Involved in the transfer of neutral lipids, including cholesteryl ester and triglyceride, among lipoprotein particles. Allows the net movement of cholesteryl ester from high density lipoproteins/HDL to triglyceride-rich very low density lipoproteins/VLDL, and the equimolar transport of triglyceride from VLDL to HDL. Regulates the reverse cholesterol transport, by which excess cholesterol is removed from peripheral tissues and returned to the liver for elimination. cholesteryl (9Z-octadecenoate)(in) = cholesteryl (9Z-octadecenoate)(out) 1,2,3-tri-(9Z-octadecenoyl)-glycerol(in) = 1,2,3-tri-(9Z-octadecenoyl)-glycerol(out) cholesteryl (9Z,12Z)-octadecadienoate(in) = cholesteryl (9Z,12Z)-octadecadienoate(out) Secreted in plasma. Expressed in adipose tissue, heart, and skeletal muscle and to a lower extent in stomach, testis, spleen, and liver. Up-regulated by cholesterol-rich diet. Belongs to the BPI/LBP/Plunc superfamily. BPI/LBP family.