Maternal HDM exposure does not increased the magnitude of the Th2 response or magnitude of the Ig response following exposure of offspring to Aspergillus fumigatus. Offspring of PBS- and HDM-exposed mothers were exposed to PBS, HDM or AF extract at 6, 8 and 9 weeks of age. Single cell suspensions of lung cells were restimulated with ConA, and production of (A) IL-4, (B) IL-5, (C) IL-13 were assessed by ELISA. (D) The frequency of CD4+ cells producing IL-13 was assessed by flow cytometry. (E) Serum isolated at time of sacrifice was assayed for total IgE. Mean + SEM shown. Data represent 2 – 5 mice pooled from 2 experiments.