Cell Transplantation into Immunodeficient Chicken Embryos Reconstituting Capacity of Different Embryonic Cells

Abstract

The findings to be described in this paper form a step in our studies on the B cell development in the chicken. In these studies we have largely used the cyclophosphamide model of immune deficiency first described by Lerman and Weidanz (1). Based on a series of experiments we have characterized the postbursal and bursal stages of B cell development (2-6). As a postbursal cell we have defined a cell which is capable of further function and maturation without any influence by the bursa of Fabricius, i.e., this cell can be transferred into cyclophosphamide-treated surgically bur- sectomized newly-hatched recipients and a full functional restoration of immune functions occurs in the recipients. Postbursal cells appear in significant numbers in the bursa around the third and fourth week after hatching, and shortly thereafter in the spleen, bone marrow and also in the thymus. In contrast, a cell type defined in functional terms as a bursal stem cell needs the bursal microenvironment for further maturation. This cell is capable of inducing a full functional as well as morphological re- constitution only when the bursal rudiment is available. No effect occurs if this cell is transferred into cyclophosphamide- treated surgically bursectomized recipients. The bursal stem cell is present in the bursa during the late embryonic development and shortly after the hatching.

Supported by grants from the Sigrid Jusélius Foundation and the Lääke Oy Research Foundation, and by NIH Contact N01-CB-43971.