Exploring Antigenic Properties and Immune Responses in Bufo himalayanus: Implications for Conservation and Biodiversity Protection

Background: The objective of the study is to investigate antigenic property of soluble antigens of Nematodes Cosmocercoides dukae isolated from infected Bufo himalayanus (Class Amphibia, order: Anura) and to investigate the nature of protective immune response in laboratory rats. Bufo himalayanus is a species found in the districts of Darjeeling, Sikkim and adjoining hills of the sub-Himalayan belt, at an altitude of 6000 ft. above the sea level and known to be heavily infested by natural gut dwelling nematode infections. The present study is a small step towards protection and conservation of this amphibian species.

Results: study of morphology of the nematode parasite confirmed it to be Cosmocercoides dukae. A crude whole body homogenate (antigenic protein) of the parasite was injected in healthy non-infected rats, spleen histo-architecture of treated rats differed from control rats. Humoral immune response assay by Gel Diffusion Precipitin (GDP) Test revealed that the parasite antigen invoked very little to no response. Study of the crude nematode antigenic protein extract concentration was 6.09 mg/ml and protein profile assay by SDS-PAGE showed seven major and several minor bands.

Discussion: Though humoral immune response assay of parasite in experimental rats evoked very little or no immune response, this would not mean absence of antibodies, rather the antibody titers were presumably very low. It is to be noted that spleen of treated rats showed a distinctive histological feature. GDP test with infected toad serum also showed negative result. But protein profile assay of antigenic protein by SDS-PAGE showed many bands of proteins, which could be isolated and tested for further characterization.

Conclusion: In order to maintain the Himalayan biodiversity, this amphibian species needs protection from such natural infective nematode parasites. If we are able to focus any light to this area, this knowledge might help the future research workers to plan for the protection of this species.