Mucosal Immunity

Question 1

cells found in the epithelium of mucosal tissue

Answer 1

intraepithelial lymphocytes(IEL)

• gamma/delta T cells
• CD8 memory T cells
• CD8 alpha:alpha T cells
• DCs

Question 2

cells found in the lamina propria

Answer 2

gamma/delta cells
CD8
CD4
-Th1
-Th17
-T reg cells 
plasma cells and memory B cells
Macs
DC
M cells

Question 3

what is Mucosal-associated lymphoid tissues

Answer 3

specialized per mucosal tissue
Lymph node-like organization
eg. tonsils

Question 4

do mucosal infections follow traditional inflammatory cascade?

Answer 4

Nope due to the gamma/delta cells in the epithelium

Question 5

what forms the Waldeyer’s ring?

Answer 5

the adenoids and the tonsils of the mouth

these are MALTs

Question 6

Mucosal immunity often employs limited inflammation, why?

Answer 6

• strong proactive immunity(IgA), limited reactive immunity
• most infections often cleared w/out inflam response
• local innate and adaptive cells respond
• inflammation occurs if infxn is severe, persistant, and/or tissue damage.
• this is rare, thus PMNs in mucosal tissue is rare

Question 7

how to bacteria gain access to the lamina propria of mucosal tissues?

Answer 7

endocytosis of the epithelial cells

this allows local activation of Macs w/out PMNs

Question 8

what are some distinctive features of mucosal immune system

Answer 8

• anatomical features: M cells, MALTs
• effector mechanisms: IgAs, microbiota
• Immunoregulatory environment: down reg immune response, inhibitory macs and tolerance inducing DCs

Question 9

what type of cells often resolve infection of mucosal surfaces?

Answer 9

local adaptive via a preemptive immune response down stream of MALT

Question 10

what is the most common identified bacterial species

Answer 10

firmicutes

Question 11

T/F the oral microbiome is diverse and changes with disease

Answer 11

True

Question 12

what is richness?

Answer 12

the number of species present

Question 13

what is diversity?

Answer 13

what are the roles of the present genera and how many different genera

Question 14

where is the microbiome shaped?

Answer 14

at mucosal surfaces

Question 15

what happens at the mucosal layer to aid in microbiome shaping

Answer 15

IgA
antimicrobial peptides
immune browsing
thus it shapes the mucosal immune system

Question 16

what affects local cytokines and CD4 T cell differentiation at mucosal surfaces?

Answer 16

the micro-biome

Question 17

what cytokine is very important in CD4 differentiation at mucosal surfaces?

Answer 17

TGF-beta

Question 18

TGF-beta + no inflammatory cytokines leads to what CD4 T cell?

Answer 18

T regulatory cells

Question 19

TGF-beta+ inflammatory cytokines leads to what CD4 T cell?

Answer 19

Th 17 cells

Question 20

what do T reg cells do?

Answer 20

inhibit mucosal inflammation

Question 21

what do Th17 cells do?

Answer 21

• neutrophil recruitment
• antimicrobial peptide production by epithelial cells
• tissue repair

Question 22

what cytokines are released by Th17?

Answer 22

IL-17 and IL-22

Question 23

why are Th17 important in the oral epithelium?

Answer 23

protect barriers and induce inflammatory when needed

Question 24

what antimicrobial peptides are released into the oral cavity?

Answer 24

B-defensins
cathelicidins
lactoferrin

Question 25

what is chronic mucocutaneous candidiasis?

Answer 25

fungal infection of skin, nails, and mucous membranes - **deficient IL-17 signaling - too much fungi

Question 26

what causes chronic mucocutaneous candidiasis?

Answer 26

deficient IL-17 receptors impaired TH 17 differentiation impaired TH 17 development

Question 27

Periodontitis

Answer 27

``` caused by increased IL-17 production chronic PMNs chronic inflamm cytokine production osteoclast activation -TOO much bacteria ```

Question 28

what role do Igs at mucosal surfaces?

Answer 28

``` pathogen neutralization toxin removal antigen browsing shapes micro-biome *mostly IgA ```

Question 29

how does the mucosal surface browse for antigens

Answer 29

``` antigen capture by Macs goblet cells uptake antigen and expose to DCs DCs can be in the epithelium M cells IgA brings it across via FcRn dead cell allows antigen to cross ```

Question 30

how are mucosal epithelial cells active immune component?

Answer 30

``` express TLR and NOD receptors form inflammasomes -phagocytose bacteria -express cytokines and antimicrobial peptides *induces local immune response ```

Question 31

how can the mucosa become inflamed?

Answer 31

epithelial damage due to bacteria over growth resulting in an inflammatory response with PMNs

Question 32

Established pathogens illicit inflammatory response how?

Answer 32

pathogen evades mucosal immunity - local Macs and DCs are activated and PMNs are recruited - TH 17 and TH1 response - this is more of a secondary response