Cell Differentiation. 15 (1984) 141-145 141 Elsevier Scientific Publishers Ireland, Ltd. CDF 00272 Detection of a nerve-specific membrane protein on differentiating PCC3/A/1 cells J6zsef Zfikfiny 1 J6zsef Farkas 1 Lfiszl6 Takfics 2, Gfibor Veres ~ and Istvfin Rask6 1 J Institute of Genetics, Biological Research ('enter of the Hungarian Academy of Sciences, H-6701 Szeged, P.O.B. 521, and -" Semmelweis University Medical School, Budapest, Hungary (Received 22 October 1984) Attempts were made to prepare monoclonal antibodies specifically reactive with cell surface components of a murine neuroblastoma cell line, Neuro 2a. One of the antibodies (1c2) reacts with a varying proportion of in vitro cultivated Neuro 2a cells, but does not react with murine embryonal carcinoma cell lines (PCC3/A/1 and F9) or with a murine fibroblast line (LM). This antibody selectively stains a subpopulation of nerve cells in murine adult central nervous system, e.g. granular cells in cerebeilar cortex, lmmunoaffinity purification of adult brain and Neuro 2a plasma membrane fractions with the antibody resulted in an electrophoretically pure protein of approx. 28 kD molecular weight as estimated by SDS-PAGE. Although this antigen is absent from PCC3/A/1 embryonal carcinoma cells, it can be demonstrated after 9 days of growth and differentiation under low density conditions by indirect immunoperoxidase staining. This monoclonal antibody may prove useful in further analysis of neural tissue development. murine neuroblastoma; murine embryonai carcinoma; monoclonal antibody Introduction Monoclonal antibodies are versatile tools in studies of cellular differentiation. Antibodies defi- ning tissue, cell type or cell-subclass-specific anti- gens are of special interest (Boller and Kemler, 1983). In the last five years, an increasing number of nerve-cell-specific monoclonal antibodies have been described, and they are beginning to be ap- plied for the experimental analysis of murine nerve tissue development (Caddy et al., 1982; Lindner et al., 1983). The existence of cloned murine neuroblastoma cell lines with nerve-specific developmental potency, the early detection of membrane antigens showing correlative changes with morphodiffer- entiation of these cells (Askeson and Herschman, 1974), and the relative ease of methodological manipulation of these cell lines prompted us to try to produce hybridomas secreting monoclonal anti- bodies specific for Neuro 2a cell membrane con- stituents and to apply them as probes of develop- ment in in vitro models of nerve cell differentia- tion. A monoclonal antibody was found which specifically reacts with a subclass of murine nerve cells. It was successfully used to detect the ap- pearance of the respective antigen-bearing cells in differentiating cultures of a multipotent murine embryonal carcinoma cell line, PCC3/A/1, which was earlier proved capable of forming nerve tissue in vitro (Nicholas et al., 1976; Zakfiny et al., 1984). 0045-6039/84/$03.00 ;,'; 1984 Elsevier Scientific Publishers Ireland, Ltd.