I-L-C-2 it: type 2 immunity and group 2 innate lymphoid cells in homeostasis

Curr Opin Immunol. 2014 Dec;31:58-65. doi: 10.1016/j.coi.2014.09.009. Epub 2014 Oct 13.


Innate type 2 immune cells are activated in response to helminths, allergens, and certain types of proteases and particulates. Recently, innate type 2 immune pathways have also been implicated in protective host responses to homeostatic perturbations, such as metabolic dysfunction, atherosclerosis, and tissue injury. In this context, innate type 2 cytokines stimulate local tissues, recruit eosinophils, and alternatively activate macrophages to restore homeostasis. As the major source of innate interleukin (IL)-5 and IL-13, group 2 innate lymphoid cells are positioned to initiate and maintain homeostatic type 2 responses. The absence of exogenous stimuli in these processes implicates endogenous pathways in the activation of type 2 immunity and suggests an alternative evolutionary trajectory for type 2 immunity, apart from its role in response to helminths and allergens.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Allergens / immunology*
  • Animals
  • Eosinophils / immunology*
  • Eosinophils / pathology
  • Helminthiasis / immunology*
  • Helminthiasis / pathology
  • Homeostasis / immunology*
  • Humans
  • Immunity, Innate*
  • Interleukin-13 / immunology
  • Interleukin-5 / immunology
  • Lymphocytes / immunology*
  • Lymphocytes / pathology


  • Allergens
  • IL5 protein, human
  • Interleukin-13
  • Interleukin-5