 ,ug of hemin per ml, and 5 ,ug of menadione per ml) (56) grown at 37°C in an anaerobic chamber (Forma Scientific, Marietta, Ohio) for 48 h. Estimates of cell numbers were made by measuring turbidity with a spectrophotometer at 480 nm and comparing with known standards obtained by counting P. gingivalis cell dilutions in a Petroff-Hauser chamber. P. gingivalis 2561, used for purified antigen preparation, was grown according to procedures previously described (45, 46). Animals. Male germfree Sprague-Dawley rats (Taconic Farms, Germantown, N.Y.) were kept under gnotobiotic conditions in plastic cages with stainless steel tops in positive-pressure plastic inflatable film isolators (Standard Safety Equipment Co., Palatine, Ill.). Each group of eight animals was kept in a separate isolator. Food pellets (diet L-485; Teklad, Madison, Wis.) and water were available ad libitum. Cage bedding consisted of 1/4-in. (1 in. = 2.54 cm) granules (Bed o' Cobs; Anderson, Inc., Maumee, Ohio) and was changed twice a week to minimize trauma to periodontal tissues from impaction of hair and bedding. All equipment, food, bedding, and water were sterilized by autoclaving. Materials entering the isolator were sprayed with 2% peracetic acid. Fecal and surface swab samples from the isolators were cultured once a week by using both aerobic and anaerobic incubation conditions. Experimental design. Six groups of eight rats each were used. Group A was sham-immunized, uninfected animals used as negative controls, and group B was P. gingivalis sham-immunized, infected animals used as a positive control for infection. The other four groups (C to F) were immunized with selected P. gingivalis antigens and subsequently monoinfected with P. gingivalis 381. Group C was immunized with heat-killed whole cells; group D was immunized with highly purified 43-kDa fimbrial protein from P. gingivalis; group E was immunized with highly purified 75-kDa cell surface component from P. gingivalis; and group F was immunized with a cell surface protein fraction which included the 43-kDa protein, the 75-kDa protein, and other proteins extracted during the purification process.

Functional characteristics of antibodies induced by Arg‐gingipain (HRgpA) and Lys‐gingipain (Kgp) from Porphyromonas gingivalis

“…In searching for the appropriate antigen, we and others have examined a group of cell surface carbohydrates designated as K-antigens (12,32,59,60), lipopolysaccharides (10,26,43,58,70), and various proteins including fimbriae and fimbrillin (11,20,21,42,64) and the 53-kDa and 67-kDa cell surface proteins (30,71,72), hemagglutinin (37) and cysteine proteases referred to as gingipains or porphypain (5,13,22,34,40,45,48,55,56). Of the P. gingivalis components studied to date, the cysteine proteases have shown the most potential for use as vaccine antigens.…”

“…There is evidence that a vaccine directed against antigens of the infecting bacteria may be effective in preventing initiation and arresting the progresses of these diseases (7,20,22,23,40,46,66). Vaccine development presents four initial sets of problems.…”

Characterization of the immunodominant antigens of Porphyromonas gingivalis 381 in high‐responder patients

“…Oral immunization of mice with P. gingivalis fimbriae induces increased levels of fimbria-specific salivary IgA and serum IgG antibodies, while subcutaneous immunization of the fimbriae results in elevated serum IgM followed by IgG responses (30,31). In addition, immunization with highly purified P. gingivalis fimbriae was found to be protective against periodontal bone destruction in P. gingivalis-infected gnotobiotic rats (8). On the other hand, Chen et al (3) have reported that immunization with P. gingivalis lipopolysaccharide does not result in readily detectable antibody levels nor does it afford protection from a challenge infection with P. gingivalis.…”

Characterization of FimA inPorphyromonas gingivalisgenotype IV

“…It is known that P. gingivalis fimbriae are highly immunogenic and immunization with fimbriae purified from P. gingivalis 381 blocks the progression of experimental periodontal disease caused by the homologous strain (Evans et al, 1992). Although purified native fimbriae may be a useful immunogen for vaccination to block or reduce the severity of periodontitis, type I-rFimA vaccineinduced antibody responses may differ substantially from naturally acquired responses because type I-rFimA proteins do not fully represent the native structure (Shoji et al, 2010).…”