POLYMORPHIC AND MONOMORPHIC HLA-DR DETERMINANTS ON HUMAN HEMATOPOIETIC PROGENITOR CELLS

Abstract

The expression of monomorphic Ia-like antigens and polymorphic (allotypic) HLA-DR determinants on CFU-GM [granulocyte-macrophage progenitor cell], SFU-E [erythropoietic burst forming cell], CFU-E [erythroid colony forming unit] and CFU-GEMM [granulocytic, erythrocytic, monocytic and megakaryocytic colony forming unit] was studied in bone marrow and peripheral blood cells from normal healthy individuals. Using various polyclonal and monoclonal anti-Ia-like antibodies, the presence of HLA-DR backbone antigens was shown on all hematopoietic progenitor cells (HPC) studied, both in complement-dependent cytotoxicity assays and in fluorescence-activated cell sorting (FACS). The expression of allotypic determinants was demonstrated on all HPC, using the HLA-DR typing sera anti-HLA-DR1, 2, 3, 4, 5 and 7. The class II antigen MT-2 was also shown on all HPC, using both monoclonal and alloantisera, whereas the MB-1 (DC-1) determinant could not be demonstrated on HPC. This might open the possibility of removing MB-1 positive malignant cells from the graft in autologous bone marrow transplantation.