先前的研究已经证实蜕皮激素在果蝇等昆虫免疫应答中的作用，但昆虫是如何调控蜕皮激素滴度变化来影响免疫应答仍然是一个谜，并且蜕皮激素在家蚕免疫应答中的作用仍不确定。我们的初步研究结果表明，蜕皮激素在家蚕免疫应答中起正调控作用；当家蚕受到细菌感染后蜕皮激素合成酶（3-脱氢蜕皮激素-3β-还原酶（3DE-3β-reductase））的活性显著上升，这有可能会提高家蚕体内蜕皮激素的滴度，而蜕皮激素则会加强家蚕对细菌的抵抗能力。本项目将在此基础上，采用荧光定量PCR，RNA干涉和真核表达系统等技术研究3DE-3β-reductase基因在家蚕免疫应答中的作用。该项目的实施和完成可望第一次阐明蜕皮激素滴度变化在家蚕免疫应答中的调控机制，其研究成果不仅可以拓展我们对蜕皮激素在昆虫免疫中作用的认知，有重要理论意义，对家蚕抗病育种也有指导意义。

Previous studies have proven that ecdysone plays an important role in fruit fly and other insect immune responses. However, how insects regulate the ecdysone to affect the immunity is still unknown, and the function of the ecdysone in the domestic silkworm immune response is also obscure. Our preliminary results suggested that the silkworm immunity can be positively regulated by the ecdysone. In addition, after infected with the bacteria, the activity of the ecdysone biosynthetic enzyme (3-dehydroecdysone-3β-reductase) was significantly increased, which may elevate the ecdysone titer that could modulate the silkworm immune response. Based on these observations, real-time quantity PCR, RNA interference and eukaryotic expression system will be used to investigate the function of the 3DE-3β-reductase gene in the silkworm immune response in this project. The implementation and completion of the project is expected to elucidate the regulation mechanism of the ecdysone titer in the silkworm immune response for the first time. The finding of this research can not only enrich our knowledge about the function of the ecdysone in the silkworm immunity, which has an important theoretical significance, but also has guiding significance for pathogen resistance silkworm breeding.