Figure 1. Expansion of MDSCs in bone marrow and bone destruction in CIA.

(A) Mice with CIA were sacrificed on day 35 and age-matched normal mice were used as controls. Bone marrow cells were stained with anti-CD11b and anti-GR-1 mAbs. Data were acquired by flow cytometry and representative dot plots are presented. (B) The frequency of MDSCs in the bone marrow of normal or CIA mice. Six mice in each group were tested. (C) Splenocytes from normal mice were labeled with CFSE and co-cultured with or without 5×10⁵ MDSCs from CIA or normal mice in anti-CD3/CD28 bound culture plates. Cells were collected and stained with APC-anti-CD4 mAb after 72 hours stimulation. Data was analyzed by flow cytometry and representative dot plots are presented. (D) The proliferation rates of CD4 T⁺ cells. Data were acquired by flow cytometry and summarized from three independent experiments. (E, F) Mice with CIA were sacrificed on day 35. Bones were fixed and decalcified with EDTA. Knee joints section were stained for TRAP (E) and with H&E (F). Six mice were tested for each group and representative images are presented. Data in B and D are shown as mean ± SD. *p<0.05, **p <0.01.