Takayanagi T, Kawaguchi H, Yabu Y, Itoh M, Yano K
Department of Medical Zoology, Medical School, Nagoya City University, Japan.
Trop Med Parasitol. 1991 Dec;42(4):394-8.
The aggregation of trypansomes, immune adherence to macrophage and protection against infection of Trypanosoma gambiense are associated with IgG3 antibody. IgG3-mediated clumping trypanosomes are readily dissociated by the aid of complement to become free. Dissociation of the clumped trypanosomes in the equivalence area released approximately fifty percent of previous bound surface antigens. These antigens were capable of binding again to new IgG3 antibody. Experiments indicated that complement deposition altered functionally bivalent IgG3 antibody in the immune complex into a univalent one. Such event in the presence of complement is of great advantage to the infected host in killing pathogens in vivo, as it allows more antibodies to attach to surface antigens and subsequently initiate complement activity.
布氏锥虫的聚集、对巨噬细胞的免疫黏附以及对布氏冈比亚锥虫感染的保护作用均与IgG3抗体有关。IgG3介导的锥虫聚集在补体的作用下很容易解离而变得游离。在等价区，聚集的锥虫解离后释放出约50%先前结合的表面抗原。这些抗原能够再次与新的IgG3抗体结合。实验表明，补体沉积可使免疫复合物中功能上二价的IgG3抗体转变为单价抗体。在补体存在的情况下，这种情况对受感染宿主在体内杀灭病原体具有很大优势，因为它能使更多抗体附着于表面抗原并随后启动补体活性。
