吞噬体
吞噬体（phagosome）也称为吞噬小体，是一种在胞吞作用中在被吞噬物质周围形成的囊泡，这种囊泡由细胞膜向细胞内凹陷产生。吞噬体是一种在免疫过程中常见的细胞结构，入侵机体内的病原微生物可在吞噬体中被杀灭、消化。在成熟过程中吞噬体需与溶酶体融合，生成兼具隔离与分解异己物质能力的吞噬溶酶体，这种经两种囊泡融合而成的新囊泡只曾在动物细胞中发现。
病原体躲避分解
一些通过胞吞作用进入病原体细菌能躲避分解，其中一部分（如考克斯氏体属细菌）可以在融合后的吞噬溶酶体中继续繁殖，[1]而另一部分（如立克次氏体属细菌）则能通过破坏吞噬体膜在吞噬体与溶酶体融合之前逃逸到细胞质基质中。[2]
包括结核分支杆菌（Mycobacterium tuberculosis）[3] [4]及鸟副结核分支杆菌（Mycobacteria avium paratuberculosis） [5]的许多分支杆菌属细菌还可以操纵寄主巨噬细胞，使含有亚硝酸的溶酶体不能与吞噬体融合成吞噬溶酶体。这种在成熟过程中被阻断的吞噬体反而会成为其中的病原体繁殖的适宜环境。[6]
参考文献
- ^ Hackstadt T and Williams J C "Biochemical stratagem for obligate parasitism of eukaryotic cells by Coxiella burnetii." Proc Natl Acad Sci U S A. 1981 May; 78(5): 3240–3244.
- ^ Winkler H H "Rickettsia Species (As Organisms)" Annual Review of Microbiology Vol. 44: 131-153
- ^ MacMicking, JD; Taylor, GA; McKinney, JD. Immune control of tuberculosis by IFN-γ –inducible LRG-47. Science. 2003, 302: 654–659. PMID 14576437.
- ^ Vandal, OH; Pierini, LM; Schnappinger, D; Nathan, CF; Ehrt, S. A membrane protein preserves intrabacterial pH in intraphagosomal Mycobacterium tuberculosis. Nat Med. August 2008, 14 (8): 849–854. PMID 18641659.
- ^ Kuehnel, MP; Goethe R, Habermann A, Mueller E, Rohde M, Griffiths G, Valentin-Weigand P. Characterization of the intracellular survival of Mycobacterium avium ssp. paratuberculosis: phagosomal pH and fusogenicity in J774 macrophages compared with other mycobacteria.. Cell Microbiol. August 2001, 3 (8): 551–566. PMID 11488816.
- ^ Tessema, MZ; Koets AP, Rutten VP, Gruys E. How does Mycobacterium avium subsp. paratuberculosis resist intracellular degradation?. Vet Q. 2001 month=November, 23 (4): 153–162. PMID 11765232.