In multicellular organisms, specialized immune cells have evolved, capable of the phagocytosis of foreign cells as well as of self cells changed by infection or cancer.

• 在多细胞生物中，则演化出具有专一性的免疫细胞，能通过吞噬作用吞食外来细胞，及那些因感染或恶性肿瘤而病变的自身细胞。