Contributions
Abstract: P967
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - Immunology
Background: The most important risk factors enhancing susceptibility for multiple sclerosis (MS) are HLA class II genes, in particular HLA DRB1*15 (DR2), implicated in the Antigen presentation to CD4+ T compartment. Autoreactive T cells have been isolated in the peripheral blood and cerebrospinal fluid (CSF) of MS patients. Numerous antigens have been investigated as potential target. In HLA-DR2+ subjects, an immunodominant T-cell epitope exists in the middle portion of myelin basic protein (MBP), corresponding to residues 85-99, that can be presented by DR2 and DQ6 to T-cell clones from MS patients.
Objective: In this study, we investigated the repertoire of T cells specific for MBP85-99 and MBP111-129 (subdominant epitope) in MS patients and in healthy donors (HD) in order to detect new disease biomarkers, which may facilitate MS management.
Materials and methods: We obtained the peripheral blood mononuclear cells (PBMCs) from a cohort of 82 MS patients (27 DR2+) and 13 HD (6 DR2+). In order to investigate the T cell receptor (TCR)-beta repertoire of T cells specific for the immunodominant epitope MBP85-99 and the less immunogenic MBP111-129, we performed the immunoscope analysis (TRBV-TRBJ spectratyping). We analyzed TCR repertoire also in IL17A and IFNgamma-secreting magnetically sorted T cells (n=6) and, where possible, in resident T cells from CSF samples (n=20).
Results: We identified MBP85-99 specific 20 TCR expansions, focusing on 2 TRBV-TRBJ rearrangements: one shared by the 75% of MS DR2+ patients at the onset of disease and one present in 50% of clinically isolated syndrome (CIS) and MS patients. We also investigated the MBP111-129 response and found several specific TCR-beta chains not shared with the immunodominant epitope. One of the shared MBP85-99 specific TCR was expanded in IL17A secreting cells; interestingly, this TCR was detectable in the CSF-resident T cells. We sequenced the shared TRBV-TRBJ rearrangement to confirm the clonotypic nature of these T cells specific for MBP85-99 in MS patients, but not detectable in the CIS and healthy subjects.
Conclusions: These results suggest that the repertoire of TCR specific for MBP85-99 may be broader in CIS than in MS patients. Antigen-specific T cells may, therefore, present a potential future target for personalized MS therapies.
Disclosure: DisclosureDr Mirabella has received honoraria for scientific lectures and advisory board activities from Biogen Novartis, Teva, Sanofi Genzyme, Bayer Shering, Merck Serono, Almirall and research support from Merck Serono, Novartis, Teva, GenzymeAll the other authors have no actual or potential conflict of interest to disclose regarding this work.
AcknowledgmentsThis work was supported by grant from Merck Italy, an affiliate of Merck KGaA, Darmstadt, Germany.
Abstract: P967
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - Immunology
Background: The most important risk factors enhancing susceptibility for multiple sclerosis (MS) are HLA class II genes, in particular HLA DRB1*15 (DR2), implicated in the Antigen presentation to CD4+ T compartment. Autoreactive T cells have been isolated in the peripheral blood and cerebrospinal fluid (CSF) of MS patients. Numerous antigens have been investigated as potential target. In HLA-DR2+ subjects, an immunodominant T-cell epitope exists in the middle portion of myelin basic protein (MBP), corresponding to residues 85-99, that can be presented by DR2 and DQ6 to T-cell clones from MS patients.
Objective: In this study, we investigated the repertoire of T cells specific for MBP85-99 and MBP111-129 (subdominant epitope) in MS patients and in healthy donors (HD) in order to detect new disease biomarkers, which may facilitate MS management.
Materials and methods: We obtained the peripheral blood mononuclear cells (PBMCs) from a cohort of 82 MS patients (27 DR2+) and 13 HD (6 DR2+). In order to investigate the T cell receptor (TCR)-beta repertoire of T cells specific for the immunodominant epitope MBP85-99 and the less immunogenic MBP111-129, we performed the immunoscope analysis (TRBV-TRBJ spectratyping). We analyzed TCR repertoire also in IL17A and IFNgamma-secreting magnetically sorted T cells (n=6) and, where possible, in resident T cells from CSF samples (n=20).
Results: We identified MBP85-99 specific 20 TCR expansions, focusing on 2 TRBV-TRBJ rearrangements: one shared by the 75% of MS DR2+ patients at the onset of disease and one present in 50% of clinically isolated syndrome (CIS) and MS patients. We also investigated the MBP111-129 response and found several specific TCR-beta chains not shared with the immunodominant epitope. One of the shared MBP85-99 specific TCR was expanded in IL17A secreting cells; interestingly, this TCR was detectable in the CSF-resident T cells. We sequenced the shared TRBV-TRBJ rearrangement to confirm the clonotypic nature of these T cells specific for MBP85-99 in MS patients, but not detectable in the CIS and healthy subjects.
Conclusions: These results suggest that the repertoire of TCR specific for MBP85-99 may be broader in CIS than in MS patients. Antigen-specific T cells may, therefore, present a potential future target for personalized MS therapies.
Disclosure: DisclosureDr Mirabella has received honoraria for scientific lectures and advisory board activities from Biogen Novartis, Teva, Sanofi Genzyme, Bayer Shering, Merck Serono, Almirall and research support from Merck Serono, Novartis, Teva, GenzymeAll the other authors have no actual or potential conflict of interest to disclose regarding this work.
AcknowledgmentsThis work was supported by grant from Merck Italy, an affiliate of Merck KGaA, Darmstadt, Germany.