Development of genus and species specific monoclonal antibodies against Schistosoma SP.from schistosoma mekongi Voge et al.,1978

Abstract

Monoclonal antibodies (MoAbs) directed against Schistosoma mekongi were produced by the in vitro fusion of the spleen cells, obtained from mice infected with S. mekongi and P3U1 myeloma cells. A total of 388 hybridoma clones were produced and grown successfully in the culture. These hybridom clones were examined for producing specific antibodies against the tegumental antigens of S. mekongi by using ELISA technique. Of the 388 clones, 53 stable clones were selected for recloning by limiting dilution method. Initial characterization of monoclonal antibodies was tested by using immunoblotting assay against tegumental antigens of S. mekongi. The clear reaction bands were observed in 13 MoAb clones. Although most MoAbs have been found to bind to rather heterogeneous epitopes ranging from Mr 125 to 29 kDa, there were two MoAbs, namely 5D4-2-1 and 6B2-1-19 which have been found to recognize single epitope at Mr 38 kDa and 97 kDa, respectively. Both 5D4-2-1 and 6B2-1-19 clones were found to secret IgM antibo dies. When these to MoAbs were tested for binding with frozen sections of S. mekongi adult male worms by immunofluorescence and immunoperoxidase assays, both of them have been found to recognize the target epitopes on the surface tegument of S. mekongi adult worm. Paraffin sections were used with immunoperoxidase assay but the sensitivity of this technique was much reduced. This may be due to the lossening of some antigenic components during the process of paraffin preparation. In this study, both polyclonal and monoclonal antibodies have been used for characterization of the antigenic epitopes on the teguments of S. mekongi, S. japonicum and S. mansoni adult worms by immunoblotting technique. The polyclonal antibodies did not give any conclusive result. On the other hand, some good results were obtained when 5D4-2-l and 6B2-1-19 MoAbs were used. The 5D4--2-1 MoAb has been found to react with the Mr 38 kDa epitope of al] three species of schistosomes used in this study. The 6B2-1-19 MoAb reacted specifically with only Mr 97 kDa epitope of S. mekongi but not with the other schistosome speicies. The finding of the genus- and species-specific monoclonal antibodies would provide a useful tool in the field of immunodiagnosis as well as vaccine development.