Development of a novel monoclonal antibody recognizing basal cells of human squamous epithelia.

The basal layer of the epithelium is usually thought to contain stem or progenitor cell populations. In order to analyze its biological characteristics, we attempted to produce novel monoclonal antibodies recognizing basal cells of the human esophageal epithelium. Hybridomas were generated from fusions between spleen cells of ddY mice immunized with esophageal epithelial cells (EECs) cultured at low calcium concentrations. A clone, NJ-E-H10, producing a monoclonal antibody (moAb) reacting with basal cells of human esophageal epithelia, was selected for its staining pattern on frozen sections of the epithelia. The immunoreactivities of NJ-E-H10 were detected in the cytoplasm of basal cells predominantly located in the interpapillary zones of the epithelia. In the primary culture of EECs, immunoreactive cells were present at the marginal area of the growing colonies, where EECs extend their cytoplasm and migrate out of the colonies. Immunoelectron microscopy demonstrated the immunoreactivities of the moAb NJ-E-H10 around the intermediate filaments of basal cells, but not on the filaments themselves. In the human skin, NJ-E-H10 positive cells were also observed in the basal layer of the epidermis as well as in keratinocytes in the outer layer of the outer root sheath in hair follicles and myoepitheial cells in the sweat glands. Since the distribution of NJ-E-H10 immunoreactivities differs from that reported by hitherto-known antibodies, the MoAb NJ-E-H10 is considered a new marker for clarifing the biological properties of the basal cell compartment in stratified epithelia.