MIC 102 Lecture Notes - Lecture 25: Complement Membrane Attack Complex, Lectin Pathway, Complement Component 3
10 Dec 2017
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Document Summary
Three broad factors determine infection outcome: virulence of infectious agent, dose of agent, strength of host defense. Virulence factors: any component that increases virulence: host defense evasion, immunosuppression, colonization, entry. Sources of infectious agents and entry into host. Sources: environmental, animal, other humans, own microbiota. Entry: various microbes have different routes of entry and colonization sites, does not necessarily need to penetrate into host tissues to cause disease. Innate mechanisms are always on and provide continuous protection. Adaptive mechanisms are responsible to specific immune challenges. Common response to infection or tissue damage: swelling locally increased fluid levels, pain nerve compression, chemical mediators, reddening increased blood flow, pus dead cells. Inflammation turned on: microbe associated molecular patterns (mamps) Alternative pathway is activated by microbial surface mamps. Lectin pathway uses lectin bound to cell surface sugars as an activator. Classical pathway requires antibody-antigen binding, so is dependent on adaptive immune system so slower process.
