Anbutsu H, Fukatsu T
National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
Insect Mol Biol. 2010 Aug;19(4):481-8. doi: 10.1111/j.1365-2583.2010.01008.x. Epub 2010 Apr 22.
How endosymbiotic bacteria cope with host insect immunity is poorly understood. Here we report previously unknown aspects of immunity-mediated interactions between male-killing/non-male-killing spiroplasmas and Drosophila host. The male-killing spiroplasma tended to reduce constitutive expression levels of some antimicrobial peptide genes, while the non-male-killing spiroplasma did not. In mutant flies whose innate immunity is constitutively up-regulated, infection densities of the male-killing spiroplasma were significantly suppressed but managed to increase during the aging of adult flies, indicating that the male-killing spiroplasma is resistant to mounted immune attacks. These findings suggest that not only immune evasion but also immune suppression and tolerance are involved in the establishment and maintenance of the insect-microbe symbiotic association.
内共生细菌如何应对宿主昆虫的免疫反应，目前尚不清楚。在此，我们报告了雄性致死/非雄性致死的螺原体与果蝇宿主之间免疫介导相互作用的一些此前未知的方面。雄性致死螺原体倾向于降低一些抗菌肽基因的组成型表达水平，而非雄性致死螺原体则不会。在先天免疫持续上调的突变果蝇中，雄性致死螺原体的感染密度显著受到抑制，但在成年果蝇衰老过程中又设法增加，这表明雄性致死螺原体对发起的免疫攻击具有抗性。这些发现表明，昆虫-微生物共生关系的建立和维持不仅涉及免疫逃避，还涉及免疫抑制和免疫耐受。
