Figure 6. Ecto-5′-nucleotidase activity facilitates the suppression of T cell proliferation by granulocytic MDSCs.

(A) MDSCs were generated from mouse bone marrow hematopoietic progenitors and CD11b⁺Gr-1^high cells were enriched (>70%) by positive immunomagnetic selection with anti-Ly-6G antibody. T cells were stimulated with anti-CD3–anti-CD28–coupled microbeads and cultured without (0) or co-cultured together with CD11b⁺Gr-1^high cells added at numbers corresponding to 3, 6 or 12% of T cell numbers in the presence of increasing concentrations of 5′-AMP. Values are expressed as mean±SEM, n=3.

(B) MDSCs were generated from mouse bone marrow hematopoietic progenitors in the absence (Control) or presence of 1 μM NECA (NECA-treated) and CD11b⁺Gr-1^high cells were purified (>95%) by flow cytometry. T cells were stimulated with anti-CD3–anti-CD28–coupled microbeads and cultured without (0) or co-cultured together with CD11b⁺Gr-1^high cells added at numbers corresponding to 6 or 12% of T cell numbers in the absence (Control, NECA-treated) or presence of 300 μM 5′-AMP (Control+AMP, NECA-treated+AMP). Data are presented as mean±SEM (n=3) of maximal thymidine incorporation.