C3 and infection: Additionally, Tlr4, Tlr13, Cxcl2, Cxcl1, Xcr1, Cxcl16, Nfkbia, Tnfaip3, Il6, Casp12, Nod2, Ccl2, Vcam1, Ncf2, Cfd, Cd46 and C3ar1 were upregulated and C3 was downregulated in the infection group, which suggested that the permeability of the BBB increased and the recruitment of monocytes, neutrophils, T cells, and natural killer cells was enhanced during the infection process.