Research overview: immune-mediated pathology and antibody-dependent enhancement in FIP

FIP is fundamentally an immunopathologic disease in which the host immune response contributes to tissue injury. The classic vasculitis and pyogranulomas arise from interactions between infected macrophages, antibody, complement, and inflammatory mediators. Historical experiments suggested antibody-dependent enhancement, in which pre-existing coronavirus antibody could worsen disease, complicated efforts to develop a safe vaccine. This overview compiles the immunopathology literature rather than one citation, describing how the balance between cell-mediated and humoral immunity influences whether infection is cleared or progresses to disease, why vaccine development has been fraught, and how understanding the immune contribution explains both the clinical features of FIP and the supportive use of immunomodulation alongside the direct-acting antivirals that now drive cure.