A murine monoclonal antibody (E10) was made against cultured cartilage cells. The E l 0 antibody binding is localized to the surface of cultured cartilage cells in suspension and is present in the cytoplasm in paraffin embedded sections. There is no reactivity with cartilage matrix, or with the matrix of cartilaginous tumors. Reactivity is removed by treatment with trypsin and hyaluronidase, but not by treatment with heparinase, neuraminidase, and chondroitinase.
Regeneration of El 0 antigen after trypsinization takes 48 hours in chondrocytes in tissue culture. SDS-polyacrylamide gel electrophoresis of an E l 0 immune precipitate of cultured chondrocytes results in two peaks: one at a very high molecular weight and a small fragment at approximately 250 kd.
Specificity has been demonstrated by cytofluorometry, immunofluorescence, and immunohistochemistry, in both frozen and paraffin-embedded tissues. Positive reactivity was seen in cultured cartilage cells, chondrocytes in fetal and adult cartilage, chondrosarcomas, and chordomas. Minimal reactivity was found in a chondromyxoid liposarcoma. Acinar cells of salivary and sweat glands and mast cells in various tissues and tumors were also positive. There was no reactivity with other tissues and tumors, including myxoid and mucinous tumors and epithelial tissues.