Methods: Mice were transferred with Th2 polarized transgenic CD4 T cells and challenged intranasally with recombinant allergen three times weekly for 3 weeks. Lungs were removed and paraffin embedded sections cut and stained with Hematoxylin and Eosin, Periodic Acid Schiff’’s or Masson’s Trichrome. Frozen lung sections were stained with florescence tagged anti-CD3, anti B220 and anti-CD11c monoclonal antibodies. Mice were treated with anti-IL-4/IL-13 monoclonal antibodies weekly.
Results: Within 15 minutes of the fourth challenge mice exhibited breathing difficulties accompanied by a sharp fall in temperature (from 37C to 30C). iBALT was detected in all challenged mice and found to contain B cells, T cells and dendritic cells. Neutralizing anti-IL-4/IL-13 inhibited inflammation by over 80% and reduced the number and size of iBALT by over 50%
Conclusions: Th2 cytokine dependent iBALT is present in the lungs of severely allergic mice that are similar to those described following influenza infection. Prevention of Th2 iBALT formation represents a promising new target for asthma therapy.