title: Failure of glatiramer acetate to modify the peripheral T cell repertoire of relapsing-remitting multiple sclerosis patients.
abstract: Glatiramer acetate (GA) is a random copolymer used as an immunomodulatory treatment in relapsing-remitting multiple sclerosis (RR-MS). Its mechanisms of action are poorly understood, and several hypotheses have been put forward, the majority of which rely on in vitro studies. It has been hypothesised that further to processing by APC, GA could provide a large number of different epitopes with a possible sequence similarity to auto-antigens, which are able to stimulate a large proportion of T cells. Given that in a previous study we showed that the circulating T cells of MS patients present more alterations of the Vbeta T cell receptor (TCR) usage than normal individuals, we explored the possible effect of GA on the ex vivo T cell repertoire of MS patients. Here we used quantitative PCR and electrophoresis to longitudinally analyse (and without any ex vivo stimulation), the CDR3 length distribution (LD) and the amount of Vbeta TCR, as well as various cytokines, in the blood T cells of 10 RR-MS patients before and after 3 months and 2 years of GA treatment. In addition, we also determined the status of responder and non-responder patients after 24 months of GA treatment based on clinical and radiological criteria. We found no significant modification of cytokine production, Vbeta TCR mRNA accumulation or CDR3-LD in the patients after short-term and long-term treatment. In addition, we did not observe any difference in CDR3-LD in the GA responder patients (n=6) compared to non-responder patients (n=4). Focusing our study on responder patients, we performed TCR repertoire analysis in the CD4+ and CD8+ compartment. Alterations of CDR3-LD were predominantly found in the CD8+ compartment, without any significant influence of GA treatment. Finally, the T cell repertoire variations in MS patients treated with GA and healthy controls were equivalent. Collectively, our data suggest that GA therapy does not induce significant variations in cytokine production or TCR usage in MS patients.
authors.affiliation: INSERM U643, 30 Bd J. Monnet, 44093 Nantes Cedex, France.
authors.forename: Laureline
authors.initials: L
authors.lastname: Berthelot
authors.forename: Patrick
authors.initials: P
authors.lastname: Miqueu
authors.forename: Ségolène
authors.initials: S
authors.lastname: Pettré
authors.forename: Marina
authors.initials: M
authors.lastname: Guillet
authors.forename: Julien
authors.initials: J
authors.lastname: Moynard
authors.forename: Sandrine
authors.initials: S
authors.lastname: Wiertlewski
authors.forename: Fabienne
authors.initials: F
authors.lastname: Lefrère
authors.forename: Sophie
authors.initials: S
authors.lastname: Brouard
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Soulillou
authors.forename: David-Axel
authors.initials: DA
authors.lastname: Laplaud
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D022801:Complementarity Determining Regions / Q000276:immunology; D016207:Cytokines / Q000235:genetics / Q000276:immunology; D005260:Female; D000068717:Glatiramer Acetate; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000188:drug therapy* / Q000276:immunology*; D009414:Nerve Growth Factors / Q000235:genetics / Q000276:immunology; D010455:Peptides / Q000627:therapeutic use*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric
chemical_list: D022801:Complementarity Determining Regions; D016207:Cytokines; D007166:Immunosuppressive Agents; D009414:Nerve Growth Factors; D010455:Peptides; D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; D000068717:Glatiramer Acetate