創傷弧菌 (Vibrio vulnificus) 為一種棲居於海水中的嗜鹽性革蘭氏陰性菌，此菌株對人類是一種伺機性的致病菌，會經由傷口或食物的感染而引起嚴重的傷口感染和敗血症，其死亡率高達50%。在人體的防禦系統中，巨噬細胞為人體先天性免疫的第一道防線，當外來
的病原體入侵體內時，巨噬細胞會進行吞噬作用並清除這些病原體。創傷弧菌的感染之所以會引起嚴重的病症，主要是因為創傷弧菌會去毒殺巨噬細胞，使人體免疫力降低，進而造成感染。
在先前的研究結果指出，大腸桿菌表現的創傷弧菌hemolysin 會引起紅血球細胞破裂，造成細胞死亡。為了要確認創傷弧菌hemolysin對巨噬細胞也具有毒殺能力，經由細胞毒殺分析與顯微鏡的觀察，創傷弧菌hemolysin 突變株對巨噬細胞的毒殺能力相較於野生株來的
低，細胞的存活數也較多，細胞的外觀也較平滑完整，顯示創傷弧菌hly 對巨噬細胞具有毒殺的能力。另外，經由propidium iodide 及annexin V 染色的分析及pan-caspase inhibitor zVAD 處理下，顯示創傷弧菌hemolysin所引起巨噬細胞的死亡型態幾乎都是呈現細胞壞死的現象，而不是細胞的凋亡。除此之外，以PEG 的保護分析，顯示創傷弧菌hemolysin對巨噬細胞形成穿孔的現象，引起細胞的死亡，此hemolysin 在細胞膜所形成的孔洞直徑大小約為1.63~2.5 nm 之間。綜合以上所言，創傷弧菌hemolysin 可能在巨噬細胞造成穿孔的現象，致使巨噬細胞以細胞壞死的方式迅速死亡，達到毒殺巨噬細胞的目的。 Vibrio vulnificus is a halophilic gram-negative bacterium that has
emerged as an increasingly important pathogen capable of causing both
serious wound infections and fatal septicemia in humans. In this study,
we used hemolysin gene mutant of V. vulnificus to characterize the
mechanism for cell death induced by V. vulnificus hemolysin in
RAW264.7 macrophages. The cytotoxicity was lower to macrophages
after infection with the hemolysin mutant than in those that were infected
with wild type of V. vulnificus. The cytopathic effect is characterized as
necrosis rather than apoptosis based on annexin V and propidium iodide
staining and pan-caspase inhibitor zVAD treatment. The hemolysin toxin
caused cell lysis through formation of membrane pores between 1.63~2.5
nm in diameter. In addition, the hemolysin mutation resulted in these
cytophatic defects, which were fully restored by in cis complementation.
Taken together, these results indicate that V. vulnificus hemolysin toxin
elicits the necrotic death through formation of membrane pores in
macrophage.
