The Bovine CD1 Family Contains Group 1 CD1 Proteins, but No Functional CD1d

Abstract

The CD1 family of proteins presents lipid Ags to T cells. Human CD1a, CD1b, and CD1c have been shown in humans to present mycobacterial lipid Ags. Cattle, like humans, are a natural host of several mycobacterial pathogens. In this study, we describe the CD1 family of genes in cattle (Bos taurus) and provide evidence that B. taurus expresses CD1a, CD1e, and multiple CD1b molecules, but no CD1c and CD1d molecules. In mice and humans, CD1d is known to present Ag to NKT cells, a T cell lineage that is characterized by a limited TCR repertoire, capable of rapidly secreting large amounts of IFN-γ and IL-4. In cattle, two CD1D pseudogenes were found and no intact CD1D genes. Consistent with this, we found complete lack of reactivity to a potent, cross-reactive Ag for NKT cells in mice and humans, α-galactosylceramide. Our data suggest the absence of NKT cells in cattle. It remains open whether other cells with the NKT-like phenotype and functions are present in this species. With its functional CD1A and CD1B genes, B. taurus is well equipped to present Ags to CD1-restricted T cells other than NKT cells. Cattle can be used as a model to study group 1 CD1-restricted T cell immunity, including its role in the defense against mycobacterial infections that occur naturally in this species.

Structural determination of lipid antigens captured at the CD1d–T-cell receptor interface

“…In adult mice, orally delivered antigen activates iNKT cells in the gut (26), suggesting that exposure to dietary lipid antigens in adult life may also have consequences. Interestingly, it is unclear whether cows have iNKT cells (27), as their CD1d does not present the long-chain α-galactosylceramide commonly used as a tool in mice and humans (28). Bovine CD1d can present short-chain α-galactosylceramides (28,29), and it is possible that an increased presence of α-hexosylceramdies in cow's milk and tissues could lead to thymic deletion of iNKT cells, as has been observed in mice in the presence of exogenous α-galactosylceramide (30).…”

Bovine tuberculosis as a model for human tuberculosis: advantages over small animal models

“…The known CD1-presented mycobacterial antigens are diverse and include mycobacterial mycolates, diacylglycerols (LAM and PIM), polyisoprenoid lipids, sulfotrehalose-containing lipids and lipopeptides [34]. Cattle express CD1a and three CD1b isoforms, but lacks CD1c [35]. T cells from cattle infected with mycobacteria, but not from uninfected cattle, react to stimulation with mycobacterial lipids (Van Rhijn, unpublished), a situation that is comparable to human tuberculosis [36].…”

Immunohistochemical Detection of Dendritic Cell Markers in Cattle

“…CD1b has been described as the most important CD molecule in this species. 36,42 The majority of CD1 molecules are strongly expressed in cortical thymocytes as well as in certain other cell types, to include DCs. 16 CD205, also known as DEC-205, is a C-type lectin that belongs to the same family of the macrophage mannose receptor and is primarily expressed on certain DCs and epithelial cells, acting as an endocytic receptor, and is involved in the capture of antigens from extracellular spaces and transferal to a specialized antigen-processing compartment.…”