Fig. 4.

Negative selection of AQP4 p133–149-reactive T cells is bypassed partially in mice deficient in thymic AQP4 expression. (A) AQP4^−/−, WT, Foxn1cre-AQP4^fl/fl, Aire^−/−, or Foxn1cre- Fezf2^fl/fl mice were immunized s.c. with peptides indicated. Peptide-specific proliferation of draining lymph node cells was measured by ³H-thymidine incorporation (mean ± SEM, representative of five experiments). Comparisons within the five experiments for p133–149 at 10 μg/mL: WT vs. AQP4^−/− (P = 0.008), WT vs. Foxn1cre-AQP4^fl/fl (P = 0.008). (B) Ten days after peptide immunization, CD4⁺ T cells from draining lymph nodes were analyzed for I-A^b:peptide tetramer binding by flow cytometry. Each data point represents the frequency (mean ± SEM) of CD4⁺ T cells bound to cognate antigen–tetramer in a single mouse. Comparisons were calculated by the Mann–Whitney U test (****P < 0.0001, ***P < 0.001, **P < 0.01, and *P < 0.05) Comparisons which did not reach statistical significance are not shown. For p133–149: WT vs. Aire^−/− (P = 0.9), WT vs. Foxn1cre-Fezf2^fl/fl (P = 0.3). For p202–218: WT vs. Foxn1cre-AQP4^fl/fl (P = 0.3), WT vs. Aire^−/− (P = 0.06).