Figure 3.

The immunosuppressive function of Gr1⁺CD11b⁺ cells is nitric oxide and cell contact dependent. A) T cells were cultured as described in Materials and Methods. The addition of the pan-nitric oxide synthase inhibitor L-NAME (1mM) reversed the suppression of both CD4⁺ and CD8⁺ T cell proliferation by Gr1⁺CD11b⁺ cells; B) The presence of a transwell abrogated the suppression of T cells by Gr1⁺CD11b⁺ cells. CD4⁺ and CD8⁺ T cells were co-cultured with purified Gr1⁺CD11b⁺ cells in the presence or absence of transwell as described in Materials and Methods. Three independent experiments were performed and one representative data set is shown. *p<0.05, **p<0.001, ***p<0.0001.

The background CPM counts were between 300–800.