Fig 1: In healthy controls and patients with MS, CD19+ T cells display a more activated, mature phenotype.a, b Coculture of T and B cells from peripheral blood mononuclear cells (PBMC) of healthy donors with Staphylococcal enterotoxin B (SEB) for 48 hours; n = 4 wells (apart from 500 ng/ml: n = 3 wells) per condition. Normalized flow cytometric data of a CD4+CD19+ and CD4+CD19− T cells (P = 0.006 in 0 µg/ml and P < 0.0001 in all other concentrations comparing CD19+ with CD19−), and b CD8+CD19+ and CD8+CD19− T cells (P = 0.0208 in 0 µg/ml and P < 0.0001 comparing CD19+ with CD19− in all concentrations) for CD69 expression; analyzed via 2-way ANOVA with Sidak’s multiple comparisons test. c–f Flow cytometric analysis of healthy control PBMCs. Comparison of CD19+ versus CD19− T cells in c differentiation (Th1, Th2, Th17, n = 11; Tc1, CCR4+CD8+, n = 8), d developmental state [CCR7+CD45RO− = TN/TSCM (naive and stem cell–like memory), CCR7+CD45RO+ = TCM (central memory), CCR7−CD45RO+ = TEM (effector memory), CCR7−CD45RO− = TEMRA (terminally differentiated); n = 10 CD4+; n = 6 CD8+], e adhesion capability (integrin α4 = CD49d; n = 10 CD4+; n = 6 CD8+), and f cytokine production (IFN-γ, GM-CSF, TNF, and IL-17; n = 11 CD4+; n = 9 CD8+); analyzed by two-tailed Wilcoxon matched-pairs signed rank test. g Flow cytometric analysis of cytokine production (IFN-γ, GM-CSF, TNF, and IL-17) of CD19+ T cells from healthy controls vs MS patients; n = 10 CD4+; n = 5 CD8+; analyzed by two-tailed Wilcoxon matched-pairs signed rank test. h, i Flow cytometric analysis of h CD19+ B cells and i CD19+CD4+ T cells of healthy controls (n = h 16; i 15), untreated RRMS (n = h 11; i 10), and Inebilizumab (INE)-treated NMOSD patient PBMCs (n = 4); analyzed via Brown-Forsythe and Welch ANOVA test via Games-Howell’s multiple comparison test after analysis for normality via D’Agostino & Pearson test. All figures are representatives of a, b or pooled from c–i 2-3 independent experiments; data is displayed as means ± SD; *=p < 0.05; **=p < 0.01; ***=p < 0.001; ****=p < 0.0001.