KI and WT (n = 5/group) mice were immunized i.p. with NP-CGG in Rehydragel. Spleens were collected on day 14 for IHC staining and FACS analysis. A) Splenic sections were stained with B220 or PNA. The numbers of GCs and the area of PNA staining was evaluated from scans of spleen sections stained with B220 or PNA using color deconvolution analysis software (Aperio Technologies). B) The cells from spleens and lymph nodes (LN) were stained with B220, GL7, Fas, CD38, and IgD antibodies. There were fewer GC B cells in KI than WT. Data are presented as mean ± SEM; p-values are indicated. C) Sera from KI and WT mice immunized with NP-CGG were collected on day 14 for measurement of Ag-specific IgM and IgG isotype antibody titers. Data are presented as mean ± SEM: *significance p<0.01. D) The relative affinities of anti-NP Abs were determined using an ELISA with BSA coupled to NP at different ratios, namely, NP4-BSA and NP14-BSA.