Fig. 4.

In vitro depletion of patient myeloid-derived suppressor cells (MDSCs) partially restores patient T cell production and proliferation of interferon (IFN)-γ. (A) PBMCs from patients with glioblastoma (GBM) (n = 3) were thawed and immediately stained for the expression of myeloid surface markers with or without the depletion of MDSC by anti-CD15 magnetic microbeads and magnetic column. Cells were then plated and stimulated with anti-CD3/CD28 antibodies, and after 72 h, IFN-γ was detected in CD3⁺ cells by FACS. Columns represent mean percentage of CD3⁺ cells staining positive for IFN-γ. (B) Patients’ PBMCs were left alone or CD33/CD15 magnetic beads were used to remove MDSCs. The cells were stimulated or not with anti-CD3/CD28 for 72 h. Then, ³H-thymidine was added 18 h before the harvest of the cells. Proliferation was measured by ³H incorporation in DNA.