Enhancing the efficacy of diagnostic candidate WbSXP-1 and development of antigen based immune- diagnostic prototype for human lymphatic filariasis

Abstract

Lymphatic filariasis (LF) is a major cause of acute and chronic morbidity affecting humans in tropical and subtropical areas of Asia, Africa, the Western Pacific, and some parts of the Americas. India accounts for a significant number of people suffering from parasitic infection. As part of the WHO sponsored Filarial Genome Project, many novel genes of W.bancrofti and B.malayi important for their diagnostic, prophylactic, chemotherapeutic potential and other genes involved in immune evasion and parasite survival mechanisms have been identified from various stages of the parasite life cycle. WHO has highlighted the importance of developing diagnostic assays, as a surveillance and measure to eliminate Lymphatic Filariasisand#8223;. Presently, problems in the immuno-diagnosis are the specificity to detect brugian and bancroftian parasites, stability of diagnostic lines, cost of assays, time and manpower associated with use of ELISA kit and PCR etc.,. These affect their application for disease assessment in endemic area. Two monoclonal antibodies namely 1F6H3 (IgG2a) and 2E12E3 (IgM) with better sensitivity were selected for validating capture ELISA. Sandwich ELISA was developed with SXP monoclonals as capture antibody and rabbit anti-SXP-1 polyclonal as detection antibody and validated against recombinant as well as native microfilaria antigen. The efficiency of sandwich ELISA was analyzed with MF positive samples and used NEN as control. The evaluated results of sandwich assay showed 100% sensitivity in the data obtained from experimental test groups. Results showed that the MF groups carried significantly higher antigen units (p lt 0.0001) compared to endemic normal, chronic pathology and non endemic normal groups. The MF group had the 100% antigen positive reactivity (0.769 ± 0.14) while EN and CP groups showed the 16.66 % (0.259 ± 0.084) and 0 % (0.271 ± 0.038) respectively.