Grenier D, Mayrand D, McBride B C
Oral Microbiol Immunol. 1989 Mar;4(1):12-8. doi: 10.1111/j.1399-302x.1989.tb00400.x.
The ability of several species of black-pigmented Bacteroides to degrade immunoglobulins A and G was confirmed in this study. The cleavage products from IgG strongly stimulated the growth of bacteria degrading IgG. Growth of Bacteroides gingivalis on limiting media supplemented with IgG paralleled growth on complete medium. The degradation of IgG and IgA by black-pigmented Bacteroides appeared to occur in 2 stages. The molecules were broken into large fragments which were subsequently degraded into small peptides not visible on SDS-PAGE. B. gingivalis degraded IgG to peptides with Mrs of 33,000 and 11,000 whereas Bacteroides asaccharolyticus, Bacteroides intermedius and Bacteroides loescheii formed only the 33,000 Mr peptide. Electrophoresis in polyacrylamide gels containing covalently linked IgG, IgA and bovine serum albumin revealed that B. gingivalis elaborated 8 electrophoretically distinct proteolytic activities. The proteases protected the cell from reaction with anti-B. gingivalis antibody and were capable of hydrolyzing antibody bound to the bacterial cell surface.
本研究证实了几种产黑色素拟杆菌降解免疫球蛋白A和G的能力。IgG的裂解产物强烈刺激了降解IgG的细菌的生长。牙龈拟杆菌在补充有IgG的限定培养基上的生长与在完全培养基上的生长相似。产黑色素拟杆菌对IgG和IgA的降解似乎分两个阶段进行。分子首先被分解成大的片段，随后这些片段被降解成在SDS-PAGE上不可见的小肽。牙龈拟杆菌将IgG降解为分子量为33,000和11,000的肽，而解糖拟杆菌、中间拟杆菌和洛氏拟杆菌仅形成分子量为33,000的肽。在含有共价连接的IgG、IgA和牛血清白蛋白的聚丙烯酰胺凝胶中进行电泳显示，牙龈拟杆菌产生了8种电泳性质不同的蛋白水解活性。这些蛋白酶保护细胞不与抗牙龈拟杆菌抗体发生反应，并且能够水解结合在细菌细胞表面的抗体。
