Immunochemical Characterization of Setaria cervi Microfilarial Antigens Using Novel Antibodies

Background: Filariasis affects millions of people in tropical and subtropical regions of the world and is caused by nematode roundworm. In order to develop a vaccine and specific diagnostic tests, it is important to characterize different stages of the filarial worms. Microfilariae (Mf) stage of the roundworm is found in host’s blood or lymph vessels and can be important not only for developing better immunodiagnostics but also for understanding immune recognition and its relevance to immunepathogenesis and protective immunity. Objective: The present study aimed to immunocharacterize Mf and adult worm antigens that could be helpful in future diagnostic tests. Methods: Four different immune sera against Setaria cervi intact live, intact live with adjuvant, intact glutaraldehyde fixed with adjuvant and total somatic Mf were prepared and used for the immunocharacterization of Mf antigens. Results: Our study results suggest that compared to fixed intact Mf, live intact Mf are more immunogenic, as the immune sera generated against intact live Mf showed high ELISA reactivity with Setaria cervi Mf and adult worm antigens. All the four immune sera IgG fractions had surface specificity as determined through considerable ELISA reactivity with S. cervi intact Mf. When tested under native conditions (immunoelectrophoresis and crossed immunoelectrophoresis), all the four immune rabbit sera were able to detect antigens of S. cervi Mf and adult stages. Conclusion: These results can be useful in detailed understanding of the complex nature of the Mf and adult antigens, which are prerequisites in the development of vaccine and more specific diagnostic tests.