cells found in the epithelium of mucosal tissue
intraepithelial lymphocytes(IEL)
- gamma/delta T cells
- CD8 memory T cells
- CD8 alpha:alpha T cells
- DCs
cells found in the lamina propria
gamma/delta cells CD8 CD4 -Th1 -Th17 -T reg cells plasma cells and memory B cells Macs DC M cells
what is Mucosal-associated lymphoid tissues
specialized per mucosal tissue
Lymph node-like organization
eg. tonsils
do mucosal infections follow traditional inflammatory cascade?
Nope due to the gamma/delta cells in the epithelium
what forms the Waldeyer’s ring?
the adenoids and the tonsils of the mouth
these are MALTs
Mucosal immunity often employs limited inflammation, why?
- 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
how to bacteria gain access to the lamina propria of mucosal tissues?
endocytosis of the epithelial cells
this allows local activation of Macs w/out PMNs
what are some distinctive features of mucosal immune system
- anatomical features: M cells, MALTs
- effector mechanisms: IgAs, microbiota
- Immunoregulatory environment: down reg immune response, inhibitory macs and tolerance inducing DCs
what type of cells often resolve infection of mucosal surfaces?
local adaptive via a preemptive immune response down stream of MALT
what is the most common identified bacterial species
firmicutes
T/F the oral microbiome is diverse and changes with disease
True
what is richness?
the number of species present
what is diversity?
what are the roles of the present genera and how many different genera
where is the microbiome shaped?
at mucosal surfaces
what happens at the mucosal layer to aid in microbiome shaping
IgA
antimicrobial peptides
immune browsing
thus it shapes the mucosal immune system
what affects local cytokines and CD4 T cell differentiation at mucosal surfaces?
the micro-biome
what cytokine is very important in CD4 differentiation at mucosal surfaces?
TGF-beta
TGF-beta + no inflammatory cytokines leads to what CD4 T cell?
T regulatory cells
TGF-beta+ inflammatory cytokines leads to what CD4 T cell?
Th 17 cells
what do T reg cells do?
inhibit mucosal inflammation
what do Th17 cells do?
- neutrophil recruitment
- antimicrobial peptide production by epithelial cells
- tissue repair
what cytokines are released by Th17?
IL-17 and IL-22
why are Th17 important in the oral epithelium?
protect barriers and induce inflammatory when needed
what antimicrobial peptides are released into the oral cavity?
B-defensins
cathelicidins
lactoferrin
what is chronic mucocutaneous candidiasis?
fungal infection of skin, nails, and mucous membranes
- **deficient IL-17 signaling
- too much fungi
what causes chronic mucocutaneous candidiasis?
deficient IL-17 receptors
impaired TH 17 differentiation
impaired TH 17 development
Periodontitis
caused by increased IL-17 production chronic PMNs chronic inflamm cytokine production osteoclast activation -TOO much bacteria
what role do Igs at mucosal surfaces?
pathogen neutralization toxin removal antigen browsing shapes micro-biome *mostly IgA
how does the mucosal surface browse for antigens
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
how are mucosal epithelial cells active immune component?
express TLR and NOD receptors form inflammasomes -phagocytose bacteria -express cytokines and antimicrobial peptides *induces local immune response
how can the mucosa become inflamed?
epithelial damage due to bacteria over growth resulting in an inflammatory response with PMNs
Established pathogens illicit inflammatory response how?
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
