Identification of a cell-surface antigen associated with activated T lymphoblasts and activated platelets

摘要: We have identified and biochemically characterized an antigen, 8A3, which is expressed on activated T lymphoblasts platelets. Monoclonal antibodies to 8A3 were raised against the primitive lymphoid/myeloid cell line KG1a additionally bound erythroleukemia-derived HEL, whilst exhibiting little or no reactivity with a panel of other hematopoietic lines. The antigen was poorly differentiated T-cell leukemias phytohemagglutinin-activated T-cells maintained in interleukin-2 (7,000 sites/cell). This though not detected resting platelets, thrombin-activated platelets (2,000 sites/platelet). Antibodies polypeptides Mr 170,000 150,000 lysates surface-iodinated cells, lymphoblasts, under both reducing nonreducing conditions. However, peptide mapping susceptibily glycosidases indicated that monomeric glycoprotein contained two N-linked endoglycosidase H-sensitive glycans, structure derived from it by proteolytic degradation. detectably phosphorylated cells vivo, nor did immune complexes containing exhibit kinase activity vitro. Structural serologic characteristics indicate different previously described leukocyte activation antigens including transferrin receptors, members integrin family adhesion molecules, "restricted" leukocyte-common antigen/CD45 cluster. Furthermore, does appear be related activation-specific platelet molecule, GMP140/PADGEM. antibody may useful monitoring status some clinical situations characterizing clinically relevant activation-associated membrane alterations.