Cockroach Allergen Bla g 7 Promotes TIM4 Expression in Dendritic Cells Leading to Th2 Polarization

• Main Authors: Lingxiao Xu, Miaojia Zhang, Wenjing Ma, Shanshan Jin, Weijuan Song, Shaoheng He
• Format: Article
• Language: English
• Published: Hindawi Limited 2013-01-01
• Series: Mediators of Inflammation
• Online Access: http://dx.doi.org/10.1155/2013/983149
• ISSN: 0962-9351; 1466-1861

As one of the most common sources of indoor aeroallergens worldwide, cockroach is important in causing rhinitis and asthma while the mechanisms underlying remain obscure. Since T helper (Th) type 2 polarization plays an important role in the pathogenesis of allergic diseases, we investigated the effect of Bla g 7, a pan-allergen from Blattella germanica (B. germanica), on Th polarization which is controlled by monocyte-derived dendritic cells (DCs). Challenged by recombinant Bla g 7 (rBla g 7), immature DCs obtained from human exhibited upregulated levels of TIM4, CD80, and CD86 and increased IL-13 secretion. Cocultured with CD4+ T cells, challenged DCs increased the ratio of IL-4+ versus IFN-γ+ of CD4+ T cells, suggesting a balance shift from Th1 to Th2. Moreover, antibodies against TIM4, CD80, and CD86 reversed the enhancement of IL-4+/IFN-γ+ ratio and alleviated the IL-13 release induced by rBla g 7, indicating that the Th2 polarization provoked by rBla g 7 challenged DCs is via TIM4-, CD80-, and CD86-dependent mechanisms. In conclusion, the present findings implied a crucial role of Bla g 7 in the development of cockroach allergy and highlighted an involvement of DCs-induced Th2 polarization in cockroach allergy.