Monoclonal antibody to chicken fetal antigens on normal erythroid cells and hematopoietic-lymphoid tumor cell lines

Hybridoma cell lines secreting antibodies to chicken fetal antigens (CFAs) were generated by the fusion of mouse P3x63Ag8 myeloma cells with spleen cells from a mouse immunized with intact SC chicken strain one-day-hatched red blood cells. Immunodepletion studies show monoclonal anti-CFA to be detecting a subset of the M_r50,000 CFA molecules recognized by polyclonal anti-CFA. Monoclonal anti-CFA is erythroid specific against in vivo-derived hematopoietic-lymph-oid cells. Exceptions to the erythroid specificity of monoclonal anti-CFA include failure to react with avian erythroblastosis virus-transformed erythroid cells both before and after butyric acid-induced differentiation and reactions with reticuloendotheliosis virus-transformed immature lymphoid cells and chicken embryo cells. Immunofluorescence and ¹²⁵l binding analyses utilizing monoclonal anti-CFA show reticuloendotheliosis virus cells to possess high levels of CFA even though the CFA determinant does not appear to be a ¹²⁵l-labeled immunoprecipitable M_r50,000 molecule. The unique property of monoclonal anti-CFA that permits it to distinguish among surface membrane antigens of normal and neoplastic cells of the same lineage makes it an important tool for future investigations of normal and abnormal cell differentiation.