IL1RL1, as known as interleukin-1 receptor-like 1 isoform 1, is and interleukin-1 receptor family glycoprotein that contributes to immune responses. As an important mediator involved in many immune and inflammatory responses, this cytokine has been implicated as a regulator of both the development and effector phases of type 2 helper T cell responses, and as a negative feedback modulator of macrophage pro-inflammatory function. Recombinant human IL1RL1, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.