Synthesis by an established lymphocyte cell line from a rheumatoid synovium.

Lymphocytes derived from the synovium of a patient with rheumatoid arthritis were shown to synthesize predominantly IgG as measured by an equilibrium binding assay. Chromatographic separation of the radiolabeled lymphocyte culture supernatant revealed rheumatoid factor activity associated with IgG and IgM. In addition, immunofluorescence studies on fixed lymphocytes demonstrated that the majority of cells stained positive for both IgG and rheumatoid factor.