补体是正常血浆中存在的一组蛋白酶系。它的主要作用是在体内免疫反应中的效应阶段杀伤携带抗原的细胞。如果携带抗原的细胞是入侵的细菌,补体能杀伤细菌,其作用对机体有利;如果携带抗原的细胞是机体自身的细胞,补体又能造成组织的损伤,其作用又对机体有害。这种既有利又有害的特点,体现了补体作用的两重性。当携带抗原的细胞(如细菌)入侵机体后,首先是由特异的抗体与之结合。不过这种结 Complement is a group of proteases present in normal plasma. Its primary role is to kill the antigen-bearing cells during the effector phase of the immune response in the body. If the antigen-bearing cells are invading bacteria, complement can kill bacteria, its role on the body beneficial; if the antigen-bearing cells are the body’s own cells, complement and can cause tissue damage, its role in turn harmful to the body. This is both beneficial and harmful characteristics, reflecting the dual role of complementarity. When the antigen-bearing cells (such as bacteria) invade the body, the first is bound by a specific antibody. However, this knot