Immunology Flashcards
What are the two generic types of immunity?
innate and adaptive
What are the main defenses the eye has against pathogens?
blink reflex
physical and chemical properties of eye surface
limited exposure/size
What are the layers of the tear film from outermost to innermost?
lipid layer- produced by eyelid (prevents evaporation)
aqueous layer- produced by lacrimal glands
mucous layer- produced by conjunctiva (asheres them to eye)
what are the main chemical properties of tears?
Lysosome: kills many bacteria (gram -ve) and fungi
Lactoferrin and transferrin (kills gram +ve bacteria)
Tear Lipids (antibacterial to cell membranes)
Angiogenin: antimicrobial effect within tear film
Secretory IgA: prevents bacterial attatchment
Complement
IL-6, IL-8, MIP: recruit leucocytes
What are the main innate immune cells in the eye?
neutrophils
macrophages
conjunctival mast cells
What are the main APCs involved in adaptive immunity in the eye?
dentritic cells
B cells
macrophages
what are the main effector cells involved in adaptive immunity of the eye?
CD4+ T cells
CD8+ T cells
B cells
what is the name of the principle APC of the external eye?
Langerhans cells:
what MHC class are Langerhans cells rich in?
II
where is there an abundance of Langerhans cells?
the corneo-scleral limbus
which part of the eye has lymphatic drainage?
the conjunctiva
what is the main APC for the conjunctiva?
dendritic cells
what does MALT stand for?
mucosa associated lymphoid tissue
which part of the eye is the ‘tough collagen coat’?
the cornea and sclera
what is the vascular supply to the sclera?
avascular
where do T cells gather in the lacrimal glands?
around intralobar ducts
where is there the greatest potential for major damage in the eye?
the vitreous, choroid and retina
what is immune privellage?
a site that can tolerate the introduction of a foreign pathogen without creating an immune response
what is ACAID?
anterior chamber associate immune deviation
what are the immunological hallmarks of ACAID?
primed CD4+ T and B cells producing non-complement-fixinf antibodies
Inhibition of delayed-type hypersensitivity
Is ACAID an active process?
yes
what are the three main factors why ocular immune privelege was established?
separation (immunological ignorance)
inhibition
regulation (ACAID)
what is symathetic ophthalmia?
a devistating eye infection most commonly caused by a penetrating traumatic injury
T cell response to the injury causes bilateral granulomatous uveitis that can lead to blindness
in sympathetic ophthalmia- what is the names given to the injured and non-injured eye?
exciting eye
sympathizing eye
why is there bilateral granulomatous uveitis in sympathetic ophthalmia?
when the antigen signal from the exciting eye reaches the lymph node, the T cells produced in response cannot differentate one eye from the other so attack both.
what are some ocular autoimmune diseases?
autoimmune uveroretinitis
Dalen-Fuchs nodule (epithelial cell clusters in retinal layers)
Keratoconjunctivitis sicca (dry eyes)
Lens-induced uveitis (when degrading lens proteins leak into capsule of the eye)
retina autoantibodies (retinopathy associated with cancer/infection/degeneratve disease)
sympathetic opthalmia
what is an example of a type 1 hypersensitivity reaction in the eye?
acute allergic conjunctivitis
what is chemosis?
oedema and swelling of the conjunctiva (has a thickened jelly-like apperance)
what is an example of a type 2 hypersensitivity reaction in the eye?
ocular cicatrical pemphigoid
blistering lesions of the eyelids ana eye surface- scarring difficult symptoms
how would you treat ocular cicatricial pemphigoid?
steroids
what in an ocular example of a type 3 hypersensitivity reaction?
autoimmune corneal meting
what is an ocular example of a type 4 hypersensitivity reaction?
corneal graft rejection
