Secretory High-Mobility Group Box 1 Protein Affects Regulatory T Cell Differentiation in Neuroblastoma Microenvironment In Vitro

Figure 1

The expression of phenotypic Treg markers in coculture experiments by flow cytometry. PBMCs obtained from 5 healthy donors were cultured in the absence (PBMC) or presence of SK-N-SH (PBMC+SH), SK-N-AS (PBMC+AS), and SH-SY5Y (PBMC+SY5Y) for 4 days prior to flow cytometric analysis. (a) The sequential gating strategy of Treg enumeration. (b) The percentage of CD4⁺T cells of PBMCs. (c) The percentage of CD4⁺CD25⁺activated T cells of total CD4⁺T cells. (d) The percentage of CD4⁺CD25⁺Foxp3⁺Treg cell of total CD4⁺T cells. The results showed that the PBMC+SH coculture condition, but not those of PBMC+AS or PBMC+SY5Y, had significant increase in the Treg frequency as compared to the control condition (PBMC), suggesting that a particular microenvironment of SK-N-SH cells mediated Treg differentiation. Values represent mean±SD of 5 independent experiments (^∗p<0.05; ^∗∗p<0.001).

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