Immunoreactivity to a monoclonal antibody (OS-3) is shared by osteoclasts and bicarbonate-secreting cells.
OS-3, a monoclonal antibody raised against macrophagic cells derived from cultured rat glomeruli, reacts with the plasma membrane of various bicarbonate-secreting cells such as epithelial cells of the pancreatic excretory duct and type B intercalated cells of the kidney, suggesting that the antigenic molecule of OS-3 is involved in bicarbonate production and/or secretion. Since osteoclasts must vigorously extrude bicarbonate to maintain cytoplasmic pH in a physiologic range during proton secretion, we examined the localization of OS-3 immunoreactivity in the bone tissue to determine the involvement of the detected molecule in the transmembrane transport of bicarbonate in osteoclasts. The OS-3 selectively stained the basolateral plasma membrane of osteoclasts. Ultrastructurally, the immunoreactivity with OS-3 was associated with small cytoplasmic projections and microplicae of the basolateral plasma membrane. This finding suggests that osteoclasts express the molecule common to bicarbonate-secreting cells to utilize it for bicarbonate transport during bone resorption.
Irie
K
K
Department of Oral Anatomy, Health Sciences University of Hokkaido School of Dentistry, Ishikari-Tobetsu, Japan. irie@hoku-iryo-u.ac.jp
Orikasa
M
M
Sakakura
Y
Y
Tsuruga
E
E
Iwanaga
T
T
Yajima
T
T
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D001639:Bicarbonates / Q000276:immunology*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004848:Epithelium / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D007678:Kidney Glomerulus / Q000166:cytology / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008954:Models, Biological; D010010:Osteoclasts / Q000276:immunology*; D010183:Pancreatic Ducts / Q000378:metabolism; D011522:Protons; D051381:Rats; D017208:Rats, Wistar
D000911:Antibodies, Monoclonal; D001639:Bicarbonates; D011522:Protons