An inhibitory Keller Cell Ig-like Receptor(KIR, previously called p58 KIR, p58.1, cl-42, NKAT1, or KIRK6), which recognizes class I MHC molecules(HLA-Cw2, -Cw4, -Cw5, and Cw6). The protein coding region of the extracellular domain of KIR2DL1(amino acids 1-202) was cloned into an E. coli expression vector. The extracellular domain of KIR2DL1 was overexpressed as insoluble protein aggregates(inclusion bodies). The recombinant KIR2DL1 protein was purified by FPLC gel-filtration chromatography, after refolding of the isolated inclusion bodies in a redox buffer.