Accumulated CD11b+Gr1+ cells under the condition of chronic psychological stress were MDSCs.

<p>BALB/c mice were subjected to 5-days restraint stress or left untreated. Bone marrow Gr1+ cells were purified. (A) Bone marrow-derived macrophages were co-cultured with bone marrow CD11b+Gr1+ cells at a ratio of 1:4, and then were stimulated with or without 50 ng/ml LPS for 24 hours. Cytokine release was determined by ELISA. Results are expressed as mean ± SD, n=5. (B) CD4+ CD25- splenic T cells were purified and labeled with CFSE. Then, T cells were co-cultured with bone marrow CD11b+Gr1+ cells at a ratio of 1:1 or 0.5:1. Stimulation was affected by antibodies against CD3 and CD28 for 96 hours. Proliferation was assessed by flow-cytometric analysis of CFSE dilution. One representative of two independent experiments with similar results is shown.