IL-27-induced PD-L1<sup>high</sup>Sca-1<sup>+</sup> innate lymphoid cells suppress contact hypersensitivity in an IL-10-dependent manner.

Overview

Innate lymphoid cells (ILCs) play an important role in maintaining tissue homeostasis and various inflammatory responses. ILCs are typically classified into three subsets, as is the case for T-cells. Recent studies have reported that IL-10-producing type 2 ILCs (ILC2₁₀s) have an immunoregulatory function dependent on IL-10. However, the surface markers of ILC2₁₀s and the role of ILC2₁₀s in contact hypersensitivity (CHS) are largely unknown. Our study revealed that splenic ILC2₁₀s are extensively included in PD-L1^highSca-1⁺ ILCs and that IL-27 amplifies the development of PD-L1^highSca-1⁺ ILCs and ILC2₁₀s. Adoptive transfer of PD-L1^highSca-1⁺ ILCs suppressed oxazolone-induced CHS in an IL-10-dependent manner Taken together, our results demonstrate that ILC2₁₀s are critical for the control of CHS and suggest that ILC2₁₀s can be used as target cells for the treatment of CHS.