Abstract: [Abstract] Objectives:Osteoclasst inhibitory lectin (OCIL) expressed by the osteoblast/stomal cells is a type-Ⅱ transmembrane protein. OCIL extracellular domain was obtained to investigate its effect on the formation of osteoclast like cells. Mehtods: based on the codon preference and degeneration, the codons of OCIL extracellular domain was changed into those preferred by E.coli coding and ligated the fragments with recombinant PCR. By induction of IPTG, the recombinant cells BL21(DE3)plysS with transfection of pMAL-c2x/hOCIL produced the soluble recombinant protein in the cell lysates. then the combination activity between maltose binding protein (MBP) and Amylose was used to purify the fusion protein. The biological action of the recombinant protein was analyzed by its effect on osteoclast formation in murine bone marrow cell culture under the stimulation of macrophage-colony stimulating factor (M-CSF) and receptor activator of nucleic factor κB ligand (RANKL). Results: osteoclast like cells (OLCs) formation was significantly blocked by the recombinant protein. Conclusion: the research successfully obtained the recombinant protein hOCIL from E.coli with biological activity that may inhibited the osteoclast like cells formation in vitro.

Key words: Osteoclast inhibitory lectin, expression, recombinant PCR, recombinant protein, Osteoclast