Immunology

Question 1

Name 5 things in place to protect the eye from infection

Answer 1

Blink reflex
Tears
Mucous layer
Chemicals
Presence of immune cells

Question 2

Blink reflex - immunological function

Answer 2

Pathogen clearing system

Question 3

Tears - immunological function

Answer 3

Allows flushing of the eye

Question 4

Mucous layer - function

Answer 4

Prevents things from sticking to the eye

Question 5

Chemicals - function

Answer 5

Lysozyme

Lactoferrin

Question 6

Immune cells in the eye - name 3

Answer 6

Neutrophil
Macrophage
Conjunctival mast cell

Question 7

What is the principle APC in the eye? and where are most found?

Answer 7

Langerhans cells

Most found at corneo-scleral limbus

Question 8

What is the only part of the eye with lymphatic drainage?

Answer 8

Conjunctiva

Question 9

The cornea is vascular / avascular ?

Answer 9

Avascular

Question 10

What is the function of the blood-ocular barrier?

Answer 10

Prevents the spread of systemic infection into the eye

Question 11

Foreign organisms that come into the eye replicate slowly / quickly?

Answer 11

Quickly

Question 12

Immune privilege - definition

Answer 12

Ability to tolerate the introduction of antigens without eliciting an inflammatory immune response

Question 13

Immune privilege and tissue grafts

Answer 13

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.

Question 14

Anterior chamber associated immune deviation (ACAID)

Answer 14

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

Question 15

Disadvantages of immune privilege

Answer 15

Immune privilege breaks down if there is significant infection or injury

Question 16

Sympathetic opthalmia - definition

Answer 16

Physical trauma to one eye which results in granulomatous uveitis in both eyes

Question 17

Sympathetic opthalmia - cause

Answer 17

Trauma

Surgery

Question 18

Sympathetic opthalmia - clinical features

Answer 18

Injured in one eye (exciting eye) initially but then there is inflammation in both eyes (exciting eye + sympathetic eye)

Question 19

Sympathetic opthalmia - complications

Answer 19

Can lead to bilateral blindness (from a unilateral injury)

Question 20

Keratoconjunctivitis sicca - clinical feature

Answer 20

Dry eyes

Question 21

Hypersensitivity reaction - definition

Answer 21

Immune response that results in bystander damage to self

Question 22

Type 1 hypersensitivity - eg

Answer 22

Allergic reaction

Acute allergic conjunctivitis

Question 23

Type 1 hypersensitivity - mechanism

Answer 23

When body encounters allergen, B cells produce specific IgE
Specific IgE antibodies attach to mast cell receptors
Immediate release of vasoactive mediators (histamine etc)

Question 24

type 2 hypersensitivity - eg

Answer 24

Ocular cicarical pemphigoid

Question 25

Type 2 hypersensitivity - definition

Answer 25

Direct cell killing aka antibody mediated cytotoxicity

Question 26

Type 3 hypersensitivity - definition

Answer 26

Immune complex mediated

Question 27

Type 3 hypersensitivity - eg

Answer 27

Autoimmune corneal melting

Question 28

Type 3 hypersensitivity - mechanism

Answer 28

Combo of antigens and antibodies which form complexes when they join together

Question 29

Type 4 hypersensitivity - definition

Answer 29

Delayed type hypersensitivity (cell mediated)

Question 30

Type 4 hypersensitivity - eg

Answer 30

corneal graft rejection

Question 31

Type 4 hypersensitivity - mechanism

Answer 31

Exaggerated immune response