Identification and functional characterization of a bovine orthologue to DC-SIGN.
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.
Yamakawa
Yoshika
Y
Department of Pathology and Infectious Diseases, Royal Veterinary College, Hatfield, UK.
Pennelegion
Christopher
C
Willcocks
Samuel
S
Stalker
Amanda
A
Machugh
Niall
N
Burt
Dave
D
Coffey
Tracey J
TJ
Werling
Dirk
D
D000818:Animals; D002417:Cattle / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D003713:Dendritic Cells / Q000737:chemistry / Q000382:microbiology / Q000502:physiology; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D037181:Lectins, C-Type / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D009000:Monocytes / Q000737:chemistry; D009163:Mycobacterium bovis / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D013997:Time Factors; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
D015815:Cell Adhesion Molecules; D006023:Glycoproteins; D037181:Lectins, C-Type; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C070165:Gp120 brain glycoprotein, Bos taurus