Extended Data Fig. 8: Definition of flyer, brief roller and roller cells visualized by in situ video microscopy of Peyer’s patches.

a, The mean velocity of wild-type (WT) and CD22-deficient (Cd22^–/–) B cells free flowing through the vessels without any interactions (namely flyer) was calculated and shown for each individual cell. Shown are pooled results (~ 50 cells per group) analyzed from 3–4 representative HEVs and 3 independent experiments. b,c, The instant velocity (b) and displacement (c) of a representative free flowing cell (Flyer), of one that interacts very briefly (<1 s) with the HEVs (namely Brief roller), or one that interacts and rolls on the HEVs for >1 sec (namely Roller) is shown together with frame-per-frame tracking of the cells (identified with *). Scale bars: 10 μm. d, In three independent in situ experiments with 1:1 ratio of WT B cells donor versus Cd22^–/– B cells donor, the total number of events (that is flyer, brief roller, or roller) was counted for each donor in 3–4 representative HEVs for the total duration of the movie (~ 250–300 total cells analyzed per group). The percentage of WT and Cd22^–/– B cells experiment per experiment is shown. ns: not significant.