Recognition of foreign targets by insect hemocytes is a crucial first step for insect immunity against invading multicellular organisms in the hemocoel. To understand the mechanism of recognition, we observed the hemocyte behavior of Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) larvae against beads and the nonparasitic nematode Caenorhabditis elegans (Maupas) (Rhabditida: Rhabditidae) in the presence of plasma ex vivo using time-lapse microscopy. Both granular cells and plasmatocytes adhered to and spread on the surface of beads and nematodes. In addition, the spread plasmatocytes actively moved over the beads and nematodes. These results suggest that not only granular cells but also plasmatocytes can recognize foreign targets in the presence of insect plasma and that spread plasmatocytes can actively search for foreign targets. Hemocyte adhesion to beads and nematodes ex vivo was similar to that of the in vivo 1 h after injection. A divalent cation chelator inhibited the spreading and adhesion of plasmatocytes ex vivo, but it did not affect the adhesion of granular cells. The present method enables the analysis of acute hemocyte response against foreign targets in the presence of plasma.

中文翻译：

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在昆虫血浆存在下，昆虫血细胞对珠子和线虫的离体观察

昆虫血细胞识别外来目标是昆虫免疫抵抗血腔中入侵的多细胞生物的关键第一步。为了理解识别机制，我们使用延时显微镜观察了大蜡螟（鳞翅目：Pyralidae）幼虫对珠子和非寄生线虫秀丽隐杆线虫（Maupas）（Rhabditida：Rhabditidae）的血细胞行为。 . 颗粒细胞和浆细胞都粘附并散布在珠子和线虫的表面上。此外，扩散的浆细胞在珠子和线虫上积极移动。这些结果表明，在昆虫血浆存在的情况下，不仅颗粒细胞而且浆细胞可以识别外来目标，并且扩散的浆细胞可以主动寻找外来目标。血细胞在体外对珠子和线虫的粘附与注射后 1 小时的体内粘附相似。二价阳离子螯合剂在体外抑制浆细胞的扩散和粘附，但不影响颗粒细胞的粘附。本方法能够在血浆存在下分析针对外来目标的急性血细胞反应。