Naïve BALB/c mice (N) received neither sensitization nor conidia challenge. Mice were sensitized with subcutaneous (SC) and intraperitoneal (IP) immunizations of soluble A. fumigatus antigen in alum followed by 5 intranasal (IN) inoculations with soluble antigen in saline. For inhalation (IH) challenge, each of the six treatment groups were exposed to airborne A. fumigatus for 10 min. B lymphocyte numbers along with Ab production were assessed at day 0 (before IH challenge) and at days 3, 5, 7, 9, 11, and 13 after conidia challenge.