Immunology Flashcards
Name a distinctive anatomical feature of gut mucosal immunity
There is an intimate relationship between mucosal epithelia and lymphoid tissue
Name a distinctive effector mechanism of gut mucosal immunity
T cell mediated immunity is predominant
There is active regulation of immune response
What are Peyer’s patches?
Groupings of lymphoid follicles in the mucous membrane that lines the small intestine
What type of cell are Peyer’s patches covered by?
M cells, which are specialised cells that have characteristic membrane ruffles
What is the function of M cells?
To engulf antigens by endocytosis and phagocytosis
The pathogen is then transported across the M cells and released at the basal surface where it is bound by dendritic cells - T cells then become activated
How are T cells activated in gut mucosal immunity?
Enter the Peyer’s patches via the blood vessels
Become activated by dendritic cells
Which is the most abundant antibody in the intestinal humoral response?
IgA
Which is the most abundant antibody generally?
IgG
What is the role of IgA in mucosal immunity?
Binds to antigens but can also export toxins and pathogens
What are intraepithelial lymphocytes (IELs)?
T cells that reside interspersed between epithelial cells in the epithelium of the small and large intestine
How many types of intraepithelial cells are there?
2 types
Which disease do intraepithelial lymphocytes play an important role in?
Coeliac disease
What is the role of intraepithelial lymphocytes in viral immunity?
They kill virally infected cells by perforin/granzyme or fas-dependent pathways
What type of hypersensitivity reaction are food allergies?
Type 1
