Human-human hybridomas for the study of anti-tumor immune response in patients with colorectal cancer.

Human-human hybridoma technology was evaluated for the study of humoral immune reactions of colorectal cancer patients against their own tumors. Six fusions were carried out with lymphocytes from mesenteric lymph nodes from patients with colorectal cancer, using the human B-lymphoma cell line LICR-LON-HMy-2 as fusion partner. A total of 294 wells with cell growth were obtained. Supernatants from 26 of these reacted in enzyme-linked immuno-sorbent assay (ELISA) with one or more colon cancer cell lines. Cells from only one of these wells (D 4213) could be cloned. The clone was shown to produce antibody which by immunocytochemical analysis reacted with a panel of colon cancer cell lines and melanoma cell lines but not with several other cancer cell lines or normal human leukocytes. By immunohistochemical analysis on formalin-fixed paraffin-embedded tissue this antibody reacted strongly with antigen expressed by autologous and allogeneic colorectal cancers. Faint staining could occasionally be observed on normal colon epithelium. D4213 is a hybrid cell line since it is tetraploid and produces kappa and lambda light chains as well as gamma and mu chains, whereas HMy-2 produces only kappa and gamma chains. The study produces only kappa and gamma chains. The study suggests that patients may possess B cells producing antibody reactive with their own malignant cells.