Murine and Humanized Mouse Models in Autoimmune Disease Research and Therapeutics Development.

Autoimmune diseases arise from a breakdown of immune tolerance and complex interplay of genetic susceptibility, environmental triggers, tissue-specific immune responses, microbiota, and regulatory pathways. Mouse models remain essential for dissecting these mechanisms, but no single model fully reproduces the heterogeneity, chronicity, and immune complexity of autoimmune disease in humans. This review summarizes classical murine and humanized mouse models used to study inflammatory bowel disease (IBD), multiple sclerosis (MS), type-1 diabetes (T1D), and rheumatoid arthritis (RA). We also highlight disease-specific scoring systems, including clinical indices, histopathology, imaging, cytokine profiling, autoantibody assessment, and human immune-cell readouts, as essential tools for standardized interpretation. Conventional murine models provide experimental control and mechanistic clarity, whereas humanized models improve assessment of human immune responses, patient-specific biology, and therapeutic translation. However, humanized systems remain limited by incomplete immune reconstitution, graft-versus-host disease, donor variability, cost, and incomplete tissue architecture. By providing a comparative framework spanning both conventional and humanized models, this review aims to guide informed model selection tailored to specific research questions in autoimmune disease biology and translational therapeutic development.