To validate and evaluate a rodent model of anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. We aim to characterize the immune response of treated animals and investigate the molecular effects of pathogenic antibodies on neuronal glutamate receptor signaling.

Anti-NMDAR encephalitis is the most common subtype of autoimmune encephalitis (AIE) and is characterized by GluN1 antibodies. Disease is associated with substantial morbidity and mortality, highlighting critical unmet therapeutic needs. Most animal models of anti-NMDAR encephalitis depend on intracerebroventricular transfer of patient-derived antibodies or cerebrospinal fluid (CSF), or immunization with structurally intact NMDARs. However, recent studies have demonstrated the induction of anti-NMDAR encephalitis in rodent models through GluN1 peptide immunization, with differing effects.

We evaluated the immunogenic potential of GluN1 peptides resembling the amino acid sequence found within the pathogenic epitope of GluN1 subunit of NMDARs. Mice that received vehicle injections and non-pathogenic GluN1 peptide immunizations served as controls. We analyzed the serum of immunized mice using quantitative western blotting (WB) and an immunofluorescent cell-based assay (CBA) against HEK293 cells overexpressing GluN1 subunits. Neuronal glutamate receptor signaling was evaluated using biochemical approaches. Our main comparator groups consisted of cohorts divided into 1) vehicle group, 2) non-pathogenic GluN1 peptide, and 3) pathogenic GluN1 peptide.

Immunization of mice with specific pathogenic GluN1 peptides reliably produced antibodies against NMDARs. This was contrasted by the absence of antibodies observed in sera from animals immunized with vehicle, non-pathogenic, and some pathogenic GluN1 peptides.

Our experiments have shown that specific GluN1 peptide immunization induces production of anti-NMDAR antibodies in mice. Future studies will investigate the regulation of synaptic NMDAR expression and neuronal glutamate receptor signaling pathways. These studies may contribute to the identification of potential therapeutic targets for novel therapies for patients with anti-NMDAR encephalitis and disorders involving antibodies targeting cell surface antigens.