Immunology Flashcards
(42 cards)
In terms of innate immunity what does the eye have?
Very little
No physical barrier and very exposed
Does have some reflex, chemical and immune cell defences.
What physical properties does the eye have?
Tears
Anti-adhesive mucous layer
Blink reflex
What chemical defensive properties does the eye have?
Lysosomes - gram -ve
Lactoferrin - gram +ve
Secretory IgA
What immune cells could be found on the eye?
Neutrophils - follow via chemotaxis release free radicals
Macrophages - phagocytosis help trigger adaptive immunity
Conjunctival mast cells
What is the main APC found on the cornea?
Langerhaans cells
What makes Langerhaan cells effective APC?
Rich in MHC II molecules
Where can langerhaan cells be found in their greatest density?
Coreoscleral limbus
What is special about the conjunctiva?
Only area with lymphatic drainage.
Specialised endothelial vessels for regulation of lymphoid cells.
What immune cells can be found diffusely through the conjunctiva?
CD4+ CD8+ T cells
IgA secreting plasma cells
What lymphatic tissue is found in the conjunctiva?
MALT - Mucosa Associated Lymphoid Tissue
What cells are found physiologically within MALT tissue?
Macrophages
Langerhaans
Mast cells
If for example eosinophils where found within MALT tissue what does this indicate?
They have been recruited by the immune system as a result of an infection/stimulation.
Why does the cornea and the sclera have a down regulated immune environment?
There is no vascular or lymphatic system so immune cells aren’t brought in.
Relative lack of APC’s
Reduced MHC I and no MHC II
What immune cells are found within the lacrimal glands?
IgA secretory plasma cells
CD8+ T cells
Why is the vitreous fluid and the uvea a down regulated immune environment?
Blood ocular barrier
Relative lack of APC
What is immune privilege?
Ability to tolerate the introduction of antigens without the initiation of an inflammatory response.
Where else within the body is immune privilege present?
Testes
Placenta
Brain
CNS
What else occurs within the ocular environment that leads to immune privilege?
Immunosuppressant molecules are produced
Inhibitory cell surface molecules released.
What does ACAID stand for?
Anterior Chamber Associated Immune Deviation
What is ACAID?
Active process by which the introduction of a foreign antigen into the ocular environment induces a systemic tolerance to the antigen?
What is the main aim of ACAID?
Protects the eye from a inflammatory response either systemically or locally.
What is sympathetic ophthalmia?
Rare bilateral granulomatous uveitis due to trauma or surgery to one eye.
What is the pathology behind sympathetic ophthalmia?
An autoimmune reaction due to antigens released during trauma.
Following the trauma what happens in sympathetic ophthalmia?
Antigens released are taken via the lymphatic system to the lymph nodes.
T- Cells are activated and travel to the eye within the blood.
First wave to travel is CD4+
Second wave is infiltrative CD8+ T cells
