The present invention relates to compositions and methods for decreasing animmune response in an animal comprising administering to said animal an agentthat binds a bioactive lipid and reduces the effective concentration of saidbioactive lipid. Also provided are methods for treating diseases or conditions,including autoimmune disorders, which are characterized by an aberrant, excessiveor undesired immune response. The methods of the invention utilize agents thatbind bioactive lipids and are capable of decreasing the effective concentrationof the bioactive lipid. In some embodiments, the agent is a monoclonal antibodythat is reactive against sphingosine-1-phosphate (SlP) or lysophosphatidicacid (LPA).
