Glatiramer acetate immune modulates B-cell antigen presentation in treatment of MS

Human peripheral blood mononuclear cells (PBMCs) were isolated from glatiramer acetate (GA; n = 20) or non-GA (control; n = 18) treated patients with MS. In addition, 6 patients were analyzed longitudinally on GA treatment. Red circles represent GA treatment, squares control treatment. (A) Mean frequency ± SEM of B-cell subpopulations defined as follows: transitional B cells (CD24^high CD38^high; transitional), mature B cells (CD24^var CD38^low; mature), antigen-activated B cells (CD27⁺; ag-activated), memory B cells (CD27^var CD38⁻; memory), and plasmablasts (CD20⁻ CD27⁺ CD38⁺; *p < 0.05; unpaired t test). (B) B-cell subset frequencies of patients with MS at 2 time points during GA therapy; line connects an individual patient (n = 6; *p < 0.05; Wilcoxon matched-pairs signed-rank test). (C) The individual patients' frequencies of BC subsets were correlated with the duration of GA treatment (*p < 0.05; linear regression). (D) MFI ± SEM of activation molecules expressed on B cells (ns; unpaired t test). (E) B-cell activation marker expression of patients with MS at 2 time points during GA therapy; line connects an individual patient (n = 6; *p < 0.05; Wilcoxon matched-pairs signed-rank test). (F) Mean MFI of molecules involved in antigen presentation expressed on B cells (*p < 0.05; unpaired t test). (G) Expression of molecules involved in antigen presentation of patients with MS at 2 time points during GA medication; line connects an individual patient (ns; Wilcoxon matched-pairs signed-rank test). (H) Shown is the frequency of positive cells regarding the respective cytokine (tumor necrosis factor [TNF], interleukin [IL]-6, and IL-10; mean ± SEM; ns; unpaired t test). (I) TNF, IL-6, and IL-10-positive B cells of patients with MS at 2 time points during GA medication; line connects an individual patient (*p < 0.05; Wilcoxon matched-pairs signed-rank test). GA = glatiramer acetate.

(A) Naive mice received a daily SC injection of 150 μg GA. On day 10 post-treatment onset, splenic B cells were isolated and analyzed (B and C) for expression of activation markers, (D–F) costimulatory molecules, and (G) the antigen-presenting molecule MHC Class II as well as (H) for secretion of cytokines. Data are shown as median; n = 4; *p < 0.05; Mann-Whitney U test. GA = glatiramer acetate.

(A) GA therapy was performed by a daily SC injection of 150 μg, starting 7 days before MOG peptide_35-55 immunization. Serum and splenic B cells were isolated on day 23 post-immunization. (B) Mean group EAE severity is given as mean ± SEM; disease incidence is indicated in brackets; n = 15; *p < 0.05; Mann-Whitney U test. (C) GA antibody titers were measured at 450 nm (data given as median; n = 3–4; ***p < 0.001; Student t test). (D) B-cell activation, expression of molecules involved in antigen presentation, and cytokine secretion were analyzed by FACS (data given as median; n = 5; *p < 0.05, **p < 0.01; Mann-Whitney U test). (E) B cells were cocultured with CFSE-labeled myelin-specific (2D2) naive T cells in the presence of 5, 25, or 100 μg/mL MOG peptide_35-55. T-cell proliferation was evaluated by CFSE dilution and stratified by division frequency as follows: few divisions (1–2; black), intermediate divisions (3; medium gray), and many divisions (≥4; light gray). T-cell divisions are shown as mean ± SEM; n = 5; *p < 0.05; Mann-Whitney U test. Differentiation of myelin-specific naive T cells into (F) Treg cells (CD25⁺FoxP3⁺CD4⁺) or (G) Th1- (IFN-γ⁺CD4⁺) and Th17 cells (IL-17⁺CD4⁺) was analyzed by FACS (data given as median; n = 5). EAE = experimental autoimmune encephalomyelitis; GA = glatiramer acetate.