Allergic diseases, derived from the dysregulation of immune tolerance mechanisms, have been 
rising in the last two decades. Recently, increasing evidence has shown that probiotic-derived 
polysaccharide capsules exhibit a protective effect against allergic diseases, involving regulation 
of Th1/Th2 balance, induction of differentiation of T regulatory cells and activation of dendritic 
cells (DCs). DCs have a central role in controlling the immune response through their interaction 
with gut microbiota via their pattern recognition receptors, including Toll-like receptors and C-typelectin receptors. This review discusses the effects and critical mechanism of probiotic-derived 
polysaccharide capsules in regulating the immune system to alleviate allergic diseases. We first 
describe the development of immune response in allergic diseases and recent relevant findings. 
Particular emphasis is placed on the effects of probiotic-derived polysaccharide capsules on allergic 
immune response. Then, we discuss the underlying mechanism of the impact of probiotic-derived 
polysaccharide capsules on DCs-mediated immune tolerance induction.