[Immunohistochemical study on keratin expression of uterine reserve cells]

An immunohistochemical expression in the reserve cells of the uterine cervix using monoclonal antibodies of cytokeratin which detected the different subtypes of keratin was studied. Although the reserve cells were positive for all the four cytokeratin antibodies (CAM5.2, M-20, M-888, M-630), different immunoreactivity was found as follows: CAM5.2 reacted uniformly and intensely in the cervical glands, but weak in the reserve cells. M-20 reacted similar to that of CAM5.2 in the cervical glands, but was weaker stained in the reserve cells than with CAM5.2. M-888 reacted uniformly and intensely in both the cervical glands and reserve cells. M-630 reacted only in the reserve cells, but seldom in the cervical glands. Hence, CAM5.2 and M-20, which detected No.8 and No.18 of antiserum for low-molecular weight cytokeratin, reacted more weakly in the reserve cells than in the cervical glands, and M-630, which detected No.5 and No.14 of antiserum for high-molecular weight cytokeratin, reacted uniformly and intensely in the reserve cells. That results suggested the reserve cells revealed the expression as the stratified squamous epithelium. As for cell proliferation on the cervical glands and reserve cells, the positive nuclear staining for proliferating cell nuclear antigen (PCNA) was found in both of them, especially in the cervical glands just above the reserve cells. Therefore, the reserve cells had characteristics of squamous cell epithelium and developed to metaplastic cells.