Immunology Lecture 14: Structure and Function of Antibodies

how many domains are constant in the light chain of IgG?

1

how many domains are variable in the heavy chain of IgG?

1

how many domains are variable in the light chain of IgG?

1

IgM can be found in both the blood and tissues. True or false?

False (it is very rare for it to be found in tissue fluids due to its size)

IgA is held together by an F chain. True or false?

False, it is held together by a J chain.

this antigen is a dimer

IgA

this class of antibody is the predominant immunoglobulin in secretions such as saliva, milk, and intestinal fluid.

IgA

this immunoglobulin is produced on body surfaces and is responsible for the defense of the intestinal and respiratory tract

IgA

this antibody is found in a mother's milk and helps provide intestinal immunity to the neonate.

IgA (mucosal!!!)

this antibody is found on B cell surfaces and has a regulatory function. It is important in B cell development.

IgD

this antibody is found on the surface of immature lymphocytes

IgD

this class of antibody is found in very low concentrations in serum and mediates allergic reactions.

IgE

this immunoglobulin is found in very small quantities in serum and is responsible for immunity to parasitic worms and allergies

IgE

This antibody has a half life of 3 weeks

IgG

functions of this antibody include: - complement activation - neutralization of viruses and toxins - opsonization - systemic immunity of newborns - antibody dependent cell-mediated cytotoxicity (NK cells)

IgG

this antibody is found in high concentrations in colostrum of large domestic species and makes up 80% of total serum antibody.

IgG

this antibody is the predominant immunoglobulin in serum and is mainly responsible for systemic defense

IgG

this class of antibody can escape from blood vessels more easily than others, making it especially important in inflammation.

IgG

this class of antibody has the highest concentrations in serum and is produced by plasma cells in the spleen, lymph nodes, and bone marrow.

IgG

this class of antibody is the second highest in concentration in serum and is produced by plasma cells in secondary lymphoid organs.

IgM

this is a very large antibody mainly produced during the primary immune response

IgM

this is the major antibody produced during a primary immune response

IgM

(IgM/IgG) predominates in a primary immune response while (IgM/IgG) predominates in a later response.

IgM, IgG

IgM is held together by disulfide bonds and ___ chain.

J

where is most of IgE found?

bound to mast cells

hypervariable regions that come together to form the antigen binding site when the protein folds

complimentary determining region

what can result from the binding of IgE to a mast cell?

degranulation

IgD uses what type of heavy chains?

delta

holds the chains together and are also important in the structure of the domain loops

disulfide bonds

IgE can activate this granulocyte (think of mutual function)

eosinophils

the part of the antigen that the antibody binds to (an antigen can have more than one of these)

epitopes

IgE uses what type of heavy chains?

epsilon

what is the function of IgA?

found on mucosal surfaces where it can neutralize toxins and block entry of pathogens

this part of the antibody dictates biological activity (including opsonization, binding of mast cells, and complement fixation)

fragment crystallizable (Fc)

IgG uses what type of heavy chains?

gamma

what are the two forms of light chain for an antibody?

lambda or kappa

the Fc portion of IgE has a high affinity for the Fc receptor on this type of cell

mast cell

IgM is (monomeric/pentameric) when it is cell-bound and is (monomeric/pentameric) when it is secreted.

monomeric, pentameric

IgM uses what type of heavy chains?

mu

where will you find IgA in the body?

mucosal surfaces (intestine, respiratory tract, urinary system, skin, mammary gland)

antigen-antibody binding is covalent or non-covalent?

non-covalent

this is a peptide that binds IgA dimers and is added to IgA as it is transported to the mucosal surface

secretory component

List the 5 classes of antibodies

1. IgG 2. IgM 3. IgD 4. IgA 5. IgE

2 major functions of IgM

1. complement activation 2. agglutination

what are the 2 functions of IgE?

1. important in defense against parasites 2. mediator of immediate hypersensitivity

how many epitopes can IgM bind?

10

what is the molecular weight of IgG?

180,000 Da

what is the molecular weight of IgE?

190,000 Da

How many domains form the light chain of IgG?

2

how many domains form the constant domain in the heavy chain of IgG?

3

how many daltons is the light chain of IgG?

30,000

what is the molecular weight of IgA?

360,000 Da

IgG has ______ heavy chain domains

4

IgG has a light chain and a heavy chain. How many domains form the heavy chain?

4

how many domains does the heavy chain have in IgA?

4

how many domains does the heavy chain have in IgM?

5

how many domains make up the heavy chain in IgE?

5

how many daltons is the heavy chain of IgG?

60,000

what is the molecular weight of IgM?

900,000 Da

all antibodies originate as _______ shed into body fluids

BCRs

From ______ and beyond are the Fc region of the antibody CL CH2 CH3

CH2

what two parts of the constant chain make up the Fc region on IgG?

CH2 and CH3

Select 1 (or more if applicable) which of the following form the antigen binding site? VH VL CH1 CL CH2 CH3

VH and VL (variable heavy domain and variable light domain)

Select 1 (or more if applicable) Which of the following form the fragment antigen binding? VH VL CH1 CL CH2 CH3

VH, VL, CH1, CL (this is the antigen binding end of the molecule)

IgA uses what type of heavy chains?

alpha

this determines the class (isotype) of antibody

the type of heavy chain

heavy chains on an antibody are identical. true or false?

true

light chains on an antibody are identical. true or false?

true

is antigen-antibody binding reversible?

yes