BIOCHEMICAL-CHARACTERIZATION AND MEMBRANE EXPRESSION OF AN ANTIGEN SHARED BY ACTIVATED AND NEOPLASTIC-CELLS OF NEUROECTODERMAL ORIGIN

The reactivity of a mAb (M16) raised against a small cell lung carcino ma line is described. M16 identifies a surface antigen expressed on ce lls of neuroectodermal origin following activation, as well as neoplas tic transformation. M16 antigen expression is increased on retinoblast oma and neuroblastoma cell lines upon 'in vitro' stimulation and it is induced 'in vivo' on glial cells activated following brain injury. Fu rthermore, glial tumors show levels of M16 molecule expression increas ing with the degree of malignancy, and in a retinoblastoma cell line, the expression of M16 was inversely related to the level of HLA-Class I and N-CAM antigens. The M16 antigen may represent a marker of both a ctivation and neoplastic progression for neuroectodermal cells.