Immunoglobulins

Question 1

What is the function of Ig’s?

Answer 1

Opsonization - sends eat me signal to phagocytes

Neutralization of virus so virus can’t attach to host cells

Question 2

What is the structure of Ig’s?

Answer 2

Y shaped polypeptide chain connected by disulfide bonds

2 heavy and 2 light chains - Each has constant and variable regions

Question 3

What is the Fab?

Answer 3

Fragment binding area
Binds antigen epitope
Consist of variable heavy and light chains

Question 4

What determines the antibody class?

Answer 4

Heavy chain determines IgG, IgA, IgM, IgD, or IgE

Question 5

What is the Fc?

Answer 5

Fragment crystalizable
Consist of Constant Heavy chains
Ch2 binds complement
Ch3 binds to macrophage

Question 6

What is the Hinge area?

Answer 6

Allows antibody to change from Y to T shape

Located between Ch1 and Ch2 regions

Question 7

What is the Ig Supergene family?

Answer 7

Proteins that have a similar structure to Ig’s and come from the same ancestral gene
Include surface ag receptors, co-receptors, cell adhesion molecules, and cytokine receptors

Question 8

What blood groups do enzymes destroy?

Answer 8

Duffy’s MN’S were destroyed

Question 9

What is the effect of papain treatment?

Answer 9

2 Fab + 1 Fc

Question 10

What is the effect of pepsin treatment?

Answer 10

1 Fab(2) + 1 Fc

Question 11

What is electrophoresis?

Answer 11

Ig will migrate in an electical field
Albumin moves the fastest toward + pole
Gamma globulns migrate the slowest

Question 12

Causes of polyclonal gammopahy

Answer 12

Chronic infection
Immune mediated disease
Liver disease

Question 13

Causes of monoclonal gammopathy

Answer 13

Narrow spike of alpha, beta, or gamma globullin
Multiple myeloma
Waldenstrom's Macroglobulinemia
Lymphoma 
Chronic lymphocytic leukemia

Question 14

What are the characteristics of IgG antibodies?

Answer 14

y heavy chain
half life = 23 days
Has Gm and Km allotype
Activates complement
Cross placenta

Question 15

What are the characteristics of IgM antibodies

Answer 15

u heavy chain
half life = 5 days
Km allotype
activates C'
Found on surface of B lymphs

Question 16

What are the characteristics of IgA?

Answer 16

a heavy chain
found in secretions
can activate alternative C'
monomeric or polymeric
30% of Anti-A and -B is IgA

Question 17

What are the characteristics of IgD?

Answer 17

Delta heavy chain

found on surface of B cells

Question 18

What are the characteristics of IgE?

Answer 18

Bound to basophils or mast cells
Binding of antigen triggers release of histamine
Involved in hypersenstivity - anaphylaxis and parasitic infections

Question 19

Which IgG subclasses can activate complement?

Answer 19

IgG1 and IgG3

IgG2 can weakly or use alternative pathway

Question 20

Which IgG subclasses can bind to Fc receptors on phagocytes?

Answer 20

IgG1 and IgG3

Question 21

Which IgG subclasses can bind to staphylococcal Protein A

Answer 21

IgG1 and IgG2

+ some allotypes of IgG3

Question 22

What subclass are Rh antibodies more commonly?

Answer 22

IgG1 and IgG3

Question 23

What subclass are Kell and Duff antibodies?

Answer 23

IgG1

Question 24

What subclass are Kidd antibodies?

Answer 24

IgG3

High complement function

Question 25

Which IgG subclass causes severe HDFN?

Answer 25

IgG1

Question 26

What IgG subclass is anti-CD47

Answer 26

IgG4 - some monoclonal antibodies don't detect

Question 27

Which IgG subclass has Gm?

Answer 27

IgG1, IgG2, + IgG3

Question 28

How does Tango Anti-IgG work?

Answer 28

Well are coated with Staph Protein A which bind to Fc portions of IgG. Plasma is added, incubated, and washed. Anti-IgG is added and crosslink antibody bound to Staph A protein on wells. Positive = smooth layer cells. Negative = Cell button

Question 29

Which IgG subclasses are considered clinically insignifcant?

Answer 29

IgG2 and IgG4 can't bind to Fc receptors on Phagocytes so IgG coated cells will not be phagocytized

Question 30

What are the three genes required for Ig production

Answer 30

Heavy gene located on Chromosome 14 Lambda gene located on Chromosome 22 Kappa gene located on Chromosome 2

Question 31

What is gene rearrangement?

Answer 31

``` The Variable (V), Diversity (D), and Joining (J) segments combine in different ways to form new sequence that recognize different epitopes Each B cell can recognize only one antigen ```

Question 32

What is Isotype switching?

Answer 32

Naive B cells only have IgM and IgD on their surface | Once activated B cell can begin to produce IgG or IgA

Question 33

How is the Isotype determined?

Answer 33

Isotype = Class | Determined by the constant Heavy region

Question 34

What is allotype?

Answer 34

Allotype may differ from person to person | Determined by Gm and Km

Question 35

What is idiotype

Answer 35

Depends on the variable/hypervariable region of the antibody molecule Located on Fab portion of antibody and provides ability to recognize different epitopes Determined by gene rearragement All antibodies that recognize the same epitope have the same idiotype regardless of class

Question 36

What is Gm?

Answer 36

Genetic marker on heavy chain of IgG1, IgG2, IgG3 | Gm is like an antigen on the the antibody and can make anti-Gm.

Question 37

What is Km?

Answer 37

markers on Kappa light chain

Question 38

What is Am?

Answer 38

Markers on IgA antibodies