Mucosal immunology Flashcards
What stem cell do B and T cells derive from
lymphoid stem cell
What precursor are dendritic cells and macrophages derived from
myeloid progenitor
What type of interactions is the GIT a site for
host-environment interactions
What are the functions of the GI epithelial barrier
physical barrier
selectively permeable
secretory function
What mediators are secreted from the GI epithelial barrier
cytokines
antimicrobial peptides
MUC proteins
What controls which substances enter the epithelial barrier
cell junctions
What structures do stem cells differentiate in the GI epithelial barrier
crypts
How do crypts Renew
stem cells at the base
proliferate/differentiate whilst moving up
cells shed at the tip of villi
How are crypts regulated
signalling molecules
Which layer of the GIT exerts tolerance
lamina propria
How is tolerance maintained in the GI mucosa
develop self-tolerance
exogenous tolerance
effective immune response
what is exogenous tolerance
non-responsiveness to a variety of environmental antigens (food and microbes)
what are the components of the epithelial barrier that ‘crosstalk’
microbiota
epithelial cells
immune cells
what does the GI microbiota consist of
mucus with commensal bacteria
How do microbes impact on intestinal epithelial cells
respond to microbes
express recognition receptors
stimulate cytokines which alter barrier permeability
How is energy provided for the microbes in the barrier
intestinal epithelial cells produce mucins which are short chain fatty acids for microbes to break down
How do immune cells impact on the intestinal epithelial cells/microbiota
promote barrier repair via cytokines
promote mucin production
impact on permeability
What is the function of Peyer’s patches
allow efficient sampling of particulate antigens
What are M cells
specialised and organised parts of the immune system in the gut
How are antigens transported across the M cell
vesicles
how are antigens in vesicles released from the M cell
released at the basal lamina
What other methods can dendrite cells use to capture antigens
‘arms’ can extend across the epithelial layer
antigens captured from lumen of the gut
What 3 signals determine T cell responses
MHC/peptide-TCR
CD80-CD28
Cytokines
How does a T cell travel to the gut after being activated
through the blood
How do activated T cells enter the gut
bind to MADCAM-1 on endothelium
gut endothelial cells express chemokines for direction
Which immune cells balance gut homeostasis
T helper cells
T regulatory cells
How are intraepithelial lymphocytes bound to the epithelium
expression of aeb7
