Characterisation of a heparan sulfate proteoglycan homologue OVPG-1 from Onchocerca volvulus

East African Medical Journal;82(12): 614-624

Objective: To determine the role of an immunodominant antigen OvPG-1 in human onchocerciasis. Design: Cross-sectional study of subjects living in three onchocerciasis endemic areas. Setting: Mbonge and Tubah divisions of Western Cameroon and in Esmeralda Province of Ecuador. Subjects: There were 94 and 99 subjects from the Cameroon rain forest and savannah respectively, and 83 endemic residents from Ecuador. Results: The IgG2 anti-OvPG-1 responses of visually impaired and microfiladermic patients were significantly higher than for their age and sex matched counterparts with normal vision and no microfiladermia (p=0.024). Furthermore, the isotype specificity of anti-OvPG-I responses varied for the various onchocerciasis endemic zones. IgGl, IgG2, IgG3 and IgE levels correlated with the presence of microfilariae in Cameroon, but not in Ecuador. Conclusion: Increased IgG and IgE levels to the antigen OvPG-1 seem to correlate with the development of onchocercal eye pathology. The present results suggest that the OvPG1 is a dominant antigen of Onchocerca volvulus with a significant role in the pathogenesis of onchocerciasis.