Infection and Immunity Flashcards
What immunological substance is transported by the Epithelial monolayer cells?
Where are paneth cells located and what do they release?
Gut immunity
We are exposed to thousands of antigens on a daily basis. There are two “immunological” defences of the GI tract, closely related to the prominent lymphatic supply/draining of the gut:
Name them
MALT and GALT
Name an area rich in MALT?
What is the two forms of GALT?
Organised and Not Organised
What does organised and non organised GALT consist of?
What is the function of GALT?
o Function: generated lymphoid cells + antibodies: IgA, IgG, IgM + induced cell mediated immunity
Name 3 examples of intra-epithelial lymphocytes
What is the function of M cells?
M (Microfold) cells do not secrete mucus or digestive enzymes, and have a thinner glycocalyx, which allows them to have easy access to the intestinal lumen for endocytosis of antigens.
The main function of M cells is the selective endocytosis of antigens, and transporting them to intraepithelial macrophages and lymphocytes, which then migrate to lymph nodes where an immune response can be initiated.
Sample antigens from the gut and transfer partiulate antigens across the epithelial layer to allow dendritic cells to then present it to help activate T and B lymphocytes
What are transepithelial dendritic cells?
The dendritic cells have long dendrites which sample antigens from the gut.
They travel from mesenteric lymph nodes
Where are peyers pathches mostly located?
What does the payers patch contain on organised collection of?
What are they covered by?
Peyer’s Patches
- Small intestine – mainly distal ileum
- Development requires exposure to bacterial microbiota
- 50 in last trimester foetus
- 250 by teens
- Organised collection of naïve T and B-cells (contain HEV)
- Covered by follicle associated epithelium (FAE)
- No goblet cells
- No secretory IgA
- Lack microvilli
- Infiltrated by T-cells, B-cells, macrophages, dendritic cells
- Antigen uptake via M (microfold) cells within FAE
- Similar isolated lymphoid follicles elsewhere in GI tract (30,000 in total)
B-Cell Adaptive Response
•B-cells
–Mature naïve B-cells expressing Ig… in PPs
–Upon activation class switch to Ig…
–Influenced by presence of T-cells and epithelium via cytokines
- Further maturation to become IgA secrete ……………… cells
- Populate ……………… ………………..
- Up to 90% of gut B cells are IgA+
B-Cell Adaptive Response
•B-cells
–Mature naïve B-cells expressing IgM in PPs
–Upon activation class switch to IgA
–Influenced by presence of T-cells and epithelium via cytokines
- Further maturation to become IgA secreting plasma cells
- Populate lamina propria
- Up to 90% of gut B cells are IgA+
What does IgA do?
the purpose of lymphocyte homing and circulation
Gut-specific homing is the mechanism by which activated T cells and antibody-secreting cells (ASCs) are targeted to both inflamed and non-inflamed regions of the gut in order to provide an effective immune response.
The most convincing argument is that by targeting the lymphocytes to the region in which they were activated it is more likely that they will come into contact with their cognate antigen. They are targeted to the region where the pathogen’s antigen is most likely to be found within the periphery.
identify the symptoms, mechanisms, diagnosis and treatment/management associated with cholera infection
What age group does rotavirus usually effect?
Where does it replicate?
What is its treatment?
How is norovirus diagnosed?
What is its symptoms?
PCR
acute gastroenteritis, recovery 1-3 days
What bacteria is associated with the illness due to antibiotics killing commensal bacteria?
Clostridum difficile
List the forms ( if applicable), the cause, the treatment for the following diseases?
Coeliac disease
Irritable Bowel Syndrome
Inflammatory Bowel Disease
List the differences between Ulcerative collitis and Crohn’s disease
