Sato H, Sato Y
Department of Bacteriology, National Institute of Health, Tokyo, Japan.
FEMS Microbiol Lett. 1994 Jan 1;115(1):63-9. doi: 10.1111/j.1574-6968.1994.tb06615.x.
Pertussis toxin, the most important protective antigen of Bordetella pertussis, is a 106-kDa hexameric protein composed of an A-protomer (subunit S1) and a pentameric B-oligomer (S2 + S3 + 2S4 + S5). The most potent mouse-protective monoclonal antibodies against both respiratory and intracerebral infections were specified for either S1 or S4 and competed with each other in binding to epitopes of native pertussis toxin captured by haptoglobin or in solution, although they did not compete on unfolded pertussis toxin. These data suggest that the protective epitope(s) of S1 and S4 are very closely correlated; they are probably close together sterically. Non-protective anti-S1 and anti-S4 monoclonal antibodies recognized inner antigenic determinants which are not exposed on the surface of native pertussis toxin and interfered with association of the A-protomer and the B-oligomer. These data suggest that the A-protomer and the S4 subunit of the B-oligomer may be closely associated in the native hexameric pertussis toxin molecule.
百日咳毒素是百日咳博德特氏菌最重要的保护性抗原，是一种106千道尔顿的六聚体蛋白，由一个A原体（S1亚基）和一个五聚体B寡聚体（S2 + S3 + 2S4 + S5）组成。针对呼吸道和脑内感染的最有效的小鼠保护性单克隆抗体分别针对S1或S4，它们在与结合珠蛋白捕获的天然百日咳毒素表位或溶液中的表位结合时相互竞争，尽管它们在未折叠的百日咳毒素上不竞争。这些数据表明，S1和S4的保护性表位非常密切相关；它们在空间上可能彼此靠近。非保护性抗S1和抗S4单克隆抗体识别未暴露在天然百日咳毒素表面的内部抗原决定簇，并干扰A原体和B寡聚体的结合。这些数据表明，在天然六聚体百日咳毒素分子中，A原体和B寡聚体的S4亚基可能紧密相关。
