STUDY ON THE SURFACE ANTIGENS AND GENOTYPES OF GROUP E STREPTOCOCCI

将E群链球菌(GES)全细胞免疫的小鼠脾细胞与骨髓瘤细胞融合，制备了抗GES表面抗原的单抗(MAb II-T、IV21和V16)。其中一株单抗(MAb II-T)在酶免疫分析(EIA)中与血清型II和V型的全细胞反应，并与这两种血清型的高压灭菌生理盐水提取液进行凝胶扩散试验。单抗IV21与血清IV型毒株发生特异性反应。另一方面，单抗V16与几乎所有的GES菌株和变形链球菌的e型菌株都有反应。采用高压灭菌法从GES全细胞中提取粗抗原。提取液经DEAE-Sephadex A-25柱层析、蛋白酶K处理、Sephadex G-200柱层析。纯化的单抗II-T是一种由98.6%的碳水化合物和1.4%的蛋白质组成的多糖(PS)，不含磷。单抗V16的碳水化合物含量为92.4%，蛋白质含量为7.6%。目前正在提纯单抗IV21的抗原。此外，从6个血清型菌株(II、IV、V、VI、VII和VIII型)和3株GeS临床分离株中提取DNA，测定这些DNA的GC含量(%)为36~38%，表明6个血清型之间的值没有明显差异。以血清型II型毒株的DNA为探针进行DNA-DNA杂交实验，只有V型毒株的DNA与探针有100%的同源性，其他毒株的DNA同源性在56%~76%之间。目前正在进行GES的核糖核酸分型。

Monoclonal antibodies(MAbs II-T, IV21 and V16) to surface antigen of group E streptococci (GES) were prepared by fusing myeloma cells with spleen cells of mice immunized with whole cells of GES.One of them, MAb II-T, reacted in an enzyme immunoassay (EIA) with whole cells of serotypes II and V strains, and in a gel diffusion test with autoclaved-saline extracts of both serotypes. MAb IV21 reacted specifically with a serotype IV strain. On the other hand, MAb V16 reacted with almost all strains of GES and serotype e strains of S.mutans. The crude antigen was extracted from whole cell of GES by autoclaving. The extract was purified by DEAE-Sephadex A-25, followed by the treatment with Proteinase K, and further by chromatography with a Sephadex G-200 column. The purified antigen for MAb II-T was a polysaccharide (PS) composed of 98.6% carbohydrate and 1.4% protein with no detectable phosphorus. That for MAb V16 was also found to consist of 92.4% carbohydrate and 7.6% protein. The antigen for MAb IV21 is now being purified. Furthermore, DNA was extracted from 6 serotypes strains (II, IV, V, VI, VII, and VIII) and 3 clinical isolates of GES.The GC contents(%) of these DNAs were determined to be 36 to 38%, indicating that there is no clear difference in the values among 6 serotypes. In DNA-DNA hybridization experiments using radiolabelled DNA of serotype II strain as a probe, the DNA of only serotype V strain showed 100% homology to the probe while others were 56 to 76% homologous. The ribo-typing of GES in now in progress.