IL1RL1 (Interleukin 1 Receptor-Like 1), also known as ST2. is a member of the interleukin-1 receptor family. It exists in two isoforms: a transmembrane form (ST2L) that functions as a receptor for interleukin-33 (IL-33) and a soluble decoy receptor (sST2) that modulates IL-33/ST2L signaling. The IL-33/ST2L axis plays a critical role in Th2-mediated immune responses, tissue inflammation, and fibrosis, implicating IL1RL1 in diseases like asthma, chronic obstructive pulmonary disease (COPD), cardiovascular disorders, and fibrotic conditions.
Antibodies targeting IL1RL1 are primarily used to study its biological functions or therapeutically block IL-33 signaling. Research-grade antibodies (monoclonal or polyclonal) enable detection of ST2 isoforms in assays such as flow cytometry, immunohistochemistry, or ELISA, aiding in mechanistic studies of disease pathways. Therapeutically, anti-IL1RL1 antibodies aim to disrupt IL-33-driven inflammation, with several candidates in clinical trials for asthma, atopic dermatitis, and eosinophilic diseases. For example, astegolimab (anti-ST2) has shown efficacy in reducing exacerbations in severe asthma. Additionally, sST2 is explored as a biomarker for heart failure prognosis.
These antibodies provide tools to dissect IL1RL1's dual roles in immunity and disease, offering potential for both diagnostic and therapeutic applications.