Cellular protein profiles of the Hodgkin's disease cell lines L428, KM-H2 and HDLM-2: a comparative study.

The origin of the malignant mononuclear Hodgkin's cell and the classic Reed-Sternberg cell in Hodgkin's disease (HD) remains controversial despite extensive immunohistological and lymphoid gene analysis. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) in combination with protein staining and radioactive labelling has not been fully exploited in analysing the HD-derived cell lines available. The NP40 solubilised cellular proteins from the three HD cell lines, L428, KM-H2 and HDLM-2 were analysed using these techniques and compared with other haemopoietic cell lines and leucocytes of myeloid and lymphoid origin. The electrophoretic patterns of the three HD cell lines, although clearly different from one another, had many features in common. No major differences between the cell types were detected by Coomassie brilliant blue staining. The HD cell lines were more readily distinguished from the myeloid and to a lesser extent the lymphoid cell lines by silver staining, but HD cell line specific proteins (13, 19, 36, 60, 150 kD) were detected only on one line, L428. Iodination of cell membrane molecules, SDS-PAGE and subsequent autoradiography revealed three molecules (118, 22, 12 kD) which were restricted to the HD cell lines and the B-cell line Mann, and one molecule (144 kD) restricted to the HD cell lines and U937. Molecules unique to HDLM-2 (211 kD) and L428 (46 kD) were also detected by this method. Cell surface labelling with NaB3H4 identified a glycoprotein of 102 kD limited to HDLM-2 and L428, as well as a glycoprotein of 97 kD present on KM-H2 alone and one of 63 kD on L428 alone. Overall the HD cell line protein profiles displayed little similarity to the patterns of the other cell types studied and provide further evidence to support functional and phenotypic studies which identify Hodgkin's cells as a unique cell type. The molecules identified as HD cell line restricted may have potential as markers for this cell type.