While Th2 immune responses are central to disease pathology in allergic asthma, there is a growing understanding that the Th2 paradigm is not sufficient to explain the entire spectrum of disease severity. Indeed, there is growing belief that severe disease may be driven by a different process than mild to moderate disease.
Using a mouse model of allergic asthma in which one strain develops a phenotype characteristic of mild asthma (C3H/HeJ), and others develop a phenotype characteristic of severe disease (A/J), we have identified several novel mechanisms through which asthma severity is regulated. We have found that the development of severe allergic asthma is associated with a limited capacity of Tregs to limit pulmonary dendritic cell activity, enhanced capacity for antigen uptake by pulmonary myeloid dendritic cells, and the development of a mixed Th2/Th17 immune response. In contrast, C3H mice demonstrate increased Treg activity, preferential antigen uptake by pulmonary plasmacytoid dendritic cells, and an exclusively Th2-biased immune response. We are presently using the A/J versus C3H/HeJ mouse model of allergic asthma to tease out the mechanisms responsible the development of severe allergic asthma.
Assistant Professor, UC Department of Pediatrics