Chapter 1: Elements of the Immune System

Question 1

Define Innate Immunity

Answer 1

Non-Antigen-Specific immune response.

*Phagocytic Cells that engulf and destroy invaders

Question 2

Toll-Like Receptors: Define

Answer 2

Antigen-presenting cells (like phagocytes). Interact w/invader molecules

Question 3

Define: Adaptive Immune Response

Answer 3

Antigen specific. Destroys invaders that were not destroyed by the Innate Immune Response

Question 4

What does the Adaptive Immune Response consist of?

Answer 4

B and T Cells.

Question 5

Macrophages
1. What marker distinguishes them from Granulocytes and Lymphocytes?

2. Name 3 roles Macrophages play w/in the Immune System?
3. What IL’s do macrophages produce?
4. Although not completely understood yet, what do we think chronic activation will do to the RPE?

Answer 5

1. Esterase
2. a. Direct destruction of foreign pathogens
   b. Activating the Immune System
   c. Strong Secretory Cell (release proteases. IL-1 (affects T cell Growth. Direct effect on CNS, w/a by-product being the start of a FEVER)
3. IL-12, 10, and 18. Also TGF-B
4. Thought that it starts the initial changes that LEAD to AGE-RELATED MACULAR DEGENERATION!

Question 6

What are the 2 major WBCs that create cytokines?

2. What is the most important Lymphocyte?

Answer 6

Macrophages and Lymphocytes

2. IL-2

Question 7

T Helper Cells

1. Th1: What cytokine profile do they have?
2. Th2: same as above? (5)

Answer 7

1. IFN-y

2. IL-4,5,13 maybe 10 and maybe TGF-B

Question 8

T Helper

1. Th1 is usually associated with what?
2. Th2: Associated with what?

Answer 8

1. Start of disease

2. related to Disease Downregulation, Allergy initiation, or Parasitic Diseases

Question 9

What is the purpose of Chemokines?

Answer 9

Direct Cell adhesion, homing, and Angiogenesis. They start directional migration of WBCs

*Plays a major role in Ocular Inflammatory disease and maybe other conditions as well.

Question 10

1. What is the basis of a large part of the ocular inflammatory process?

Answer 10

1. T-cell Responses to an Antigen.

Question 11

Studies of inbred mice showed something interesting in regards to uveitis. What was shown in regards to Thymic expression of T-cell receptors?

Answer 11

1. 4 strains were resistant to Uveitis when ARRESTIN was used as the IMMUNIZING Antigen and all 4 expressed arrestin in their thymus.

However, B10.A and B10.RIII were susceptible to uveitis induction when IRBP was used as the immunizing antigen.

Question 12

Where do B cells come from?

Answer 12

1. From the Same PLURIPOTENTIAL STEM CELL in the Bone Marrow as the T CELL comes from.

Question 13

What will the B cell develop into?

Answer 13

a Plasma cell that can secrete Immunoglobulin

Question 14

What is the role of the B Cell?

Answer 14

It’s the EFFECTOR Cell in HUMORAL IMMUNITY

Question 15

B Cells: At first, they express what to things on their surface?

Answer 15

IgM and IgD

Question 16

What are the five major classes of immunoglobulins expressed?

Answer 16

GAMED

Question 17

The Structure of immunoglobulin has a symmetry w/2 heavy and 2 light chains that are UNIFORMLY SEEN in ALL CLASSES EXCEPT…?

Answer 17

IgM and IgA

Question 18

For a PRIMARY RESPONSE, B cells will produce what?

2. IF they encounter these antigens again, what will they switch to?

Answer 18

1. IgM

2. They will switch production to IgG.

Question 19

What is the MAJOR circulating Immunoglobulin in Humans?

Answer 19

IgG (about 75%)

*Crosses BBB and enters eye.

Question 20

IgM: Where is it normally seen?

Answer 20

Pentamer. Linked by Disulfide Bonds and J Chains. Stays w/in Systemic Circulation and WONT cross the BBB or the Placenta!!

Question 21

Initial Antibody Responses to Exogenous Pathogens are from what class?

Answer 21

IgM

Question 22

What’s the major role of both IgG and IgM?

2. They help effector cells thru what process?

Answer 22

They Interact w/Both EFFECTOR CELLS and the COMPLEMENT SYSTEM. They do this to LIMIT Invasion of the Exogenous Organism.

2. OPSONIZATION (Antibody coating on an invading organism)

Question 23

IgA: It’s what kind of Immunoglobulin?

Answer 23

1. Major Extravascular Immunoglobulin (Gut, Respiratory Tract, Tonsils, Salivary and LACRIMAL Glands)

Question 24

IgE: It’s slightly heavier than what chain?

2. What 2 cells have Fc Receptors for IgE?
3. Important Defense Mechanism against what?
4. Important role in what?

Answer 24

1. IgG. Due to heavy chain having an extra Constant Domain
2. Mast Cells and Basophils (reason why they thing it mediates Allergic or Anaphylactoid Reaction)
3. Parasites
4. Ocular surface disease, but not ocular inflammation

Question 25

Mast Cells: Store what? 2. Involved in what?

Answer 25

1. Histamine (Type I hypersensitivity RxN involved) | 2. External Ocular Conditions

Question 26

Where does Eosinophils come from? 2. What do these cells contain?

