Abstract
Subcutaneous injection of fimbriae from Porphyromonas gingivalis strain 381 in Freund's incomplete adjuvant (FIA) resulted in an excellent serum anti-fimbrial immunoglobulin G (IgG) response in guinea-pigs and BALB/c mice. Administration of P. gingivalis fimbriae also elicited distinct cellular immune responses to the fimbriae in terms of ear lobe reaction in BALB/c but not in BALB/c nu/nu mice, and of skin reaction in guinea-pigs. When the guinea-pigs were given a semi-synthetic adjuvant GM-53--sodium beta-N-acetylglycosaminyl-(1-->4)-N-acetylmuramyl-L-alanyl-D-isogl utaminyl- (L)-stearoyl-(D)-meso-2, 6-diaminopimelic acid-(D)-amide-D-alanine--and fimbriae in FIA by subcutaneous injection, more enhanced production of serum anti-fimbrial IgG and stronger cellular immune responses were induced in the guinea-pigs than in those given fimbriae alone. Synthetic peptide FP381(202-221), which corresponds to the amino-acid residue numbers 202-221 based on the amino-acid sequence of fimbrilin from P. gingivalis strain 381, elicited humoral and cellular immune responses in guinea-pigs immunised with the fimbriae or FP381(202-221). Furthermore, subcutaneous administration of synthetic peptide FP381(61-80) with GM-53 induced lesser degrees of humoral and cellular immune responses in guinea-pigs than did FP381(202-221). However, when the fimbriae or FP381(61-80) were administered with bovine serum albumin (BSA), markedly elevated levels of specific anti-BSA antibody were seen in the serum of BALB/c mice. These results clearly indicated that fimbriae from P. gingivalis 381 and their oligopeptide segments induced humoral and cellular immune responses and exhibited immuno-adjuvant activities in guinea-pigs and BALB/c mice.