Ig's and Antigens

Question 1

What are the three roles of antibodies in immunity?

Answer 1

Neutralization
Opsonization
Complement fixation

Question 2

What Ig is most prominent in serum?

Answer 2

IgG

Question 3

Which Ig is most common in everything but serum?

Answer 3

IgA

Question 4

What is agglutination?

Answer 4

aggregation of antigens by antibodies, which cause clumping

Question 5

Which Ig causes agglutination?

Answer 5

IgM, recognize antigens (ABO groups) on RBCs and causes cell clumping and lysis

Question 6

Why does Cold Agglutination Disease (CAD) occur?

Answer 6

passes through the acral blood vessels, the cooling IgM binds and agglutinates RBCs, activates complement

Question 7

What’s the difference between primary and secondary Cold Agglutination Disease?

Answer 7

primary: idiopathic
secondary: due to underlying disease such as lymphoproliferative disorders, infection, or autoimmune disorder

Question 8

_____________ CAD makes up 15% of autoimmune hemolytic anemias.

Answer 8

Primary

Question 9

What’s the function of IgA?

Answer 9

mucosal immunity via neutralization

Question 10

IgA monomer is located in _________

IgA dimer is ____________

Answer 10

monomer = serum
dimer = secreted

Question 11

Which antibody lives longest?

Answer 11

IgG

Question 12

Which antibody is a pentamer?

Answer 12

IgM

Question 13

Which antibody could be a dimer (most often), a monomer, or trimer?

Answer 13

IgA

Question 14

Which antibody is least present in serum?

Answer 14

IgE

Question 15

Function of IgD?

Answer 15

tolerance

expressed on surface of B cells

Question 16

Why are IgE levels in serum low?

Answer 16

because IgE binds to FC-epsilon receptors on mast cells and basophils almost immediately after production

Question 17

Which antibody is the primary response for agglutination?

Answer 17

IgM

Question 18

Which two antibodies neutralize toxins/bacteria/viruses?

Answer 18

IgG and IgA

Question 19

Which antibody functions in defense against parasites and hypersensitivity (allergy) reactions?

Answer 19

IgE

Question 20

What is neutralization?

Answer 20

when antibodies prevent the adherence of toxins, bacteria, or viruses to the host

Question 21

What is opsonization?

Answer 21

the antibody coats the target in order to promote an immune response

Question 22

What are two methods of opsonization?

Answer 22

phagocytosis

antibody-dependent cell-mediated cytotoxicity (ADCC)

Question 23

Which cells are involved in phagocytosis?

Answer 23

neutrophils, macrophages, and dendritic cells

Question 24

Which cells are involved in ADCC?

Answer 24

NK cells and eosinophils

Question 25

What are the four things that complement activation does?

Answer 25

enhances uptake kills susceptible bacteria promotes inflammation attracts immune cells to the area

Question 26

Which two antibodies activate the classical complement cascade?

Answer 26

IgM and IgG

Question 27

Why is IgM so effective in agglutination?

Answer 27

It has 10 binding sites! (pentameric)

Question 28

Which antibody function is the basis of passive immunization?

Answer 28

neutralization IgG and IgA neutralize microbes and their toxins, which is used when someone needs protection against a virus emergently. The patient gets these antitoxin antibodies pumped into their system.

Question 29

Fc receptors promote ________________ of opsonized targets

Answer 29

phagocytosis

Question 30

What determines which cells react to antibodies?

Answer 30

Fc receptor expression on cell surface

Question 31

FCgammaRI allows IgG to ________

Answer 31

activate phagocytosis

Question 32

FCgammaRIII allows IgG to _____________

Answer 32

do ADCC

Question 33

FCepsilonR1 allows IgE to __________

Answer 33

ADCC | - causes degranulation of mast cells to increase allergic response

Question 34

the poly Ig receptor (pIgR) allows IgA to move where?

Answer 34

across the membrane | from lamina propria to lumen

Question 35

What type of dendritic cell presents self-antigens to T cells? A) Langerhan B) Interdigitating C) Follicular

Answer 35

Interdigitating Located in thymus

Question 36

What type of dendritic cells are APC's to B cells?

Answer 36

Follicular in lymphoid follicles

Question 37

What type of dendritic cells are found in the skin?

Answer 37

Langerhan

Question 38

When Langerhan's take up antigen, they are ___________

Answer 38

immature

Question 39

When Langerhans present antigen to T cells, they are _________

Answer 39

mature