創傷弧菌是造成人類感染的病原體，它會導致嚴重的傷口感染和致命性的敗血症。在創傷弧菌感染的機制中，宿主細胞的毒殺被認為是重要機制。創傷弧菌的毒素RtxA是由4701個氨基酸，分子量大小為〜501 kDa。創傷弧菌rtxA基因破壞後會造成細胞的毒殺能力大幅下降。在以前的研究中，我們發現創傷弧菌的h會造成巨噬細胞的毒殺作用。為了分析創傷弧菌RtxA毒素和H毒素對巨噬細胞的細胞毒殺作用，以rtxA基因、h基因或rtxA/h基因缺失的創傷弧菌突變株的菌體及培養上清液分析對巨噬細胞的毒殺反應。在菌體毒殺細胞的結果顯示，rtxA突變株、h突變株及rtxA/h雙突變株的細胞毒殺力均比野生株低。在培養上清液對細胞毒殺的結果顯示，h突變株的毒殺力明顯低於野生株及rtxA突變株。由以上結果顯示，創傷弧菌h基因是培養上清液中毒殺巨噬細胞的主要毒素。 Vibrio vulnificus is a human pathogen. It causes serious wound infection and fatal septicemia. The cytotoxicity is regarded as the important mechanism in the pathogenesis of this bacterium infection. V. vulnificus RtxA toxin is composed of 4701 amino acids wiht a molecuar mass of ~501 kDa. The rtxA inactivation resulted in decrease in cytotoxicity of Vibrio vulnificus in host cells. In previous studies, we found that the h contributes cytotoxicity to V. vulnificus in macrophages. To examine the cytotoxic effect of RtxA and H toxins of V. vulnificus on macrophages, macrophages were treated with V. vulnificus strains lacking rtxA or h or rtxA/h or culture supernatants of the mutants. The mutants lacking rtxA, h or rtxA/h induced a significant decrease of cytotoxicity as compared with wild type. In addition, the culture supernatant of h or rtxA/h mutants did not cause a significant cytotoxicity, while the culture supernatant of rtxA mutant induced similar levels of cytotoxicity as the wild type. These results indicated that H is a major cytotoxin in culture supernatant of V. vulnificus in this study.
