Orchestration between ILC2s and Th2 cells in shaping type 2 immune responses

The type 2 immune response is critical for host defense against large parasites such as helminths.On the other hand,dysregulation of the type 2 immune response may cause immunopathological conditions,including asthma,atopic dermatitis,rhinitis,and anaphylaxis.Thus,a balanced type 2 immune response must be achieved to mount effective protection against invading pathogens while avoiding immunopathology.The classical model of type 2 immunity mainly involves the differentiation of type 2 T helper(Th2)cells and the production of distinct type 2 cytokines,including interleukin-4(IL-4),IL-5,and IL-13.Group 2 innate lymphoid cells(ILC2s)were recently recognized as another important source of type 2 cytokines.Although eosinophils,mast cells,and basophils can also express type 2 cytokines and participate in type 2 immune responses to various degrees,the production of type 2 cytokines by the lymphoid lineages,Th2 cells,and ILC2s in particular is the central event during the type 2 immune response.In this review,we discuss recent advances in our understanding of how ILC2s and Th2 cells orchestrate type 2 immune responses through direct and indirect interactions.

Current understanding of Th2 cell differentiation and function

Helper T cell(Th)has been identified as a critical immune cell for regulating immune response since 1980s.The type 2 helper Tcell(Th2),characterized by the production of interleukin-4(IL-4),IL-5 and IL-13,plays a critical role in immune response against helminths invading cutaneous or mucosal sites.It also has a functional role in the pathophysiology of allergic diseases such as asthma and allergic diarrhea.Currently,most studies have shed light on Th2 cell function and behavior in specific diseases,such as asthma and helminthes inflammation,but not on Th2 cell itself and its differentiation.Based on different cytokines and specific behavior in recent research,Th2 cell is also regarded as new subtypes of T cell,such as IL-9 secreting T cell(Th9)and CXCR5+T follicular helper cells.Here,we will discuss the latest view of Th2 cell towards their function and the involvement of Th2 cell in diseases.