Chapter 16 - Part 2 Flashcards
what do intracellular and viral infections the host response causes what?
tissue injury
what happens first in a primary viral infection?
virus infects epithelial cells and replicates amongst them
what is the effect of intracellular viral infection?
epithelial cells make Type I Interferons (IFN-alpha) which involves an autocrine feedback loop
what does IFN-alpha do?
inhibits viral gene replication and upregulates MHC class I molecules
what transports Ag to local LNs via lymphatics?
professional APCs ie Langerhans in the skin
what is the 1st cytokine to respond to infection? whats next?
TNF, then IL-1, then IL-6
what is the cause of swollen and painful LNs?
when lymphocytes become trapped in the local inflamed node
what do Th1 cells secrete to activate virus-specific CTLs?
IFN-Gamma, IL-2
As Th and CTLs leave the LN and ultimately enter the blood, what are their key attributes
virus-specific TCR
up-regulated adhesion molecules
up-regulated cytokine production
Where may NK cells be recruited at during virus infection?
early, innate anti-viral role when activated by epithelium cytokines (IFN-alpha)
later when activated by Th1 cells specific for the virus
what is innate immunity mediated by and what cytokines are involved?
phagocytes and NK cells
IL-12 and IFN-Gamma
what is adaptive immunity mediated by and what eliminates microbes?
cell-mediated
T cells activate phagocytes to eliminate
what kind of pathogens in the endogenous pathway?
how are they degraded?
intracellular pathogens (viruses) loaded onto MHC class I and complex activates CTLs
by proteosomes, shuttling done by TAP proteins into ER
what kind of pathogens in exogenous pathway?
how are they destroyed?
extracellular pathogens are engulfed by phagosomes via MHC Class II, activate helper T cells to make Abs
activated DCs and macrophages produce what?
what do they activate?
IL-12 and IL-15
activate NK cells (provide earl defense against microbes)
What TLR does M. tuberculosis use?
how does M. tuberculosis survive?
TLR2
in phagosomes by preventing acid-containing lysosomes from fusing with phagosomes
how is M. tuberculosis killed?
by macrophages destroying microbes in phagosomes and then by cross presentation of cytosolic Ags to kill the infected cells (CTLs)
what intracellular bacteria evades immune response by inhibition of phagolysosome formation?
M. tuberculosis, Legionella pneumophila
what intracellular bacteria evades immune response by inactivation of ROS and nitrogen species?
Myobacterium leprae (phenolic glycolipid)
what intracellular bacteria evades immune response by disruption of phagosome membrane, escape into cytoplasm?
Listeria monocytogenes (hemolysin protein)
what is the outcome in patients with Myobacterium leprae with a Th1 response?
Tuberculoid leprosy
what is the outcome in patients with Myobacterium leprae with a defective Th1 or dominant Th2 response?
Lepromatous leprosy (high bacterial count)
how are intracellular pathogens eliminated?
cell-mediated immunity mechanisms
what kind of response is required for clearance of a fungal infection?
Th1
Dectin-1 plays an important role in what?
where is it expressed? what kind of receptor does it have?
antifungal innate immunity
macrophages, receptor for Beta-glucans
what does the binding of Dectin-1 and Beta-glucan mediate?
ROS and activation of NF-KB, secretion of proinflammatory cytokines
Dectin combined with what TLRs combine to enhance responses triggered by fungi?
TLR2 and TLR6
what are the principal mechanisms of protective immunity against protozoa?
Abs, phagocytosis, macrophages
what are the principal mechanisms of protective immunity against metazoa?
scistosoma - killing by eosinophils, macrophages
filaria - cell-mediated immunity
what parasites use antigenic variation as immune evasion?
trypanosomes, plasmodium
what parasites use acquired resistance to complement and CTL as immune evasion?
Schistosomes
The parasite Filaria and trypanosomes use what mechanism for immune evasion?
inhibition of host immune responses
The parasite Entamoeba uses what mechanism for immune evasion?
Ag shedding
What immune components are important for extracellular bacteria protection?
Ab, complement, neutrophils, Th2 cells, NK cells (ctyokines)
What immune components are important for intracellular bacteria protection?
Th1 cells, Macrophages
NK (cytokines)
What immune components are important for virus protection?
Ab, Th2, Th1, CTLs
NK (lysis)
What immune components are important for fungi protection?
Th1, Macrophages
What immune components are important for parasite protection?
Ab, Th1, Macrophages
what was the earliest type of vaccine? latest?
live attenuated (ie. MMR)
polyvalent (ie Strep)
what kind of vaccine does the flu and pneumoniae use?
conjugate
what type of vaccine is used for inactivated polio?
killed or inactivated vaccine
what kind of vaccine used for Hep B?
Diptheria and tetanus?
Recombinant
Subunit
