Fig. 8: CECs from human bone marrow express ARG1 and ARG2 and suppress T cells proliferation.

a Representative plots of CD71⁺ and CD235⁺ CECs in the aspirate of human bone marrow of total live cells. b Percentages of ARG1⁺ and ARG2⁺ CECs in the human bone marrow based on intracellular staining. c Mean fluorescence intensity (MFI) of ARG1-PE and ARG2-APC in CECs. d Representative histograms of ARG1 and ARG2 levels in CECs from human bone marrow. Fluorescence-minus-one (FMO) is shown as unstained controls. e, f Proliferation triggered by αCD3/αCD28 of CTV-labeled CD4⁺ (e) and CD8⁺ (f) T cells co-cultured with CECs isolated from the human bone marrow. T cell to CEC ratio was 1:2 (n = 9). The proliferation of T cells in co-culture with CECs was calculated as a percentage of maximum proliferation (100%) of T cells that was triggered by αCD3/αCD28 antibodies and cultured without CECs. Representative histograms shows CTV-BV421 fluorescence of CD4⁺ (e) or CD8⁺ (f) T cells co-cultured with CECs at a 1:2 ratio in the presence of ARGi (OAT-1746, 500 nM). P values were calculated with Friedman’s test with Dunn’s post hoc test. Data show means ± SD (b, c) or means ± SEM (e, f). n values are the numbers of individual patients used to obtain the data or the number of biological replicates in in vitro experiments. The source data underlying b, c, e, f are provided as a Supplementary Data 2 file.