Marker proteins have proven to be helpful in the diagnosis of solid tumors when conventional cytology alone does not provide a clear result. Most human cell lines are derived from tumors. Therefore, we routinely test the expression of tissue markers on all human cell lines using a panel of well-characterized monoclonal antibodies (mAbs) to confirm their tissue origin.

Tissue-specific markers are routinely applied in the diagnosis of leukemia/lymphoma. For immunophenotyping, blood cells are labeled with antibodies directed against proteins or other macromolecules on the surface of the cells. By choosing a set of specific antibodies, the differentiation status of the leukemic cell can be determined. The same technique can be applied to characterize leukemia and lymphoma cell lines (1, 2; Figure 1).

Using a similar technique, the histological origin of tumor cells can be verified. Acetone-fixed cells are stained with antibodies directed against intermediary filaments (Figure 2). Intermediary filaments provide structure to the cells. Different intermediary filaments are expressed in different tissues, e.g. cytokeratins in epithelial tissues, neurofilaments in neuronal tissues etc. Therefore, the histological origin of cell lines can be determined using antibodies specifically recognizing the various filaments (3). For the assessment of antibody-protein interactions, fluorescence dye-labeled antibodies are used. The expression of intermediary filaments or of cell surface markers is verified by UV-light microscopy or by flow cytometry.

Immunophenotyping is part of the accessioning procedure of each human cell line at the DSMZ cell lines bank. Staining is repeated at regular intervals and when new antibodies are included in the antibody panel. Most recent results are shown in the individual data sheet of each individual cell line, in most cases including pdf showing expression of individual CD markers as histograms. Customers are invited to inquire for additional information (e.g. previous analyses or analyses of CD markers not shown as pdf).

Explanation of symbols: -, less than 5% positive; (+), 5-15% positive or not consistently positive; +, > 15% positive. Expression levels of antigens may slightly vary from batch to batch of an individual cell line, and between various antibody clones of one marker protein.

1. Matsuo Y, Drexler HG: Immunoprofiling of cell lines derived from natural killer-cell and natural killer-like T-cell leukemia-lymphoma. Leukemia Res 27: 935-945 (2003).
2. Hu Z, Quentmeier H, Meyer C, Kaufmann M, MacLeod RAF, Drexler HG: New cytokine-dependent acute myeloid leukemia cell line MUTZ-11 with disomic chromosome rearrangement t(16;17). Leukemia Res 28: 509-515 (2004).
3. Quentmeier H, Osborn M, Reinhardt J, Zaborski M, Drexler HG: Immunocytochemical analysis of cell lines derived from solid tumors. J Histochem Cytochem 49: 1369-1378 (2001).