Figure 4. B1a cells express RANKL in the inflamed joint of CIA mice.

A., B. Flow cytometric analysis of RANKL expression on CD19⁺CD43⁻ B2 and CD19⁺CD43⁺ B1 cells in A, CD19⁺CD43⁺CD5⁺ B1a and CD19⁺CD43⁺CD5⁻ B1b cells in B in the inflamed joint of CIA mice on day 30 post 1^st CII-immunization. C. The frequencies of RANKL⁺ B2, B1, B1a and B1b cells were enumerated from three independent experiments (n = 5-7 per group in each experiment). D. Peritoneal B1a cells from CD45.1⁺ BoyJ mice were intraperitoneally transferred into CD45.2⁺ C57 mice and followed by CII immunization for CIA induction. On day 17 after cell transfer, RANKL expression on donor CD45.1⁺ B1a cells in the PC, SP, LN and joint tissue (Jt) were detected by flow cytometry. The flow profiles are representative data from three independent experiments with similar results.