Porphyromonas gingivalis fimbriae use beta2 integrin (CD11/CD18) on mouse peritoneal macrophages as a cellular receptor, and the CD18 beta chain plays a functional role in fimbrial signaling.
In this study, we demonstrate that Porphyromonas gingivalis fimbriae use molecules of beta2 integrin (CD11/CD18) on mouse peritoneal macrophages as cellular receptors and also show that the beta chain (CD18) may play a functional role in signalling for the fimbria-induced expression of interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) genes in the cells. Using a binding assay with 125I-labeled fimbriae, we observed that fimbrial binding to the macrophages was inhibited by treatment with CD11a, CD11b, CD11c, or CD18 antibody but not by that with CD29 antibody. Western blot assays showed that the fimbriae bound to molecules of beta2 integrin (CD11/CD18) on the macrophages. Furthermore, Northern blot analyses showed that the fimbria-induced expression of IL-1beta and TNF-alpha genes in the cells was inhibited strongly by CD18 antibody treatment and slightly by CD11a, CD11b, or CD11c antibody treatment. Interestingly, intracellular adhesion molecule 1 (ICAM-1), a ligand of CD11/CD18, inhibited fimbrial binding to the cells in a dose-dependent manner. In addition, ICAM-1 clearly inhibited the fimbria-induced expression of IL-1beta and TNF-alpha genes in the cells. However, such inhibitory action was not observed with laminin treatment. These results suggest the importance of beta2 integrin (CD11/CD18) as a cellular receptor of P. gingivalis fimbriae in the initiation stage of the pathogenic mechanism of the organism in periodontal disease.
Takeshita
A
A
Departments of Oral Microbiology, Meikai University School of Dentistry, Keyakidai, Sakado City, Saitama 350-0283, Japan.
Murakami
Y
Y
Yamashita
Y
Y
Ishida
M
M
Fujisawa
S
S
Kitano
S
S
Hanazawa
S
S
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D018821:CD18 Antigens / Q000378:metabolism / Q000502:physiology*; D010861:Fimbriae, Bacterial / Q000378:metabolism*; D005786:Gene Expression Regulation; D016167:Integrin alphaXbeta2 / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007375:Interleukin-1 / Q000235:genetics; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D016177:Macrophage-1 Antigen / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D016966:Porphyromonas gingivalis / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D000911:Antibodies, Monoclonal; D018821:CD18 Antigens; D016167:Integrin alphaXbeta2; D007375:Interleukin-1; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen; D011956:Receptors, Cell Surface; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1