Lupinus mutabilis Sweet (Tarwi) γ-conglutin Modulates TNF-α and IL-1α Transcriptional Expression in Human Monocytes Infected with Leishmania (V.) peruviana

Abstract

Background: γ-Conglutin is a hemagglutinating lectin found in the seeds of the Andean legume Lupinus mutabilis. Leishmania (Viannia) peruviana is the etiological agent of cutaneous leishmaniasis, which is endemic in Peru. Leishmaniasis is a neglected disease that lacks an effective and non-toxic treatment. The aim of this study was to evaluate the effect of γ-conglutin from L. mutabilis Patón Grande ecotype (CoPG) on human monocyte cultures before infection with L. (V.) peruviana and to determine the production of molecules that stimulate cellular immunity. Methods: CoPG was isolated by chromatography from a hexane extract of L. mutabilis seeds. Monocytes were obtained by density gradient centrifugation. The effect of CoPG on their viability was determined by the MTT assay. To assess superoxide and nitric oxide production, monocyte cultures were pre-treated with CoPG and then infected with L. (V.) peruviana. Transcriptional expression of TNF-α and IL-1α in CoPG-treated and parasite-infected monocytes was determined by RT-PCR. Result: CoPG retained its hemagglutinating activity throughout the isolation process. The purified protein had a molecular weight of 47 KDa. Besides, CoPG at a 20 µg mL-1 induced the production of superoxide on the treated monocytes. This CoPG concentration also promoted the overexpression of IL-1α and TNF-α on the infected monocytes. The present study showed that CoPG has a novel in vitro immunomodulatory effect. The discovery of bioactive proteins from L. mutabilis may uncover a wide range of new applications for this Andean plant.