Fig. 1.

Stages of alum-based murine asthma models. Mice are typically primed/sensitized (i.e. naïve T cell activation) to a protein antigen (often ovalbumin) in combination with alum (aluminum hydroxide gel) on days 0 and 10. Most models use either intraperitoneal (IP) or subcutaneous (SC) injections. During this time, antigen presenting cells (APCs) receive activation signals, presumably from the adjuvant, to endocytose antigen, process it, migrate to the draining lymph nodes and present peptides to circulating naïve T cells. It is also in the secondary lymphoid organs where cognate T : B cell interactions result in B cell activation with subsequent affinity maturation and isotype switching to produce antigen-specific IgE and IgG1. Intranasal (IN) challenge with antigen recruits primed lymphocytes to the lung and initiates a fulminant eosinophil-dominated inflammatory response. It is during this second phase that this alum-based model is most useful for the study of intervention in allergic disease.