Human leukocyte function-associated antigens on lympho-hemopoietic precursor cells.
The expression of human leukocyte function-associated antigens (HLFA, equivalents of murine LFA-1) was studied on early lympho-hemopoietic cells in infant thymus and normal bone marrow by double immunofluorescence methods, cell sorting and colony-forming assays. Monoclonal antibodies MHM-24 recognizing the alpha chain (180 kDa) and 60.3 and 60.1 identifying the beta chain (95 kDa) were used. The vast majority of thymocytes including large terminal deoxynucleotidyl transferase (TdT)-positive blast cells are HLFA positive. On the other hand, most B cell precursors in the bone marrow, identified by the expression of nuclear TdT, do not show surface HLFA which appears at the pre-B cell stage (cytoplasmic mu positive, surface Ig negative). Cell sorting experiments revealed an enrichment of early myeloid cells (myeloblasts and colony-forming unit cells) in the HLFA-negative fraction. Erythroid cells appeared to be completely negative from the burst-forming unit erythrocyte stage onwards. Anti-HLFA-antibodies, capable of blocking T cell and natural killer function, may have therapeutic potential without interfering with precursor cell development in man.
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology*; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D003114:Colony-Forming Units Assay; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D016169:Lymphocyte Function-Associated Antigen-1; D008214:Lymphocytes / Q000276:immunology*; D009000:Monocytes / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D016169:Lymphocyte Function-Associated Antigen-1