During this period, research converged on immunopathogenesis and translational modelling of inflammatory arthritis. Emphasis on controlled animal models—such as adjuvant-induced arthritis in rats and collagen-induced arthritis—facilitated dissection of immune mechanisms and the testing of immunomodulatory therapies. The work also highlighted the role of infectious triggers and immune complexes in disease processes, linking systemic immunity to joint inflammation. Historical Significance: Adjuvant-induced arthritis became a standard reproducible rodent model for dissecting pathogenesis and evaluating therapies, while collagen-induced arthritis established an autoimmune paradigm responsive to immunomodulation. Studies showing that streptococcal components can trigger arthritis framed infectious and immune-driven triggers, and early evidence that circulating immune complexes participate in rheumatoid arthritis provided a basis for diagnostics and targeted therapies.