Human neoplastic cell line distribution, immunoprecipitation and immunohistopathological study of a gp200 cell surface glycoprotein (LCA) detected by a monoclonal antibody elicited with an ALL cell line.

The antigen recognized by a newly produced monoclonal antibody (bra55; IgG1) elicited by the non-T, non-B acute lymphoblastic leukemia cell line REH 6, was expressed on all examined hemopoietic neoplastic cell lines (including non-T, non-B, T, B and myeloid leukemia cell lines), but not on examined nonhemopoietic human tumor cell lines (such as carcinoma, sarcoma, melanoma and neuroblastoma cell lines), as demonstrated by indirect immunofluorescence and enzyme-linked immunoassay. Specific immunoprecipitation of 125I-lacto-peroxidase radioiodinated cell surface proteins and sodium metaperiodate/tritiated sodium borohydride 3H-radiolabeled cell surface sialoglycoproteins followed by electrophoretic analysis (SDS-PAGE) demonstrated that the immunoprecipitated antigen is a cell surface 200 kDa sialoglycoprotein (on the non-T, non-B ALL cell line REH 6), with variation in its electrophoretic mobility (in the Mr range of 170,000-210,000) on different examined cell lines. These properties are characteristic for the leukocyte common antigen (LCA, T200). Immunoperoxidase staining of several normal and malignant tissues, as well as some nonhemopoietic tumor tissues confirmed the type of antigen tissue distribution pattern characteristic for LCA.