The most abundant class of antibodies found in blood serum and lymph and active against bacteria, fungi, viruses, and foreign particles. Immunoglobulin G antibodies trigger action of the complement system.免疫球蛋白G：存在于血清和淋巴中的最多抗体类，能有效地对抗细菌、真菌、病毒和异质微粒。免疫球蛋白G抗体会引起补体系统活动