Serum proteins promoting [3H]thymidine uptake by Trypanosoma (Schizotrypanum) cruzi (Chagas) in vitro.

Five proteins capable of stimulating [3H]thymidine uptake by Trypanosoma cruzi in vitro were isolated from fetal calf serum by (NH4)2SO4 precipitation and ion exchange column chromatography. The proteins were partially characterized by immunodiffusion, immunoelectrophoresis, polyacrylamide gel disc electrophoresis, and SDS electrophoresis. As estimated by SDS electrophoresis, using 4 standards, the molecular weight of protein 1 was 100,000, that of protein 2 was 76,000, and that of proteins 3-5 was 68,000 daltons.