Human antibody to OFA-I, a tumor antigen, produced in vitro by Epstein-Barr virus-transformed human B-lymphoid cell lines.

We established two long-term human B-lymphoblastoid cell lines (L55 and L72) transformed by Epstein-Barr virus that produced IgM kappa antibodies to the human tumor antigen, OFA-I. Periphral blood lymphocytes obtained from melanoma patients were used as the source of the B lymphocytes. Antibody specificity was determined by the immune adherence assay using various human cancer and noncancer tissues as targets. L55 antibody (designated anti-OFA-I-1) reacted with a variety of human tumor types whereas L72 antibody (designated anti-OFA-I-2) reacted only with tumor cells of neuroectodermal origin (melanoma, glioma, and neuroblastoma). The levels of IgM detected in the spent medium of 1 X 10(6) L55 and L72 cells were 4 and 9 micrograms/ml, respectively, by radioimmunoassay.