Downregulation of the H-2K(d) gene by siRNA affects the cytotoxicity of murine LAK cells

To investigate the effect of the H-2K(d) gene on the lymphocyte membrane, we constructed a small interfering RNA (siRNA) that targets the H-2K(d) gene and compared the cytotoxicity of mouse lymphokine-activated killer (LAK) cells with different H-2K(d) expression states. H-2K(d)-targeting siRNA was transfected into spleen lymphocytes of BALB/C mice. Flow cytometry (FCM) was then performed to examine the expression of the H-2K(d) gene in the transfected and control cells. Additionally, the cytotoxicity of the transfected cells toward the H22 and K562 cell lines was evaluated in vitro using the LDH release assay. H-2K(d)-targeting siRNA significantly reduced the expression levels of the target protein, whereas pure transMessenger and non-silencing siRNA did not inhibit H-2K(d) expression at the concentrations tested. The cytotoxicity of siRNA-treated LAK cells toward H22 and K562 cells was reduced significantly. The knockdown of H-2K(d) gene expression by siRNA may be associated with LAK cell cytotoxicity toward neoplasm cell lines.