An assay for erythrocyte chalone using chick embryo red blood cells

As mature mammalian erythrocytes do not contain nuclei, erythrocyte chalone has previously been detected by its inhibitory effect on normoblasts, often obtained from a mixed cell source. Chick embryo blood consists entirely of mature nucleated red cells and was used to test the effect of heterologous erythrocytic extracts on haemopoiesis. The model was adapted to detect the presence of inhibitors of erythropoiesis as contaminants of partially purified leucocyte extracts.