In vitro lipopolysaccharide treatment alters regulatory T cell properties in chickens

The objective of this study was to identify the effect of in vitro lipopolysaccharide (LPS) treatment on regulatory T cells (Tregs) from chickens. Tregs had approximately 30-fold higher TLR 2-type 2 and six-fold higher TLR 4 mRNA content than CD4+CD25− cells. Tregs were treated with either 0 or 1 μg/ml LPS for 0, 2, and 4 d. LPS treatment increased the IL-2 mRNA amount in Tregs at 2 and 4 d post-LPS treatment. LPS treatment increased the IL-10 mRNA amount in Tregs at 4 d post-LPS treatment. The total live cell numbers were approximately two-fold higher at 2 d and three-fold higher at 4 d in the 1 μg/ml LPS-treated groups than in the 0 μg LPS-treated controls. LPS treatment abrogated suppressive properties of Tregs at 2 d post-LPS treatment. At 4 d post-LPS treatment, Tregs became supersuppressive. In conclusion, chicken Tregs are differentially activated to facilitate immune response during the early stage of inflammation and to facilitate immune suppression at a later stage of inflammation.