Figure 4. The increased liver injury induced by ConA was dependent on intrahepatic NK cells in HCV mice.

A, B, C. and D. Hepatic NK cell numbers and activation were upregulated in HCV mice after challenge with ConA. Mice injected with pattB-HCV-Fluc or pattB-Fluc were treated with ConA (10 μg/g body weight) and sacrificed at 12, 24 and 36 h after challenge. Hepatic MNCs were isolated and analyzed by flow cytometry using anti-NK1.1 and anti-CD3 antibodies. (A) The total number of intrahepatic MNCs is shown. The results represent one of three independent experiments (n=4). The percentages (B) and total numbers of (C) NK cells among hepatic MNCs are shown. (D) The surface expression of CD69 on CD3-NK1.1+ cells was also analyzed. *P<0.05. These results are representative examples from one of three experiments. (E, F and G) Depletion of NK cells alleviated ConA-induced hepatic injury. E. Depletion of NK cells was confirmed by flow cytometry. F. At 24 h after ConA treatment, serum ALT and AST levels were determined (n=5). *P<0.05. G. Representative photographs of H/E-stained liver sections obtained from an HCV mouse or an antibody-depleted HCV mouse at 24 h after challenge with ConA (magnification: 100×, the arrow indicates the parenchymal loss). H. Activated NK cells induced liver injury in NK cell-depleted HCV mice. Hepatic NK cells were isolated by negative selection using an NK cell isolation kit from HCV mice treated for 6 hours with ConA (10μg/g body weight). The purification of hepatic NK cells from 6-hour ConA-treated HCV mice is shown. Purified NK cells (1×10⁶) were adoptively transferred into the liver of anti-ASGM1-treated HCV mice that had been treated with ConA (10μg/g body weight) for 6 hours for the similar condition as the donor mice. Serum ALT and AST levels were measured 24 hours after NK cell transfer (n=3). Hepatic NK cells isolated from untreated HCV mice served as the control.