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Updated: Jul 6, 2026
Determination of Vaccine Immunogenicity Using Bovine Monocyte-Derived Dendritic Cells
Published on: May 19, 2023
Identification and functional characterization of a bovine orthologue to DC-SIGN
Yoshika Yamakawa1, Christopher Pennelegion, Samuel Willcocks
1Department of Pathology and Infectious Diseases, Royal Veterinary College, Hatfield, UK.
Insights
Researchers identified a DC-SIGN-like molecule in bovine dendritic cells (DC). This molecule binds to pathogens like HIV-1 gp120 and Mycobacterium bovis, suggesting a role in bovine immune responses.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN) is a C-type lectin primarily found on dendritic cells (DCs).
- DC-SIGN plays a role in DC-T cell interactions and pathogen binding, including Mycobacterium bovis and HIV-1 gp120.
Purpose of the Study:
- To identify and characterize the bovine ortholog of DC-SIGN.
- To investigate the functional role of this bovine DC-SIGN-like molecule in pathogen binding and uptake.
Main Methods:
- Gene identification and PCR amplification of the bovine DC-SIGN ortholog.
- Western blot analysis to detect the protein in bovine DC lysates.
- Functional assays using FITC-labeled OVA and FITC-gp120 to assess binding and uptake by bovine and human DCs.
- Blocking experiments with anti-DC-SIGN antibodies and assessment of Mycobacterium bovis binding.
- Confocal microscopy and pulse-chase studies to confirm surface expression and internalization.
Main Results:
- A single-copy bovine DC-SIGN gene was identified, with 100% match to predicted sequences.
- A protein of similar molecular weight to human DC-SIGN was detected in bovine DC.
- Bovine DCs exhibited time- and temperature-dependent binding of FITC-gp120, blocked by anti-DC-SIGN antibody.
- Blocking DC-SIGN reduced Mycobacterium bovis binding to bovine DCs.
- DC-SIGN was confirmed on the surface of bovine DCs and internalized rapidly.
Conclusions:
- Evidence supports the existence of a DC-SIGN-like molecule specifically expressed by bovine DCs.
- This molecule likely plays a significant role in the interaction of bovine DCs with pathogens, including Mycobacterium bovis.
Abstract:
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.
