Effect of lipids on the conformation of an antigenic determinant for experimental autoimmune neuritis

The conformation of SP-26, the synthetic peptide (residues 53-78) of myelin P2 protein that causes experimental autoimmune neuritis (EAN) in the peripheral nervous system, has been studied in lipid environments and in water/trifluoroethanol (TFE) mixture using circular dichroism (CD) spectroscopy and Fourier transform infra-red (FTIR) spectroscopy. SP-26 becomes more structured on binding with micelles formed from anionic lipids and in the presence of TFE. On the other hand, zwitterionic lipids have a denaturing effect or no effect on the conformation of SP-26. The present results suggest that the disease-modulating effects of various lipids are closely related to their ability to induce conformational change in the antigenic region of P2 protein.