Visceral leishmaniasis is a Neglected Tropical Disease of high mortality caused by the protozoan Leishmania infantum. Its transmission cycle is complex, and it has in the domestic dog its main reservoir. The diagnostic tests currently used rely on prokaryotic systems’ proteins, but their low sensitivity increases the disease’s burden. The plant transient expression of recombinant proteins allows the production of complex antigens. However, this system has limited competitiveness against the bacterial production of purified antigens. Thus, we have shown that the L. infantum K39 antigen’s fusion to a hydrophobin allows its production for diagnostic tests without the need for intensive purification. The sera of naturally infected dogs specifically detect the semi-purified rK39-HFBI protein. The test validation against a panel of 158 clinical samples demonstrates the platform’s viability, resulting in sensitivity and specificity of 90.7 and 97.5%, respectively. Thus, the use of semi-purified antigens fused to hydrophobins can become the standard platform for large-scale antigens production to expand diagnostic tests for other human and veterinary diseases worldwide.

Most cases of Hepatitis C are asymptomatic and symptoms appear when the disease is already hepatic. The present study aimed at the production and purification of the Hepatitis C virus core protein (HCV) in the prokaryotes system and its subcloning in eukaryonite expression vectors. The E. coli bacterium was selected to perform the synthesis of the protein of interest, which was purified by affinity chromatography and detected by western blotting. In addition, the sequence of interest was recombined in plasmids for targeting to plant cell sub-compartments, which were confirmed by PCR. The processes performed were successful and the subsequent expression in the different cell compartments will allow the best performance for the production of immunogens and enable the production of diagnostic kit.

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