(A, B) PCV2 infected wild-type (gC1qR+/+) or gC1qR knockout (gC1qR−/−) PAMs for 24 h, then the cells were stimulated by LPS/IFN-γ for 6 h or 24 h. The expression of IL-12p40 were measured by ELISA and qPCR. And the expression of gC1qR were analyzed by western blotting as the bottom panel showed. (C, D) The gC1qR+/+ and gC1qR−/− PAMs were infected by rAd-Blank, rAd-Rep, or rAd-Cap for 24 h, respectively. Then the cells were further stimulated by LPS/IFN-γ for 6 h or 24 h, and the expression of IL-12p40 were measured by ELISA and qPCR. The expression of PCV2 Rep, Cap and host gC1qR were analyzed as the bottom panel by western blotting. **P < 0.01 versus PCV2 or rAd-Cap infected gC1qR+/+ PAMs. ##P < 0.01 versus mock infection gC1qR+/+ PAMs.