Fig. 4

Natalizumab increases TNF and IL-6 production of B cells in vitro. Peripheral blood mononuclear cells (PBMC) were collected from healthy donors (n = 8). Two hundred thousand PBMC were pre-incubated for 4 h with increasing concentrations of natalizumab (NAT) or an isotype control IgG4 antibody followed by 40 h simultaneous incubation with NAT/control and 1 μg/ml CpG. Each dot represents the values of one healthy donor. Whiskers indicate mean ± standard error of the mean; *P < 0.05; ***P < 0.001; ****P < 0.0001; unpaired t test. a, b Thereafter, GolgiPlug, 500 ng/ml ionomycin, and 20 ng/ml phorbol 12-myristate 13-acetate (PMA) were added for an additional 6 h. Geometric mean fluorescent intensity (gMFI) of intracellularly accumulated cytokines (tumor necrosis factor (TNF), interleukin (IL)-6 and IL-10) in a B cells (CD19⁺) and b CD14⁺ myeloid cells was determined via flow cytometry. c Without further stimulation, expression of activation markers and co-stimulatory molecules on B cells were determined using flow cytometry