Phosphorylcholine epitopes on oxidized phospholipids (PC-epitopes)

Phosphorylcholine (PC) epitopes are molecular patterns typically found on the polar head groups of phosphatidylcholine in cell membranes (Horkko et al., 1999, J. Clin. Invest.). While usually sequestered or shielded in healthy cells, these epitopes become exposed or modified on oxidized phospholipids (OxPL), oxidized low-density lipoprotein (OxLDL), and the surface of apoptotic cells, acting as damage-associated molecular patterns (DAMPs) (Binder et al., 2003, Nat. Med.). They are recognized by the innate immune system through C-reactive protein and natural IgM antibodies, which facilitate the clearance of cellular debris and neutralize pro-inflammatory lipids (Shaw et al., 2000, J. Clin. Invest.). In the context of atherosclerosis, the accumulation of PC-exposed OxLDL in the arterial wall drives macrophage activation and foam cell formation (Virmani et al., 2000, Arterioscler. Thromb. Vasc. Biol.). Therapeutic strategies involve using monoclonal antibodies, such as BI-204, to target these PC epitopes to inhibit plaque progression and stabilize existing lesions (Gronholdt et al., 2010, J. Am. Coll. Cardiol.). This approach aims to mimic the protective effects of natural anti-PC antibodies, which are inversely correlated with cardiovascular risk in humans (de Faire et al., 2010, J. Intern. Med.). Beyond cardiovascular disease, these epitopes play roles in systemic lupus erythematosus and chronic inflammatory conditions where apoptotic cell clearance is impaired (Su et al., 2008, Rheumatology).

Other names

Phosphocholine epitopesOxPL-PCOxidized LDL epitopesPC-containing oxidized phospholipidsOxidized low-density lipoprotein epitopes

Monoclonal antibodies bind to exposed phosphorylcholine epitopes on oxidized LDL and apoptotic cells, preventing their uptake by macrophages to inhibit foam cell formation and neutralizing pro-inflammatory signaling (Gronholdt et al., 2010, J. Am. Coll. Cardiol.).