The Sabin PDP is currently engaged in collaboration for early research and development for a bivalent therapeutic vaccine for the treatment of chronic Chagas disease (American trypanosomiasis). It would be the first therapeutic vaccine for this disease. The vaccine is comprised of two Trypanosoma cruzi recombinant proteins formulated on alum. One of the antigens is a unique T. cruzi 24 kDa antigen (Tc24) and the other is a unique T. cruzi surface transialidase (TSA-1). Pre-clinical work includes initial expression and characterization of the antigens in preparation for advancing the pre-clinical process development .