Overexpression of human homologs of the bacterial DnaJ chaperone in the synovial tissue of patients with rheumatoid arthritis

Objective To study the expression of the chaperone family of J proteins in the synovial tissue of patients with rheumatoid arthritis (RA) or osteoarthritis. Methods Rabbit antibodies specific for a synthetic peptide (pHSJ1: EAYEVLSDKHKREIYD), representing the most conserved part of all J domains thus far identified—among them the Drosophila tumor suppressor Tid56—were used in immunohistochemical analyses of frozen sections of synovial tissue and immunoblotting of protein extracts of adherent synovial cells. IgG specific for Tid56 was also used. Results Both antisera predominantly and intensely stained synovial lining cells from RA patients; other cells did not stain or stained only faintly.…