(a-c) Activated EV- or P2RY8-transduced polyclonal B cells were transferred into preimmunized Abcc1 +/+, +/− or −/− mice (a), into preimmunized BM chimeric mice of the type indicated (b), or into preimmunized Abcc1+/+ mice reconstituted with μMT BM mixed at a 3:1 ratio with Abcc1+/+ or −/− BM. (c). Immunofluorescence for P2RY8- or EV-transduced B cells (GFP, green) in the GCs (CR1, red) of SRBC immunized mice relative to endogenous follicular B cells (IgD, blue). Scale bars 100μm. (d) Irradiated Abcc1+/+ or −/− mice were reconstituted with P2RY8-GFP or EV-GFP transduced Abcc1+/+ or −/− BM. Following reconstitution, PPs were analyzed for the frequency of GFP+ cells in the follicular and GC B cells compartment. The ratio of GFP+ cells in the GC B cells vs in the follicular B cells was plotted (n=6–7, exact number shown by number of symbols in the plot). Data are pooled from two experiments and representative of four experiments (d); or representative of four (a,b,c) biological repeats, with approximately 40 GCs visualized per biological repeat. P values determined by one-way ANOVA with Tukey’s multiple comparisons test (d). *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. Graphs depict mean with s.d. and points represent biological replicates.