Chicken fetal antigen: example of an antigenically complex oncodevelopmental membrane glycoprotein.

CFA is a complex onco-developmental membrane marker system that is being investigated at the cellular, molecular, genetic and functional levels. CFA appears to be a family of genetically-determined carbohydrate side chains attached to a membrane-bound polypeptide chain. Unique combinations of the thirteen serologically detectable CFA determinants are expressed on erythroid and lymphoid cells of all avian species tested. Whether or not CFA determinants are hematopoietic specific markers remains to be established. The CFA determinants are proving to be useful membrane markers for the study of normal as well as neoplastic hematopoietic cellular differentiation. The probability that CFA determinants are differentiation-stage-specific markers for cells of both the erythroid and lymphoid series coupled with the observation that one of the CFA determinants acts as a cell membrane binding site for an arbovirus makes this antigen system a valuable tool for studying the cellular differentiation blockage hypothesis of neoplasia.