Flashcards
Innate immune response
Cards in this deck (31)
- 1What is innate immunity?- A non-specific defence mech. that a host uses immediately or w/in several hours after exposure to antigen
- 2What are the characteristics of innate immunity?- Immunity you are born with
- V. fast response
- Ancient evo
- Same resp. each time, NO memory
- Uses set handful of molecules to recog. pathogen is pres.
- Induces and directs acquired resp - 3What components make up innate immunity?-Physical/ anatomical barriers
- Secreted compounds
- cellular components
- 4What are the main physical/anatomical innate immunity barriers?- Skin
- GI tract
- Respiratory tract
- Mucosal epithelia - 5What secreted compounds are involved w/innate immunity?- Antibacterial compounds
- COMPLEMENT
- Natural antibodies
- Cytokines - 6What are some of the main cellular components of innate immunity?- Phagocytes
- NK cells
- Dendritic cells - 7What is the main goal of innate immunity?- Prevent pathogen entry!
- 8How is the skin an effective barrier against pathogen entry?- Dry, outer protective layer
- Diff. for pathogens to penetrate
- FA prod. inhibits microbes on skin - 9How is the resp. tract an effective barrier against pathogen entry?- Cells joined tightly together - tight junctions
- Cilia
- Mucus - 10How is the GI tract an effective barrier against pathogen entry?- Peristalsis (involuntary constriction and relaxation of muscles of intestine or another canal)
- HCl prod.
- Low pH
- Acid hydrolases bacteria digestion/degradation - 11What is complement?- Series of diff. plasma proteins that circ. in blood and tiss. fluids
- Operates via cascade - one prod. induces next
- Key protein= C3 (activated by C3 convertase)
- 3 pathways (classical, alternative, mannose-binding lectin) - 12What are PAMPs?- Pathogen-associated molecular patterns
- Small molecular motifs conserved within a class of microbes
- Not pres. in host
- Essential for survival of pathogen - 13What are PRRs?- Pattern recognition receptors
- Examples; Toll-like receptors (TLRs) and collectins
- Det. proteins (PAMPs) presented by cells of the innate immune syst.
- They also mediate initiation of antigen-specific adaptive immune response + release of inflammatory cytokines - 14What are collectins?- PRRs
- Family of proteins pres. in solute
- Has collagen-like region and a lectin region = collectin
- Collagen-like region interacts w/effector parts of immune syst
- Lectin region interacts w/sugar molecules on surface of pathogen (e.g. mannose) - 15What are TLRs?- PRRs; Toll-like receptors
- Tol receptors found in drosophila, at least 11 mammalian homologues (functions known in 9) -> toll-like - 16Where are TLRs 1-9's cellular locations in mammals?
- 17What are the other PRRs?- NOD-like receptor
- RIG-like receptors
- Cytosolic DNA sensors - 18What is the microbiome and what is it called w/in body?- The microorganisms in a particular environment (including the body or a part of the body).
- Also called Commensal microorganisms as can have symbiotic relationship w/host - 19A pathogen that breaches the host’s anatomic and chemical barriers will encounter the cellular defences of innate immunity; how does this proceed?
- 20What is the common myeloid progenitor (CMP)?- Precursor of the macrophages, granulocytes (the collective term for the white blood cells called
neutrophils, eosinophils, and basophils), mast cells, and dendritic cells of the
innate immune system. - 21What are the three different types of phagocytes?- Macrophages
- Granulocytes (neutrophils, basophils, eosinophils)
- Dendritic cells - 22What are macrophages?- Specialised cells involved in the detection, phagocytosis and destruction of pathogens
- Reside in most tiss.
- Most arise during embryonic dev. but some mature from monocytes circ. in blood and migrate to tiss.s
- Relatively long lived cells
- Involved in innate and adaptive resp. - 23What do macrophages do?- They have phagocytic functions w/in the innate immune syst.
- Also dispose of pathogens and infected host cells targeted by adaptive immune resp.
- Pres. parts of antigen on surface for adaptive immune cells (APCs)
- Orchestrate immune resp. such as helping induce inflammation + rel. inflammatory mediators that activate and/or recruit other immune cells to the area
- Also act as general scavenger cells in body, clearing it of dead cells and cell debris. - 24What are granulocytes and what do they do?- Named for densely staining granules in cytoplasm - Diff granules in each which stain diff colours and perform distinct functions
- Also called polymorphonuclear leukocytes as have oddly shaped nuclei
- Short lived (few days)
- Increased prod. during immune resp.
- The Phagocytic neutrophils most numerous and imp. in innate immune resp.
- Eosinophils and basophils thought to be most useful against parasitic infection as rel. their degrading contents (enzymes+toxic proteins) outside of cell - 25What are mast cells and what do they do?- Migrate from bone marrow and mature in peripheral tiss. especially skin, intestines, and airway mucosa
- Have granules cont. many inflammatory mediators such as histamine, various proteases - 26What are dendritic cells and what do they do?- Phagocytic cells w/several related lineages w/unclarified functions
- Most have many membranous processes
- Take up particulates via phagocytosis
- Continuously ingest extracellular fluid + contents by process called macropinocytosis
- Main function not degradation of pathogens; act as sensory cells, pathogens trigger them to prod. mediators that activate other immune cells - 27What are the basic steps of phagocytosis?
- 28What killing mechanisms do macrophages and neutrophils use?- Reactive oxygen intermediates (ROS) -> seen more in neutrophils -> following phagocytosis there is respiratory burst (w/incr. oxygen uptake) -> O2 reduced by NADPH oxidase forming hydroxyl radicals
and hypochlorite -> all leads to DNA damage and alterations in bacterial membranes
- Reactive nitrogen intermediates (RNI) -> seen more in macrophages -> L-arginine to L-citrulline
generates NO radicals, catalysed by inducible nitric oxide synthase
(iNOS, NOS2) induced by cytokines
and bacterial components -> all leads to DNA damage and alterations in bacterial membranes - 29What are cytokines?- Intracellular messengers
- Any protein secreted by immune cells that affects the behaviour of nearby cells bearing appropriate receptors.
- Only bind to specific receptors
- Can have activating or deactivating functions (or both)
- The resp. a cytokine induces in a target cell is typically related to amplifying an effector mechanism of the target cell, - 30What are chemokines?- Class of cytokines with chemoattractant properties
- Attract cells w/chemokine receptors from bloodstream to tiss.
Help organise various cells in lymphoid tiss. into discrete regions where specialised resp.s can take place - 31What are natural killer (NK) cells?- Large lymphocyte-like cells w/distinct granular cytoplasm that arise from the common lymphoid progenitor (CLP) in bone marrow
- Kill virally infected cells and tumour cells
- Responsive to TNFa, IL-12
- Prod. IFNg
- Lack the antigen specific receptors of adaptive immune cells but expr. members of various families of innate receptors which can resp. to cellular stress and infections by v. specific viruses (means has imp. role in innate resp. to viruses)
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- Undergrad The Immune System in Health and Disease Flashcards on Innate immune response, created by Liberty Grisman-Hughes on 08/11/2021.
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- Liberty Grisman-Hughes
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