Innate Immunity Flashcards
T/F innate immunity is NOT essential for effective host defense at the early stage of infection
False. it is very essential
T/F adaptive immunity is essential for microbe clearance
True
what are the three general steps of the innate immune response
- recognition of the pathogen by host cells
- recruitment of host cells at the site of infection
- activation of destructive effector mechanisms
are intracellular or extracellular microorganisms accessible to soluble molecules and phagocytes
extracellular
how are intracellular microorganisms dealt with
they require killing or activation of infected cells
what are the defense mechanisms for dealing with infection in interstitial spaces, blood, and lymph
complement, macrophages, and neutrophils
what are the defense mechanisms for dealing with infection in epithelial surfaces
antimicrobial peptides
what are the defense mechanisms for dealing with infection in the cytoplasm
NK cells
what are the defense mechanisms for dealing with infection in vesicles
activated macrophages
PRR
pattern recognition receptors
PRR encoded in germline possess limited or broad diversity?
limited
T/F innate immunity recognizes structures shared by one class of microbes but not present on normal host cell
False. structures shared by various classes of microbes
is PRR distribution clonal or nonclonal
nonclonal
PAMP
pathogen associated molecular patterns
what do PRRs recognize
PAMPs
define PAMPs
molecules expressed and/or produced solely by microbes and recognized by PRR expressed by immune cells
PRR expression and ligands are ______
redundant
where are PRRs located in the cell
plasma and endosomal membrane and in the cytosol
TLR
toll-like receptors
define TLRs
expressed on cells that are components of the innate immune system. PAMPs are recognized by TLRs
TLR-4 recognizes:
LPS
TLR-3 recognizes
sdRNA (double stranded)
how is TLR4 unique as a TLR
it’s the only TLR that recruits two adapter proteins
what are the two adapter proteins that TLR4 recruits
MyD88 and TRIF
recruitment of adapter proteins by TLRs leads to what?
activation of transcription factors and cytokine production
which adapter protein does TLR3 recruit
TRIF
recruitment of adapter protein TRIF triggers what?
IFN alpha & beta production (which then leads to antiviral state)
recruitment of adapter protein MyD88 triggers what?
increased expression of cytokines, adhesion molecules, and costimulators. (which causes acute inflammation and stimulation of adaptive immunity)
epithelia can be three kinds of barriers:
physical - saliva in oral cavity
chemical - kill microbes by disrupting outer membranes of bacteria and some virus
cellular
general characteristics of a neutrophil
most abundant - 1 x 10^11/day
short lived (6 hrs in blood)
2 kinds of granules: specific & azurophilic
no lysosome
which cells are first to reach site of infection
neutrophils
3 steps in neutrophil activation and function
active recruitment
microbe recognition and phagocytosis
destruction
which cell is second to reach site of infection
monocytes in blood (macrophages in tissues)
general characteristics of monocytes
10x less abundant in blood than neutrophils
long lived
when do macrophages come into the immune response
later stages, 1-2 days after infection
T/F macrophages divide and persist at inflammation site
True
two functions of classical/M1 macrophages
trigger inflammation, kill microbes
T/F dendritic cells do not have phagocytic capabilities
False. They do
what do classical DCs do
link innate and adaptive immune responses.
- capture and display microbial antigens to naive T lymphocytes
- tune T cell response by secreting cytokines
what do plasmacytoid DCs do
produce type 1 interferon (IFN alpha/beta) that possess antiviral activities
what are the two kinds of DCs
classical and plasmacytoid
T/F NKCs express somatically rearranged clonally distributed antigen receptors
False. They do not
are NKCs phagocytes?
nope
do NKCs need activation to kill?
nope
what is the NKC killin function enhanced by
IL-12 and IFN alpha/beta
how is a NKC inactivated
signals from inhibitory receptors block the signals from activating receptors (MHC class I is bound)
how is a NKC activated
lack of inhibitory receptor from MHC class I triggers activation
how does a NKC kill virus-infected cells
perforin and granzymes
what do NKCs produce and what does that do
IFN-gamma. activated macrophages and leads to killing of phagocytosed microbes
where are mast cells found
tissues like skin and lungs near blood vessels
where are basophils and eosinophils found
blood
when activated, what do mast cells, basophils and eosinophils do
release proteolytic enzymes and substances that contribute to inflammation
how many signals does lymphocyte activation require
two
what is signal 1
antigen binding to antigen receptor
what is signal 2 and what is it for
molecules provided by innate cells. for lymphocyte T activation
what is signal 3 also called
differentiation signal
APC
antigen presenting cell
