[Expression and identification of recombinant mouse gene B7-H4].

Objective: To construct a eukaryotic expression vector encoding the gene of extracellular region of mouse B7-H4, to express it in yeast cell line and to determine its biological activity.

Methods: The extracellular region of the mouse B7-H4 gene was amplified with Xho I and EcoR I by PCR from a mouse B7-H4 chimeric plasmid. Digested with Xho I and EcoR I, the mB7-H4 gene was inserted into the yeast expression plasmid Ppic9. The DNA sequence was confirmed by double digestion and the Ppic9-mB7-H4 plasmid was transfected into the yeast cells. The expression of mB7-H4 was confirmed by PCR, Western Blot and ELISA analysis, and its biological function was determined.

Result: Ppic9-mB7-H4 transfectants expressed mB7-H4 in yeast cells, and mB7-H4 effectively inhibited the proliferation of T lymphocytes with a fractional inhibition rate of 28.3 % and inhibited IL-2, IL-4, IL-10 and IFN-gamma production with fractional inhibition rates of 68.8%, 78.8%, 67.6% and 77.7%, respectively.

Conclusion: The eukaryotic expression plasmid mouse B7-H4 has been successfully constructed and the expressed products of B7-H4 possess biological activity.