title: Human dendritic cell lysosome-associated membrane protein expressed in lung type II pneumocytes.
abstract: 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.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Akasaki
authors.forename: Nobuki
authors.initials: N
authors.lastname: Nakamura
authors.forename: Naoko
authors.initials: N
authors.lastname: Tsukui
authors.forename: Sadaki
authors.initials: S
authors.lastname: Yokota
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Murata
authors.forename: Ryohei
authors.initials: R
authors.lastname: Katoh
authors.forename: Akihiro
authors.initials: A
authors.lastname: Michihara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuji
authors.forename: Ernesto T A
authors.initials: ET
authors.lastname: Marques
authors.forename: J Thomas
authors.initials: JT
authors.lastname: August
mesh_terms: 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
chemical_list: D015703:Antigens, CD; D000949:Histocompatibility Antigens Class II; D051907:Lysosomal Membrane Proteins