Anti-CD20 Depletes Meningeal B Cells but Does Not Halt the Formation of Meningeal Ectopic Lymphoid Tissue

Abstract

ObjectiveTo investigate whether anti-CD20 B-cell-depleting monoclonal antibodies (ɑCD20 mAbs) inhibit the formation or retention of meningeal ectopic lymphoid tissue (mELT) in a murine model of multiple sclerosis (MS).MethodsWe used a spontaneous chronic experimental autoimmune encephalomyelitis (EAE) model of mice with mutant T-cell and B-cell receptors specific for myelin oligodendrocyte glycoprotein (MOG), which develop meningeal inflammatory infiltrates resembling those described in MS. ɑCD20 mAbs were administered in either a preventive or a treatment regimen. The extent and cellular composition of mELT was assessed by histology and immunohistochemistry.ResultsɑCD20 mAb, applied in a paradigm to either prevent or treat EAE, did not alter the disease course in either condition. However, ɑCD20 mAb depleted virtually all B cells from the meningeal compartment but failed to prevent the formation of mELT altogether. Because of the absence of B cells, mELT was less densely populated with immune cells and the cellular composition was changed, with increased neutrophil granulocytes.ConclusionsThese results demonstrate that, in CNS autoimmune disease, meningeal inflammatory infiltrates may form and persist in the absence of B cells. Together with the finding that ɑCD20 mAb does not ameliorate spontaneous chronic EAE with mELT, our data suggest that mELT may have yet unknown capacities that are independent of B cells and contribute to CNS autoimmunity.

Effects of a Fully Humanized Type II Anti-CD20 Monoclonal Antibody on Peripheral and CNS B Cells in a Transgenic Mouse Model of Multiple Sclerosis

“…Unless a treatment is administered that is neuroregenerative, no improvement in clinical score can be expected. In further support of our study, Brand et al, 2021 [ 61 ] also did not observe any changes in the clinical course of spontaneous chronic EAE after anti-CD20 treatment despite efficient depletion of B cells in the periphery.…”

Siponimod Inhibits the Formation of Meningeal Ectopic Lymphoid Tissue in Experimental Autoimmune Encephalomyelitis

“… 22 Recently, we demonstrated that anti-CD20 monoclonal antibodies, despite its superior efficacy in treating RMS and moderate efficacy in treating primary progressive MS, neither ameliorated EAE nor reduced the extent of mELT formation in the 2D2xTh mouse model. 20 Apparently, anti-CD20 monoclonal antibodies only depleted B cells from mELT without changing any other obvious features. Of interest, a very recent study demonstrated that evobrutinib, a Bruton tyrosine kinase inhibitor, reduced the areas of meningeal contrast enhancement in an EAE model in Swiss Jim Lambert J mice immunized with proteolipid protein peptide (PLP139-151) using serial ultra-high-field MRI.…”

“…Spleen cells were processed and analyzed as previously published. 20 The following anti-mouse antibodies were used: CD16/CD32 (BD, 2.4G2), CD45.2 (BioLegend, 104, FITC), CD19 (BioLegend, 6D5, PerCP), CD45R/B220 (BioLegend, RA3-6B2, AF647), CD3e (BD, 145-2C11, PE), and CD4 (BD, RM4-5, PB).…”

“…Organ Preparation, Cell Isolation, and Flow Cytometric Analysis Spleen cells were processed and analyzed as previously published. 20 The following anti-mouse antibodies were used: CD16/CD32 (BD, 2.4G2), CD45.2 (BioLegend, 104, FITC), CD19 (BioLegend, 6D5, PerCP), CD45R/B220 (BioLegend, RA3-6B2, AF647), CD3e (BD, 145-2C11, PE), and CD4 (BD, RM4-5, PB). Histology, Immunohistochemistry, and Imaging Histologic sections of the spinal cord and spleen were prepared, stained with hematoxylin and eosin (HE), Luxol fast blue-periodic acid-Schiff (LFB-PAS) reaction as well as immunohistochemistry (IHC) and evaluated as recently described.…”

Breaching Brain Barriers: B Cell Migration in Multiple Sclerosis

“…The animal model 2D2xTh leads to spontaneous development of EAE with meningeal lymphoid follicles but does not require B cells for pathology. Depleting peripheral B cells before the EAE onset did not halt the production of these follicles nor reduce clinical severity [ 169 ]. Depleting peripheral B cells after the onset of EAE also did not affect the number or size of the meningeal follicles.…”