Identification of Porphyromonas gingivalis by an ELISA using a cellulose acetate paper point

The ELISA testing method with a cellulose acetate paper point for detecting Porphyromonas gingivalis in subgingival plaque samples was investigated. Rabbit polyclonal IgG (Poly Pgf-I) and mouse monoclonal antibodies (mAbs Pgf-I) against fimbriae from P. gingivalis 381 were obtained. Poly Pgf-I and mAbs Pgf-I reacted with cell suspensions consisting of the range of 2 × 10⁴ to 2 × 10⁶ P. gingivalis 381 cells by the ELISA method. The developed paper point could be classified into four degrees, -, +, ++ and +++ according to the number of P. gingivalis cells. Poly Pgf-I and mAbs Pgf-I reacted with P. gingivalis cells, whilst neither of these antibodies reacted with whole cells of other oral or non-oral black-pigmented bacterial species. Analysis by the ELISA method resulted in definite immunoreactivity in subgingival plaque samples of patients with adult periodontitis, whilst no detectable reactivity was found in those of normal healthy subjects. The simple and rapid ELISA method using the paper point may be useful for the identification of P. gingivalis.