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IMF-093-03-0001-en	How can low-affinity IgM still bind antigen strongly?	Affinity is the strength of one binding interaction, while avidity is the combined strength of multivalent binding, and IgM gains high avidity through its multiple binding sites.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0002-en	Why does detecting IgM not simply date an infection as recent?	IgM dominates the early primary response, but persistence, cross-reactivity, natural antibodies and reactivation limit simple timing conclusions.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0003-en	How does the neonatal Fc receptor explain both newborn protection and the long half-life of IgG?	It carries IgG across the placenta, so maternal IgG protects the newborn but can also transmit pathogenic autoantibodies, and it rescues IgG from degradation, extending half-life.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0004-en	What makes secretory IgA suited to mucosal defence?	Dimeric IgA is carried through epithelium by the polymeric-immunoglobulin receptor, a receptor-derived secretory component protects it from proteolysis, and it neutralises microbes and toxins with relatively little inflammation.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0005-en	Why does allergen-specific IgE not by itself prove clinical allergy?	It indicates sensitisation, and without a compatible exposure history it does not show that a clinical reaction will occur.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0006-en	Why does neutralisation not require Fc activity, and what limits it?	It works by blocking attachment, entry, fusion, enzyme action or toxin-receptor binding, so it depends on epitope access and concentration, and viruses escape by changing epitopes.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0007-en	Why does soluble monomeric IgG not strongly activate phagocytes?	Fc gamma receptors are triggered by clustered IgG on a coated particle, and receptor clustering is required, so single soluble molecules generally do not signal strongly.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0008-en	Why is class switching largely irreversible, and what does defective switching cause?	DNA recombination joins the variable region to a downstream constant gene and deletes the intervening DNA; defects cause hyper-IgM syndromes with impaired class-switched defence.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0009-en	How does affinity maturation select better antibodies, and what risk does it carry?	Somatic hypermutation alters variable regions, clones compete for antigen on follicular dendritic cells and follicular T-cell help, and higher-affinity clones survive; it risks autoreactivity and translocation.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0010-en	Why may antihistamines and adrenaline be insufficient in hereditary angioedema?	C1-inhibitor deficiency causes swelling through bradykinin rather than histamine, without typical urticaria, so it needs pathway-specific therapy, though airway emergency still requires immediate assessment.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0011-en	Why does paroxysmal nocturnal haemoglobinuria cause blood-cell injury and thrombosis?	Blood cells lose glycosylphosphatidylinositol-anchored complement regulators, so complement attacks them without the usual host protection.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0012-en	Why do early classical-component deficiencies cause lupus-like disease while C3 deficiency causes pyogenic infection?	Early classical components are needed for immune-complex clearance, whereas C3 is central to opsonisation, so losing it causes severe recurrent pyogenic infection.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0013-en	How are immune complexes normally cleared, and what happens when they persist?	Complement tags them and erythrocyte complement receptors carry them to liver and spleen for phagocytic removal; persistent complexes deposit in glomeruli, vessels, joints or skin and activate complement and Fc receptors.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending
IMF-093-03-0014-en	What syndrome can follow defects in cytotoxic granule exocytosis, and what characterises it?	Haemophagocytic lymphohistiocytosis, with uncontrolled activation, fever, cytopenias, organ enlargement and inflammation.	Integrated Medical Foundations; chapter 93, TTS module 3; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: bb29bbff5befbcc123767e40bfaefbf864419fd9094f82a71691be8c076c4370; editorial review pending	imf lang::en chapter::093 module::093-03 review::pending