The complement pathway, a cornerstone of immunology, encompasses distinct types, functions, and disease implications that intricately shape our immune responses. Comprising three main pathways – classical, lectin, and alternative – this system orchestrates a dynamic interplay of interactions to bolster our defenses against infections. The classical pathway is triggered by antigen-antibody complexes, while the lectin pathway responds to pathogen-specific carbohydrates. The alternative pathway, on the other hand, offers a rapid, antibody-independent response. These pathways collectively contribute to opsonization, inflammation, and the formation of membrane attack complexes that eliminate threats. Understanding the complement pathway is pivotal, as deficiencies or dysregulations can lead to various diseases, such as Paroxysmal Nocturnal Hemoglobinuria (PNH) and autoimmune disorders. Multiple Choice Questions on Complement Pathway and Immune Response 1) Complements ...