ABSTRACT
The present paper deals with the immune reaction between a monoclonal IgG1 antibody and Trypanosoma gambiense. The aggregation of trypanosomes, immune adherence to macrophages and protection against infection are associated with the antibody. IgG1-mediated clumping of trypanosomes is readily dissociated by the addition of complement. Dissociation of the clumped trypanosomes in the equivalence area released approximately fifty percent of previously bound surface antigens. These antigens were capable of binding again to new IgG1 antibody. Complement deposition rendered bivalent IgG1 antibody in the immune complex functionally univalent. Such an 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 to initiate complement activity.
Subject(s)
Animal Population Groups , Animals , Antibodies, Monoclonal/immunology , Antigens, Surface/immunology , Cell Aggregation/immunology , Complement System Proteins/immunology , Female , Humans , Immune Adherence Reaction , Infant , Macrophages/immunology , Male , Rats , Trypanosoma brucei gambiense/immunologyABSTRACT
Intact and papain-treated Trypanosoma gambiense clone populations, each expressing special antigens on their cell surfaces, were mixed with rabbit antiserum in the presence of complement. Two distinct types of immune reaction between trypanosomes and antisera were observed: clumping followed by dissociation (CD) and inhibition of aggregation (IA). Special antigens on the cell surface of trypanosomes exposed after papain digestion are implicated in both types of immune reaction. IA was considered to be more effective as an immunological response which would allow the infected host to clear the pathogen without any obstruction of capillaries and impairment of blood flow caused by clumping masses of trypanosomes.