Evaluation of the humoral response against mycobacterial peptides, homologous to MOG35-55, in multiple sclerosis patients

Bacillus Calmette-Guerin (BCG) and Mycobacterium avium subspecies paratuberculosis (MAP) have been associated with multiple sclerosis (MS). Clinical data indicates that BCG vaccination exerts anti-inflammatory effects in MS; conversely, MAP is thought to be one of the possible infectious factors responsible of MS through a molecular mimicry mechanism. A peptide-based indirect ELISA was used to detect antibodies against the encephalitogenic myelin oligodendrocyte glycoprotein (MOG)(35-55) epitope, and two mycobacterial peptides sharing sequence homology with the latter: MAP_2619c(352-361)/BCG_1224(355-364) and BCG_3329c(64-74). Among 40 MS patients and 39 healthy volunteers included in the study, only MOG(35-55) was capable of inducing a significantly higher humoral response in MS subjects compared to controls. Indeed, 11 out of 40 MS subjects (27.5%) and only 2 out of 39 controls (5%) were antibody-positive for MOG(35-55) (p = 0.01, AUC = 0.65). These findings strengthen the importance of MOG(35-55) in MS pathogenesis. The MAP and BCG MOG-homologues epitopes investigated were not recognized in MS patients. Overall, the results allow us concluding that sharing homology of linear epitopes is necessary but not sufficient to induce antibody-mediated cross-reactivity. (C) 2014 Elsevier B.V. All rights reserved.