New antigenic candidates in multiple sclerosis: identification by serological proteome analysis.

Myelin antigen targets that are clearly associated with pathogenic events in multiple sclerosis (M.S.) patients remain to be defined. We recently demonstrated that the analysis of global IgG antibody response against human brain antigens using one-dimensional (1-D) immunoblotting, allowed us to discriminate M.S. patients from controls (both healthy subjects and patients with Sjögren's syndrome). Additionally, this approach also differentiated the three clinical forms of M.S. Indeed, 42 brain antigenic bands (26 from healthy brain and 16 from the M.S. brain) showed the discriminant IgG immune responses. The aim of our study was to characterize the 26 discriminant antigenic bands detected in healthy brain. Protein identification was successively performed by 1-D and two-dimensional (2-D) immunoblottings using sera from 18 M.S. patients, followed by mass spectrometry (MS) analysis and a database search. One hundred and two antigenic spots were then detected on 2-D immunoblots, with M.S. sera against healthy brains. Sixty-four spots were successfully matched with 2-D Coomassie brillant blue stained gels, which were further selected for MS analysis and annotated leading to the identification of 14 of the 26 discriminant antigens. Thus, serological proteome analysis may provide a useful tool for the identification of potentially new M.S.-associated antigens, whose relevance to physiopathological events remains to be defined.