Migration of chicken yolk sac cells to bursa of fabricius supernatants.

Investigators have suggested that a bursal chemotactic factor exists that selectively attracts hemopoietic stem cells. This theory was investigated by determining the ability of embryonic (10- through 14-day) bursal supernatants to cause migration of age-matched yolk sac cells using blind well chambers. Supernatants of 10, 11, 13 and 14-day bursae caused specific migration of yolk sac cells whereas 12-day bursal supernatants inhibited migration of 12-day yolk sac cells. Ten-day migrating cells consisted of pro- and basophilic erythroblasts and hemopoietic stem cells which formed erythroid colonies in a chorioallantoic membrane-colony forming unit (CAM-CFU) assay.