We investigate how antibodies at the body’s barrier tissues—skin, intestine, and lungs—protect against infection yet can also drive allergy and inflammation. Focusing on B-cell pathways (germinal center and extrafollicular responses), antibody class switching, affinity, and Fc N-glycosylation, we aim to pinpoint mechanisms that determine protective vs. pathogenic outcomes. The goal is to improve diagnostics, vaccination strategies, and precision therapies for infections, allergies, and auto-inflammatory diseases. The program unites PIs from UzL and CAU within the “Infection and Inflammation” research focus and the Cluster of Excellence “Precision Medicine in Chronic Inflammation.”