2. Cytokines of the interleukin-10 Family

By subtractive hybridization, we cloned a cellular gene (ak155) with 25% identity and structural similarity to interleukin-10 (IL-10), from HVS-transformed human T-cells. Specifically, these cells overexpress ak155 and secrete the derived protein into the supernatant. In other T-cell lines and in native peripheral blood cells, ak155 is transcribed at low level. The protein forms homodimers similarly to IL-10 and induces STAT phosphorylation in epithelial target cells via members of the type-2 family of cytokine receptors. AK155, also termed IL-26, belongs to a newly described family of cytokines which are structurally, but not functionally, related to IL-10.