immunology Flashcards
name a feature of the mucous layer of tears?
anti adhesive
what do lysozymes protect against?
gram –ve bacteria, fungi (destroy bacteria cell wall)
what does lactoferrin and transferrin protect against?
gram +ve bacteria
what do tear lipids protect against?
antibacterial to cell membranes/scavenger of bacterial products
what do angiogenin protect against?
antimicrobial effect within tear film
what does secretory IgA protect against?
attachment
what does the adaptive immune system of the eye require?
Antigen presenting cells (APC = dendritic cells, B cells, macrophages)
Lymphatic drainage to lymph node
Variety of effector cells (incl. CD4+ T cells, CD8+ T cells, B cells)
what are the features of langerhan cells?
Principle APC for external eye
Rich in Class II MHC molecules
Abundant at corneo-scleral limbus, less in peripheral cornea, absent from central 1/3rd of cornea
Very important in corneal trasnplants
what is the only part of the eye to have lymphatic drainage?
the conjunctiva
what are the features of the cornea and sclera?
Avascularity
No lymphatics/lymphoid tissue
Relative lack of APCs
Langerhans cells only in peripheral cornea
Downregulated immune environment
what are the features of the lacrimal gland and its drainage system?
More plasma cells (IgA) and CD8+ T cells compared to conjunctiva
T cells in small groups around intralobar ducts
Resting lymphoid cells very rarely observed
Diffuse lymphoid tissue and follicles (40-50%) in mucosa (MALT)
what eye organs have a down regulated immune environment?
vitreous humour, choroid and retina
which sites in the eye are immune privileged?
Cornea
Anterior Chamber
Lens
Vitreous cavity
Subretinal space
what are the features of ocular immune privilege?
Unique anatomical features of a blood-tissue barrier and a lack of direct lymphatic drainage
Ocular microenvironment is rich in immunosuppressive molecules and inhibitory cell surface molecules that influence the reactivity of immune cells
what is sympathetic ophthalmia?
Rare, bilateral, granulomatous uveitis due to trauma (more common) or surgery (less common) to one eye
