Lecture 23 Flashcards
How do mucosal immune responses differ from sytemic immune responses?
Mucosal immune responses are set up to be proactive and avoid inflammation, systemic responses promote inflammation
What is mucus made out of?
mixture of glycoproteins, proteoglycans, peptides and enzymes
What are the two layers of mucus for?
outer layer: loose, sweep away bacteria
second layer: a barrier so bacteria cannot get in
how often does the intestinal lining renew?
every 3-4 days
What does a gnotobiotic animal have?
- several anatomical changes
- reduced size of lymphoid organs
- low serum
- fewer mature T cells
- impaired immune responses, (especially Th1, Th17)
- underdeveloped Peyer’s patches
How does the adaptive immune system control the gut microbiota?
The healthy gut tissue is populated with effector B cells and T cells that are
poised to respond to any invader from the gut lumen. This happens in the
absence of infection.
Where do the peyers patches in the intestine drain into?
small: mesenteric lymph nodes
large: superior mesenteric and colic lymph nodes
How do the secondary lymphoid tissues of the gut continuously sample the
contents of the gut?
bacteria go into peyer’s patch via M cell (can also be a weak point for viruses to get into)
How can a dendritic cell sample gut bacteria without an M cell?
send up trans-epithelial dendrites that
extend between epithelial cells and reach the lumen to sample bacteria.
What are the 6 methods of antigen capture?
- Transcytosis through M cells.
- Transport of antibody-coated
particles by Fc receptor-mediated
binding. - Through gaps when cells die by
apoptosis or from apoptotic bodies. - Capture through dendrite extensions.
- Uptake through goblet cells.
- Dendritic cells squeezing between
epithelial cells to directly sample the
lumen.
