Immunodiagnostic Properties of Wucheraria bancrofti SXP-1, a Potential Filarial Diagnostic Candidate Expressed in Tobacco Plant, Nicotiana tabacum.

Transgenic tobacco plants were developed expressing WbSXP-1, a diagnostic antigen isolated from the cDNA library of L3 stage larvae of Wucheraria bancrofti. This antigen produced by recombinant Escherichia coli has been demonstrated by to be successful as potential diagnostic candidate against lymphatic filariasis. A rapid format simple and qualitative flow through immune-filtration diagnostic kit has been developed for the identification of IgG antibodies to the recombinant WbSXP-1 and is being marketed by M/S Span Diagnostics Ltd in India and Africa. Here, we present the results of experiments on the transformation and expression of the same filarial antigen, WbSXP-1, in tobacco plant, Nicotiana tabacum, to produce plant-based diagnostic antigen. It was possible to successfully transform the tobacco plant with WbSXP-1, the integration of the parasite-specific gene in plants was confirmed by PCR amplification and the expression of the filarial protein by Western blotting. The immunoreactivity of the plant-produced WbSXP-1 was assessed based on its reaction with the monoclonal antibodies developed against the E. coli-produced protein. Immunological screening using clinical sera from patients indicates that the plant-produced protein is comparable to E. coli-produced diagnostic antigen. The result demonstrated that plants can be used as suitable expression systems for the production of diagnostic proteins against lymphatic filariasis, a neglected tropical infectious disease which has a negative impact on socioeconomic development. This is the first report of the integration, expression and efficacy of a diagnostic candidate of lymphatic filariasis in plants.Key MessageTransgenic tobacco plants with WbSXP-1, a filarial diagnostic candidate, were developed. The plant-produced protein showed immunoreactivity on par with the E. coli product.