Developmental Expression of Chicken Fetal Antigen on Peritoneal Macrophage: Implications for Hematopoietic Differentiation

Chicken fetal antigen (CFA) was demonstrated by both complement-mediated microcytotoxicity and immunofluorescence to be present on the cell surface of activated peritoneal macrophage. While CFA-positive macrophage were observed in young birds, the antigen was absent from adult macrophage. A comparison of cell surface CFA on macrophage, lymphocytes, and erythrocytes indicated that unique subsets of CFA determinants are characteristic for each differentiation lineage. As a result, CFA can serve as a cell surface marker for differentiation-specific gene expression. Since CFA determinants are known to be at least partly defined by carbohydrates, it is suggested that hematopoietic heterogeneity for CFA may result from lineage-specific carbohydrate microheterogeneity.