Preparation of cell populations with stabilized erythropoietic potential from the primitive streak chick blastodisc: some implications for control of gastrulation.

Improved methods for preparation from primitive streak chick blastodiscs of cell suspensions capable of forming erythroid cells in culture have been developed. When blastodiscs were preincubayed with hyaluronidase in the absence of collagenase before cell dispersion and a high concentration of methyl-alpha-mannoside was present in all media, the yields of cells were some 10-fold higher than those obtained by former procedures. Cell suspensions obtained consisted almost entirely of viable cells, yielded large numbers of free mature erythrocytes in liquid culture, and formed erythroid colonies and bursts in solidified medium. The capacity to form differentiated cells after resedimenrtation through Ficoll density gradients was partly stabilized. Addition of gee yolk homogenate to the blastodiscs immediately following treatment with hyaluronidase and to all media used thereafter largely stabilized the capacity to form erythroid cells during resedimentation through Ficoll density gradients. Possible relevance of observations made during development of the procedures to the control of onset of cell migration in the process of gastrulation is indicated.