Figure 3.

Tasquinimod reduces the MDSC suppressive capacity and increases T cell proliferation in vitro. (A) MACS sorted CD11b⁺ BM cells were cocultured in the presence of 5TGM1 MM conditioned medium, CD3/CD28 microbeads and splenic CFSE-labeled T cells of naive mice with/without tasquinimod (TasQ). MDSC and T cells were cocultured at a ratio of 1/4, 1/2 and 1/1, respectively. After 72 hours, T cell proliferation was analyzed using flow cytometry (n=8, Mann-Whitey U test). (B) Supernatant was collected from this assay and IFN-γ was analyzed by ELISA (n=8, Mann-Whitey U test). (C) CD11b⁺ cells were sorted from the BM of the 5TGM1MM model and treated with vehicle or tasquinimod for 24 hours. The mRNA level of genes was measured with RT-qPCR and calculated with the ΔΔC. The data are expressed relative to their respective controls set to 1 (n=5, unpaired t-test). (D) The CD11b⁺ F4/80⁺ population and M2 macrophage subset (CD11b⁺ F4/80⁺ CD206⁺) were detected by flow cytometry (n=5, Mann-Whitey U test). *p<0.05, **p<0.01, ****p<0.0001. Error bars indicate SD. BM, bone marrow; CFSE, carboxyfluorescein succinimidyl ester; MACS, magnetic-activated cell sorting; MDSC, myeloid-derived suppressor cell; MM, multiple myeloma.