Differential cytokine expression in T cell subsets from bovine peripheral blood

Although distinct cytokine expression in T cell subsets is well understood in mice and humans, limited information is available on bovine T cell subsets. In the present study, we analyzed the mRNA expression of 10 kinds of cytokines and CD25 expression in CD4(+), CD8(+), WC1(+) and WC1(-) gamma delta T cell subsets in bovine peripheral blood by Concanavalin A (Con A) stimulation. CD25 expression was significantly increased in CD4(+), CD8(+) and WC1(+) gamma delta T cells, but not in WC1(-) gamma delta T cells by Con A stimulation. In CD4(+) T cells, the mRNAs of Interleukin (IL)-2, IL-6, IL-10, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, TNF-beta and transforming growth factor (TGF)-beta were expressed in control cultures, and IL-3, IL-4 and granulocyte-macrophage colony stimulating factor (GM-CSF) were newly expressed when the cells were stimulated with Con A. CD8(+) T cells expressed the mRNAs of IL-6, TNF-alpha, TNF-beta and TGF-beta in control cultures, and newly expressed those of IL-2, IFN-gamma and GM-CSF, but did not express those of IL-3, IL-4 or IL-10 after Con A stimulation. The cytokine expression profile of WC1(+) gamma delta T cells was similar to that of CD8(+) T cells. However, WC1(-) gamma delta T cells did not express any cytokine mRNA except TGF-a mRNA. These results will contribute to elucidate the participation of T cell subsets in immune responses against infectious disease in cattle.