Hashii N, Kondo S, Iguchi T, Nishibuchi M, Hisatsune K
Department of Microbiology, School of Pharmaceutical Sciences, Josai University, Sakado, Saitama, Japan.
Microbiol Immunol. 2000;44(4):229-34. doi: 10.1111/j.1348-0421.2000.tb02488.x.
Chemical and serological studies have been carried out on the O-antigenic lipopolysaccharides (LPS) of six strains, U-6443, W-90144, X-3972, AD-7999, 90A-6611 and KX-V212, of Vibrio parahaemolyticus isolated from patients. The O-serotypes of these strains have not been identified because they were not agglutinated by any diagnostic antisera against known O-serotype strains. A compositional sugar analysis of their LPS revealed that out of the six O-untypeable (OUT) strains, U-6443, W-90144 and AD-7999 strains belonged to chemotype II (chemotype of O2), 90A-6611 and KX-V212 strains to chemotype III (chemotype of O3, O5, O11 and O13) and X-3972 strain to chemotype IV (chemotype of O4). A structural analysis of LPS isolated from KX-V212 revealed that the inner core region of the LPS consisted of only one mole of 2-keto-3-deoxy-D-manno-octonic acid, which carried a phosphate group at position C4 and the outer core at position C5. In passive hemolysis tests performed by using LPS as the antigen to sensitize sheep red blood cells (SRBC), and diagnostic antisera (O1 to O11) or anti-whole-cell rabbit antisera raised against O12, O13 and the six OUT strains, strong cross-reactivity was observed among LPS derived from the strains belonging to chemotype II (U-6443, W-90144, AD-7999 and O2). Strong cross-reactivity was also observed between X-3972 (chemotype IV) and O4 LPS. In contrast, LPS from two of the strains belonging to chemotype III (90A-6611 and KX-V212) did not react with any of the antisera raised against known O-serotypes. Cross-absorption tests showed that the O-antigens of U-6443, W-90144 and AD-7999 were identical to that of O2, and the O-antigen of X-3972 to that of O4. On the other hand, after the absorption of antisera raised against 90A-6611 and KX-V212 with O2 cells, the hemolytic activities against SRBC sensitized with homologous LPS were still retained at a high titer, whereas the hemolytic activities against SRBC sensitized with LPS from other O-serotype strains were completely eliminated. A cross-absorption test revealed that the O-antigens of these two strains were identical to each other. Thus, it was demonstrated that the O-serotype of OUT strains 90A-6611 and KX-V212 was not involved in the known O-serotypes; rather it represented a novel serotype which has not hitherto been reported.
对从患者分离出的6株副溶血性弧菌（U-6443、W-90144、X-3972、AD-7999、90A-6611和KX-V212）的O抗原脂多糖（LPS）进行了化学和血清学研究。这些菌株的O血清型尚未确定，因为它们不能被任何针对已知O血清型菌株的诊断抗血清凝集。对其LPS的组成糖分析表明，在这6株不可分型O（OUT）菌株中，U-6443、W-90144和AD-7999菌株属于化学型II（O2的化学型），90A-6611和KX-V212菌株属于化学型III（O3、O5、O11和O13的化学型），X-3972菌株属于化学型IV（O4的化学型）。对从KX-V212分离出的LPS的结构分析表明，LPS的内核区域仅由一摩尔2-酮-3-脱氧-D-甘露糖辛酸组成，其在C4位置带有磷酸基团，在外核的C5位置带有磷酸基团。在用LPS作为抗原致敏绵羊红细胞（SRBC）进行的被动溶血试验中，以及使用诊断抗血清（O1至O11）或针对O12、O13和6株OUT菌株产生的抗全细胞兔抗血清进行试验时，在属于化学型II的菌株（U-6443、W-90144、AD-7999和O2）衍生的LPS之间观察到强烈的交叉反应。在X-3972（化学型IV）和O4 LPS之间也观察到强烈的交叉反应。相比之下，属于化学型III的两株菌株（90A-6611和KX-V212）的LPS与针对已知O血清型产生的任何抗血清均无反应。交叉吸收试验表明，U-6443、W-90144和AD-7999的O抗原与O2的O抗原相同，X-3972的O抗原与O4的O抗原相同。另一方面，在用O2细胞吸收针对90A-6611和KX-V212产生的抗血清后，对同源LPS致敏的SRBC的溶血活性仍以高滴度保留，而对来自其他O血清型菌株的LPS致敏的SRBC的溶血活性则完全消除。交叉吸收试验表明，这两株菌株的O抗原彼此相同。因此，证明OUT菌株90A-6611和KX-V212的O血清型不涉及已知的O血清型；相反，它代表了一种迄今尚未报道的新型血清型。
