Antibodies

Question 1

Immunoglobulin G molecules from two different individuals represent two different ————- of the same class of imunoglobulins (e.g. IgE) beacuse they are encoded by two different alleles of the same gene

Answer 1

Allotypes

Question 2

—————– Are determined from allelic differences in the same antibody isotypes that differ between people

Answer 2

Allotypes

* Antibody isotypes (IgG, IgM, IgA, IgE, IgD)

Question 3

The isotype of an antibody is determined by the constant regions of the light chain or heavy chain?

Answer 3

heavy chains

Question 4

The unique structure of the antigen binding site created by the variable regions of the light and heavy chains is called the ————– of the antibody

Answer 4

Idiotype

Question 5

Two antibodies of the same allotype and isotype that bind different antigens are different ———– .

Answer 5

Idiotypes

Question 6

What region of the antibody accounts for the unique antigen binding sit, which ultimately distinguishes between idiotypes?

Answer 6

Variable region

Question 7

Which immunoglobulin fixes complement,crosses the placenta, Opsonizes bacteria, and neutralizes bacteria toxins and viruses?

Answer 7

IgG

Question 8

Which immunoglobulin prevents the attachment of bacteria and viruses to mucous membranes but cannot fix complement?

Answer 8

IgA

Question 9

Which immunoglobulin is found in secretions?

Answer 9

IgA

Question 10

What is the structure of Immunoglobulin A in secretions?

Answer 10

Dimer

Question 11

What is the structure of Immunoglobuline M ?

Answer 11

Pentamer/ Monomor

Question 12

Which immunoglobuline is produced as part of the primary response to an antigen, fixes complement, but does not cross the placenta?

Answer 12

IgM

Question 13

Which immunoglobulin has an unclear fxn and can be found on the surface of B cells and in serum?

Answer 13

IgD

Question 14

Which immunoglobulin is the antigen receptor on the surface of B cells?

Answer 14

IgM

Question 15

Which immunoglobulin induces the release of mediators from mast cells and basophils when an individual is exposed to an allergen?

Answer 15

IgE

Question 16

Which immunoglobuline mediates immunity to helminths and protozoa?

Answer 16

IgE

Question 17

Which type of Antibody activates Eosinophils?

Answer 17

IgE
* It also activates mast cells and basophils

Question 18

which 2 immunoglobulins are joined by J chains?

Answer 18

IgA and IgM

Question 19

The 5 isotypes of the Heavy (H) chains

Answer 19

α, γ, ε, δ, μ

Question 20

the 2 isotypes of the light (L) chains

Answer 20

κ, λ

Question 21

Fxn of the Fab regions

Answer 21

The Fab regions bind to antigens -mediate Ag recognition

Question 22

fxn of the Fc region

Answer 22

the Fc region of the antigen-couples antibody binds to molecules (e.g. C1q) or Fc receptors on cells - mediates effector functions

Question 23

What are FcRs and their fxn?

Answer 23

FcRs –> Fc receptors
they mediate many effector fxns of antibodies by binding to the Fc portion of the Abs

Question 24

what cells express FcRs ?

Answer 24

Immune cells, Epithelial cells, and endothelial cells

Question 25

Most diverse group of FcRs?

Answer 25

**FcγRs** * the main mediators of antibody functions in the body

Question 26

What immunoglobuline do FcγRs bind to?

Answer 26

**IgG**

Question 27

If FcγRs are expressed by **phagocytic cells (macrophages)** they will induce ----------------

Answer 27

**phagocytosis** (Opsonisation)

Question 28

If FcγRs are expressed by **cytotoxic cells (NK cells)** they will induce ---------------- upon binding to IgG-antigen complexes

Answer 28

**ADCC- antibody dependent cell mediated cytotoxicity**

Question 29

Fc receptor expressed by NK cells

Answer 29

**FcγRIII (CD16)**

Question 30

Explain how FcγRs on NK cells induce antibody-dependent cell-mediated cytotoxicity **(ADCC)** of antibody-coated target cells

Answer 30

Ab binding to **FcγRIII (CD16)** on NK cells --> directs the cytotoxic activity to a specific cellular target (Viral infected cells)

Question 31

What Fc receptor is Often associated w/ allergy symptoms and is expressed by mast cells/ basophils and eosinophils ?

Answer 31

**FcεR**

Question 32

**FcεR** Upon binding to **--------------------** it triggers a signaling cascade that results in **degranulation and release of histamine, proteases, and other inflammatory mediators**

Answer 32

**IgE-antigen complexess**

Question 33

Fc receptor expressed by Epithelial cells?

Answer 33

**pIgR** - Polymeric immunoglobulin receptor

Question 34

Fxn of PIgR receptors?

Answer 34

* **Transport of IgA and IgM from blood to the lumen of multiple tissues** (Gastrointestinal, Respiratory, Reproductive tract) * Responsible for **carrying IgA into body secretions: tears and milk** * Responsible for the **transfer of IgA to gut mucosa to protect against ingested microbes and toxins**

Question 35

Fxn of **FcRn** in children vs adults | *Neonatal

Answer 35

**Children:** carries antibody ingested in mother’s milk across epithelial cells of the intestine into the bloodstream **Adults:** , its expression on cells that line the bloodstream helps to maintain IgG levels in serum by protecting them from degradation

Question 36

FcRn receptor are expressed by?

Answer 36

epithelial cells and endothelial cells