Figure 4

Flow cytometry analyses to determine the frequency of IgA ⁺ and IgG ⁺ B cells in mucosal tissues of PEDV infected sows. Mononuclear cells were isolated from ileum (A, B, G, H), mesenteric lymph nodes (C, D, I, J), and spleen (E, F, K, L), and stimulated ex vivo with PEDV whole virus-derived antigen (B, D, F, H, J, L) or medium control (A, C, E, G, I, K) for 6 days. The frequency of B cells positive for IgA (A–F) and IgG (G–L) antibodies were determined by flow cytometry. Each bar represents the mean of percent of lymphocytes positive for IgA or IgG positive B cells ± SEM from six sows. Lowercase alphabet indicates statistically significant difference between uninfected and PEDV-infected corresponding parity sow groups, and asterisk indicates statistical difference between the indicated PEDV-infected sow groups (“a” or *P < 0.05, “b” or **P < 0.01 and “c” or ***P < 0.001).