Innate immune system, fever, intro to antibiotics Flashcards
1
Q
Immunity
A
- The ability to resist organisms or toxins that tend to damage the tissues and organs.
2
Q
Acquired immunity
A
- Immunity that does not develop until the body is attacked by a bacterium, virus, or toxin.
- It often takes weeks to months for this type of immunity to develop
3
Q
Innate Immunity
A
- Immunity that comes from general process - not from processes directed at the specific organism.
- It is the first line barrier and rapid response mechanism to prevent invasion.
- Protects the body during period between microbe exposure and start of adaptive response
- Components are inherited from parent to child (present at birth).
4
Q
Components of the Innate Immune system
A
- Physical barries - tight junctions in skin, epithalial and mucous membrans, mucus, vascular endothelial cells that prevent penetration of the intestines.
- Enzymes in epithelial and phagocytic cells (lysozymes)
- Inflammation- related serum proteins - complement componenets, C-reactive protein
- Antimicrobial peptides on cell surface and in phagocyte granules
- Cell receptors that sense micro-organisms and signal a defensive response
- Cells that release cytokines and other inflammatory mediators
- Phagocytes - neutrophils, monocytes, macrophages
- The microbiome - collection of bacteria, fungi, and viruses that live in and on the body. Microbiome plays a role in the maturation of the immune system, protects aginst pathogen overgrowth, and aids in the balance between inflammation and immune homeostasis.
5
Q
Main function of the innate immune system
A
- Detection of micro-organisms and first-line defense against invasion and infection
- Response of innate immune system is due to proteins ability to recognize and interact with components specific to the microbe (Pattern Recognition Receptors)
- Regulation of inflammation - swelling, redness, heat, and pain are due to the actions of innate immunity
- Maintenance of immunologic homeostasis in host
- Activation and instruction of adaptive immune responses
6
Q
Pattern Recognition Receptors (PRR)
A
- Receptors that recognize a specific components of the microbe. There are 2 groups of PRRs
- Secreted and circulating pattern recognition receptors - mediate direct microbial killing, act as helper proteins for transmembrane receptors, and enhance phagocytosis.
- Cell-associated pattern recognition receptors - membrane bound PRRs. They are found on mnay cells of the innate immune system and various antigen-presenting cels. On these cells, transmembrane signaling PRRs induce rapid upregulation of other PRRs on activation.
7
Q
Pathogen-associated molecular patterns (PAMPs)
A
- Patterns that are highly conserved in pathogens, allowing them to be recongized by PRRs
- Features:
- Only produced by microbes
- Typically invariant strucutres shared by enture classes of pathogens
- Structures are necessary for integrity, survival, and pathogenicity of the micro-organism (makes it so PAMPs can’t mutate to avoid host defense)
8
Q
Cells of the Innate immune system
A
- Neutrophils, monocytes, macrophages, eosinophils, basophils, mast cells, natural killer cells, epithelial cells, platelets, innate lymphoid cells, dendritic cell, and adipocytes
- Phagocytes (neutrophils, monocytes, and macrophages) are the critical component.
9
Q
Neutrophils
A
- Most abundent circulating phagocyte
- First cell recuited in areas of infection/inflammation (neutrophils are attaracted to chemotactic factors generated at these sites.
- Once they reach infected site, neutrophils phagocytose the invading micro-organisms that have been opsonized (prepared for phagocytosis) by innate and acquried immune preocesses.
- Once ingested, microbicidal mechanisms kill the microbes
10
Q
Monocytes and macrophages
A
- Monocytes - develop in the bone marrow and circulate before entering tissue
- Most serve to renew macrophage population by differentiating into macrophages characterisitic for the tissue
- Macrophages - express many PRRs on cell surface
- Respond rapidly to presence of microbes
- Digest microbes and present microbial antigens to lymphocytes to initiate adaptive immune response
- Secrete various proteins that mediate host defense and inflammation
11
Q
Eosinophils
A
- Release extracellular traps carrying gransules that secrete their contents when stimulated
- Play role in resisting parasitic infection
- These cell circulate, but are mainly found in the lamina propria of the GI tract
12
Q
Basophils
A
- Leukocytes that only appear in the blood
- Play a role in inflammation and in the allergic response
13
Q
Mast cells
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- Found in the interstitium of peripheral tissue
- Express TRL
- On PRR activation, mast cells release tumor necrosis factor alpha and IL-8
- Produce classic inflammatory mediators (histamine, heparine, leukotrienes, platelet-activating factor), proteases, and AMPs
- Have immunomodulatory, antimicrobial, and antiprotozoan function
14
Q
Natural Killer Cells
A
- Lymphoid cells that don’t express antigen-specific receptors
- When activated, NK cells release granules that damage the target cell membrane and induce apoptosis
- Distinguish and avoid healthy host cells through receptors that recognize MHC class 1 molecules expressed on healthy (bindings of these receptors inhibits NK activity)
15
Q
Dendritic cell
A
- Major antigen presenting cell - starts life in unprogrammed, innate, state
- Phagocytotic
- Plays role in linking adaptive and innate immunity
- Capture, process, and present antigens to t-cells to induce adaptive immunity or tolerance to self-antigens
17
Q
Skin layers
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