Fig. 1

Diagram of the experimental design and identification of GC-B cells in the spleen. (A) Mice were immunized with MAP2-3 or MAPctrl 5 times. After one month of the last immunization, all mice were inoculated with heat-killed S. aureus (2 × 10⁷ CFU/mice) via i.p. The splenocytes, lymph node cells, and bone marrow cells were isolated 7 days after the inoculation. The percentage of different immune cells, including GC-B cells, plasma cells, memory B (Bm) cells, memory T (Tm) cells, etc. was identified by flow cytometry, respectively. Isolated splenocytes were stimulated with LTA or heat-killed S. aureus and the level of cytokines was determined by RT-PCR or ELISA. (B) Flow cytometry analysis of GC-B cells. Gating strategy and representative FACS of GC-B cells. (C) The percentage of GC-B cells in spleens. MAP2-3 vs. MAPctrl: p < 0.001; MAP2-3 vs. Blank: p < 0.001. n = 5–6 mice/group. *** p < 0.001