Immunology

Question 1

what innate barriers are lacking in the eye?

Answer 1

no physical barrier

not many commensal bacteria

Question 2

solutions to lack of physical barrier in the eye

Answer 2

blink reflex
tears
limiting exposure (eyes sit back in the head)

Question 3

adaptive immune system in the eye

Answer 3

Langerhans cells are abundant at the corneo-scleral limbus

Question 4

immunological properties of the conjunctiva

Answer 4

only part with lymphatic drainage
endothelial venules that regulate migration of immune cells
contain MALT (mucosa associated lymphoid tissue)
commensal bacteria

Question 5

immunological properties of the cornea and sclera

Answer 5

downregulated
avascular
Langerhans only in peripheral cornea

Question 6

immunological properties of lacrimal gland and drainage

Answer 6

contain IgA and CD8+ T cells

drainage system has MALT

Question 7

immunological properties of vitreous, choroid and retina

Answer 7

downregulated
blood-ocular barrier
lacks APCs

Question 8

what is immune privilege?

Answer 8

able to tolerate foreign antigens without eliciting an inflammatory immune response

Question 9

how does the eye have immune privilege?

Answer 9

lacks blood and lymphatic drainage

Question 10

function of immune privilege

Answer 10

prevent collateral damage

Question 11

what is anterior chamber associated immune deviation (ACAID)?

Answer 11

foreign antigen in the eye induces a systemic tolerance to that antigen
the eye is ignorant to non-self

Question 12

what is sympathetic ophthalmia?

Answer 12

bilateral granulomatous uveitis

Question 13

causes of sympathetic ophthalmia

Answer 13

trauma
surgery

there is an AI reaction to ocular antigens that were exposed during causative event

Question 14

what is the injured eye called in sympathetic ophthalmia?

Answer 14

exciting eye

Question 15

what is the other eye called in sympathetic ophthalmia?

Answer 15

sympathising eye

Question 16

why is sympathetic ophthalmia bilateral?

Answer 16

T cells return to both eyes as there is lack of specificity

Question 17

what are hypersensitivity reactions?

Answer 17

immune reactions that result in bystander damage to self

Question 18

what happens in a type 1 (immediate) hypersensitivity reaction?

Answer 18

B cells produce IgE in response to antigen
excess IgE left over binds to mast cells via Fc receptor
upon re-encounter the mast cells release IgE and their own vasoactive substances (histamine)

Question 19

what happens in type 2 (direct killing) hypersensitivity reaction?

Answer 19

cells killed by NK or complement (MAC)

Question 20

what happens in type 3 (immune complex mediated) hypersensitivity reaction?

Answer 20

antigen-antibody complex

Question 21

what happens in type 4 (delayed) hypersensitivity reaction?

Answer 21

T cells are activated by intracellular pathogen

when re-exposed there is an exaggerated immune response

Question 22

what is the anterior surface of the lens made up of?

Answer 22

simple cuboidal epithelium

no malignancies reported