Overexpression and function analysis of KIR2DL4 expressed in NK-92 cell lines

Objective To obtain human KIR2DL4 stable expression and its regulation role in NK-92 cells. Methods RT-PCR technique was used to amplify KIR2DL4 cDNA from human decidue tissue and the full length KIR2DL4 cDNA was obtained, the cDNA was subcloned into retrovirus vector to make the combined plasmid KIR2DL4-pLNCX. The recombinant plasmid was transfected into target cells followed by screening with G418 and limiting dilution. Cell surface KIR2DL4 expression was detected with FACS. IFN-γ production and cytotoxicity analysis was determined with ELISA and LDH release test respectively. Results KIR2DL4 molecule stably expressed on KIR2DL4-pLNCX transducted NK-92 cells and showed no effect on expression of other endogenous receptors. HLA-G positive target cells showed a high degree of resistance to the cytotoxicity of NK-92 cell through the expressed KIR2DL4 receptor compared with the control group and the cytotoxicity to the HLA-G transfected K562 cells partially increased after KIR2DL4 blocking. Furthermore, cross-linking of KIR2DL4 could induce the production of IFN-γ. Conclusion Functional KIR2DL4 molecule expressed stably on the NK-92 cells.