Monoclonal antibody characterization of sarcoma-associated antigen p102.

A membrane protein of Mr 102,000 Da (p102) was detected in 51 out of 53 human sarcomas, using a murine IgG1 monoclonal antibody 23-26. Antigen expression in sarcoma histologic subtypes appeared dependent on the amount of fibrous tissue matrix present in the original specimen. High levels of p102 antigen were also found in all sarcoma, carcinoma cell lines and neonatal skin fibroblasts tested. Low levels of p102 were also expressed in membranes from some specimens of melanoma, lung and colorectal carcinoma, first trimester fetus, fat, lung and liver while skin specimens expressed slightly higher levels of antigen. Lectin affinity absorption indicated p102 was mannose containing glycoprotein, isoelectric point (pI) 4.7 and affinity constant of 2.3 x 10(9) M-1, with 5.9 x 10(5) binding sites per cultured human HT-1080 fibrosarcoma cell. The overexpression of p102 in sarcomas and other neoplastic tissues suggests that this protein may be associated with the neoplastic state.