A chicken leukocyte common antigen: biochemical characterization and ontogenetic study.

A monoclonal antibody, designated CL-1, was produced by immunizing mice with chicken peripheral blood lymphocytes (PBL) and selected in an indirect immunofluorescence assay. CL-1 characterizes a cell surface antigen expressed on all chicken hemopoietic cells except mature erythrocytes. Cells stained by CL-1 were detected at early stages of embryonic development in the various hemopoietic compartments. CL-1 reacts with two chicken PBL proteins of 200 kDa and 215 kDa which are probably the homologues of the T-200 and B-220 antigens previously described in the mouse. Moreover, CL-1 does not react with quail hemopoietic tissues and can be useful in experiments using quail-chick chimeras to study the ontogeny of the hemopoietic system.