Distribution in tissue sections of the human groEL stress-protein homologue.

A monoclonal antibody (ML30) raised against the 65 kDa heat-shock protein of mycobacteria showed widespread staining of sections from standard paraffin-embedded human tissues. The staining had a granular pattern and was particularly marked in cells with abundant mitochondria. Increased staining was observed in the synovial lining, histocytes and in the endothelium of reactive and rheumatoid synovium; it was also increased in the reactive lung alveolar lining. It is suggested that the antibody identifies an epitope in mitochondria of a protein homologous with the groEL heat-shock protein of bacteria.