A monoclonal antibody to antigens expressed on MLR-activated T cells inhibits granulocyte macrophage colony formation.
A monoclonal antibody specifically reactive with MLR-activated T cells (MLR2) was added to light density normal marrow cells, depleted of adherent cells and T lymphocytes, and plated in soft agar for granulocyte macrophage colony formation. Colonies from MLR2-treated marrow cells were reduced to less than 10% of expected growth. The inhibition was not complement dependent, did not require the continuous presence of MLR2 in culture, and could not be detected also when human placenta-conditioned medium was used in the place of leukocyte feeder layers as a source of colony-stimulating factor (CSF). Co-culture experiments with MLR2 treated and untreated marrow cells further excluded the possibility of an indirect effect of MLR2 on CFU-c via auxiliary cells. The results of this study suggest that myeloid progenitor cells express a lymphoid antigen that is absent on resting or activated B cells and on resting T cells, but is expressed on activated T cells.
D000042:Absorption; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D004306:Dose-Response Relationship, Immunologic; D006098:Granulocytes / Q000166:cytology*; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D008264:Macrophages / Q000166:cytology*; D009194:Myeloma Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D009194:Myeloma Proteins