EXPRESSION OF A 130-KDA MESOTHELIAL AND CILIATED CELL AG (MCP130) IN NORMAL AND DEVELOPING HUMAN AND RAT LUNG AND ITS ROLE AS A DIAGNOSTIC MARKER FOR MESOTHELIOMAS AND TUMORS OF THE FEMALE REPRODUCTIVE-SYSTEM

BACKGROUND: Proteins in human lung lavage were analyzed to identify ce ll-specific markers for potential use in the study of the biology and pathology of pulmonary cells. EXPERIMENTAL DESIGN: Proteins associated with pulmonary surfactant were used to raise mAb. An Ab to a 130-kDa protein (MCp130) was reactive with ciliated and mesothelial cells. Exp ression of this Ag in normal organs, developing lung, and tumors was i nvestigated. RESULTS: By Western blotting, the Ah stained a protein of about 130 kDa. In formalin-fixed, paraffin-embedded tissues from adul t human and rat organs, the Ab specifically stained the luminal/apical surfaces of pulmonary and nonpulmonary ciliated and mesothelial cells . Staining of fetal airway cells was independent of ciliation. Airway cell staining was detectable in human fetal lungs at 12 weeks of gesta tion and at Day 18 of gestation in fetal rat. The Ab reacted with huma n and rat fetal mesothelial cells at the gestational ages of 15 weeks and 17 days, respectively. It also stained ciliated cells in endosalpi nx and endometrium. Human epithelial mesotheliomas and ovarian and end ometrial carcinomas stained selectively, whereas other pulmonary tumor s and tumors of other organs did not react with the Ab. CONCLUSIONS: T his 130-kDa mesothelial and ciliated cell plasma membrane protein appe ars in developing lung at an earlier age than secretory proteins. The marker is of potential use in the study of development of the differen t cell lineages in the lung and female reproductive tract. The Ah is e xpected to be useful in the diagnosis of epithelial mesotheliomas and ovarian/endometrial carcinomas, because it selectively stains these tu mors and is reactive with formalin-fixed, paraffin-embedded tissues.