Figure 2.

Lipopolysaccharide (LPS) does not impair allosuppressive phenotype or function of CD4⁺ regulatory T-cells (Treg) expanded after alloanergization. (a) Phenotype of expanded Treg after alloanergization and repeated exposure to alloantigen in the absence of presence of LPS. Bar charts show mean ±SD) frequencies of CTLA-4⁺, CD39⁺, TNFR2⁺, GITR⁺, GARP⁺, and LAP⁺ cells expressed as a proportion of CD4⁺ FOXP3⁺ Treg at baseline (B/L), after alloanergization (A) and after subsequent allorestimulation (AR). Data are for five to nine HLA-mismatched stimulator-responder pairs. *P < 0.05, **P < 0.01. (b) Allosuppressive function of CD4⁺ Treg at B/L, after alloanergization (A) and subsequent AR in the absence or presence of LPS. Mean percentage suppression (±SD) of alloproliferative responses of untreated responder cells by CD4⁺ Treg are shown. Data are for three to six HLA-mismatched stimulator-responder pairs. P values are for two-tailed t-tests, ns; nonsignificant.