Anti-IL-6 Receptor Antibody Suppresses Visual Dysfunction in AQP4 Peptide-Immunized Mice

To investigate whether an anti-interleukin-6 (IL-6) receptor antibody (MR16-1) can prevent retinal and optic nerve dysfunction, as well as myelitis, in a mouse model of myelitis induced by immunization with aquaporin-4 (AQP4) peptide.

Mice immunized with AQP4 peptide received MR16-1 or vehicle. Retinal function was assessed by electroretinography (ERG), including b-wave, a-wave, and positive scotopic threshold response (pSTR) amplitudes. Histologic analysis evaluated inflammatory cell infiltration and aberrant Müller cell activation (punctate pattern of glial fibrillary acidic protein staining). Blood-retinal barrier (BRB) integrity was assessed using Evans blue dye, IgG leakage, and transendothelial electrical resistance (TEER) in primary mouse retinal microvascular endothelial cells (mRMECs) exposed to mouse serum.

AQP4 peptide immunization led to reductions in ERG b-wave and pSTR amplitudes and increased inflammatory cell infiltration, Müller cell alteration, and retinal vascular permeability. MR16-1 treatment significantly mitigated these changes, suppressing reductions in pSTR and b-wave amplitude, preventing inflammation and aberrant Müller cell activation, and reducing vascular leakage. The improvement of a-wave amplitude was not significant. Serum from MR16-1-treated mice did not reduce mRMEC TEER, while serum from AQP4 peptide-immunized mice reduced it.

IL-6 receptor blockade with MR16-1 has the potential to suppress AQP4 peptide immunization-related retinal and optic nerve dysfunction and pathology, likely by protecting BRB integrity and suppressing inflammation. These findings support the therapeutic potential of IL-6 inhibition in preserving visual function in neuromyelitis optica spectrum disorder (NMOSD).

IL-6 receptor blockade may be a viable strategy for preventing visual impairment in patients with NMOSD.