Antibody responses to modified and native MSA. Mice were immunized with the indicated antigens. Serum was collected after the second booster immunization and the IgG antibody titres to respective immunogen and native MSA were measured by ELISA. MDA, malondialdehyde; NonRed, reduced nonanal; HNE, 4-hydroxynonenal; Nat, native MSA. In the last panel, reactivity to MDA-MSA is shown as an irrelevant antigen. Values are means of duplicate wells, error bars are SEM.