Characterization of a cell surface molecule expressed on B-lymphocytes and Hodgkin's cells

An antigen specifically expressed on the surface of plasma membrane of B-lymphocytes and Reed-Sternberg cells was identified using a newly developed monoclonal antibody produced by immunization by BALB/c mouse with a Hodgkin's cell line (HDLM-3). The antibody was termed anti-BLA.36 (B lymphocyte antigen.36) to indicate its predominant reactivity and the molecular weight of the corresponding antigen. By using immunoperoxidase techniques, expression of BLA.36 was detected on Hodgkin's, B-, and pre-B-cell lines, but not on other hematopoietic, melanoma, or carcinoma cell lines. In normal tissues, BLA.36 was detectable predominantly on cells in the germinal center and mantle zone of reactive follicles in lymph nodes and spleen. In hematopoietic malignancy, BLA.36 was detectable on the surface of Reed-Sternberg cells, mononuclear Hodgkin's cells, and also on malignant cells of B-cell lineage. Under these conditions, T-lymphocytes, histiocytes, granulocytes, macrophages, stromal cells in lymphoid tissue, and both normal and neoplastic epithelial cells were consistently negative for the expression of the antigen, with the single exception of a variable proportion of Kupffer cells in normal liver. Biochemical and immunological analyses indicate that BLA.36 is distinct from previously identified antigens of hematopoietic cell lineage, including CD20 and CD75 (LN2) which have similar molecular weights. When BLA.36-positive cell lines were cultured in the presence of the antibody, cell growth was adversely affected. Such an effect was eliminated by removal of the antibody from the culture, suggesting a possible growth-related function of the antigen. Anti-BLA.36 may serve as a probe to study growth-related functions of the corresponding antigen during normal growth of the B-lymphocyte, as well as in the neoplastic proliferations occurring in Hodgkin's disease and antigen-positive B-cell lymphomas. Finally, the antibody has already demonstrated its usefulness for the identification of Reed-Sternberg and Hodgkin's cells, and also normal and malignant B-lymphocytes in frozen as well as formalin- or B5-fixed/paraffin-embedded tissue sections.