Fig. 1

Number of CD4⁺IFN-γ⁺ cells in mesenteric lymph nodes (MLN) of pigs infected with different PEDV variants. PEDV-specific CD4⁺IFN-γ⁺ stimulation effect of MNC isolated at 3, 7, 14 dpi from MLN of PEDV infected pigs, and homologous and heterologous PEDV reinfection at 21 dpi (7dpri) with EAS1 (A), classical variant PEDV recall antigen activation, and CBR1 (B), pandemic variant PEDV recall antigen activation. The red dash line demonstrated the baseline of PEDV in unexposed pigs (negative control at 0 dpi). G1I = EAS1-infected group; G2I = CBR1-infected group; G1HomoRI = EAS1-infected group following by EAS1 reinfection at 14 dpi; G1HeteRI = EAS1-infected group followed by CBR1 reinfection at 14 dpi; G2HomoRI = CBR1-infected group following by CBR1 reinfection at 14 dpi; G2HeteRI = CBR1-infected group followed by EAS1 reinfection at 14 dpi.