Exam 2- Innate Immunity Flashcards
innate immunity has ________ barriers and ________ barriers
anatomical
physiological
are neutrophils present in normal, healthy tissues?
no
what is the primary function of phagocytes?
identify, ingest, and destroy microbes
what do macrophages and neutrophil surface receptors bind to on microbial surfaces (common constituent)?
pathogen-associated molecular patterns (PAMPs)
inflammation is traditionally defined by the presence of ______, ______, ______, and ______
heat
pain
redness
swelling
what does dilation and increased permeability of blood vessels in inflammation account for?
heat, redness, swelling
what causes the pain in inflammation?
migration of cells into tissue and their local actions
what do macrophages release in response to invading pathogens?
cytokines
what do interleukins 1 and 6 (IL-1 and IL-6) induce?
hypothalamus to induce fever
liver to produce soluble proteins quickly- acute phase proteins (APP)
what does TNF-alpha do?
makes blood vessels stickier to induce cell migration and activating migrating macrophages
promotes platelet aggregation and clotting to help limit spread infection
what does IL-8 do?
directs neutrophils
what does IL-12 do?
promotes local natural killer cell activity and stimulates IFN-gamma release
later in response primes antigen-specific T lymphocytes
how are pathogens destroyed?
phagosome
phagolysosome
what do macrophages and neutrophils produce after phagocytosis to kill the engulfed microorganism?
hydrogen peroxide
superoxide anion
nitric oxide
how can neutrophils kill pathogens extracellularly?
neutrophil extracellular traps (NETs): activated neutrophils generate web extracellular fibers of DNA, histones, granule proteins (elastase)
what do mast cells release after being exposed to certain types of bacteria?
TNF
histamine
proteases
mast cells are considered to particularly effective in aiding immune cell recruitment in view of their strategic association with __________________
blood vessels
what are Toll receptors?
transmembrane receptors that signal the presence of pathogens, from effector cells
the effects of bacterial LPS on macrophages are mediated by DC14 binding to ________________________
Toll-like receptor 4
true/false: Toll-like receptors are found not only on the cell surface, but also on intracellular membranes
true
what are cytosolic receptors?
Toll-like receptors in cytosol
three major classes of
what mediates leukocytes leaving the blood stream (extravasation)?
cytokines and chemokines
what is the dual function of the innate immune system?
early defense against pathogen attack
alert adaptive immune system to pathogen invasion
how does the dual function of the innate immune system operate?
the Toll pathway
natural killer cells selectively kill cells that bear ___________ levels of MHC class I molecules
very low
how do natural killer cells balance their engagement to distinguish between healthy and infected cells?
both activation and inhibition receptors
what activates the lectin-binding pathway in complement?
terminal mannose residues via mannos-binding lectin
N-acetylglucosamine residues
what are the two major families of antimicrobial peptides?
defensins and cathelicidins
how does host cell damage trigger innate immunity?
damage-associated molecular patterns (DAMPs)
what are two physiological barriers to microbes?
acid pH of skin
secretions of mucus membranes
what does a pathogen-associated molecular pattern binding to a cell receptor lead to?
phagocytosis
induces secretion of cytokines and chemokines
what are some receptors on phagocytes that help macrophages and neutrophils recognize pathogens?
macrophage mannose receptor
scavenger receptors
complement protein receptors
toll-like receptors
what do mast cells do in innate immunity?
release TNF, histamine, and proteases
alter vascular permeability, airways, gastrointestinal motility, and epithelial sloughing
why is the activation of adaptive immunity dependent upon molecules induced due to innate immune recognition and signaling?
Toll signaling leads to production of molecules on antigen presenting cells that are essential for adaptive immune responses: important for activation CD4 T cells
what are the three major classes of cytosolic receptors?
nucleotide-binding oligomerization domain (NOD)-like receptors (NLR)
retinoic acid-inducible gene (RIG)-like (RLR)
cytosolic DNA sensors (CDS)
how does rolling along the endothelium result in extravasation?
first leukocytes bind to vascular endothelium through interactions between molecules induced on endothelium and their carbohydrate ligands on the leukocyte
rolling results in induction of cell adhesion molecules (CAMs) and activation receptors on the leukocyte by contact with chemokines such as IL-8
what immunomodulatory cytokines do natural killer cells produce?
IFN-gamma
TNF-alpha
what are antimicrobial peptides and how/when are they made?
naturally occurring peptide antibiotics
constitutively expressed or induced by microbes or their products
parts of animal most likely to come into contact with pathogens from environment
