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

Cossu D¹, Mameli G¹, Masala S¹, Cocco E², Frau J², Marrosu MG², Sechi LA³.

Author information

¹Department of Biomedical Sciences, Section of Experimental and Clinical Microbiology, University of Sassari, Italy.
²Multiple Sclerosis Centre, Department of Public Health, Clinical and Molecular Medicine, University of Cagliari, Italy.
³Department of Biomedical Sciences, Section of Experimental and Clinical Microbiology, University of Sassari, Italy. Electronic address: sechila@uniss.it.

Abstract

Bacillus Calmette-Guérin (BCG) and Mycobacterium avium subspecies paratuberculosis (MAP) have been associated withmultiple 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_2619c352-361/BCG_1224355-364 and BCG_3329c64-74. Among 40 MS patients and 39 healthy volunteers included in the study, only MOG35-55 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 MOG35-55 (p=0.01, AUC=0.65). These findings strengthen the importance of MOG35-55 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.