Mechanism of Metarhizium rileyi evading cellular immune responses in Helicoverpa armigera
Mechanism of Metarhizium rileyi evading cellular immune responses in Helicoverpa armigera
复制标题
莱氏绿僵菌逃避棉铃虫细胞免疫反应的机制
DOI：
10.1002/arch.21769
复制
发表时间：
2021-02-15
影响因子：
2.2
通讯作者：
Liu, Xu-Sheng
中科院分区：
文献类型：
--
作者：
Li, Li;Zhong, Ke;Liu, Xu-Sheng
昆虫病原真菌进入宿主血腔后，转变为不被宿主血细胞识别的酵母样菌丝体，并在血淋巴中广泛复制。菌丝体逃避宿主细胞免疫的机制尚不清楚。本研究比较了莱利绿僵菌分生孢子和菌丝体对棉铃虫的免疫应答和宿主模式识别受体的识别作用。我们发现，宿主血细胞的吞噬和吞噬菌丝体的能力弱于对分生孢子的反应，这表明菌丝体更能够逃避宿主的细胞免疫。此外，我们发现H.菌丝体的棉铃虫β-1，3-葡聚糖识别蛋白比分生孢子低得多。未观察到H.棉铃虫C型凝集素3（HaCTL 3）对菌丝体，HaCTL 3的结合显着低于菌丝体比分生孢子，表明宿主PRRs具有较低的亲和力菌丝体比分生孢子。这项研究提供了直接的证据表明，昆虫病原真菌逃避宿主细胞免疫的机制涉及宿主PRR无法充分识别菌丝体，引发细胞免疫反应。
Upon entry into the hemocoel of host insects, entomopathogenic fungi switch to yeast-like hyphal bodies that are not recognized by host hemocytes and replicate extensively in the hemolymph. The mechanism by which hyphal bodies evade host cellular immunity is not well understood. This study compares Metarhizium rileyi conidia and hyphal bodies with respect to elicitation of the immune response of Helicoverpa armigera and recognition by host pattern recognition receptors (PRRs). We found that the ability of host hemocytes to phagocytize and nodulate hyphal bodies was weaker than those responses against conidia, suggesting that hyphal bodies are more able to evade host cellular immunity. Additionally, we found that the binding affinity of H. armigera beta-1,3-glucan recognition proteins was much lower for hyphal bodies than for conidia. We observed no agglutination response of H. armigera C-type lectin 3 (HaCTL3) against hyphal bodies, and HaCTL3 bound significantly less to hyphal bodies than to conidia, indicating that host PRRs have a lower affinity for hyphal bodies than for conidia. This study provides direct evidence that the mechanism whereby entomopathogenic fungi escape host cellular immunity involves the inability of host PRRs to sufficiently recognize hyphal bodies to elicit the cellular immune response.