IL1R1, also known as interleukin-1 receptor type 1, associates with the corecptor IL1RAP to form the high affinity interleukin-1 receptor complex which mediates interleukin-1-dependent activation of NF-kappa-B, MAPK and other pathways. It is an important mediator involved in many cytokine induced immune and inflammatory responses. Recombinant human IL1R1, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.