Anti-Orai1 Antibody is a humanized monoclonal antibody targeting Calcium Release-Activated Calcium Modulator 1 (Orai1/CRACM1). Orai1 forms the pore subunit of the Calcium Release-Activated Calcium (CRAC) channel on the plasma membrane, mediating Store-Operated Calcium Entry (SOCE). In T lymphocytes, antigen receptor stimulation depletes endoplasmic reticulum calcium stores, triggering STIM1 to activate Orai1 and induce sustained calcium influx, a critical step for NFAT activation and cytokine (e.g., IL-2) production. This antibody specifically binds to the extracellular loops of Orai1, blocking the channel pore or disrupting STIM1-Orai1 coupling, thereby inhibiting SOCE and downstream immune responses. It is widely used in research on autoimmune diseases, inflammation, and calcium signaling-dependent tumors.