Bovine γδ T Cells Are a Major Regulatory T Cell Subset

Abstract

In humans and mice, γδ T cells represent <5% of the total circulating lymphocytes. In contrast, the γδ T cell compartment in ruminants accounts for 15–60% of the total circulating mononuclear lymphocytes. Despite the existence of CD4+CD25high Foxp3+ T cells in the bovine system, these are neither anergic nor suppressive. We present evidence showing that bovine γδ T cells are the major regulatory T cell subset in peripheral blood. These γδ T cells spontaneously secrete IL-10 and proliferate in response to IL-10, TGF-β, and contact with APCs. IL-10–expressing γδ T cells inhibit Ag-specific and nonspecific proliferation of CD4+ and CD8+ T cells in vitro. APC subsets expressing IL-10 and TFG-β regulate proliferation of γδ T cells producing IL-10. We propose that γδ T cells are a major regulatory T cell population in the bovine system.

Loss of Immunization-Induced Epitope-Specific CD4 T-Cell Response following Anaplasma marginale Infection Requires Presence of the T-Cell Epitope on the Pathogen and Is Not Associated with an Increase in Lymphocytes Expressing Known Regulatory Cell Phenotypes

“…In cattle, WC1.1 ϩ and WC1.2 ϩ ␥␦ T cells had suppressive function in vitro and expressed high levels of IL-10 (28), but this was not measured in the context of chronic infection. In calves infected with bovine respiratory syncytial virus (BRSV), the WC1.2 ϩ subset of ␥␦ T cells produced high levels of IL-10 and transforming growth factor beta (TGF-␤) when stimulated with BRSV ex vivo, suggesting a regulatory function for these cells (29 (30). Unfortunately, we did not have sufficient cells to perform similar cytokine assays on purified ␥␦ T-cell subsets.…”

“…ϩ T cells have a demonstrated regulatory function in mice and humans (43), recent studies show a lack of suppressive function of these cells in cattle (28,30). In contrast, ␥␦ T cells, and in particular the WC1.2 ϩ subset of ␥␦ T cells, have been implicated in the suppression of bovine CD4 and CD8 T cells in vitro (28)(29)(30).…”

“…In contrast, ␥␦ T cells, and in particular the WC1.2 ϩ subset of ␥␦ T cells, have been implicated in the suppression of bovine CD4 and CD8 T cells in vitro (28)(29)(30). To determine if regulatory T cells increased in cattle undergoing acute A. marginale infection, PBMC and spleen cells were analyzed by flow cytometry after staining cells with MAb to detect regulatory T-cell markers.…”

“…In cattle, although FoxP3 ϩ T cells have been identified, they have not been shown to have suppressive activity, whereas subsets of ␥␦ T cells have regulatory activity for bovine T cells ex vivo (28)(29)(30).…”

Expresión de los Genes de los Receptores TCR-delta en la Mucosa Yeyunal de Crías de Alpaca (Vicugna pacos)

“…En los rumiantes, los linfocitos Tγδ también se encuentran en altas concentraciones a nivel sanguíneo y esa concentración es mayor cuando son jóvenes. Dichos linfocitos son necesarios para una inmunorreacción celular temprana en animales cuyas inmunoglobulinas no atraviesan la placenta (Guzman et al, 2014 En el presente trabajo se investiga la expresión de los genes de los polipéptidos gamma y delta que conforman el TCR de los linfocitos en la mucosa intestinal de las crías de alpacas, hipotetizando que la expresión de los genes del TCRγδ en la mucosa intestinal de yeyuno de crías de alpaca se incrementa en las primeras semanas de vida. En este estudio, el objetivo principal fue determinar la expresión de los genes codificadores del TCRγδ en la mucosa intestinal de yeyuno de crías de alpacas.…”