Fig. 3. DOCK8 supports GC B cell survival but is not required for cell-cycle progression.

(A) Schematic for adoptive transfer of Dock8^wt/wt or Dock8^cpm/cpm BCL2.Tg GFP⁺ MD4 B cells into C57BL/6 recipients 1 day prior to immunization with SRBC-HEL. On day 8, mice were administered the first nucleotide label (2 mg of EdU), followed by a second nucleotide label (3 mg of BrdU) after an interval of either 1 or 3.5 hours. Splenic B cells were assessed for GC status 30 min after the BrdU dose. (B and D) Representative contour plots for EdU and BrdU incorporation by MD4 GC B cells (Live B220⁺CD95⁺GL7⁺IgM^a+GFP⁺ HEL⁺) at (B) 1.5 and (D) 4 hours after the first EdU dose. (C and E) Proportion of unlabeled, BrdU⁺, EdU⁺, and BrdU⁺EdU⁺ cells from samples as in (B and D), respectively. Data pooled from (C) two and (E) three independent experiments with n = 3–6 mice per group. (F) Representative contour plots for B220⁺CD95⁺GL7⁺IgM^a+GFP⁺HEL⁺ B cells in G0/G1, S, and G2/M cell cycle stages. (G) Proportion of cells in each cell cycle stage 30 min after BrdU dose with data pooled from two independent experiments with n = 4–5 mice per group. (C, E and G) Circles represent individual mice and bars show means with 95% confidence intervals. Unpaired two-tailed Welch’s t tests, corrected for multiple comparisons using the Holm–Šídák method were used for analysis with ****P<0.0001.