NK cell-based approach for screening novel functional immune genes

Abstract

The human genome project provides extensive opportunities for the discovery of novel functional immune genes. In order to find innate immune genes that might regulate the function of NK cells from a cDNA library, we used an NK cell line, NK-92, as a platform to screen candidate genes. After comparing with other gene transfer methods, electroporation was selected as the best gene transfection approach to deliver cDNA expression plasmids containing candidate genes into the NK-92 cells. When the transferred gene was stably expressed in NK-92 cells, the functional changes in the NK-92 cells were examined, including cytotoxicity, cytolytic molecules, cytokine production, and proliferation. Two novel genes were selected as functional genes that regulate NK cell function from among more than 100 candidate genes, for which the proliferation and cytotoxicity of NK-92 cells were examined as primary indicators. This was followed by extensive flow cytometry analysis and RT-PCR. The primary data indicated that the two novel genes negatively influenced the cytotoxicity of NK-92 cells by inhibiting the expression of several activating receptors and immune functional genes. Therefore, we describe an efficient method for the discovery of novel functional genes in NK cells by using an NK cell line as a screening platform.