Isolation and Characterization of Conventional and Non-conventional Type 2 Innate Lymphoid Cells (ILC2s) from Human...

Innate lymphoid cells (ILCs) are a relatively new family of lymphoid cells that lack lineage cell surface markers but produce various effector cytokines. Based on phenotype and function, the group 2 ILCs (ILC2s) mirror the features of the adaptive CD4⁺ Th2 cell subset. In humans, they are traditionally characterized as the Lin^-IL7Rα⁺CRΤΗ2⁺CD161⁺ cell population that produces type 2 cytokines - IL-5 and IL-13. However, the commonly used surface markers for human ILC2s leave a majority of type 2 cytokine-producing ILC2s unaccounted for. Recently, we characterized a distinct type 2 cytokine-producing Lin^- population that lacks surface expression of canonical CRTH2 but expresses CD30 and TNFR2. Herein, we describe a detailed protocol for isolation, staining, and analysis of the conventional Lin^-CRTH2⁺IL7Ra⁺ and the non-conventional Lin^-CD30⁺TNFR2⁺ ILC2 populations.