Immunology 2 Flashcards
T or F: innate immunity discriminate very effectively between host cells and pathogens
true
what is a lysozyme
a chemical barrier present in secretions like mucus, tears, saliva and uses hydrolysis to break apart the peptidoglycan wall -> lysis of bacterial cell wall
what are antimicrobial peptide - defensins
- part of innate immunity
- small, heterogeneous, cationic peptides
- kill gram-negative and gram-positive bacteria
functions: - destabilize membranes and pore formation in bacterial cell walls
- degradation of bacterial proteins
- inhibit viral binding and entry
- inhibit virus particle assembly
explain phagocytosis and phagocytes
- one of the first lines of defense if microbes do invade tissue
- engulf and destroy microorganisms
- key role in innate immunty as they can recognize, ingest, and destroy many pathogens without aid of an adaptive immune response
what are the major phagocytes in the body?
macrophages and neutrophils
T or F: Phagocytosis can also occur after an antibody has bound to an antigen - the antibody can act as a “signal” that triggers efficient phagocytosis
true
what are some examples of pattern recognition receptors?
- toll-like receptors
- nod-like receptors
- lectins
Steps of Phagocytosis
- a PRR binds to a microbe or an opsonin created by another cell binds to the microbe
- the microbe is engulfed (forms a phagosome)
3 & 4. microbe killing (phagosome fuse with lysosome) - microbe remnants are either digested and used OR excreted
what is a NADPH oxidase complex?
- if a particle is too large to phagocytose, macrophages will surround it and “place” their NADPH oxidases close to it to try to kill it
- uses a large amount of oxygen
what are some neutrophil granules?
- defensins
- cathepsin
- cathelicidins
- lysozyme
- lactoferrin
what can neutrophils do when they’re in an environment with many bacteria?
they can lyse and release their DNA into the ECF known as NET
what are the cytokines that are secreted in response to TLR activation?
inflammatory cytokines and interferons
what are interferons?
- has interferon alpha, beta, and lambda
- autocrine and paracrine signalling molecules that are effective in activating macrophages, NK cells, and inducing an antiviral state
what do Nod-like receptors do?
- recognize DAMPs associated with cellular stress
- activates expression of inflammatory cytokines
steps of acute inflammation
- alteration of vascular caliber - vasodilation
- capillaries and venules become more “leaky”
- emigration and activation of leukocytes
vasodilation during acute inflammation leads to what?
increased blood flow in inflamed tissue
what is lymphangitis?
the lymphatic vessels become inflamed
what is a cytokine?
- influence the differentiation of a wide variety of cells including leukocytes
- mediate - activate or inactivate - the activity of many cells
- increase or decrease the production of wide variety of stem/hematopoietic cells
what is a chemokine?
- bind to cell-surface receptors
- induce movment of leukocytes along the chemokine concentration gradient
- mediate adhesion of leukocytes for the purposes of: differentiation and inflammation/migration
what are the 2 major chemokine families?
CXC and CC
CXC chemokines attract…
neutrophils, are angiogenic, and are very similar in structure
what does CC chemokines do?
Act on/attract a wide variety of other leukocytes
what inflammatory mediators increase the ability of leukocytes to migrate to a target?
- histamine, thrombin
- TNF and IL1
- Chemokines
