Oral administration of poly--glutamic acid prevents the development of atopic dermatitis in NC/Nga mice

Bacillus subtilis-derived poly--glutamic acid (PGA) has demonstrated adjuvant activity in promoting Th1/Th17 cell differentiation. Here, the NC/Nga (NC) mouse model was used to determine whether PGA modulates the outcome of atopic dermatitis (AD), which is known to be a Th2-biased immune disease. We found that oral administration of PGA dramatically reduced the development of AD in NC mice. Antigen-presenting cells activated with PGA produced pro-inflammatory cytokines, such as IL12/23 and IFN, which, in turn, induced the differentiation of Th1 and Th17 cells. Concomitantly, Th2 responses, such as high levels of serum IgE, were dramatically decreased. Furthermore, in vivo PGA treatment altered several cellular components of allergic reactions, such as mast cells and eosinophils. Taken together, our results strongly demonstrate that in vivo treatment with PGA at early time points can prevent the development of AD in NC mice and suggest that PGA may have therapeutic applications for human AD.