A murine monoclonal antibody, 1C5, was produced by fusion of spleen cells obtained from mice immunized with CAC-1, a human cell line of adenocarcinoma derived from uterine cervix, and NS/1 myeloma cells. 1C5 can be used for the staining of routine formalin-fixed and paraffin-embedded tissue sections. 1C5-defined antigen was found to have a molecular weight of 26,000. The 1C5-defined antigen was resistant to neuraminidase and trypsin treatment, but sensitive to periodate treatment, indicating that an epitope of the 1C5-defined antigen is a carbohydrate moiety. Immunohistochemical study using immunoperoxidase staining demonstrated that 1C5 reacted with 87% of adenocarcinomas of the uterine cervix, 39% of endometrial carcinomas of the uterus, 100% of ovarian mucinous cystadenocarcinomas, 43% of ovarian serous cystadenocarcinomas, 45% of adenocarcinomas of the colon, and 40% of gastric adenocarcinomas, thus showing the broad reactivity to adenocarcinoma cells of various origins. However, 1C5 did not show any reactivity to ectocervix epithelium, cervical intraepithelial neoplasia, or squamous cell carcinoma of the uterine cervix. In addition, adenocarcinoma of the uterine cervix exhibited strong cytoplasmic reactivity with 1C5, whereas endometrial carcinoma of the uterus showed the luminal reactivity. 1C5 also reacts with 95% ethanol-fixed malignant cells in cervical smears.
The present study was supported by Grants-in-Aid from the Ministry of Health and Welfare of Japan.