IL6 and infection: The transcription levels of IL‐10 in the brain of mice in the PDL1‐IgG1FC i.t. group showed a significant downregulation on the 7th day (p = 0.0364) after infection compared with that in the IgG1Fc adenovirus i.t group (Figure 5C), and there was no significant difference in the transcriptional level of inflammatory cytokine TNF‐α and IL‐6 (Figure S4C).