Extracellular 37-kDa antigenic protein from Actinobacillus actinomycetemcomitans induces TNF-alpha, IL-1 beta, and IL-6 in murine macrophages.
The extracellular antigens of Actinobacillus actinomycetemcomitans Y4 (serotype b) contain a 37-kDa protein which is a major target for IgGs from patients suffering from severe alveolar bone loss. Since the 37-kDa protein has not been studied sufficiently, our investigation focused on its characteristics, e.g., its localization, specificity, and whether it directly stimulates macrophages to produce cytokines. The 37-kDa protein was purified from the culture supernatant of the Y4 strain by means of chromatofocusing and gel filtration. The 37-kDa protein is a unique glycoprotein which forms immune complexes with monoclonal antibodies against rhamnose-fucose polysaccharide. Patients with A. actinomycetemcomitans-associated periodontitis had higher antibody titers to the purified 37-kDa protein than healthy subjects (p < 0.001). Anti-37-kDa protein antibodies recognized a 37-kDa band in the cytosolic, ribosomal, and total membrane fractions from Y4 cells. Extracellular substances from other strains of A. actinomycetemcomitans (serotypes a and c) also reacted in the Western blots, but Haemophilus spp. or several periodontopathic bacteria did not. These results suggested that the 37-kDa protein is a cytosolic protein that is passed through the cell membrane, and its protein portion is specific for A. actinomycetemcomitans but common to serotypes. This protein induced Il-1 beta, Il-6, and TNF-alpha release from murine macrophages. The Il-6-inducing activity of the 37-kDa protein was higher than that of LPS. These findings suggested that the 37-kDa protein which is released from live cells plays a role in A. actinomycetemcomitans-associated periodontitis, as antigen inducing the release of inflammatory cytokines which are associated with alveolar bone loss.
Tani
Y
Y
Department of Periodontology, Nagasaki University School of Dentistry, Japan.
Tani
M
M
Kato
I
I
D016976:Aggregatibacter actinomycetemcomitans / Q000145:classification / Q000276:immunology*; D016301:Alveolar Bone Loss / Q000276:immunology / Q000382:microbiology; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology* / Q000302:isolation & purification; D000954:Antigens, Surface / Q000276:immunology* / Q000302:isolation & purification; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology* / Q000302:isolation & purification; D015153:Blotting, Western; D002462:Cell Membrane / Q000276:immunology; D002850:Chromatography, Gel; D003600:Cytosol / Q000276:immunology; D000939:Epitopes; D005260:Female; D005643:Fucose / Q000276:immunology; D006190:Haemophilus / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000276:immunology; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000276:immunology; D007525:Isoelectric Focusing; D008070:Lipopolysaccharides / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D010518:Periodontitis / Q000276:immunology / Q000382:microbiology; D011134:Polysaccharides / Q000276:immunology; D012210:Rhamnose / Q000276:immunology; D012270:Ribosomes / Q000276:immunology; D012703:Serotyping; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000276:immunology
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes; D007074:Immunoglobulin G; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011134:Polysaccharides; D014409:Tumor Necrosis Factor-alpha; D005643:Fucose; D012210:Rhamnose