Detection of Leishmania lipophosphoglycan binding proteins in the gut of the sandfly vector

Binding to the midgut microvillar surface in the sandfly Phlebotomus papata si is a prerequisite for successful development of Leishmania major within the gut of the vector. This paper describes a method for detecting microvil lar-associated proteins which act as ligands for the parasite surface glyco conjugate lipophosphoglycan (LPG). Adhesion of LPG to midgut proteins was v isualized by probing midgut extracts with LPG using a Western ligand blotti ng technique. Procyclic L. major LPG bound to a microvillar polypeptide ban d of 65 kDa (estimated in the non-reduced state) and bound variably to seve ral lower molecular weight bands, probably degradation products or subunits of the primary binding polypeptides. Specificity of binding was confirmed by co-incubating biotinylated LPG with an LPG-specific mAb which resulted i n a great reduction in binding.