Phosphorylcholine (PC)

Phosphorylcholine is a structural component of a variety of prokaryotic and eukaryotic pathogens. In some cases, PC in infectious agents can benefit the infected host due to its targeting by both the innate and adaptive immune responses. PC exhibits a surprising range of immunomodulatory properties that might be to the detriment of the host.Phosphorylcholine is part of platelet-activating factor; the phospholipid phosphatidylcholine as well as sphingomyelin, the only phospholipid of the membrane that is not built with a glycerol backbone. Treatment of cell membranes, like those of RBCs, by certain enzymes, like some phospholipase A2 renders the phosphorylcholine moiety exposed to the external aqueous phase, and thus accessible for recognition by the immune system. Antibodies against phosphorylcholine are naturally occurring autoantibodies that are created by CD5+/B-1 B cells and are referred to as non-pathogenic autoantibodies.