C5a is the activator of endothelial cells expression adhesion molecule P-selector, which can be expressed on the surface of those cells, triggered adhesive response of PMN and endothelial cell surface.

• C5a是内皮细胞表达粘附分子P-选择素的激动剂，而P-选择素在内皮细胞激活时能迅速经细胞排列作用表达于内皮细胞表面，触发中性粒细胞(PMN)在内皮细胞表面的粘附反应。