AdCMV.NK4 induces NK4 protein in SKG mice. SKG mice were injected intravenously with AdCMV.NK4 (1 × 109 plaque-forming units (pfu)) into the tail vein. One day after injection, serum and liver were obtained and NK4 protein levels in the serum (A) and NK4 protein expression in the liver (B) were measured by hepatocyte growth factor (HGF) enzyme-linked immunosorbent assay (ELISA) or immunohistochemistry, respectively. Data in (A) are represented as the means ± SD (n = 6). The arrows in (B) represent NK4 protein expression in hepatocytes. Original magnification, ×100.