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Flashcards in SI LEC - Antibodies Deck (41):
1

composition of AB

82-96% polypeptide
2-14% CHO

2

Antibody molecule has 2 separable functions:


1) specific binding to antigen eliciting response
2) biological activity

3

-Discovered that hyperimmunizing rabbits resulted in increased gamma
-Purification revealed antibody activity resided in this serum portion

kabat and tiselius

4

Antibodies Are Made Up Of:

2 Light Chains (identical)
2 Heavy Chains (identical)

5

Each Light Chain bound to Heavy Chain (L-H) by

Disulfide Bonds

6

Heavy Chain bound to Heavy Chain (H-H) by

Disulfide Bonds

7

First a/a of amino terminal vary for both H and L Chains (Variable Region)

__

8

First 100 a/a of amino terminal vary for both H and L Chains (__ Region)

Variable

9

: Ag-binding site

CDR (Complementarity Determining Regions)

10

The folded domains of the H chain line up w/ the L chains forming an ___

immunoglobulin fold/barrel

11

Antigen is captured w/in barrel by binding to a small number of amino acids at strategic locations known as

hypervariable regions.

12

Immunoglobulins (with possible exception of IgM & IgE) contain hinge between

CH1 & CH2

13

Is there homology between AA sequence of hinge & heavy chains

None

14

residues in hinge region

proline and cysteine

15

hinge region residue involved in formation of interchain disulfide bonds

Cysteine

16

hinge region residue
prevents folding in a globular structure, allowing flexibility between
two Fab arms of the Y-shaped antibody; ;

Proline

17

hinge region residue
allows open & close to accommodate
binding to two epitopes

Proline

18

hinge region residue
because it is open, it can be cleaved by proteases
(e.g. papain) to generate the Fab & Fc fragments

Proline

19

: centered on using analytic ultracentrifuge on the basis of MW

Gerald Edelman

20

: worked on the use of papain to cleave IgG into 3 pcs.

Rodney Porter

21

Used 7M urea to unfold IgG : exposed the sulhydryl bonds

Gerald Edelman

22

Gerald Edelman Used ___ to unfold IgG : exposed the sulhydryl bonds

7M urea

23

unfolding IgG exposed __

sulhydryl bonds

24



Treatment with mercaptoethanol yielded



Treatment with mercaptoethanol = 4 chains:

25

breaks S-S bonds

mercaptoethanol

26

used PEPSIN :

Alfred Nansoff

27

Treatment with proteolytic enzyme, papain,

2 capable of ag rxn (fragment antigen binding)
1 could be crystallized (fragment- crystallizable)

28

specifically bind antigen,
can’t precipitate
univalent/one binding site each,
identical to each other

Fab

29

: crystallizable (thus homogenous) , can’t bind ag,
responsible for biological activity of molecule
after Ag bound to Fab portions

Fc

30

This proteolytic enzyme was found to cleave IgG at the carboxy-terminal side of the interchain disulfide bonds, yielding one single fragment (Fc) and antigen binding fragment called F(ab)2.

pepsin

31

found in urine of patients with MM

Bence Jones Protein :

32

BJP: peculiar behavior ppt at __

60C,

33

BJP: peculiar behavior
reappears upon ___

cooling

34

BJP: dissolves at __

80C

35

Two main types of LC

Lambda
Kappa

36

First 110 amino acids at terminus : constant or variable?

highly Variable (V)

37

First 110 amino acids at terminus of HEAVY CHAINS: highly Variable (V)

110 AA

38

Remaining aa can typically be divided up to 3 or more constant regions

WHAT CHAIN

HEAVY

39

Immunoglobulin variations
class of Ig, unique aa sequence that is common to all Ig molecules of a given class in a given species

Isotype

40

Immunoglobulin variations
genetic difference, depends on existence of allelic forms of the Ig , result of different forms of the same gene, involve changes of 1-3 AA in constant region

Allotype

41

Immunoglobulin variations
one of several thousand Ig, each of which directed toward specific epitope

Idiotype

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