C4A and ischemia: The mean neurological scores of C4/− and Prnp−/− mice after 1 h of ischemia were significantly lower than those after 24‐h reperfusion, no significant difference was seen between the C4/− mice and the Prnp−/− mice, neither after 1 h of ischemia nor at the end of 24‐h reperfusion (Figure 5B).