Helix pomatia A hemagglutinin: selectivity of binding to lymphocyte surface glycoproteins on T cells and certain B cells

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Abstract
Human and mouse lymphocytes were surface‐labeled by lactoperoxidasecatalyzed iodination, or by galactose oxidase oxidation followed by reduction with tritiated sodium borohydride. The labeled cells were lysed with Nonidet P‐40. Proteins binding to Helix pomatia A hemagglutinin (HP) were isolated by affinity chromatography on HP‐Sepharose and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. A major cell surface glycoprotein (apparent mol. wt. 150000, using reducing conditions) on human lymphocytes was responsible for almost all binding of HP. This protein was present on normal and malignant thymus‐derived lymphocytes, e.g. thymocytes, blood T cells and T leukemia cell lines. It was also found on chronic lymphocytic leukemia cells, one null cell leukemia line, one unidentified leukemia line, one lymphoblastoid cell line of B origin and on one stem cell lymphoma line. In contrast, this protein was not found on various B cells at different steps of differentiation, e.g. four B lymphoma lines or one myeloma line. It was also absent from a histiocytic leukemia line. However, two of the four B lymphoma lines and the myeloma line had another HP‐binding surface glycoprotein (mol. wt. 200000) instead of the 150000 protein. Studies of mouse lymphocytes similarly showed that thymus‐derived lymphocytes (normal and malignant) but not normal adult B cells expressed a major HP‐binding surface glycoprotein of apparent mol. wt. 130000 (reducing conditions).