Antibodies

Question 1

Immunogenicity:

Answer 1

The capacity to induce an immune response.

Question 2

Immunogenicity requires (3):

Answer 2

1. Be foreign to immunized host.
2. Possess a certain molecular weight.
3. Possess a certain degree of molecular complexity.

Question 3

Antigenicity:

Answer 3

The ability to bind with antibodies or cells of the immune system.

Question 4

Plasma cells make antibody in:

Answer 4

Germinal centers (white pulp of spleen, cortex of lymph nodes or in MALT).

Question 5

Somatic hypermutation:

Answer 5

Slight mutation in the rearranged genome give rise to slight variations in the ability of the antibody to bind. Sometimes it is a change in affinity.

Question 6

The recombination events in B-cells to produce antibodies are mediated by:

Answer 6

V(D)J recombinase

- RAG 1 and RAG2 genes

Question 7

Antibody that functions in neutralization:

Answer 7

IgG, IgA

Question 8

Antibody that functions in opsonization:

Answer 8

IgG1

Question 9

Antibody that functions in sensitization for killing by NK cells:

Answer 9

IgG1, IgG3

Question 10

Antibody that functions in sensitization of mast cells:

Answer 10

IgE

Question 11

Antibody that functions in sensitization of basophils:

Answer 11

IgE

Question 12

Antibody that activates compliment:

Answer 12

IgM, IgG3

Question 13

Antibody able to cross epithelium:

Answer 13

IgA (dimer)

Question 14

Antibody able to cross placenta:

Answer 14

IgG1

Question 15

Antibody able to diffuse into extravascular sites:

Answer 15

IgG

Question 16

IgM

Answer 16

• Pentamer.
• First antibody made in the primary response.
• Fixes compliment, does NOT mediate phagocytosis or cross placenta.

Question 17

IgA

Answer 17

• Monomer (majority) or dimer.
• Major immunoglobulin found in seromucous secretions.
• Fixes complement and mediates phagocytosis (monomer).

Question 18

IgG

Answer 18

• Monomer.
• 4 subclasses.
• Characterize the secondary antibody response.
• Can fix compliment.
• IgG1 and IgG3 can mediate phagocytosis
• Can cross placenta

Question 19

IgE

Answer 19

• Scarce in plasma.
• Found on surface of mast cells and basophils.
• Response to parasites.
• Common in allergic states.
• Shortest half life (2 days).
• Mediates allergic reactions.