Immuno 4

Question 1

all antibodies are of a class of protein called

Answer 1

immunoglobulin

Question 2

structure of an immunoglobulin

Answer 2

4 polypeptide chains bound together by disulfide bonds

2 light chains, 2 heavy chains

Question 3

what are the 2 regions of the immunoglobulin

Answer 3

variable and constant region

Question 4

variable region of an immunoglobulin

Answer 4

(also called FAB- fragment antigen binding)
-the end of the immunoglobulin and the one that forms the structure that will bind to a specific antigen (fingers), variations

Question 5

constant region of an immunoglobulin

Answer 5

• backbone that doesn’t have as many variable combinations (only varies from one class to another)
• (also called fragment Fc region)

Question 6

5 immunoglobulins and percentages

Answer 6

1. IgG - 80%
2. IgA - 15%
3. IgM - 5%
4. IgD - 0.2%
5. IgE - 0.002%

Question 7

where is IgG usually found

Answer 7

epithelial tissue such as skin and conjunctiva of the eye

Question 8

IgG is primarily responsible for

Answer 8

fixation of complement and opsonization

Question 9

IgG is the principle source of ____ immunity against organisms in _____ space

Answer 9

humoral immunity against organisms in extravascular space

Question 10

IgA is associated with ___ tissue

Answer 10

epithelial

Question 11

what is IgA in the blood stream versus in the tissue

Answer 11

blood: monomer
tissue: dimeric

Question 12

what is secretory IgA

Answer 12

is after dimer and secretory component are added

-it bathes epithelial tissue

Question 13

how does secretory IgA work?

Answer 13

it inhibits virus particles from sticking on from epithelial surface- “it slides off like teflon paint”

Question 14

in secretory IgA, what forms the monomers and what connects them to make a dimer

Answer 14

monomers are produced by lymphocytes

-dimer formed from connections from J chain

Question 15

a unique feature of IgM is its

Answer 15

high molecular weight

5 monomers

Question 16

IgM is especially efficient at

Answer 16

fixing complement (at attaching complement once it is activated to the invading organism)

Question 17

what immunoglobulin is “first at the scene” at the site of infection

Answer 17

IgM

Question 18

role of IgM is protecting _____ space

Answer 18

intravascular space 
(blood vascular system inside the vessels)

Question 19

IgD

Answer 19

nearly all IgD appears on the surface of lymphocytes (like IgM does too)- so could be related or coordinated with IgM

Question 20

IgE is also called the

Answer 20

“skin sensitizing antibody”

Question 21

IgE normally has a physiological role to

Answer 21

protect mucosal surfaces

Question 22

IgE triggers release of certain agents that start inflammation response such as

Answer 22

• vasodilation of blood vessels

- chemotactic factors which attract macrophages

Question 23

what is an allergy (hypersensitivity)?

Answer 23

an exaggerated immune response

Question 24

type I hypersensitivity is also known as

Answer 24

immediate Rx, anaphylaxis

Question 25

what occurs during initial exposure during type I hypersensitivity ?

Answer 25

B cells -> plasma cells, plasma cells produce type of IgE called reagin which binds to mast cells

Question 26

what occurs during second exposure during type I hypersensitivity ?

Answer 26

allergen binds to IgE, destabilizing the cell membrane which bursts (if the allergen bridges two IgE molecules)
-explosive degranulization releases components from mediators

Question 27

explosive degranulation causes the mediators to release :

Answer 27

• histamine
• heparin
• prostaglandins
• proteolytic enzymes

Question 28

the mix of mediators in type I hypersensitivity causes

Answer 28

• smooth muscle contraction
• vasodilation (redness)
• increased vascular permeability (tissue starts to lose fluid)
• mucous secretion (causing hay fever symptoms)

Question 29

what occurs with the mast cell in immediate hypersensitivity?

Answer 29

all those packets of mediators inside the mast cells blow up and released all at once

Question 30

what occurs in systemic anaphylaxis

Answer 30

release of a bunch of mast cells throughout the body:
-smooth muscle contraction and bronchioles constrict
-arterioles dilate, drastically reducing blood pressure
-permeability of the vessels increases and they start losing fluid
(shock)

Question 31

what occurs during localized anaphylaxis

Answer 31

localized release of mediators- often in mucous membrane, resulting in hay fever
-if in lower respiratory tract, bronchial asthma (deeper and airborne)

Question 32

type IV hypersensitivity is also called

Answer 32

cell-mediated, delayed

Question 33

what occurs during onset on type IV hypersensitivity

Answer 33

subset of T lymphocytes called delayed type hypersensitivity cells (TH1) recognize antigen, react, and release cytokines which can cause tissue damage

Question 34

process during type IV hypersensitivity

Answer 34

• T lymphocytes recruited via cytokines
• cytokines increase capillary permeability: macrophages have exaggerated response (tissue damage)
• special T cells amplify the whole thing

Question 35

why is it called delayed hypersensitivity

Answer 35

the whole process for T cells to proliferate, send out cytokines, and recruit macrophages can take a day or two

Question 36

type IV hypersensitivity is involved in what pathologies

Answer 36

• autoimmune diseases
• transplant rejection
• killing cancer cells
• contact dermatitis

Question 37

what is contact dermatitis

Answer 37

occurs with certain products (cosmetics, TPAs, metals)

-it is an immune reaction to something that isn’t biologic

Question 38

how can contact dermatitis illicit an immune response

Answer 38

small molecules called haptens when attached to a carrier (protein in the skin)- this combination is antigenic