Immunological activities of monoclonal IgG1 antibody against Trypanosoma gambiense.

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.

Diversity of complement-mediated immune reaction to Trypanosoma gambiense.

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.

Multi-dot enzyme-linked immunosorbent assay for serodiagnosis of trematodiasis.

A nitrocellulose membrane strip dotted with crude antigens of trematodes, such as Paragonimus miyazakii, P. westermani, Fasciola sp., Clonorchis sinensis and Schistosoma japonicum was applied for serodiagnosis of trematodiasis. With peroxidase conjugated anti-human IgG and 4-chloro-1-naphthol as a substrate, antibodies in trematodiasis patient sera were clearly detected on the strip as bluish purple spots. Densities of the spots correlated well with values obtained by standard micro-ELISA. Cross-reactions among the trematode antigens, which is occurred more frequently than by ELISA, were observed with this method. However, the darkest spot correlated with the infecting parasite in all cases. With the high reliability and advantage that crude antigens can be used, this simple method, multi-dot ELISA, is considered to be useful for serodiagnosis of trematodiasis.