Anti Bodies

Question 1

General structure of antibodies what stabilises it

Answer 1

Quaternary structure, 2 light chains and two heavy chains stabilised by disulphides bridges bridges between shapes forming the characteristic Y shape

Question 2

Two main regions of antibodies, which one is used for antigenic recognition of pathogens

Answer 2

We have a constant fraction, where sequence is identical for each antibody of a specific isotope (A,G,E,M…) and variable fraction, which is responsible for specificity towards specific antigen of specific pathogen

Question 3

What the constant region used for? And the variable region?

Answer 3

Variable region is responsible for the antibodies specificity constant region is important for effector functions, and joining with surface cell receptors

Question 4

what is the Fc region of the antibody

Answer 4

The Fc region is the crystalize able fraction of the antibody, also known as the constant fraction. Only varies between different isotypes and its used for interactions with surface receptors and determining effector functions

Question 5

What is the Fab region

Answer 5

The antigen binding fraction which also contains the variable regions that give antibodies their unique specificity

Question 6

Name the two regions that make up an antibody

Answer 6

Constant regions and variable region

Question 7

Who determines the specificity of an antibody

Answer 7

The variable regions, or the Fabs of the antibodies containing the CDR loops (3 on heavy and and 3 on light). Thanks to somatic recombination

Question 8

Name two proteolytic enzymes used in antibody modification

Answer 8

Papain and pepsin, Used to generate fragments with a modified function (from antibodies)

Question 9

What does PaPain cause

Answer 9

proteolytic Cleavage of antibodies removing Fab regions, generating 2 Fab fragments and 1 Fc fragment

Question 10

Pepsins mechanism of action

Answer 10

Proteolytic cleavage of generating a fragment composed of only two Fab regions, this cleavage also breaks down the Fc portion of the antibody into peptides, generating peptides and and F(ab)2 fragment

Question 11

Nomenclature of fragment generated by Pepsin

Answer 11

F’(ab)2

Question 12

Is the hypervariable region on what terminal of polypeptide

Answer 12

N terminal of polypep chain

Question 13

what are antibodies classified by

Answer 13

Classified by constant fractions of both light and heavy chains. Heavy chain FC–IgM, A, E, D, G, and light chain FC- Kappa and landa where landa is more common due to isotypic exclusion

Question 14

what antibodies team up forming dimers or pentamers how do the join to each other, and which ones have an extra constant region

Answer 14

IgA’s forming dimers and IgM’s forming pentamers ( big and slow one of reasons IgM is not a gent opsonizer) IgM and IgE have extra CH region

Question 15

Isotypes of light chain constant regions, are they both produced in a particular b cell?

Answer 15

Kappa and landa, NO thanks to isotypic exclusion (allelic exclusion) in a particular b cell only one isotype is being produced.

Question 16

What are the effector functions for antibodies

Answer 16

Neutralization (with agglutination), complement activation, Opsonization, ADCC

Question 17

what antibody has 4 subclasses

Answer 17

IgG, subclasses 1,2,3,4

Question 18

main antibody in acute immune response

Answer 18

IgM

Question 19

most abundant serum isotype

Answer 19

IgG 70-89% and M is 5-10%

Question 20

Epitope

Answer 20

Region of antigen that binds to paratope on antigen, also called the antigenic determinant, Two type linear and conformational determinants. Tip; there can be different epitopes on one antigen—relate to monoclonal antibody screening process

Question 21

antigenicity

Answer 21

the ability of an antigen to bind to a specific antibody or t cell receptor,

Question 22

immunogenicity

Answer 22

The ability of an antigen to generate and immune response, specifically through the activation of lymphatic cells, antigens that can do this are also called IMMUNOGENS

Question 23

Haptens

Answer 23

antigen that are not immunogenic on their own, need to associate with molecules called “carriers” in order to create an immunogenic response

Question 24

Paratope

Answer 24

Region on Fab the binds to epitope of antigen

Question 25

IgD, how common is it in serum

Answer 25

Not common, mainly found bound to b cells as BCR’s

Question 26

what are IgEs mainly involved in

Answer 26

IgE are mainly involve in the allergic response and helminth immune responses

Question 27

What are IgM’s functions

Answer 27

IgM’s are the main antibodies in an accute immune response, mainly for pentamers joined by J chains

Question 28

Types of epitopes or determinants

Answer 28

Linear determinants and conformational determinants

Question 29

what’s responsible for the high variability of the antigen binding regions, when does it occur

Answer 29

somatic recombination occurs during maturation of b cells, we see recombination’s between D J sequences and D V sequences on heavy chains and DV sequences on Light chains, combines generate billions of possible antigens for any pathogenic antigen the body can encounter

Question 30

what’s the difference between Light chain and heavy chain somatic recombination

Answer 30

The variability, heavy chains have up to 9,000 possible recombination’s while the kappa and alpha have 200 and 270 respectively. A lot more variability can be achieved on the heavy chain thanks to the fact that they have the joining regions which are also involved in the recombination

Question 31

What are CDR`s…What do they determine

Answer 31

The determine the antigen specificity of an an antibody (the paratope of the antibody) also known as complementary determining regions.

Question 32

Structure of CDR`s , where on the antibody are they

Answer 32

On Fab, forming part of variable regions, The form loops at the tips, 3 from light chains and 3 from heavy chains

Question 33

Immunogen

Answer 33

An antigen that is immunogenic, no all antigens are immunogenic

Question 34

What types of molecules are the best immunogens

Answer 34

carbohydrates and glycoproteins ( peptides most, those are the one incorporated in HlA)

Question 35

Antibody maturation

Answer 35

Occurs in already differentiated b cells and we see somatic hypermutation in which we see improvements to paratope specificity and overall function, and isotype recombination in which IgM’s are converted to IgG,A,or E