Recognition of a granulocyte-specific membrane protein by monoclonal antibodies

Using membranes isolated from leukemic myeloblasts as immunogen, two granulocyte specific monoclonal antibodies 38D2 and 41D2 were developed. The antibodies are positive in membrane immunofluorescence with granulocytes and bands; they give no reaction with monocytes, platelets, leukemic myeloblasts, lymphoblasts, myeloid cell lines, and immature myeloid cells from bone marrow. Both monoclonal antibodies precipitate the same membrane glycoprotein (MW: 70-78 kd, pI: 6-7), which corresponds to a membrane glycoprotein characteristic for granulocytes, as concluded from two-dimensional polyacrylamide gelelectrophoresis patterns obtained from surface labelled myeloid cells. The monoclonal antibodies did not influence the granulocyte functions tested: phagocytosis of opsonized bacteria, chemiluminiscence after stimulation with various stimuli, and chemotaxis.