Figure 6. AP4 is essential for humoral responses against chronic viral infection.

(A and B) Frequencies and absolute numbers of B220⁺GL7⁺Fas⁺ cells in the spleens of Tfap4^f/fCd79a^icre/+ and control Tfap4^f/fcre⁻ mice 30 days after infection with LCMV-c13. Data are pooled from two independent experiments.

(C and D) Analysis of plasma LCMV loads in Tfap4^f/fCd79a^icre/+ and control Tfap4^f/fcre⁻ mice (C) and Tfap4^f/-Aicda^cre/+ and control Tfap4^f/+Aicda^cre/+ mice (D) after infection. Data are pooled from six (C) and three (D) independent experiments.

(E) Titers of LCMV-binding serum IgG in Tfap4^f/fCd79a^icre/+ and control Tfap4^f/fcre⁻ mice 80 days after infection. Data are pooled from six independent experiments.

(F) Cumulative frequency distribution of somatic mutations of the Igh variable regions in GC B cells in (B). Data are pooled from two independent experiments.

(G) Neutralizing serum antibody titers from Tfap4^f/fCd79a^icre/+ and control Tfap4^f/fcre⁻ mice 80 days after LCMV infection. Neutralizing titers were shown as 1/EC₅₀. Data are pooled from six independent experiments.

Data in (B and E) are show by means ± SD. Lines in (C, D and G) represent medians. Unpaired Student’s t test for (B and E). Mann-Whitney’s ranked test for (C, D and G). Kolmogorov-Smirnov test for (F). n = 7 for Tfap4^f/fcre⁻ and n = 11 for Tfap4^f/fCd79a^icre/+ (A and B); for each time point n = 10–19 for Tfap4^f/fcre⁻ and n = 16–25 for Tfap4^f/fCd79a^icre/+ (C); for each time point n = 9–11 per group (D); n = 12 for Tfap4^f/fcre⁻ and n = 14 for Tfap4^f/fCd79a^icre/+ (E); n = 6 per group (F); n = 14 for Tfap4^f/fcre⁻ and n = 25 for Tfap4^f/fCd79a^icre/+ (G). See also Figure S6.