Flashcards in Immunology Deck (31):
Name 5 things in place to protect the eye from infection
Presence of immune cells
Blink reflex - immunological function
Pathogen clearing system
Tears - immunological function
Allows flushing of the eye
Mucous layer - function
Prevents things from sticking to the eye
Chemicals - function
Immune cells in the eye - name 3
Conjunctival mast cell
What is the principle APC in the eye? and where are most found?
Most found at corneo-scleral limbus
What is the only part of the eye with lymphatic drainage?
The cornea is vascular / avascular ?
What is the function of the blood-ocular barrier?
Prevents the spread of systemic infection into the eye
Foreign organisms that come into the eye replicate slowly / quickly?
Immune privilege - definition
Ability to tolerate the introduction of antigens without eliciting an inflammatory immune response
Immune privilege and tissue grafts
Tissue grafts are normally attacked by the immune system as they are recognised by the body as foreign.
Tissue grades can survive for extended periods without transplant rejection in immune privilege sites.
Anterior chamber associated immune deviation (ACAID)
Placing foreign antigen into the ocular microenvironment.
Aims to down-regulate the immune response within the eye
Protects the eye from damage of an immune response
Disadvantages of immune privilege
Immune privilege breaks down if there is significant infection or injury
Sympathetic opthalmia - definition
Physical trauma to one eye which results in granulomatous uveitis in both eyes
Sympathetic opthalmia - cause
Sympathetic opthalmia - clinical features
Injured in one eye (exciting eye) initially but then there is inflammation in both eyes (exciting eye + sympathetic eye)
Sympathetic opthalmia - complications
Can lead to bilateral blindness (from a unilateral injury)
Keratoconjunctivitis sicca - clinical feature
Hypersensitivity reaction - definition
Immune response that results in bystander damage to self
Type 1 hypersensitivity - eg
Acute allergic conjunctivitis
Type 1 hypersensitivity - mechanism
When body encounters allergen, B cells produce specific IgE
Specific IgE antibodies attach to mast cell receptors
Immediate release of vasoactive mediators (histamine etc)
type 2 hypersensitivity - eg
Ocular cicarical pemphigoid
Type 2 hypersensitivity - definition
Direct cell killing aka antibody mediated cytotoxicity
Type 3 hypersensitivity - definition
Immune complex mediated
Type 3 hypersensitivity - eg
Autoimmune corneal melting
Type 3 hypersensitivity - mechanism
Combo of antigens and antibodies which form complexes when they join together
Type 4 hypersensitivity - definition
Delayed type hypersensitivity (cell mediated)
Type 4 hypersensitivity - eg
corneal graft rejection