Kraus W, Dale J B, Beachey E H
Department of Veterans Affairs Medical Center, Memphis, TN 38104.
J Immunol. 1990 Dec 15;145(12):4089-93.
The localization of opsonic and tissue-cross-reactive epitopes within the amino terminus of type 1 streptococcal M protein was investigated by using murine mAb raised against synthetic peptides of type 1 M protein. Two mAb (IIIA2 and IIIB8) reacted with epitopes located within amino acid residues 1-12 of type 1 M protein. These antibodies opsonized type 1 streptococci and did not cross-react with human kidney and heart tissue. Another mAb (IC7) reacted with mesangial cells of renal glomeruli and human myocardium. The cross-reactive epitope of mAb IC7 was localized to position 13-19, indicating that it is not the same epitope as the previously described vimentin-cross-reactive epitope at position 23-26 of type 1 M protein. In Western blots of mesangial cell and myocardial proteins, mAb IC7 cross-reacted with a 43-kDa protein. Neither vimentin nor actin inhibited the binding of mAb IC7 to the cross-reactive protein, as determined by Western blot or immunofluorescence inhibition tests. These results provide evidence that type 1 M protein contains at least one autoimmune epitope shared with both human glomeruli and myocardium.
通过使用针对1型M蛋白合成肽产生的鼠单克隆抗体，研究了调理素和组织交叉反应性表位在1型链球菌M蛋白氨基末端内的定位。两种单克隆抗体（IIIA2和IIIB8）与位于1型M蛋白氨基酸残基1 - 12内的表位发生反应。这些抗体可调理1型链球菌，且不与人肾和心脏组织发生交叉反应。另一种单克隆抗体（IC7）与肾小球系膜细胞和人心肌发生反应。单克隆抗体IC7的交叉反应性表位定位于第13 - 19位，表明它与先前描述的1型M蛋白第23 - 26位的波形蛋白交叉反应性表位不是同一表位。在系膜细胞和心肌蛋白的蛋白质印迹中，单克隆抗体IC7与一种43 kDa的蛋白发生交叉反应。通过蛋白质印迹或免疫荧光抑制试验确定，波形蛋白和肌动蛋白均未抑制单克隆抗体IC7与交叉反应蛋白的结合。这些结果提供了证据，表明1型M蛋白含有至少一种与人肾小球和心肌共有的自身免疫表位。
