title: Existence of a pool of T-lymphocyte colony-forming cells (T-CFC) in human bone marrow and their place in the differentiation of the T-lymphocyte lineage.
abstract: The existence and characteristics of bone marrow T-cell progenitors have not yet been established in man. Several pieces of evidence such as the reconstitution of certain immunodeficiencies by bone marrow graft suggest that T-cell precursors are present in the bone marrow. We report the growth of T-cell colonies from bone marrow populations using PHA-stimulated lymphocyte-conditioned medium containing T-cell growth factor (TCGF). Rosetting experiments and complement-dependent cytotoxicity assays with monoclonal antibodies indicate that the bone marrow T colony-forming cells (T-CFC) are E- OKT 3- and la+, i.e., immature progenitors. The colonies derived from these cells have the phenotype of mature T cells: E + OKT 3 + la- with either helper (OKT 4+) and suppressor (OKT 8 +) antigens. These results suggest that a thymic microenvironment may not be necessary for the in vitro proliferation and differentiation of the T-cell lineage in adult humans. These methodologies may permit direct investigation of early phenomena concerning the T-cell lineage, such as the acquisition of self-tolerance, the formation of a repertoire of specificities, and the HLA restriction phenomena that we believe takes place before the thymic maturation.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002469:Cell Separation; D003114:Colony-Forming Units Assay; D003165:Complement System Proteins; D003602:Cytotoxicity, Immunologic; D000949:Histocompatibility Antigens Class II; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D010641:Phenotype; D013601:T-Lymphocytes / Q000166:cytology*
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D003165:Complement System Proteins