Cutaneous leishmaniasis is a neglected tropical disease caused by the parasite Leishmania and transmitted by sandflies. It has become a major health problem in many tropical and subtropical countries, especially in regions of conflict and political instability. Currently, there are only limited drug treatments, and no available licensed vaccine; thus, the need for more therapeutic interventions remains urgent. Previously, a DNA vaccine encoding a 15 kDa sandfly (Phlebotomus papatasi) salivary protein (PpSP15) and recombinant non-pathogenic Leishmania tarentolae secreting PpSP15 have been shown to induce protective immunity against L. major in mice, demonstrating that PpSP15 is a promising vaccine candidate. In ... More
Cutaneous leishmaniasis is a neglected tropical disease caused by the parasite Leishmania and transmitted by sandflies. It has become a major health problem in many tropical and subtropical countries, especially in regions of conflict and political instability. Currently, there are only limited drug treatments, and no available licensed vaccine; thus, the need for more therapeutic interventions remains urgent. Previously, a DNA vaccine encoding a 15 kDa sandfly (Phlebotomus papatasi) salivary protein (PpSP15) and recombinant non-pathogenic Leishmania tarentolae secreting PpSP15 have been shown to induce protective immunity against L. major in mice, demonstrating that PpSP15 is a promising vaccine candidate. In this study, we developed a fermentation process in yeast with a yield of ∼1g PpSP15/L and a scalable purification process consisting of only two chromatographic purification steps with high binding capacity for PpSP15, suggesting that PpSP15 can be produced economically. The biophysical/biochemical analysis of the purified PpSP15 indicated that the protein was of high purity (>97%) and conformationally stable between pH 4.4 and 9.0. More importantly, the recombinant protein had a defined structure similar to that of the related PdSP15 from P. duboscqi, implying the suitability of the yeast expression system for producing a correctly-folded PpSP15.,Copyright © 2020. Published by Elsevier Inc.
