Continuous production of monoclonal rheumatoid factor by EBV-transformed lymphocytes

Human B lymphocytes are immortalized by Epstein–Barr virus (EBV, ref. 1). The virus can be used to establish lymphoblastoid cell lines that produce and actively secrete specific antibodies 2 . The original method, which we have used for various antigens 2–4 is based on selection of the specific surface antigen receptor-positive lymphocytes from the peripheral blood lymphocytes of a donor who was previously sensitized to the corresponding antigen. Furthermore, by cloning the polyclonal anti-NNP cell Une we have produced human monoclonal antibodies for the first time in vitro 5 . About 5–20 µg ml −1 stably produced 5 specific antibody is obtained in the supernatant of the cell lines. This approach can be used for the in vitro production of monoclonal human autoimmune antibodies by EBV-immortalized lymphocytes from patients with autoimmune diseases. We demonstrate the continuous production in vitro of a monoclonal IgM anti-IgG antibody (rheumatoid factor, r.f.) by a lymphoblastoid cell line established from a patient with rheumatoid arthritis.