Ohta Masayuki, Watanabe Ayako, Mikami Tetsuo, Nakajima Yuichi, Kitami Madoka, Tabunoki Hiroko, Ueda Kenjirou, Sato Ryoichi
Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan.
Dev Comp Immunol. 2006;30(10):867-77. doi: 10.1016/j.dci.2005.12.005. Epub 2006 Jan 10.
Hemocytes play an important role in cellular reactions in the immune system. Although the recognition of pathogens is thought to involve pattern-recognition proteins (PRPs) in insects, the exact mechanisms by which insect hemocytes recognize pathogens are not clear. This study examined the mechanism by which Bombyx mori hemocytes recognize microorganisms and pathogen-associated molecular patterns (PAMPs) using flow cytometry and fluorescence microscopy. Fluorescence-labeled bacterial or fungal cells were observed to bind to hemocytes and this binding was inhibited by adding lipoteichoic acid (LTA) or beta-1,3-glucan. Lipopolysaccharide (LPS) bound to hemocytes directly. These results suggest that hemocytes have a mechanism that recognizes LPS, LTA, and beta-1,3-glucan directly. Previously, we identified two types of C-type lectin (BmLBP and BmMBP) and showed that they recognize a variety of PAMPs leading to the induction of nodule formation. These lectins enhanced hemocyte binding to microorganisms and their direct binding to hemocytes suggests that hemocytes have a mechanism for recognizing microorganisms using lectin receptors.
血细胞在免疫系统的细胞反应中发挥着重要作用。虽然人们认为昆虫中病原体的识别涉及模式识别蛋白（PRPs），但昆虫血细胞识别病原体的确切机制尚不清楚。本研究使用流式细胞术和荧光显微镜检查了家蚕血细胞识别微生物和病原体相关分子模式（PAMPs）的机制。观察到荧光标记的细菌或真菌细胞与血细胞结合，并且通过添加脂磷壁酸（LTA）或β-1,3-葡聚糖可抑制这种结合。脂多糖（LPS）直接与血细胞结合。这些结果表明，血细胞具有直接识别LPS、LTA和β-1,3-葡聚糖的机制。此前，我们鉴定出两种C型凝集素（BmLBP和BmMBP），并表明它们识别多种PAMPs，从而导致结节形成的诱导。这些凝集素增强了血细胞与微生物的结合，并且它们与血细胞的直接结合表明血细胞具有利用凝集素受体识别微生物的机制。
