Tolerized mice resist subsequent sensitization and challenge.

(A) BALB/c mice were initially sensitized with OVA or HDM under the cover of anti-CD4 as described in Figure 1. Those mice were sensitized with the same antigens on days 50 and 64, and subsequently challenged i.n. (B) Animals trated with anti-CD4 were protected from BAL eosinophilia (n = 6, ** P<0.01 for OVA; * P<0.05 for HDM). (C) CD4-blockade prevented production of IgG1 and IgE in subsequent sensitizations (n = 6, *** P<0.001 and ** P<0.01 as indicated). (D) Tolerance to OVA or HDM prevented AHR to inhaled MCh (n = 6). Data are representative of three independent experiments.