Antibodies and Antigens

Question 1

What are the effector properties of Ab’s?

Answer 1

Toxin neutralization
Activation of complement
Opsonization
Direct antibacterial activity

Question 2

Structure of Ab?

Answer 2

Four polypeptide chains, two light and two heavy bound by covalent disulfide bridges.

Question 3

Describe th eheavy and light domains?

Answer 3

H and L divided into variable and constant regions. The variable regions contains the Ag binding site and the C regions determines the biological properties of Abs.

Question 4

What does Papain do?

Answer 4

they cleave Ab into two Fab fragments and an Fc fragment.

Allows separation of two monovalent fab fragments.

Question 5

What does pepsin do?

Answer 5

Generates single bivalent antigen fragment F(ab’)2

Question 6

What are the two types of L chains?

Answer 6

Kappa and lambda

Question 7

What determines the class of antibody?

Answer 7

The five different types of H chains

A,G,M,D,E

Question 8

Membrane IgM

Answer 8

Long tail into the plasma membrane to transmit signal to inside the cell. IgM is on the cell membrane

Question 9

Hinge?

Answer 9

Allows the distance between angiten binding sites to be moved closer or further apart

Question 10

What Ag’s are recognized by Ab’s?

Answer 10

Everything!
Conformational Determinant- important for toxin neutralization
Linear determinant– can recognize denatured or not denatured
Neoantigenic determinant created by proteolysis.
Also recognizes nucleic acids and polysaccharides

Question 11

What Ig has the highest affinity

Answer 11

IgG

Question 12

Ab’s formed in primary response have higher or lower affinity than memory response?

Answer 12

Lower affinitiy

Question 13

Avidity?

Answer 13

Ability of an Ag to bind to Ab based on affinity and valence

Question 14

Valence?

Answer 14

Number of Ab binding sites
2 for IgG, IgD, IgE and Serum IgA, and Membrane IgM
4 for secreted IgA
10 for serum IgM

Question 15

What kind of Ag recognized by T cell Receptors?

Answer 15

Peptide MHC complexes

Question 16

What kind of Ag can be recognized by immunoglobins?

Answer 16

Proteins, lipids, polysaccharides, small chemicals

Question 17

Who has higher affinity Antibody or T cell receptor?

Answer 17

Antibody

Question 18

Who has higher affinity Antibody or T cell receptor?

Answer 18

Antibody

Question 19

B cell receptor generation?

Answer 19

Bone marrow: lymphocyte precursor cells to pre b cell. Pre B cell synthesizes its pre-B cell receptor (receptors made one at a time-surrogate light chain). Pre B cell receptor tested to make sure signals are received correct, incorrect ones degraded.

Question 20

B cell where is it immature and mature?

Answer 20

B cell is immature after leaving bone marrow, but completely differentiated. It goes through circulation and is activated (mature) in the spleen.

Question 21

secretable form of immunoglobins?

Answer 21

Dont contain the transmembrane receptor

Question 22

Where is IgA found?

Answer 22

GI tract lumen. It is a dimer with a secretory domain. Secreted by plasma cells below epithelium. The secretion protects IgA from degradation by proteases.
Monomer in the blood

Question 23

What does a proliferating B cell differentiate into if exposed to IFN-y?

Answer 23

IgG3 for phagocytosis

Question 24

What does proliferating B cell differentiate into if exposed to TGF-B?

Answer 24

Mucosal defenses IgA

Question 25

What does proliferating B cell differentiate into if exposed to IL-4?

Answer 25

IgE for allergy responses or IgG1 for phagocytosis

Question 26

What are the proliferating cytokines?

Answer 26

IL-2, IL-4, IL-5 allow for proliferation of an activated B cell

Question 27

Can IgA on epithelial surfaces activate complement?

Answer 27

No, IgA in the blood can activate complement. Epithelial surface IgA is a dimer and blood is a monomer.