Fig. 1: TIGIT deficiency promotes proinflammatory CD4⁺ T cells in patients with PM.

PBMCs were collected from polymyositis (PM), dermatomyositis (DM), systemic lupus erythematosus (SLE), or healthy controls (HC). TIGIT, CD226, and CD96 expression in cells in PBMCs was measured by flow cytometry. a Schematic employed to visualize TIGIT, CD226, and CD96 on T cells binding to CD155 on antigen-presenting cells (APC). b–g CD4⁺ T cells from HC or PM, DM or SLE patients were stimulated with anti-CD3/CD28 beads (αCD3/CD28) for 3 d. The expression of TIGIT, CD226, and CD96 in pre- and post-activation of CD4⁺ T cells was measured by flow cytometry of biological replicates (HC = 27, PM = 27, DM = 23, SLE = 23). h Naive CD4⁺ T cells isolated from PBMCs of HC or patients with PM, were stimulated with αCD3/CD28. TIGIT expression was measured by flow cytometry. Data from four biologically independent replicates. h–l Total CD4⁺ T cells from patients with PM or HC were transfected with pcDNA3.1-hTIGIT or pcDNA3.1-Vector by electroporation. Cells were then stimulated by αCD3/CD28 for 3 d. h Overexpression of TIGIT was confirmed by Western blot. The experiment was repeated three times independently with similar results. i, j Overexpression of TIGIT in CD4⁺ T cells from HC or PM was confirmed by flow cytometry. Data from five biologically independent replicates. k, l IFNγ and IL-17A production by CD4⁺ T cells from PM patients or HC was measured by flow cytometry. Data from five biologically independent replicates. m–o CD4⁺ T cells from PM patients or HC were stimulated with αCD3/CD28 in the presence of CD155-Fc (10 μg/ml) or control IgG1 for 3 d. IFNγ, IL-17A, and FoxP3 expression in CD4⁺ T cells from PM patients or HC was measured by flow cytometry. Data from five biologically independent replicates. All data are mean ± SEM. Statistics were done by one-way ANOVA with adjustments for multiple comparisons in c, e, g, and two-way ANOVA with adjustments for multiple comparisons in j, l, n, and o.