Dissociation of IgG antibody-mediated clumps of Trypanosoma brucei gambiense by complement.
Aggregated trypanosome masses that had formed in the region of equivalence in the absence of complement were readily dissociated by complement. Complement-mediated dissociation of the clumped trypanosomes in the area of equivalence released approximately 50% of the previously bound surface antigens. These antigens were capable of rebinding to new IgG antibody. Experiments indicated that complement deposition altered the bivalent IgG antibody in the immune complex into a univalent form. The occurrence of such an event in the presence of complement provides a great advantage to the infected host in the killing of pathogens in vivo, as it enables a greater number of antibodies to attach to surface antigens and subsequently initiate complement activity.
Takayanagi
T
T
Department of Medical Zoology, Medical School, Nagoya City University, Japan.
Kawaguchi
H
H
Yabu
Y
Y
Itoh
M
M
Yano
K
K
D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D002478:Cells, Cultured; D003165:Complement System Proteins / Q000276:immunology*; D005260:Female; D007074:Immunoglobulin G / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D008297:Male; D011817:Rabbits; D051381:Rats; D014347:Trypanosoma brucei gambiense / Q000276:immunology*
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D007074:Immunoglobulin G; D003165:Complement System Proteins