Fig. 4

Immune status and Inflammatory cytokine analysis after challenge in different vaccine groups. a Serum neutralizing antibody titer against different VOCs before (0 dpi) and after (7 dpi) Beta variant challenge. b PBMCs were isolated before (0 dpi) and after (7 dpi) Beta variant challenge, and stimulated by spike peptide pools. The INF-γ concentrations of supernatant were quantified and presented. c–f Multiple inflammatory cytokines in BALs and lung tissue homogenate were measured and expressed as concentrations. The concentration of pro-inflammatory cytokines, such as IL-1β, IL-6, TNF-α, IFN-γ, IL-8, IL-12, and IL-18, in lung tissues (c) and BALs (e). The concentration of chemokines, including IL-8, MCP-1, MIP-1β, and MIP-1α, in lung tissues (d) and BALs (f). One spot represents one animal