title: Characterization of prothymocytes with cloning capacity in human bone marrow.
abstract: The identity of human bone marrow (BM)-derived T cell precursors with colony forming capacity has led to controversy because of contamination with mature clonogenic T cells. We achieved 2 Log elimination of mature T cells from BM using a cocktail of monoclonal antibodies: CD2, CD3, CD4, CD6, and CD8 followed by two successive baby rabbit C' treatment. T cell depleted BM can generate colonies of CD2+, CD3+, Ti+, mostly CD4+, in the presence of PHA, rIL2, and a prothymocyte differentiating activity derived from phytohemagglutinin (PHA) induced mononuclear cells. These precursors could be enriched three- to sixfold by percoll gradient centrifugation and then significantly bypass the number of contaminant mature T cells as shown by limiting dilution analysis. Colony generation by marrow precursors was inhibited by the addition of autologous T cells. This inhibition was mostly caused by the T8+ subset. CFU-TL growth was dramatically inhibited by eliminating CD7+ cells suggesting their positivity for this surface marker. These precursors needed major histocompatibility complex (MHC) II-positive cells for optimal growth but lack DR themselves.
authors.affiliation: Research Center on Hematologic Diseases, Hopital Jean Bernard, Poitiers, France.
authors.forename: M D
authors.initials: MD
authors.lastname: Mossalayi
authors.forename: J C
authors.initials: JC
authors.lastname: Lecron
authors.forename: P
authors.initials: P
authors.lastname: Goube de Laforest
authors.forename: G
authors.initials: G
authors.lastname: Janossy
authors.forename: P
authors.initials: P
authors.lastname: Debré
authors.forename: J
authors.initials: J
authors.lastname: Tanzer
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D003114:Colony-Forming Units Assay; D006133:Growth Substances / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D010641:Phenotype; D013601:T-Lymphocytes / Q000166:cytology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D006133:Growth Substances