Sargent S J, Beachey E H, Corbett C E, Dale J B
J Immunol. 1987 Aug 15;139(4):1285-90.
Synthetic peptide fragments spanning the entire amino acid sequence of pep M5 were used to detect epitopes cross-reactive with heart tissue components other than myosin. Heart-cross-reactive pep M5 antibodies were affinity purified by absorption to and elution from purified sarcolemmal membranes. Only one of the synthetic peptides, SM5(164-197)C, inhibited reactivity of the affinity-purified antibodies with pep M5 by ELISA. SM5(164-197)C linked to KLH evoked both opsonic and heart-cross-reactive antibodies in rabbits. In addition to type 5, the immune sera opsonized M types 6, 18, 19, and 49 streptococci. The antisera reacted strongly with isolated cardiac sarcolemmal membranes by immunofluorescence. In Western blots of cardiac tissue, the anti-SM5(164-197)C reacted with a 40 kDa protein but not with myosin. The reaction was inhibited by pep M5 and SM5(164-197)C but not by any of the other peptides spanning pep M5. The cross-reactive anti-SM5(164-197)C affinity purified on sarcolemmal membranes opsonized types 5, 6, and 19 but not type 24 streptococci. These results indicate that SM5(164-197)C contains heart-cross-reactive, opsonic epitopes that are shared among heterologous serotypes of group A streptococci.
跨越pep M5整个氨基酸序列的合成肽片段用于检测与肌球蛋白以外的心脏组织成分发生交叉反应的表位。通过与纯化的肌膜进行吸附和洗脱，对与心脏发生交叉反应的pep M5抗体进行亲和纯化。在酶联免疫吸附测定（ELISA）中，只有一种合成肽SM5(164 - 197)C能抑制亲和纯化抗体与pep M5的反应性。与钥孔血蓝蛋白（KLH）偶联的SM5(164 - 197)C在兔体内诱发了调理素抗体和与心脏发生交叉反应的抗体。除了5型外，免疫血清还能调理6型、18型、19型和49型链球菌。抗血清通过免疫荧光与分离的心脏肌膜发生强烈反应。在心脏组织的蛋白质印迹分析中，抗SM5(164 - 197)C与一种40 kDa的蛋白质发生反应，但不与肌球蛋白发生反应。该反应被pep M5和SM5(164 - 197)C抑制，但不被跨越pep M5的任何其他肽抑制。在肌膜上亲和纯化的交叉反应性抗SM5(164 - 197)C能调理5型、6型和19型链球菌，但不能调理24型链球菌。这些结果表明，SM5(164 - 197)C含有与心脏发生交叉反应的调理素表位，这些表位在A组链球菌的不同血清型之间是共享的。
