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Preventing infection at mucosa
8.15 at 8am by Dr. Kozlowski
33
Immunology
Professional
08/15/2011

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Cards

Term
Mucosal infections are responsible for how many deaths of children under five annually?
Definition
10 million (4 million preventable by vaccine)
Term
Why are mucosal tissues more vulnerable than skin?
Definition
pathogens can survive longer in moist environments
Term
T/F Hormones can influence the immune response of the female genital tract.
Definition
true
Term
What are immune inductive sites?
Definition
nearby follicles or draining lymph nodes
Term
T/F There are cells specialized for uptake of luminal antigens in all mucosal surfaces.
Definition
True (M cells in intestines and dendritic cells in all)
Term
How does simple columnar epithlium protect against pathogens? how is it vulnerable?
Definition
they have a single impermeable layer of cells with tight junctions. However, it can easily be traumatized allowing pathogens to directly enter the host
Term
How do non-keratinised stratified squamous epithelium protect against pathogens? What are the disadvatages to this strategy?
Definition
mutliple layers reduce vulnerability. However they don't have tight junctions and are more permeable to small pathogens like viruses
Term
Name the two goals of the mucosal immune system.
Definition
Sterile protection and local containment
Term
What are commensals?
Definition
the good bacteria!
Term
Whats the difference between outer and inner mucus layers?
Definition
outer is loosely adherent with degraded mucus and most commensals are here
inner is firmly adherent to mucosal surface and has concentrated IgA and antimicrobials and some commensals
Term
How do natural flora protect us?
Definition
1)compete for attachment sites on epithelial cells 2)competition for nutrients 3) production of growth inhibitors
Term
How does lactobaccilli inhibit growth via production of growth inhibitors in the female reproductive tract?
Definition
lactobaccilli makes lactic acid to lower the pH
Term
List the cells that act as general innate effectors of the mucosal immune system.
Definition
NK cells, macrophages, neutrophils, monocytes, dendritic cells
Term
T/F Epithelial cells are not responsible for producing cytokines.
Definition
FALSE. epithelial cells produce cytokines including chemokines in the mucosal surfaces
Term
The lamina propria is populated by what kind of T cells?
Definition
resting memory cells or recently activated T cells
Term
How do epithelial cells screen for PAMPS? What do they do once they sense them?
Definition
via basolateral TLR and intracellular nucleotide-binding oligomerization domain (NOD) proteins. They then secrete chemokines to attract neutrophils and monocytes from blood
Term
In what tissues can you find M cells? Where in those tissues?
Definition
in the tonsils and intestines, near the dome region of local follicles
Term
T/F The apical surfaces of M cells are covered with mucus.
Definition
FALSE, the apical/luminal surfaces are exposed
Term
How do m cells bind antigens?
Definition
lectin-like binding
Term
Besides M cells, what other cell captures luminal antigens?
Definition
dendritic cells
Term
T/F In the intestines, immune inductive sites are adjascent to immune effector sites.
Definition
true
Term
How do lymphocytes know to go to the mucosal surface associated with the infection?
Definition
DC imprint tissue-specific "signature" on activated naive lymphocytes, which up-regulates homing receptors. After going through circulation, they bind to HEV expressing both their homing receptor adhesion molecules and tissue-specific chemokines. They also migrate towards epithelium where concentrations of tissue-specific chemokine are greatest
Term
Where do activated B and T cells go once they leave the mucosa?
Definition
Peyer's patch or local lymph aggregation>efferent lymphatics>lymph node>circulation>HEV>tissue
Term
What chemokines/receptors are given to activated lymphocytes to help them find the small intestine?
Definition
lymphocytes express alpha4beta7 and CCR9 chemokine receptor.
This binds to MADCAM on HEV and the CCL25 chemokine
Term
Why is mucosa rich in IgA?
Definition
TGF-beta is a molecule that helps suppress the immune system at mucosal surfaces and incidently causes local mucosal plasma cells to switch to making IgA
Term
What is S-IgA?
Definition
Secretory-IgA, consisting of IgA dimer with a secretory component added by the epithelial cells that have transported IgA to their apical surface
Term
Why is mucosal IgA dimeric or tetrameric?
Definition
in order to bind the poly-Ig receptor on the epithelial cell, IgA needs a J chain. J chains are only found on polymeric IgA
Term
How does secretory IgA help prevent infection?
Definition
can bind and neutralize pathogens and toxins either in the lumen or internalized in endosomes of epithelial cells. ALso, IgA can export toxins and pathogens from the lamina propria WHILE being secreted, neutralizing viruses or toxins in the lamina propria
Term
Besides IgA, what other Ig helps neutralize pathogens in the lamina propria?
Definition
serum IgG can transudate into the lamina propria via fenestrated capillaries
Term
What is the incidence of people with IgA deficiency?
Definition
1/500 caucasians
Term
How do people with IgA deficiency compensate?
Definition
they make more defensins and transportable IgM (patients lacking pIgR are worse off because secretory antibodies are very important!)
Term
What types of cells characterize inductive sites? effector sites?
Definition
inductor=naive cells
effector=plasma cells and activated T cells
Term
Which cells/Igs help downregulate inflammatory response in mucosal surfaces?
Definition
phagocytic but noninflammatory macrophages, tolerance inducing DC and T cells, and noninflammatory IgA antibody
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