[ODP22] 5. 病原性-b. 毒素・エフェクター・生理活性物質

[ODP-132] ボツリヌス菌および関連するクロストリジウム属細菌が産生するメンブレンベシクルに対する炎症応答の解析

小林 伸英¹，安部 公博²，赤木 佐千代¹，阿松 翔¹，松村 拓大¹，野村 暢彦²，尾花 望³，藤永 由佳子¹ (¹金沢大・医・細菌学，²筑波大・生命環境，³筑波大・医・TMRC)

Clostridium botulinum produces botulinum neurotoxin complexes that cause botulism. Previous studies elucidated the molecular pathogenesis of botulinum neurotoxin complexes; however, it currently remains unclear whether other components of the bacterium affect host cells. Recent studies provided insights into the role of bacterial membrane vesicles (MVs) produced by some bacterial species in host immunity and pathology. We herein examined and compared the cellular effects of MVs isolated from 4 strains of C. botulinum with those of closely related C. sporogenes, and 2 strains of the symbiont C. scindens. MVs derived from all strains induced inflammatory cytokine expression in intestinal epithelial and macrophage cell lines. Cytokine expression was dependent on MyD88 and TRIF, signal adaptor proteins for Toll-like receptors (TLRs). MVs were phagocytosed by RAW264.7 cells, and the inhibition of phagocytosis did not reduce the induction of cytokine expression. On the other hand, the inhibition of dynamin or phosphatidylinositol-3 kinase (PI3K) suppressed the induction of cytokine expression by MVs, suggesting the importance of these factors downstream of TLR signaling. The present results indicate that MVs from C. botulinum and related clostridial species induce host inflammatory responses.