title: Monoclonal antibodies OKT 11 and OKT 11A have pan-T reactivity and block sheep erythrocyte "receptors".
abstract: Monoclonal antibodies OKT11 (gamma 1) and OKT11A (gamma 2) are described and appear to have similar binding specificities. They bind, in immunofluorescence, with greater than 95% of infant thymocytes, staining both cortical and medullary cells, 65-80% of blood lymphocytes and selectively stain the T cell-dependent paracortical areas of tonsil. A small proportion (9-12%) of bone marrow lymphocytes stain, but this population excludes the terminal transferase-positive cells. Both the gamma 1 and gamma 2 antibodies stain the surface membrane Ig-negative lymphocytes in blood and tonsil and are to block sheep E rosette formation (to normal or leukemic T cells). In contrast, other monoclonal anti-T reagents tested (OKT1, OKT3, OKT4, OKT6, OKT8, OKT9, OKT10) did not block E rosette formation. E rosette formation and OKT11 bindings are coincident on T-ALL cell lines and both are trypsin-sensitive. In a series of 145 leukemias and 26 leukemic cell lines investigated, only leukemias with a T cell phenotype including E rosette positivity were reactive with OKT11 and OKT11A. OKT11A binds to a polypeptide of approximately 50 000 molecular weight on thymic lymphocytes. This structure may carry the recognition site for sheep erythrocytes. These antibodies provide additional useful markers for T cell analysis and are of potential therapeutic value.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D000954:Antigens, Surface / Q000302:isolation & purification; D001667:Binding, Competitive; D004912:Erythrocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007938:Leukemia / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D012397:Rosette Formation; D012756:Sheep; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology; D014357:Trypsin / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D014357:Trypsin