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The Non-Specific (Innate) Immune System .docx

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Natural Science
NATS 1670
Motti Anafi

Nonspecific (Innate) response The Inflammatory Response - Acoordinated set of nonspecific defenses in response to damaged cells and bacterial proteins - Inflammation is characterized by: o Swelling o Redness o Pain o Heat (locally or systematically) Example of inflammation: When a splinter is in your skin: -mast cells release histamine -histamine diffuses into capillaries causing them to dilate -activated proteins called complement proteins and other chemicals attract phagocytes to the area -the phagocytes engulf and digest dead cells and bacteria -histamine and complement signaling cease -histamine secreted from mast cells increases permeability of the blood vessels during inflammation -leads to leakage of blood plasma and cells (phagocytes) to the injured site o Bacteria cell lysis o Phagocytes engulf and destroy bacteria cells Neutrophils -provide the first line of defense -the main cell types seen in an inflammatory response in its initial phase o Respond to chemotaxis signal from the injured site o Directed cell motion towards area with higher concentration of chemotaxis agent -neutrophils are the principal cells that engulf and destroy the invading micro-organisms Recognition -they have surface receptors for: o Common bacterial cells o Bacterial secreted substances Macrophages -are the other population of phagocytic cells -main activities: o Phagocytosis (the fusion between phagosome and lysosomes and toxic compounds destroy the pathogen) o Antigen presentation for specific immune response Natural Killer cells -kill virus infected cells and cancer cells Interferon o Synthesized by virus-infected cells o Binds to interferon receptor of nearby uninfected cells o Induces them to eliminate viral genome (RNA) and black viral protein synthesis and replication. o Does not protect the original infected cell o Does not prevent viruses from invading the protected cells o Interferon is not virus-specific o Synthesis in response to one virus will also protect against other viruses. o Side effects o Interferon as a drug- it’s not a very successful drug at this level Specific or adaptive immunity Aresponse to a specific molecule (antigen) The immune system can “remember” invaders and react more promptly to second exposures to infection Immune system usually develops memory Only an exposure to the same antigen will activate this memory response The specific immune system distinguishes between self and non self and only reacts against non self It is possible even within this complicated system for your immune system to react against yourself o Specific response o Immunological memory o Cellular (T cells) o Humoral ( B cells) o Antibodies HumoralAdaptive Immunity Antigens (Ag) are substances that induce a specific immune response and subsequently react wit
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