Human dendritic cell lysosome-associated membrane protein expressed in lung type II pneumocytes.
Human dendritic cell LAMP (hDC-LAMP) is a unique member of the lysosome-associated membrane protein (LAMP) family with a tissue distribution initially described as restricted to major histocompatibility class II (MHC II) compartments of activated DC before the translocation of MHC II to the cell surface [Immunity 9 (1998) 325]. In this report, we show that hDC-LAMP is also expressed by lung type II pneumocytes, another cell type with constitutive expression of MHC II. A recombinant hDC-LAMP protein and a monospecific anti-hDC-LAMP polyclonal antibody were prepared. The antibody reacted specifically with hDC-LAMP sequences of hDC-LAMP protein expressed in transfected cells and with a 54 kDa protein of normal human lung tissue with properties corresponding to those of transgene expressed hDC-LAMP. Immunohistochemical analysis of hDC-LAMP in human lung showed its presence in alveolar type II epithelial cells (type II pneumocytes) as well as in cells in the interfollicular area of bronchus-associated lymph nodes, where interdigitating DCs are concentrated, and with lesser staining of alveolar macrophages. The native protein contained approximately 16% carbohydrates, most of which are sialyl N-linked oligosaccharides, with an acidic isoelectric point (pI 4.8). The restricted localization of this protein to lung type II pneumocytes and DCs is in contrast to hLAMP-1, which was present in many cell types of the lung and lymph node. Type II pneumocytes are known to express MHC II and the abundant expression of hDC-LAMP in these cells as well as in DCs suggests its possible relationship to specific MHC II related function(s) of DC and type II pneumocytes.
Akasaki
Kenji
K
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
Nakamura
Nobuki
N
Tsukui
Naoko
N
Yokota
Sadaki
S
Murata
Shin-ichi
S
Katoh
Ryohei
R
Michihara
Akihiro
A
Tsuji
Hiroshi
H
Marques
Ernesto T A
ET
August
J Thomas
JT
D015703:Antigens, CD / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D051907:Lysosomal Membrane Proteins; D008970:Molecular Weight; D014018:Tissue Distribution; D014162:Transfection / Q000379:methods
D015703:Antigens, CD; D000949:Histocompatibility Antigens Class II; D051907:Lysosomal Membrane Proteins