Onco-Neural Antigen: A New Neural Differentiation Antigen Expressed by Neuroblastoma, Oat Cell Carcinoma, Wilms' Tumor, and Sarcoma Cells

Abstract

This investigation defined a new neural differentiation antigen that is expressed by a number of tumors derived from neuroectoderm and surprisingly by some derived from mesoderm. Heteroantisera were prepared by immunizing rabbits with cultured human neuroblastoma cells followed by extensive absorption with nine different types of normal non-neural tissues and cells; sera were evaluated with cultured cells and radioiodinated staphylococcal protein A to detect binding of antibodies to cell surface antigens (CSA). One antiserum that was raised against LA-N-1 neuroblastoma cells was analyzed in detail. It reacted well with seven neuroblastoma cell lines including LA-N-1; it also reacted, but to a lesser degree, with medulloblastoma, rhabdomyosarcoma, and leiomyosarcoma cell lines. Seventeen additional cell lines and noncultured acute leukemia cells were minimally reactive or nonreactive with the serum. Absorption of the serum with homogenates of adult brain or adrenal reduced its binding to neuroblastoma cells more than 80%. Greater than 65% of the reactivity with LA-N-1 neuroblastoma cells also was absorbed by homogenates of 10 of 10 neuroblastomas, seven of seven Wilms' tumors, five of eight sarcomas, two of three oat cell carcinomas, and one of six melanomas. Eight other types of malignancies did not remove significant activity compared to control non-neural normal tissue absorbents. Sequential absorption with adult brain or adrenal followed by the positive tumors demonstrated that both normal and tumor cells expressed the same antigen. We term the neural differentiation antigen(s) that is expressed by tumors derived from neuroectoderm and mesoderm an onco-neural antigen (ONA).