Immunodiagnosis of Chagas disease: Synthesis of three latex–protein complexes containing different antigens of Trypanosoma cruzi

This article describes the physical adsorption and the chemical coupling of 3 antigenic proteins of Trypanosoma cruzi onto polystyrene (PS) based latexes to be used as novel immunodiagnosis reagents for detecting the Chagas disease. The coupled proteins were a homogenate of T. cruzi, or a recombinant protein (either Ag36 or CP1). With the homogenate, between 30 and 60% of the total-linked protein was chemically coupled, showing a small dependence with the pH. For Ag36 and CP1, around 90% of the total-linked protein was chemically coupled, with a maximum coupling at pH 5 ( i.e., close to the isoelectric point). The chemical coupling of CP1 was less affected by the pH than the coupling of Ag36.