Rabbit Interleukin-36 Receptor Antagonist (IL-36Ra) is an anti-inflammatory cytokine that regulates IL-36–mediated immune responses in rabbits (Oryctolagus cuniculus). IL-36Ra is a member of the IL-1 cytokine family and functions as a natural inhibitor of the IL-36 signaling pathway by binding to the IL-36 receptor (IL-36R, also known as IL1RL2) without inducing receptor activation, thereby preventing proinflammatory cytokines such as IL-36α, IL-36β, and IL-36γ from activating downstream signaling. Through this mechanism, rabbit IL-36Ra suppresses activation of intracellular pathways including NF-κB and MAPK, helping to limit inflammatory mediator production and regulate immune responses at epithelial barrier tissues such as the skin and mucosal surfaces. In rabbits, IL-36Ra contributes to maintaining immune homeostasis and controlling excessive inflammatory responses during infection or tissue injury. In cell culture, recombinant rabbit IL-36Ra is commonly used to inhibit IL-36–induced inflammatory signaling in epithelial and immune cells, enabling investigation of cytokine regulation, epithelial–immune cell interactions, and inflammatory pathway modulation in vitro. Rabbit IL-36Ra is also studied in translational biomedical research, as rabbit models of skin inflammation and wound healing help researchers investigate IL-36 pathway regulation and evaluate potential anti-inflammatory therapeutic strategies relevant to human inflammatory skin diseases.