Insilico design and characterization of OvMCBL01 chimeric antigen as a potential biomarker for the diagnosis of human onchocerciasis

Onchocerciasis is a parasitic disease that has a significant socioeconomic impact, especially in Sub-Saharan Africa. Due to successes recorded by programs set up to combat this disease, the public health goal of the disease in Africa has shifted from control of transmission to elimination. To define treatment endpoints, monitor elimination efforts, confirm elimination, and conduct post elimination surveillance, precise diagnosis is required. Current diagnostic tools are invasive, insensitive, and cannot distinguish between past and current infection. Furthermore, about 25% of infected persons are diagnosed as false negatives due to genetic variation, hence the need for more robust diagnostic tools. In the quest to identify novel biomarkers, mass spectrometric analysis was done using the parasite crude extract. This analysis revealed that 1393 proteins are expressed in the adult and microfilariae stages. Insilico screening performed to select proteins 1) with signal peptides, 2) not related to humans or other helminths, 3) are antigenic predicted only 6 proteins possessing these qualities. Predicted linear B-epitopes in the selected proteins were used to construct a chimeric antigen (OvMCBL01) that was predicted to be more antigenic than the constituent epitopes and the individual proteins. Furthermore, it was predicted to be stable upon expression in host cells with a stability index of 39.43. Bioinformatics tools were used to predict, refine, and validate the 3D structure of the chimera. This chimera will be validated serologically for its diagnostic potentials in onchocerciasis detection.