Table 2.

Published studies of glatiramer acetate and B cell-mediated mechanisms

References	Humans/rodent	Key finding
Full publications
Bakshi et al. [89]	Mice	Increased proliferation and activation of immune cells including T and B cells
Basile et al. [86]	Humans	Development of anti-GA antibodies, with isotype switching from IgG1 to IgG4 during long-term GA treatment
Begum-Haque et al. [90]	Mice	GA treatment of mice with EAE biased B cell cytokine production from pro-inflammatory (IL-6, IL-12, and TNF-α) to anti-inflammatory (IL-4, IL-10, and IL-13) GA downregulated expression of BAFF and APRIL
Begum-Haque et al. [91]	Mice	Transfer of GA-conditioned B cells to mice with EAE led to:  Increased production of immunoregulatory (anti-inflammatory) cytokines  Reduced CNS inflammation  Reduced expression of chemokine receptors associated with trafficking of inflammatory cells into the CNS  Increased BDNF, which has been shown to regenerate and repair damaged neural tissue
Bomprezzi et al. [92]	Mice/humans	Mice with EAE: marked increase in GA-specific IgE and IgG1 antibody responses; these may have contributed to the improved symptoms and reduced mortality observed Patients with RRMS: significant increase in GA-specific IgG4 antibodies but not GA-specific IgE, IgG1, IgG2, or IgG3; increase in IgG4 not associated with clinical outcomes
Brenner et al. [93]	Humans	All treated patients developed anti-GA antibodies IgG1 antibody concentrations were 2- to 3-fold higher than those of IgG2, indicating that Th2 responses were involved in mediating the clinical effect of GA
Carrieri et al. [94]	Humans	GA treatment induced a specific and significant decrease of circulating CD19+ B cells in patients with RRMS
Dooley et al. [15]	Humans	Some evidence of effect of GA on B cells (BAFF increased), but no changes in proportions of B cells
Farina et al. [95]	Humans	18 of 20 GA-treated patients with MS had low but significant titers of GA-reactive IgG4 antibodies, a finding that is consistent with GA-mediated induction of Th2-like regulatory T cells
Ireland et al. [65]	Humans	In vitro exposure to GA of naïve or memory B cells from patients with MS did not influence B cell proliferation or production of IL-6 (pro-inflammatory cytokine) or IL-10 (anti-inflammatory cytokine)
Ireland et al. [96]	Humans	B cells obtained from patients with MS treated with GA failed to proliferate in response to high-dose CD40 ligand when combined with additional activation stimuli GA treatment also:  Restored IL-10 production  Transiently reduced IL-6 production (in a subset of patients)  Reduced the total frequency of B cells, plasmablasts, and memory cells  Increased the number of naïve B cells  Elevated IgG and IgM production
Jackson et al. [69]	Humans/mice	There was a direct interaction between GA and human and murine BCRs inducing B cell activation BCR recognition of GA was required for efficacy in EAE B cells served as an antigen-presentation source for GA GA reduced concentrations of the pro-inflammatory cytokines IL-6 and TNF-α in 50% of purified B cell samples from patients with MS
Kala et al. [97]	Mice	Purified B cells from GA-treated mice:  Had increased production of IL-10  Suppressed EAE in recipient mice; this effect was attenuated in recipient mice that were B cell deficient
Karussis et al. [98]	Humans	Following long-term treatment with GA, all patients developed GA-reactive IgG1, IgG2, IgG4, and IgA antibodies Comparing short- and long-term treatment:  There was no change in the concentrations of IgG1, IgA, or IgG4  IgG2 decreased
Rovituso et al. [99]	Humans	B1 cells were depleted (vs. healthy controls) in untreated patients, and in GA-, IFN-, and natalizumab-treated patients with MS
Rovituso et al. [100]	Humans	Patients with RRMS treated with GA were subdivided into B cell responders (brain-specific B cells present in the blood) and non-responders (brain-specific B cells absent) The presence of brain-specific B cells in the blood correlated with responsiveness to GA
Sellebjerg et al. [101]	Humans	GA treatment resulted in the development of IgG and IgG4 anti-GA antibodies during the first months of treatment Antibody concentrations were not correlated with clinical or MRI disease activity
Sellner et al. [102]	Humans	GA treatment was associated with decreased expression of the adhesion molecule ICAM-3 on the surface of B cells in patients with RRMS GA did not alter the expression of other B cell surface adhesion molecules (ICAM-1, LFA-1, and VLA-4)
Teitelbaum et al. [103]	Humans	Patients with MS treated with GA developed anti-GA antibodies, with a peak at 3 months and a gradual decrease to concentrations just above baseline from 12 months
Congress abstracts (from 2011 onwards)
Begum-Haque et al. [104]	Mice	GA treatment downregulated osteopontin expression on B cells and CD44+ cells in EAE This was associated with a decrease in expression of IL-17 (pro-inflammatory) and a concomitant rise in the expression of the anti-inflammatory cytokines IL-10 and IL-13
Begum-Haque et al. [105]	Mice	Expression of B (and T) regulatory phenotypes was increased in GA-treated EAE mice IL-10 was increased and IFN-γ was decreased GA-conditioned B cells had a significant downregulatory effect on chemokines CXCR4 and CXCR5, and on TLR9 expression in the spleen There was no change in VLA-4 expression on regulatory B or T cells
Criscuolo et al. [106]	Humans	GA targeted B cells in RRMS Data from gene-set enrichment analysis suggested that it may inhibit activation and/or maturation of B cells by blocking ion channels known to be essential for cell proliferation
Begum-Haque et al. [107]	Mice	In vitro, addition of GA to bone marrow cells from EAE mice significantly decreased osteopontin and IFN-γ expression In vivo, GA treatment in EAE mice led to an increased production of immunoregulatory cytokines (IL-10, IL-13), elevated BDNF expression in the CNS, and reduced CNS inflammation
Hertzenberg et al. [108]	Mice	Anti-CD20 exacerbated disease severity and altered the cytokine profile of myeloid APC (more TNF, less IL-10) in EAE induced by MOG p35-55 Anti-CD20 reduced development of myelin-specific T cells and ameliorated disease severity despite a similar pro-inflammatory differentiation of myeloid APCs in MOG-induced EAE GA treatment reversed the pro-inflammatory APC differentiation and improved EAE
Häusler et al. [109]	Mice	GA treatment ameliorated MOG p35-55-induced EAE; this was mediated, in part, by reduced IL-6 secretion by B cells GA reversed the exacerbation of MOG p35-55-induced EAE by anti-CD20, which was mediated by regulatory B cell properties GA prolonged the improvement in MOG-protein-induced EAE seen with anti-CD20 after anti-CD20 was stopped

APC antigen-presenting cell, APRIL a proliferation-inducing ligand, BAFF B cell activating factor, BCR B cell receptor, BDNF brain-derived neurotrophic factor, CNS central nervous system, CXCR C-X-C chemokine receptor, EAE experimental autoimmune encephalomyelitis, GA glatiramer acetate, ICAM intercellular adhesion molecule, IFN interferon, Ig immunoglobulin, IL interleukin, LFA lymphocyte function-associated antigen, MOG myelin oligodendrocyte glycoprotein, MRI magnetic resonance imaging, MS multiple sclerosis, RRMS relapsing-remitting multiple sclerosis, Th T helper cell, TLR Toll-like receptor, TNF tumor necrosis factor, VLA-4 very late antigen (integrin α4β1)