(a-b) GGG was measured in the bile (a) and spleen (b) of Ggt5−/− and control (Ggt5+/+ and +/− littermates) by LC-MS/MS. For bile n=22 control and n=16 Ggt5-/−. Spleens were pooled in groups of five (n=6 control, n=5 Ggt5−/−). (c-d) Empty vector (EV) and P2RY8-transduced activated splenic B cells were transferred into preimmunized Ggt5 +/− or −/− mice (c), or Ggt5 BM chimeric mice 8 weeks following reconstitution (d). Immunofluorescence for P2RY8- or EV-transduced B cells (GFP, green) in the splenic GC (CR1, red) of sheep red blood cell (SRBC) immunized mice relative to endogenous follicular B cells (IgD, blue). Scale bars 100μm. Data are pooled from one (a) or three (b) experiments; or representative of six (c) or two (d) biological repeats, with approximately 40 GCs visualized per biological repeat. P-values determined by unpaired two-tailed Student’s t-test (a,b) *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. Graphs depict mean with s.d. and points represent biological replicates.