ILC2s - resident lymphocytes pre-adapted to a specific tissue or migratory effectors that adapt to where they move?

ILC2s - resident lymphocytes pre-adapted to a specific tissue or migratory effectors that adapt to where they move? Curr Opin Immunol. 2018 Nov 22;56:76-81 Authors: Germain RN, Huang Y Abstract A cardinal feature of the T-cell adaptive immune system is the antigen-dependent activation of naïve T cells in secondary lymphoid sites, followed by the migration of the resultant effector cells through the efferent lymph to the blood and then into a peripheral tissue site of infection or tumor growth. In contrast, the current view of innate lymphocytes (ILCs), the innate counterparts of T cells, is that they are tissue-resident cells, adapted to their specific environments during development and performing their effector functions locally upon cytokine stimulation. Here we present recent findings that challenge the latter as defining the properties of ILCs, at least ILC2s. Our studies show that IL-25, administrated experimentally or generated in response to helminth infection, triggers local proliferation and activation of intestinal ILC2s that are the precursors to inflammatory ILC2 (iILC2) cells. These cells downregulate CD69 expression, upregulate S1P receptors and move across the villus lymphatic endothelium in an S1P-depndent manner. They subsequently enter the blood stream, through which they traffic to distant organs such as the liver and lung. In the lung, these iILC2 cells play a crucial role in host defense during the pulmonary st...
Source: Current Opinion in Immunology - Category: Allergy & Immunology Authors: Tags: Curr Opin Immunol Source Type: research