The follicular B cells in Ubr5^ΔHECT mice have an altered phenotype and diminished differentiation capabilities. (A) Representative histogram of cell-surface markers of follicular B cells (B220⁺CD21⁺CD23⁺). (B) Bar graphs of relative MFI of follicular B cells depicted in panel A (N ≥ 5). (C) Representative PNA IHC staining of spleen 7 days poststimulation with SRBC (N = 3). (D) Percentage of GC staining to the white pulp within the spleen (N = 3). (E) Absolute number of germinal center cells (B220⁺PNA⁺CD95⁺) (N = 4). (F) Representative flow cytometry plots of B220⁺ and CD138⁺ plasma cells in the peripheral blood. (G-H) Bar graphs representing percentages of B220⁺ and CD138⁺ cells in the peripheral blood depicted in panel F (N ≥ 5). (I) Bar graph of ELISpot indicating number of antibody-secreting cells (ASC) from SRBC-activated splenocytes (N = 12). (J) Bar graphs of ELISA indicating relative expression for different immunoglobulin types before (day 0) and after (day 8) immune system stimulation with SRBC (N ≥ 4). *P < .05, **P < .01, ***P < .001, ****P < .0001.