Antibodies and Antigens Lecture

Question 1

Immunogenicity

Answer 1

the ability of a given molecule to induce an immune response

Question 2

General characteristics that contribute to immunogenicity are

Answer 2

phylogenetic foreignness
chemical nature
size
complexity
route of uptake
host

Question 3

Antigen

Answer 3

a molecule that binds specifically with an antibody of T cell receptor

Question 4

Epitope

Answer 4

the actual part of an antigen that binds to an AB or T cell receptor binding site

Question 5

Most antigens have multiple ______. These are called _______

Answer 5

epitopes
multivalent antigens

Question 6

epitopes can be

Answer 6

repeated within Ag molecule or not
overlapping
formed by linear arrays of AAs
conformational (AAs not in sequence)
Neo-epitopes (exist/exposure after AG changes such as phosphorylation, protealysis)

Question 7

Adjuvant

Answer 7

a compound that is given with an antigen when immunizing a host, to augment the immune response achieved

Question 8

Abs are a family of millions of

Answer 8

structurally related glycoproteins

Question 9

each unique Ab has a specific binding sites for pieces of

Answer 9

antigen (called an epitope)

Question 10

Abs are produced by

Answer 10

B lymphocytes/Plasma cells

Question 11

Abs are produced in two broad forms-

Answer 11

1. bound to B cell membranes
2. secreted soluble form

Question 12

Abs bound to B cell membranes act as

Answer 12

B cell receptors for antigens

Question 13

Abs secreted in soluble form are

Answer 13

free floating and able to bind Ag in plasma, mucosal secretions, interstitial fluids

Question 14

When Abs bind to Ags they can

Answer 14

Remove the Ag
neutralize the Ag
kill organism expressing the Ag
Trigger ‘hypersensitivity’ reactions

Question 15

Abs bind to Ags and remove the Ag by

Answer 15

precipitating it out or inducing phagocytosis

Question 16

Abs bind to Ags and neutralize the Ag by

Answer 16

preventing a microbial enzyme from working or a virus from binding

Question 17

Abs bind to Ags and kill organism expressing the Ag by

Answer 17

poking holes in them

Question 18

Abs bind to Ags and trigger hypersensitivity reactions by

Answer 18

histamine release, immune complex activation of complement proteins

Question 19

Antibody structure- two symmetrical branches made up of 2 identical ______ and 2 identical _____

Answer 19

light chains
heavy chains

Question 20

One L chain is ______ to one H chain by ________ and other two H chains are attached to each other by _______

Answer 20

covalently attached
S-S bonds
S-S bonds

Question 21

Both L and H chains are made up of

Answer 21

repeating homologous units

Question 22

each Ab has identical combining sites to which the

Answer 22

NH2-terminal ends of both L and H chains contribute

Question 23

Variable regions

Answer 23

regions that recognize epitopes and make the ab combining site
are specificity

Question 24

The N-terminal lg domain of each L and H chain contains _ hypervariable regions called _____

Answer 24

3
complementarity determining regions (CDRs)

Question 25

CDRs are ____ to the epitope

Answer 25

complimentary

Question 26

Due to the way L and H chains fold, CDRs end up in the _______

Answer 26

hypervaraible loops, which come together

Question 27

The hypervariable loops formed by the CDRs actually

Answer 27

extend from the surface of the Ab molecule to form the Ab combining site

Question 28

the furthest and most variable CDR

Answer 28

CDR3- most highly involved in the actual binding

Question 29

AAs outside of the CDRs can

Answer 29

contribute to the binding site but most of the time do not

Question 30

The C-terminal end of the H and L chains are comprised of

Answer 30

Ig domains
but have very little variability

Question 31

Constant regions are opposed to

Answer 31

variable regions
do NOT interact with the antigen/epitope

Question 32

C regions of the H chains actually mediate

Answer 32

most of the biological functions of the antibody and the isotype of the Ig

Question 33

H chain C regions are numbered

Answer 33

CH2, CH2, numbering from the NH2 terminus

Question 34

Hinge region

Answer 34

between CH1 and CH2- allows flex and is of different lengths in different isotypes

Question 35

Any given Ab has how many of each L chain C regions

Answer 35

2 K or 2 ^
never one of each

Question 36

Abs can be expressed in

Answer 36

secreted or membrane forms

Question 37

The membrane form of Abs is ONLY found on

Answer 37

the B cells that make that given Ab

Question 38

Membrane forms of Abs differ in

Answer 38

AA sequence at the COOH terminus of the H chain C region

Question 39

Secreted forms of IgG and IgE are

Answer 39

monomeric

Question 40

The membrane forms of all isotypes is

Answer 40

monomeric

Question 41

The secreted forms of IgA and IgM are

Answer 41

covalently bound multimers, joined through the tail pieces at the carboxyl ends of M and A H chains

Question 42

IgM and IgA also have a _____ which is S-S bonded to the tail pieces for stabilization

Answer 42

J piece

Question 43

Abs are

Answer 43

at least bi-valent
flexible

Question 44

Ab membrane form is the

Answer 44

B cell receptor

Question 45

Ab secreted form acts

Answer 45

throughout the body

Question 46

Ab B regions combine with Ag in a

Answer 46

highly specific manner

Question 47

Ab C regions of their H chains interact with

Answer 47

multiple cell types and soluble inflammatory molecules, which mediate effector function

Question 48

Synthesis of immunoglobulins

Answer 48

synthesized on membrane bound ribosomes and glycosylated in the rough endoplasmic reticulum

Question 49

Once assembled, immunoglobulins

Answer 49

move to golgi complex to undergo modifications of their carb molecules

Question 50

Immunoglobulins are transported to plasma membrane in

Answer 50

vesicles and either and either anchored or secreted

Question 51

Monoclonal

Answer 51

each B cell makes Abs of one specificity. These are all clones of each other

Question 52

Polyclonal

Answer 52

Serum contains LOTS of Abs of millions of specificities because an animal contains millions of different B cells.

Question 53

Affinity maturation

Answer 53

process that yields Abs that bind tightly to their Ag

Question 54

Affinity maturation involves

Answer 54

subtle changes through somatic mutations in Ag-stimulated B cells that produce new V regions structures

Question 55

B cells with higher affinity receptors are

Answer 55

selected by Ag becoming the most dominant

Question 56

Abs can distinguish between

Answer 56

linear proteins determinants that differ by a single conserved AA in their sequence

Question 57

Even is specificity is very high

Answer 57

eptitope might be part of multiple Ags

Question 58

Cross reactions occur when

Answer 58

an Ab combines with multiple epitopes
when specificity is low

Question 59

Affinity of an Ab is

Answer 59

the pure measure of the on/off rate between Ag and Ab combining site

Question 60

Avidity is the term for

Answer 60

true, overall strength of attachment of an Ab to its Ag

Question 61

Affinity + valency=

Answer 61

avidity

Question 62

Types of common assays that use Abs

Answer 62

enzyme-linked immunoabsorbant assays
radioimmunoassays
hemagglutination assays
flow cytometry
immunohisochemistry
western blot assays
dipstic assays