Flashcards in Mucosal Immunology Deck (95)
What is the name of the specific immune follicles in the Large intestine?
WHat is the name of the specific area related to immunity in the small intestine?
What is concentrated in muscosal sites?
Specialised lymphoid tissue
Why is the immune system highly vulnerable to infection
Due to the fragility and permeability of the tract. Any food we ingest could be contaminated and require an immune response to remove the antigen
What 5 types of cells are found in the monolayer separating the microbiota from the lamina propria
What is the benefit of the villi and crypts
THey provide a large surface area for antigens to interact
What is the purpose of the Paneth cells
They are defensins
What occurs in the Peyer's Patches?
Antigen sampling and immune activation
What types of cells is the large intestine mostly made up of?
Crypts (not villi), enterocytes and lots of goblet cells and mucus
Which has the higher bacterial load? the small or large intestine
Why do enterocytes have a much more important contribution to antimicrobial peptide production in the large intestine?
There are no Paneth cells in the large intestine
Where do natural killer T cells have a more significant role to play?
In the colon
What are the main secretors of antimicrobial peptides
The Paneth Cells
What 3 types of cells capture, initiate the local immune response and carry out effector functions to clear any infection?
Intestinal epithelial associated - innate immunity, antigen capture and effector function
Peyer's patches and lymphoid follicles - antigen capture and initiation
Lamina propria - effector cells (remove the danger and repair any damage)
How do dendritic cells capture antigens across the epithelium?
They can extend their processes to capture antigens from the lumen of the gut
What are the direct antigen sampling organisms of the gut?
The Peyer's patches
Describe the structure of Peyers patchs
covered by an epithelial layer containing specialised cells (M cells) which have characteristic membrane ruffles
What is situated directly below an M Cell?
Describe the steps of the M cells
Uptake of antigen by endocytosis and phagocytosis
Transporation of antigen across the M cells in vesicles released at the basal surface
Antigen is bound to dendritic cells, activating T cells
What is the major effector molecule in the gut called?
What type of cells enter the Peyer's patches form blood vessels?
What happens to the T cells in the Peyer's patch when an antigen is transported across M cells?
They become activated by dendritic cells
What is the make up of the humoral intstinal response?
As peristalsis occurs, what happens to IgA
It is moving and being produced continuously
How does IgA move accross the membrane from the lamina propria to the lumen?
Endocytosis then transcytosis
What is the function of IgA cells
They bind and neutralise pathogens and toxins to prevent damage to the epithelial cells
What 3 ways can IgA work>
Bind to the antigen in the gut or on the mucus layer
Neutralise antigens in endosomes
Export toxxins and pathogens from the lamina propria whilst being secreted
What molecule takes over this role in patients who are IgA deficient?
How frequently are intraepithelial lymphocytes found?
1 in every 10 epithelial cells