Answer 26

Bone marrow from a Myeloid Progenitor...separate stem cell from neutrophils. 2. Anti-inflammatory agents (like Histaminase). also, H2O2....cause death of invading organisms.

Question 27

Neutrophils are the most abundant what? 2. What is their role?

Answer 27

WBC 2. Acute Inflammation. Attracted to inflammatory sites by IL-8 and Interferon-y and C5a. * Phagocytosis

Question 28

Complement System: Purpose of proteins in this system?

Answer 28

1. Act as a Substrate for enzymes that precede it in the cascade and then they act as part of a proteolytic complex for the next protein in the cascade.

Question 29

Complement System: Classic Component pathway?

Answer 29

C1q, C1r, and C1s...Form an enzyme that CLEAVES C4 to C4a and C4b. C4b binds to cell membrane, then C2 binds, then it's split by C1s to C3a and C3b. They join next, to make C4b,2a,3b. This new complex cleaves C5 into C5a and C5b. C5b binds to cell membrane, and C6,7, and 8 bind to it. This new complex then leads to C9 polymerization into the membrane

Question 30

Alternate pathway: What does it need?

Answer 30

Does not need Antibody but can be activated directly by BACTERIAL CELL WALLS...so it's NONSPECIFIC.

Question 31

Why has Complement been an area of special focus?

Answer 31

Due to possible role in PATHOGENESIS of AMD. (Complement has been found in DRUSEN of AMD eyes.

Question 32

Type 1 RxN: Mediated by what? 2. What do they bind to? 3. What happens to these cells 4. Example?

Answer 32

1. IgE 2. Mast Cells or Basophils 3. Degranulaiton of these cells occur 4. Ex: Hay Fever: Lg amt of Edema w/o Structural damage

Question 33

Type 2: RxN: Mediated by what?

Answer 33

1. Cytotoxic Antibodies. Mediate Hemolytic Disorders

Question 34

Type 3: AKA? 2. What is it exactly? 3. Believed to be a major contributor to what disease?

Answer 34

1. Immune Complex-Mediated Inflammatory Response. 2. Binding of Antibody to an Antigen then it deposits as a Complex...and can START the COMPLEMENT CASCADE 3. Intraocular Inflammatory Disease like Behcet's Disease

Question 35

Type 4: Mediated by what?

Answer 35

T CELSS...so Cell-mediated immune response, NOT Humoral Response. **Sarcoidosis *Probably really IMPORTANT in Intraocular Inflammatory disease (t-cell dysregulation/ T-cell controlled inflammatory responses)

Question 36

Type 5?

Answer 36

Antibody can be a stimulant to a target cell or organ...like Graves' Disease (LATS Antibody)

Question 37

1. The Eye is considered to be a PRIVILEGED what? | 2. What is missing from the eye?

Answer 37

1. Immune Site. | 2. Lymphatic Drainage.

Question 38

What 4 ways are believed to help the eye protect itself?

Answer 38

1. Blood-Ocular Barrier 2. Soluble or Membrane Bound Inhibitors that block the function of an organism. 3. Kill invaders or cells that could cause unwanted inflammation 4. There may be a way to induce tolerance.

Question 39

It appears that the Eye expresses FasL like the testes and brain do. What do we think this does?

Answer 39

1. Allows for APOPTOTIC Cell death in cells that express Fas, thus is looks to be 1 Method of IMMUNE PRIVILEGE in the EYE.

Question 40

There are many cells in the eye that can communicate with the immune system. What are they?

Answer 40

1. Langerhans' Cells (cornea) and CB (that express Ia) 2. Muller Cells (major effect on T Cells) 3. RPE (similar characteristics to Macrophages) 4. Vascular Endothelium

Question 41

What does corneal endothelial cells do?

Answer 41

Block T-cell proliferation.

Question 42

Why do most fungal lesions tend to begin as Choroiditis?

Answer 42

Due to HIGH BF to the Choroid and its anatomy that can act as sort of a TRAP for MANY BLOODBORNE PATHOGENS!

Question 43

1. The retina is an extension of what? | 2. It has Many Tight Junctions. Why could inflammation be an issue here?

Answer 43

1. of the CNS 2. It can Alter PERMEABILITY which can ALTER Retinal Function. We can see Autotoxicity due to high degree of Oxidative Metabolism in the Retina that could create Oxygen Radicals.

Question 44

Class I Antigens: 1. All Controlled by what 3 Loci in Humans? 2. Are they Homogenous? 3. They can serve as Recognition Antigens for what?

Answer 44

1. A,B,C. 2. No. Heterogeneous. 3. For CD8 (Cytotoxic) T Cells when they attack Virally infected Cells

Question 45

Class II Antigens 1. Produced by what? 2. Class III Antigens: Made w/in what region? Control what?

Answer 45

1. HLA-D/DR Locus | 2. MHC Region and control LEvels of C1,2, and 4.

Question 46

Variants of the CFH Gene have been associated with what disease of the eye?

Answer 46

AMD and Multifocal Choroiditis

Question 47

What can be seen in the Aqueous Humor of pt's with Uveitis?

Answer 47

Immune Complexes