Immunology Flashcards
(39 cards)
Describe the physiological function of mucosal tissues
- gas exchange
- food absorption
- sensory activities
- reproduction
Name the mucosal tissues of the human body
- lachrymal gland
- salivary gland
- gastro-intestinal gland
- kidney
- mammary gland
- uterus
- bladder
- vagina
- oral cavity
- sinus
- conjunctive
- oesophagus
- stomach
- intestine
- trachea
- lungs
Name the sections of a lymph node
- cortical sinus
- secondary lymphoid follicle (with germinal centre)
- afferent lymphatic vessel
- paracortical area (mostly T cells)
- germinal centre
- marginal sinus
- senescent germinal centre
- efferent lymphatic vessel
- artery
- vein
- medullary sinus
- medullary cords (macrophages and plasma cells)
- primary lymphoid follicle (mostly B cells)
Describe the distinctive anatomical features of gut mucosal immune system
- intimate relationship between mucosal epithelia and lymphoid tissue
- organised lymphoid structures unique to mucosal sites
- specialised antigen uptake mechanisms
Describe the distinctive effector mechanism of gut mucosal immune system
- activated / memory T cells predominate
- natural effector / regulatory T cells
Describe the distinctive immunoregulatory environment of gut mucosal immune system
- active down regulation of immune response
- inhibitory macrophages and tolerising dendritic cells
Where are intestinal lymphocytes found?
In organised tissues where immune responses are induced and scattered throughout the intestine, where they carry out effector functions
- scattered lymphoid tissues
- organised lymphoid tissues
Describe peyers patches
- covered by an epithelial layer containing specialised cells called M cells
- M cells have characteristic membrane ruffles
- antigen catchers and reaction vesicle
How do M cells take up antigens?
- endocytosis
- phagocytosis
How can dendritic cells capture antigens from the lumen of the gut?
They can extend processes across the epithelial layer
The mucosal immune system consists of which two distinct compartments?
- epithelium
- lamina propria
T cells enter peyers patches from blood vessels, directed by what?
Homing receptors
- CCR7 and L-selectin
What binds MAdCAM-1 on endothelium?
Gut homing effector T cells
Gut epithelial cells express what specific for gut homing T cells?
Chemokines
Where is MAdCAM also found?
In the vasculature of other mucosal sites
Secreted IgA on the gut surface can do what to pathogens and toxins?
Can bind and neutralise
What can export toxins and pathogens from the lamina propria while being secreted?
IgA
What is able to bind and neutralise antigens internalised in endosomes?
IgA
Describe intraepithelial lymphocytes
- special T cells in the gut
- activated appearance containing full killing machinery
- restricted antigen receptor repertoire
- expression of alpha e ; beta 7 integrin anchors them in the epithelium
- 2 types with different recognition mechanisms
- immunopathology coeliac disease
Where do intraepithelial lymphocytes lie?
Within the epithelial lining of the gut
The intraepithelial lymphocytes are what type of cell?
CD8- positive T cells
Activated IEL kills infected epithelial cells by what?
Perforin / granzyme and Fas-dependent pathways
Epithelial cells undergo stress as a result of what?
Infection, damage or toxic peptides and express MIC-A and MIC-B
What binds to MIC-A,B to activate IEL?
NKG2D
