Ochiai K, Fukushima K, Shiota T, Ikeda T
Department of Microbiology, Nihon University, School of Dentistry at Matsudo, Chiba, Japan.
J Dent Res. 1990 Feb;69(2):477-82. doi: 10.1177/00220345900690021201.
Four hybrid cell lines secreting monoclonal antibodies (McAbs) against glucosyltransferase synthesizing water-insoluble glucan (GTase-I) were generated by fusion of myeloma cells (P3U1) with splenocytes from mice immunized with GTase-I from Streptococcus sobrinus B13-N. Cell lines 29E7, 21GC7, and 42HB8 were found to secrete an IgG2a-type immunoglobulin, and 29EG, an IgM-type immunoglobulin. These two isotypes of McAbs were used for the determination of the binding sites on the GTase molecule, with use of an enzyme-linked immunosorbent assay. The binding site for McAb 29EG was different from the site that bound other McAbs. McAb 29EG was found to inhibit water-insoluble glucan synthesis by GTase-I by 50%, and 29E7 was found to inhibit it weakly. However, other McAbs did not show any inhibitory effect in spite of binding to GTase-I. McAb 42HB8 strongly inhibited GTase-I-mediated adherence of heat-killed cells of S. sobrinus B-13N to glass surfaces. When the McAbs were tested for their cross-reactivity among GTase preparations from different mutans streptococci, McAb 29EG reacted with S. cricetus and S. sobrinus, but not with other mutans streptococci. Three other McAbs, 21GC7, 29E7, and 42HB8, were found to react only with the enzyme from S. sobrinus. These findings indicated that the specificity of the McAbs studied varied with respect to the antigenic sites on the GTase-I molecule, and that some of the sites differed in their functions.
通过将骨髓瘤细胞（P3U1）与用来自远缘链球菌B13 - N的葡糖基转移酶免疫的小鼠脾细胞融合，产生了四种分泌抗合成水不溶性葡聚糖的葡糖基转移酶（GTase - I）单克隆抗体（McAbs）的杂交细胞系。发现细胞系29E7、21GC7和42HB8分泌IgG2a型免疫球蛋白，而29EG分泌IgM型免疫球蛋白。利用酶联免疫吸附测定法，将这两种同种型的单克隆抗体用于确定GTase分子上的结合位点。McAb 29EG的结合位点与结合其他单克隆抗体的位点不同。发现McAb 29EG可抑制GTase - I合成水不溶性葡聚糖达50%，而29E7对其抑制作用较弱。然而，其他单克隆抗体尽管与GTase - I结合，但未显示出任何抑制作用。McAb 42HB8强烈抑制GTase - I介导的远缘链球菌B - 13N热灭活细胞与玻璃表面的黏附。当测试这些单克隆抗体在不同变形链球菌GTase制剂之间的交叉反应性时，McAb 29EG与仓鼠链球菌和远缘链球菌发生反应，但与其他变形链球菌无反应。发现其他三种单克隆抗体21GC7、29E7和42HB8仅与远缘链球菌的酶发生反应。这些发现表明，所研究的单克隆抗体的特异性在GTase - I分子上的抗原位点方面存在差异，并且其中一些位点在功能上也有所不同。
