Role of transferrin in uptake of non-physiological metals into cells

At physiological concentrations of citrate the uptake of 59Fe, 67Ga, and 239Pu into human type B lymphocytes of splenic origin is the same in viable and in non-viable cells. Addition of transferrin has no effect on the uptake into non-viable cells but in viable cells it increases the uptake of Fe and Ga but decreases that of Pu. Uptake decreases as transferrin concentration increases although this is less marked with Ga.