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Identification and functional characterization of a bovine orthologue to DC‐SIGN
Author(s) -
Yamakawa Yoshika,
Pennelegion Christopher,
Willcocks Samuel,
Stalker Amanda,
MacHugh Niall,
Burt Dave,
Coffey Tracey J.,
Werling Dirk
Publication year - 2008
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0807523
Subject(s) - dc sign , biology , polyclonal antibodies , c type lectin , microbiology and biotechnology , bovine serum albumin , dendritic cell , antibody , lectin , antigen , biochemistry , genetics
Dendritic cell‐specific ICAM‐3‐grabbing nonintegrin (DC‐SIGN) C‐type lectin is almost exclusively expressed at the cell surface of DC. In addition to its normal function facilitating contact of DC with T cells, DC‐SIGN has been shown to bind a variety of pathogens, including Mycobacterium bovis , and HIV‐1 envelope protein gp120. In this study, we identified the bovine ortholog of the human DC‐SIGN gene within the bovine genome, which exists as a single copy. PCR amplified a product, showing a 100% match with the predicted sequences as well as a sequence predicted to be similar to that of SIGNR7. Furthermore, a protein with the same molecular weight as human DC‐SIGN was detected by Western blot in cell lysate derived from bovine DC. To characterize this molecule functionally, the uptake of FITC‐labeled OVA and FITC‐labeled gp120 (FITC‐gp120) by bovine and human DC was assessed. FITC‐gp120 was shown to bind to bovine DC in a time‐ and temperature‐dependent manner. Binding was blocked by a polyclonal anti‐DC‐SIGN antibody but not by a control antibody. Furthermore, blocking of this molecule also reduced the binding of M. bovis bacillus Calmette‐Guerin expressing GFP. Confocal microscopy showed that DC‐SIGN was expressed on the surface of bovine DC. Subsequent pulse‐chase studies revealed that FITC‐gp120 was internalized by bovine monocyte‐derived DC as early as 10 min. Thus, there is evidence of a DC‐SIGN‐like molecule expressed specifically by bovine DC. This molecule may play an important role in the infection of bovine (DC) cells with M. bovis .