Immunology Flashcards
What is the difference between the innate immune systme of the eye and the rest of the body in terms of physical barrier and commensals?
the eye doesnt have any skin- tranparent and exposed, doesnt have many commensals
How does the eye combat its lack of innate immune system?
blink reflex; physical and chemical proerties of eye surface; limit exposure and size
What are the layers of the tear film?
lipid; aqueous and mucin
What is the physical function of tears?
flushing and muscous layer is anti-adhesive
What are the chemical proerties of tears?
lysozymes; lactoferrin and transferrin; tear lipids; angiogenin; secretory IgA; complememtn; leukotriens
What is the difference between lysozyme and lactoferrin/transferrin?
lysoszyme works again gram -ve bacteria and fungi whereas lactoferrin/tranferring work against gram +ve bacteria
What cells are foudn in tears?
neutrophils; macrophages; conjunctival mast cells
What does the adaptive immune system require?
antigen presenting cells; lympathic drainage and a variety of effector cells
What is the principal APC for the external eye?
langerhan cells
where are langerhan cells found?
limbus, less in peripheral cornea and absent from central 1/3rd of cornea
What is the only part of the eye with lymphatic drainage?
eye
What type of immune tissue is found in the cnojuctiva?
mucosa associated lymphoid tissue
What type of immune environment is the cornea and sclera?
downregulated
What type of cells does the lacrimal gland have more than than the conjuctiva?
plasma cells (IgA) and CD8+
What is the lymphatic drainage for the lacrimal gland?
MALT
What is immune privilage?
the ability to tolerate the introduction of antigens without eliciting an inflammatory response
What creates ocular immune privilege?
blood-tissue barrier and lack of direct lympathic drainage; rich in immunosuppressive molecules; anterior chamber-assocaited immune deviation
What are the immunological hallmarks of anterior chamber associated immune deviation?
generation of primed CD8+ T and B cells that produce non-complement-fixing antibodies; inhibition of delayed type HS and B cells that secrete complement-fixing antibodies (inhibition of a cell-mediated immune response)
what is the purpose of ACAID?
protects the eye and visual axis from the collateral damage of an immune response to infection by suppressing a potenetially damaing response
What are the 3 aspects of ocular immune privilege?
separation-immunological ignorance; inhibition- intraocular immunosuppressive microenvironment and regulation- peripheral tolerance (ACAID_)
What is sympathetic ophthalmia?
bilateral granulomatous uveitis due to trauma or surgery to one eye
What causes sympathetic ophthalmia?
secondary to development of autoimmune reaction to ocular antigens exposed at point of trauma or surgery
What is the injured eye in sympathetic ophthalmia known as?
exciting eye
what is the other eye in sympathetic ophthalmia known as?
sympathising
What are the primary mediator of sympathetic ophthalmia?
T cells - initially CD4+ and then CD8+
What is a Dalen-Fuchs nodule?
epithelial cell clusters in retinal layers
What is keratoconjuctivitis sicca?
dry eyes
What is chemosis?
oedema of the conjuctiva?
What are the signs of acute allergic conjuctivitis?
itchy, watery, puffy eyelids and chemosis
What happens during ocular cicatricial pemphigoid?
clistering and scarring of conjuctiva- AI conjuctivitis
What type of molecules are reduced in the corneal cells?
MHC class 1 and 2
What precents antigenic information escaping from the cornea and migration of APC?
lack of blood and lymph vessels from corneA
What are SE of steroids in the eye?
glaucoma and cataracts