Airway epithelial cells suppress antigen-specific T cell proliferation.

A: Gating strategy for assessment of T cell proliferation by CFSE dilution. All CD4+ cells having a lower CFSE intensity than non-proliferated control cells were designated as “CFSE-low” cells. Proliferation of OVA-specific DO11.10 T cells was induced by DC-mediated OVA-presentation or T cell-depleted splenocyte ( = APC) presentation of pOVA for the indicated time (B) or on day 4 (C–E). Cultures w/o antigen served as controls. Epithelial-mediated suppression was assessed in co-culture with the LA4-cell line, a murine, type II pneumocyte cell line. B: Pulmonary epithelial cells inhibit antigen-induced T cell proliferation. C: Epithelial-mediated suppression of T cell proliferation is independent from type of antigen-presenting cell. Epithelial-mediated suppression of T cell proliferation is almost entirely dependent on cell-contact of epithelial cells with T cells and DC (D) or APC (E). TC  =  T cell, DC  =  dendritic cell, OVA  =  Ovalbumin, pOVA  =  OVA-peptide, APC  =  T cell-depleted splenocyte, ns  =  not significant. *p<0.05 compared to all other variables tested or as designated by bars, calculated by Mann-Whitney-U test. 2C: ***p<0.001 1way ANOVA with Bonferroni's Multiple Comparison Test Representative experiments of n = 5–12 experiments.