LAPCs contribute to the pathogenesis of allergen-induced allergic airway inflammation in mice

Background: The inflammatory immune response associated with allergic airway inflammation in asthma involves T helper type 2 (Th2) immunity. Given the data that a newly described late activator antigen-presenting cell (LAPC) population promotes Th2 immunity in viral infections, we undertook studies to investigate whether LAPCs have a pathogenic role in allergic airway inflammation. Methods: We employed acute ovalbumin (OVA) and house dust mite (HDM) sensitization and challenge models to establish allergic airway inflammation in mice, followed by the analysis of lungs and draining lymph node (DLN) cell infiltrates, immunoglobulin E (IgE) production, and airway hyper-responsiveness (AHR). We tested whether adoptive transfer of LAPCs isolated from mice with established allergic airway inflammation augments the development of sensitization in naive mice. Results: We provide evidence that in both OVA and HDM mouse models of allergic inflammation, LAPCs accumulate in the lungs and draining lymph nodes (DLNs), concomitant with the onset of lung pathology, allergen-specific IgE production, eosinophilia, and Th2 cytokine production. Adoptive transfer experiments using OVA-activated LAPCs reveal exacerbation of disease pathology with an increase in lung inflammatory cells, eosinophilia, circulating IgE, Th2 cytokine production, and a worsening of AHR. OVA-activated LAPCs preferentially increased GATA-3 induction in naive CD4(+) T cells. Conclusions: Together, these data suggest an important role for LAPCs in polarizing the Th2 response in mouse models of allergic airway inflammation.