抄録
Langerhans cells (LCs) in the squamous metaplastic epithelium of the trachea and the urinary bladder of vitamin A-deficient rats were examined. Both round, immature cells which were considered to be precursor LCs, and mature LCs with prominent dendritic processes, were recognized in the present study. Both cells were positive for anti-protein kinase type II antibody (PKC-II), and although the former did not have Birbeck granules (BGs), the latter did. The precursor LCs without BGs first appeared in the early stage of squamous metaplasia. As the differentiation of squamous metaplasia progressed, the number of BG bearing LCs increased, and the precursor cells became mature LCs in the later stage of squamous metaplasia of both the trachea and the urinary bladder. In the later stage of squamous metaplasia of the urinary bladder, LCs with BGs also appeared in the lamina propria. These findings indicate that precursor cells which probably migrate from the bone marrow, disperse into the metaplastic squamous epithelium in morphologically immature forms, and mature into BG bearing LCs as a result of contact with squamous epithelium.
