BIOL 435 Ch. 3 Part Two (Recognition and Response)

Question 1

5 distinct classes of Ab (isoptopes)

Answer 1

1. IgA: alpha H
2. IgD: delta H
3. IgE: epsilon H
4. IgG: gamma H
5. IgM: mu H
   * based on differences in heavy chain structure

Question 2

Ab class in B-cell

Answer 2

• first IgM and IgD

- if activated, switch of classes at constant region

Question 3

light chain isotopes

Answer 3

1. Kappa
2. Lambda
   *determined when Ab is made
   >tries one of them, than the other, if neither works=dies

Question 4

Ab structure

Answer 4

-puzzled it together
>Papain
>Pepsin
>beta mercapto EtOH
-CHO on heavy chains

Question 5

papain

Answer 5

-digest an Ab into 3 segments
>2 same (Ag binding= Fab)
>1 different (fragment crystalizable= Fc)
-150,000 Da

Question 6

pepsin

Answer 6

-digest Ab into a single fragment with 2 Ab binding sites (F(ab)2)

Question 7

beta mercapto EtOH

Answer 7

• 2 H. chains: 50,000 Da each

- 2 L. chains: 22,000 Da each

Question 8

IgG

Answer 8

• 4 Ig domains in H chain
• 2 disulphide bonds
• most common
• hinge region

Question 9

IgD

Answer 9

• 4 Ig domains in H. chain
• 1 disulphide bond
• hinge region

Question 10

IgE

Answer 10

• 5 Ig domains in H. chain
• 2 disulphide bonds
• no hinge

Question 11

IgA

Answer 11

• 4 Ig domains in H. chain
• hinge region
• can be secreted: dimer joined by J-chain
• monomer in blood

Question 12

IgM

Answer 12

• original
• secreted version=pentamer
• 5 Ig domains in H-chain
• no hinge
• disulphide bonds between subunits to form pentamer
• J-chain

Question 13

type of Ab to produce

Answer 13

• signals will tell what type

- variable region/specificity remains the same

Question 14

BCR complex

Answer 14

• molecules involved in signal transduction
  1. Ab/BCR molecules
  2. Ig alpha and Ig beta
  3. CD19, CD81, CD21

Question 15

Ig alpha and Ig beta

Answer 15

-transduce signals via ITAMs

>tyrosines available to be phosphorylated

Question 16

ITAMs

Answer 16

-immunoreceptor tyrosin-based activation motifs

Question 17

CD19, CD81, CD21

Answer 17

• transmit and relay signals to cell interior

* CD12: co-receptor, binds to An indirectly via C3d

Question 18

TCR structure

Answer 18

-similar to Ig domains
-2 subunits (alpha and beta)
>constant region
>variable region
*always membrane bound: no soluble form

Question 19

2 TCR types

Answer 19

• alpha beta
• gamma delta
• have diverse An binding characteristics

Question 20

variable regions (TCR)

Answer 20

-have 3 CDRs forming peptide-specific binding site

Question 21

constant regions (TCR)

Answer 21

-each contain transmembrane signals

Question 22

TCR respond to soluble An

Answer 22

• can’t do like BCR can
• need MHC help peptides
• peptide sources can be from endogenously (ex. virus, cancer) or exogenously (put onto surface) processed An

Question 23

MHC

Answer 23

-major histocompatibility complex

Question 24

TCR complexes

Answer 24

• with co-receptor involved in An recognition
• want many safeties
  1. CD3
  2. CD4, CD8
  3. CD28

Question 25

CD3

Answer 25

• contains ITAMs that transmit signal to cell

- 6 molecules on cell surface (3 dimers)

Question 26

CD4, CD8

Answer 26

• function on increasing avidity of peptide binding by TCR

- bind to MHC (if not=wont be activated)

Question 27

CD28

Answer 27

• engages CD80 or CD86 on APC to fully activate a naive T-cell
• co-receptor

Question 28

3 dimers

Answer 28

• delta-epsilon
• gamma-epsilon
• zeda-zeda / zeda-mu
• ITAMs on intracellular side to pass signal in