The polyclonal anti-idiotypic antibody (Anti-Id) has been raised against a monoclonal antibody (mAb) that specifically binds to phosphatidylcholine (PC). The anti-Id bound strongly to PC-specific mAbs, but not to the other mAbs that bind to phosphatidylserine, indicating that the anti-Id recognizes the cross-reactive idiotopes expressed on the PC-specific mAbs. The anti-Id also showed an extensive cross-reaction with the PC-specific lipid transfer protein isolated from bovine liver and inhibited the lipid transfer activity of the protein. These results strongly suggest that the anti-Id recognizes a common structure shared between PC-specific mAbs and the PC-specific lipid transfer protein.
