Innate lymphoid cell type 1 (ILC1)

Innate lymphoid cell type 1 (ILC1) is a specialized subset of the innate lymphoid cell family that functions as the innate counterpart to Th1 cells [1, 11]. These cells are primarily defined by their expression of the transcription factor T-bet and their ability to produce type 1 cytokines, most notably interferon-gamma (IFN-γ) and tumor necrosis factor (TNF) [1, 6, 11]. ILC1s are predominantly tissue-resident cells found in mucosal tissues, the liver, and the skin, where they provide a rapid first line of defense against intracellular pathogens such as viruses and certain bacteria [1, 2, 11]. Unlike natural killer (NK) cells, which are also part of Group 1 ILCs, ILC1s are generally non-cytotoxic or possess only weak cytotoxic potential [1, 11]. In clinical contexts, dysregulated ILC1 activity is associated with chronic inflammatory and autoimmune diseases, including Crohn's disease and rheumatoid arthritis, and they play complex roles in the tumor microenvironment [1, 4, 13]. Therapeutic targeting of ILC1s is achieved through the use of biologics that inhibit their activating cytokines (e.g., IL-12/IL-23 inhibitors), block their effector outputs (e.g., TNF inhibitors), or modulate their signaling and trafficking pathways [3, 7]. Understanding the plasticity of ILC1s, which can transdifferentiate into other ILC subsets depending on environmental cues, remains a key challenge in developing precise therapeutic interventions [4, 13].

Other names

Group 1 innate lymphoid cellILC1Non-cytotoxic group 1 ILCT-bet+ ILC1

Modulation of ILC1 activity through inhibition of activating cytokines (IL-12, IL-23), blocking effector cytokines (TNF-alpha), or inhibiting intracellular signaling (JAK/STAT) and trafficking (S1P receptors).