Expression of CD44 during early development of the chick embryo

CD44, the major cell-surface receptor for hyaluronate, is expressed on many cell types to mediate different functions including cell activation, homing and adhesion. The early pattern of CD44 expression was determined in the avian embryo by using a specific monoclonal antibody in whole-mount and tissue sections. CD33, was first expressed on cephalic neural fold cells and later on by subpopulations of pre-and migraton, cranial neural crest cells. Trunk neural crest cells did not express CD44. At the 18-20 somite stage, CD44 expressing cells were also localized in the caudal region of the embryo, in the mesoderm of the remaining primitive streak and in the caudal ectoderm and above the secondary neural tube Juring the process of cavitation. In addition, some hemopoietic cells present in the blood stream were also CD44 positive. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.