Surface marker for hemopoietic and endothelial cell lineages in quail that is defined by a monoclonal antibody.

A mouse monoclonal antibody raised in response to quail immunoglobulin mu chain was found to exhibit a broad reactivity towards hemopoietic and endothelial cells in the quail (Coturnix coturnix japonica). Indirect immunofluorescence assays were performed at several stages of embryonic development and until 3 weeks after hatching, on either isolated cells or tissue sections. They revealed that the defined surface marker, referred to as MB1, (i) is expressed early on both intra- and extraembryonic hemopoietic stem cells and is transmitted to the whole progeny of these precursors, with the exception of mature erythrocytes, and (ii) is a constant feature of the endothelial cell surface throughout ontogenesis and adult life. In addition, this epitope is included in several soluble plasma components. MB1 expression was not detected in chicken tissues, and this characteristic was used to confirm its lineage restriction in quail-chicken chimeras. We stress the value of this species- and lineage-specific marker in study of the development of the hemopoietic and endothelial cell families, with special reference to their possible early common embryonic origin.