MONOCLONAL-ANTIBODIES RECOGNIZE ANTIGEN EXPRESSED BY OSTEOBLASTS

A marrow stromal osteogenic cell line (MBA-15) was used to create mono clonal antibodies (MoAbs), In this study, we describe a series of MoAb s for mouse marrow stroma (MMS) (MMS-25/17, MMS-85/12, MMS-302/40, and MMS-319/4) that recognized antigens expressed by stromal cells includ ing osteoblastic cells, The MoAbs were screened against various cell a nd tissue types. MMS-85/12 was positive in detecting an antigen that w as highly abundant in osteoblastic cells and primary adherent bone mar row cultures (BMC) but was negative for the marrow adipocytes copartne r, The MMS-85/12 MoAb is an IgGl immunoglobuliun. The immunohistochemi cal staining pattern is suggestive of the antigen being associated wit h the osteoblasts' plasma membrane and with the extracellular matrix c onstituent secreted by these cells, Western blotting and immunoprecipi tation indicated that the antigen that was recognized by MMS-85/12 app arently had a molecular weight of 84 kD.