Johnson D R, Ferrieri P
J Clin Microbiol. 1984 Apr;19(4):506-10. doi: 10.1128/jcm.19.4.506-510.1984.
Studies were carried out on the distribution of the Ibc protein antigenic marker in wild-type strains of group B streptococci of diverse serotypes isolated from epidemiological studies. Rabbits were immunized with group B streptococcal strain H36B, a prototype Ib strain, to produce antibody to the Ibc protein antigens. One antiserum (no. 970) contained antibody only against the trypsin-sensitive (TS) portion of the Ibc antigen. A second antiserum (no. 973), however, contained antibody to both the TS and the trypsin-resistant (TR) determinants or components of the antigen. A total of 785 wild-type strains of group B streptococci were serotyped by using antiserum 973 as well as antisera to the polysaccharide types Ia, Ib, II, III, and IV. Remarkably, 59% of all the strains tested (462 of 785) reacted positively with the Ibc antiserum, although not all carried both components of the Ibc antigen. Of the 99 Ib strains examined, 84% carried both TS and TR components. In contrast, 96% of the 202 Ic strains carried only the TR component of the Ibc antigen. Antiserum 970 failed to identify these strains. Routine typing with an antiserum which contains antibodies to only one portion of the Ibc antigen could result in significant serotype misidentification. Differentiation of group B streptococcal strains by the presence or absence of individual TS or TR components of the Ibc antigen could prove to be a useful additional epidemiological and serological marker. It is noteworthy that wild-type Ic strains carry, ordinarily, only the TR component, in contrast to the prototype Ic strain, which possesses the complete Ibc protein antigen. The possible contribution of the Ibc antigen to group B streptococcal virulence is of interest and requires further study.
对从流行病学研究中分离出的不同血清型B族链球菌野生型菌株中的Ibc蛋白抗原标志物分布进行了研究。用B族链球菌H36B菌株（一种I b型原型菌株）免疫兔子，以产生针对Ibc蛋白抗原的抗体。一种抗血清（编号970）仅含有针对Ibc抗原胰蛋白酶敏感（TS）部分的抗体。然而，第二种抗血清（编号973）含有针对抗原的TS和胰蛋白酶抗性（TR）决定簇或成分的抗体。使用抗血清973以及针对多糖类型Ia、Ib、II、III和IV的抗血清对总共785株B族链球菌野生型菌株进行了血清分型。值得注意的是，尽管并非所有菌株都携带Ibc抗原的两种成分，但所有测试菌株中有59%（785株中的462株）与Ibc抗血清呈阳性反应。在检测的99株I b型菌株中，84%同时携带TS和TR成分。相比之下，202株I c型菌株中有96%仅携带Ibc抗原的TR成分。抗血清970无法识别这些菌株。使用仅含有针对Ibc抗原一部分抗体的抗血清进行常规分型可能会导致严重的血清型错误鉴定。根据Ibc抗原单个TS或TR成分的有无来区分B族链球菌菌株可能会成为一种有用的额外流行病学和血清学标志物。值得注意的是，与具有完整Ibc蛋白抗原的原型I c型菌株相比，野生型I c型菌株通常仅携带TR成分。Ibc抗原对B族链球菌毒力的可能贡献值得关注，需要进一步研究。
