Innate Immunity

numm17's version from 2015-10-12 07:34

Innate (I) or Adaptive (A)?


Question Answer
specificity inherited in genomeI
expressed by all cells of a particular typeI
triggers immediate responseI
recognizes broad classes of pathogenI
interacts with a range of molecular structures of a given typeI
encoded in multiple gene segmentsA
requires gene rearrangementA
clonal distributionA
able to discriminate between even closely related molecular structuresA
natural killer cellsI
B lymphocytesA
T lymphocytesA
useful receptors not heritableA
some responses are anti-selfA
expansion requiredA
differentiation requiredA
loss of specificity and flexibilityI
appeared earlier in evolutionI (cartilaginous fish)

Barrier Functions


Question Answer
what is primary defensive barrier for sites exposed to outside environment?epithelial cell layer
epithelial cells are joined by _____tight junctions
epithelial cells secrete ____ to defend against bacteriadefensins
defensins mechanism of actionbind acidic molecules in bacterial cell wall
what type of defensin is expressed in neutrophils?alpha
what stimulates release of defensin alpha?binding to TLRs on neutrophils
what type of defensin is secreted into the saliva?histatins (His-rich)

Cells of the innate immune system



Question Answer
which cells perform phagocytosis?neutrophils and macrophages
neutrophils and macrophages are derived from which progenitor cells?GM-CFCs
what are GM-CFCs?granulocyte-monocye colony-forming cell
primary function of neutrophils?phagocytosis
describe development of neutrophilsGM-CFC --> bands --> PMN cells (polys) --> into circulation, eventually tissues
at what point do neutrophils stop dividing?after release from marrow into circulation
what are PMNs?polymorphonuclear; neutrophils
which molecules affect production and release of neutrophils?TNF-alpha, IL-1, G-CSF, GM-CSF
what is a "shift to the left" and what does it indicate?presence of immature neutrophils in circulation; sign of increased mobilization of neutrophils from marrow
which cells are the first to arrive at an inflammatory site?neutrophils
primary function of macrophages?phagocytosis AND antigen presentation to T cells
possible actions when a macrophage encounters antigen?phagocytoses antigen, and then 1 releases anti-immune signals; 2 release nothing; 3 release pro-immune signals
describe development of macrophagespromonocytes in bone marrow --> monocytes in circ (<--> marginal monocytes on vessel walls) --> tissue; type determines differentiation
in lung, what type of macrophage will develop?alveolar macrophages
in liver, what type of macrophage will develop?Kupffer cells
in CNS, what type of macrophage will develop?microglia
in bone, what type of macrophage will develop?osteoclasts
which molecules promote maturation of promonocytes?IL-3, M-CSF, GM-CSF
what are M-CSFs?macrophage colony stimulating factors
what are GM-CSFs?granulocyte macrophage colony stimulating factors

Cells from Lymphocyte Lineage


Question Answer
primary function of NK cells?kill cells w/ intracellular infection
mxn of NK cell action?release cytotoxic granules
how do NK cells recognize targets?via its activating and inactivating receptors; most cells have activating ligands during development, but tumor and infected cells DON'T have inactivating ligands
which molecules activate NK cells?interferon alpha and beta
difference between NK cells and classic lymphocytes?NK cells are more granular
what are ILLs?innate-like lymphocytes
differences between ILLs and classic lymphocytes?ILLs don't have classic lymphocytes features: no memory, no polymorphic receptors
examples of ILLsintraepithelial γδ cells, B1 cells, NK T cells
fx of intraepithelial γδ cellsrelease cytokines during inflammation
fx of B1 cellsbacterial infection resistance
B1 antibodies vs. classic B cell antibodies?B1 cells make "natural" antibodies that don't target specific structures
NK T cells recognize ____lipid (NOT protein) antigens
fx of NK T cellsrelease cytokines after lipid antigen ID

Pattern recognition


Question Answer
what are PAMPs?Pathogen Associated Molecular Patterns
PAMP fx?activate innate immune system
PRR fx?recognize PAMP of pathogen
what are PRRs?Pattern Recognition Receptor
most important requirement for PAMPexpressed by pathogens, NOT host
PAMPs are usually which molecules, and are rarely what type?usually not protein; usually polysaccharides or nucleotides
best example of PAMPLPS: bacterial wall lipopolysaccharide
three types of PRRsextracellular, endocytic, signaling
examples of extracellular PRRsCRP (C-reactive protein) and MBL (mannan-binding lectin)
which molecules are a part of the acute phase response?CRP and MBL
what is the acute phase response?production and secretion of immune-activation proteins in liver
functions of extracellular PRRsopsonization, activation of complement cascade
functions of endocytic PRRsphagocytosis
example of endocytic PRRMMR (macrophage mannose receptor)
example of signaling PRRTLR, NODs
function of signlaing PRRsense PAMPs; start innate and adaptive immunity cascade
CRP targets ____ on _____phosphocholine on bacterial cell walls
MBL targets ____ on _____mannose residues on yeast, bacteria cell walls
where are endocytic PRRs expressed?phagocytes (macrophages and neutrophils)
____ are cell-surface signaling PRRs; ____ are intracellular signaling PRRsmost TLRs; TLR4 and NOD1 and NOD2

TLR4 signaling


Question Answer
what is the target of TLR4 activation?NFκB
NFκB is usually found where? why?cytoplasm; bound to inhibitor, IκB
what is the ligand of TLR4?LPS
LPS is bound toLBP - LPS binding protein
in order for TLR4 activation, how must LPS be presented to receptor?LPS-LBP complex binds to CD14 receptor on macrophage; binding pair the binds to and activates TLR4
what macrophage receptor plays a role in TLR4 activation?CD14
upon activation, the ____ domain of TLR4 binds ____cytoplasmic; MyD88
MyD88 actions?launches phosphorylation cascade, ultimately phosphorylating IκB
how is IκB degraded?phosphorylation by cascade initiated by MyD88 results in loss of affinity for NFκB; once without binding partner, is degraded
location of NFκB after TLR4 activation?nucleus
action of NFκB?transcription factor: induces immune-related genes