Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressed on pleural mesothelial cells (PMCs) were involved in expansion of effector regulatory T cells (eTregs).

<p>Purified CD4⁺ T cells from tuberculous pleural effusion were cultured for 5 d in medium alone (T), or in the presence of anti‒CD3 mAb (T + α-CD3), or in the presence of autologous PMCs without or with anti‒CD3 mAb (T + PMC and T + PMC + α-CD3, respectively). In some cocultures of CD4⁺ T cells and PMCs plus anti‒CD3 mAb, PMCs were pre-incubated with anti‒ICAM-1 (α‒ICAM-1), ‒VCAM-1 (α‒VCAM-1) mAb, or an irrelevant isotype control (IgG1). eTregs were identified by intracellular FoxP3 staining. (A) Representative flow cytometric dot plots show FoxP3 expression in CD45RA^- CD4⁺ T cells. (B) Comparisons of percentages of FoxP3 ^highCD45RA^-CD4⁺ T cells in each group. The results are reported as mean ± SEM from 5 independent experiments. The comparisons were determined by Kruskal-Wallis one-way analysis of variance on ranks. *p < 0.05 compared with medium control, † p < 0.05 compared with irrelevant isotype IgG control.