PROBLEM TO BE SOLVED: To provide compositions and methods for decreasing an immune response in an animal for treating diseases caused by an aberrant, excessive or undesired immune response.SOLUTION: Methods for decreasing an immune response in an animal comprise administering to the animal an agent that binds a bioactive lipid and reduces the effective concentration of the bioactive lipid. Also provided are methods for treating diseases or conditions, including autoimmune disorders, which are characterized by an aberrant, excessive or undesired immune response. Also provided are agents that bind a bioactive lipid and are capable of decreasing the effective concentration of the bioactive lipid, e.g., a monoclonal antibody that is reactive against sphingosine-1-phosphate (S1P) or lysophosphatidic acid (LPA).SELECTED DRAWING: None【課題】過剰な、異常な又は望ましくない免疫応答による疾患の治療のため、動物において免疫応答を低減するための組成物と方法の提供。【解決手段】動物において免疫応答を低減するため、生理活性脂質に結合し、前記生理活性脂質の有効濃度を低下させる薬剤を前記動物に投与する方法。また、異常な、過剰なまたは望ましくない免疫応答によって特徴づけられる、自己免疫疾患を含む、疾患または状態を治療するための方法も提供される。生理活性脂質に結合して、その生理活性脂質の有効濃度を低下させることが可能な薬剤、例えば、スフィンゴシン-1-リン酸(S1P)またはリゾホスファチジン酸(LPA)に対して反応性のあるモノクローナル抗体。【選択図】なし