Figure 2.

Anti-OX40L suppresses memory T cell induced AHR and airway inflammation. (A) Experimental protocol for anti-OX40L administration. Unprimed control mice were injected i.p. with alum alone (Alum), while primed mice were sensitized with OVA adsorbed to alum (Alum-OVA). 25 d later, all mice were challenged with aerosolized OVA on 4 consecutive days (days 25–28; indicated by arrows). Either PBS (Group A: Alum/OVA), or control IgG (Group B: Alum-OVA/IgG-OVA) or anti-OX40L (Group C: Alum-OVA/RM134L-OVA) were administered i.p. on each challenge day. (B) 1–3 h after the last aerosol challenge, individual mice were assessed for AHR. Results are the mean percent change in Penh levels above baseline (saline-induced AHR), after exposure to increasing concentrations of inhaled methacholine. Values are calculated from four mice in each group per experiment. Similar results were seen in three experiments. (C) Total leukocyte numbers were enumerated in BAL at different times (0, 1, 2, 3, and 4 d) after exposure to aerosolized OVA (indicated by arrows). (D) Total numbers of eosinophils were calculated from differential stained BAL cytospins. Results are the mean number of cells ± SEM from two separate experiments with four mice per group in each experiment.