Figure 1. CD4⁺CD25⁻Nrp1⁺ T cells possess potent suppressive function in vitro.

(A) Freshly isolated CD4⁺CD25⁻Nrp1⁺ T cells (10⁵, C57BL/6) were co-cultured with syngeneic responder CD4⁺CD25⁻ T cells (C57BL/6) in different ratios (0, 1∶8, 1∶4, 1∶2, 1∶1) in order to address stimulation induced by irradiated BALB/c (donor) splenocytes (10⁵). Cell proliferation was determined by ³H thymidine incorporation. (B) Cytokine content of the MLRsup where the suppressor cell versus CD4⁺CD25⁻ T cell was 0 (CTR) and 1∶1 (Nrp1) was evaluated by ELISA. Results are presented as mean ± SD values of triplicate wells, and are representative of 3 independent experiments. *P<0.05, **P<0.01, ***P<0.001. Nrp1 = neuropilin-1, MLRsup = mixed-lymphocyte reaction supernatants, CTR  =  control group, ³H-TdR  =  metabolic incorporation of tritiated thymidine, cpm  =  cells per million, NS  =  not significant.