title: Kat1-antigen--a reliable immunological marker for identifying osteoclast precursors of rats: detection of subpopulations among precursors and initiation of osteoclastogenesis.
abstract: Previously we found a unique cell surface antigen [Kat1-antigen (Kat1-Ag)] expressed on rat osteoclasts. In the present study, we focused on the expression of this antigen in preosteoclasts, mononuclear precursors of osteoclasts. Immunohistochemical and immunoelectron microscopic observations of the Kat1-Ag expressed in vivo showed the antigen to be present on mononuclear cells having the morphological features of preosteoclasts. The relationship between Kat1-Ag expression and calcitonin receptor (CTR) expression was examined in detail by a double-detection technique for CTR and Kat1-Ag by use of autoradiography and immunocytochemistry, respectively. In a culture system for forming mononuclear preosteoclast-like cells, almost 100% of the mononuclear cells expressing Kat1-Ag also expressed CTR, demonstrating that Kat1-Ag is a reliable immunological marker for identifying preosteoclasts. Interestingly, a significant number of the CTR-positive mononuclear cells did not express the Kat1-Ag. Detection of these cells expressing CTR but not Kat1-Ag strongly suggests the presence of subpopulations in preosteoclasts. We also obtained evidence suggesting that expression of the Kat1-Ag is initiated during the postmitotic stage of the osteoclast progenitors.
authors.affiliation: Section of Oral Cellular and Molecular Biology, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, Maidashi 3-1-1, Fukuoka 812-8582, Japan. kukitat@dent.kyushu-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Kukita
authors.forename: A
authors.initials: A
authors.lastname: Kukita
authors.forename: L
authors.initials: L
authors.lastname: Xu
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Iijima
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis; D001854:Bone Marrow Cells / Q000378:metabolism; D002478:Cells, Cultured; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D010010:Osteoclasts / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D018003:Receptors, Calcitonin / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism
chemical_list: D000954:Antigens, Surface; D015415:Biomarkers; D018003:Receptors, Calcitonin