Isolation and identification of innate lymphoid cells (ILCs) for immunotoxicity testing

Innate lymphoid cells (ILCs) comprise a family of innate immune cells that orchestrate mucosal immune responses: initiating, sustaining, and even curbing immune responses. ILCs are relatively rare (≤1% of lymphocytes in mucosal tissues), lack classical cell-surface markers, and can be divided into three subsets (type 1-3 ILCs) based on differences in cytokine production, phenotype, and developmental pathway. Because ILCs can only be identified by combinations of cell-surface markers and cytokine production, multicolor flow cytometry is the most reliable method to purify, characterize, and assess the functionality of ILCs. Here, we describe the methods for cell preparation, flow cytometric analysis, and purification of murine ILCs from the lung.