Abstract
A monoclonal anti-human fibronectin antibody (2.3F9) was produced from a cell fusion involving the spleen cells from a BALB c mouse immunized with human myoblast cells and P3X63 Ag8 mouse myeloma cells. 2.3F9 antibody is of the IgM class. Radioimmunoassay showed that 2.3F9 antibody bound to human skin fibroblasts and muscle cells but not to peripheral lymphocytes, red blood cells, or the lymphoblastoid cell line Bristol 8, showing that the antigen is not present on all human cells. Ouchterlony immunodiffusion analysis revealed a precipitin line with plasma fibronectin (cold insoluble globulin). Immunoprecipitation with antibody 2.3F9 from NP40 extracts of [ 35S]methionine human muscle cultures revealed the specific precipitation of a protein of 220,000 molecular weight that comigrated with fibronectin. The antibody is not species specific and cultures of rat muscle cells were stained using indirect immunofluorescence, although the staining was weak. The cross-reactivity may therefore not be complete across species. Human myoblasts are low in fibronectin but as the cultures divide and form myotubes the level increases dramatically. The myotubes are devoid of fibronectin, however, and the majority of staining is associated with the mononucleated cells. These results were confirmed using a myogenic human muscle clone where myoblasts were found to synthesize and accumulate fibronectin while myotubes did not. Immunofluorescent staining of transverse and longitudinal sections of human muscle detected fibronectin on the epimysium, endomysium, and perimysium.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call