5. Antigen Receptors

Question 1

Types of antigen receptors (5)

Answer 1

• B-cell receptor
• T-cell receptor
• Nonspecific immunoreceptors:
  1. Opsonic receptors: FcR and CR
  2. PRRs

Question 2

Difference between T and B cell receptors

Answer 2

• B cells recognize the non-processed antigens

- T cells need presentation of peptides by MHC molecule (from APC)

Question 3

Structure of immunoglobulin

Answer 3

• 2 same heavy chains and 2 same light chains in mirror image configuration
• Each has an N terminus (amino end): variable part of Ig -> responsible for identification of antigens
• C terminus (carboxyl): constant regions

Question 4

Function of affector and effector regions of antibody

Answer 4

Affector region: connects to surface of antigen

Effector region: can execute the function of the molecule, not limited only to the Fc region of the molecule

Question 5

Can TCR be found in soluble form? Why/why not

Answer 5

No, always attached to a cell. Because T cells can only recognize antigens presented by other cells

Question 6

Heavy chain will be generated from..

Answer 6

One random V (65), D (27), and J(6) -> gives a great diversity

Question 7

The naive B-cell R only expresses immunoglobulins..?

Answer 7

IgM and IgD

Question 8

Isotopic difference

Answer 8

Means different heavy chains

Question 9

Allotypic difference

Answer 9

Genetically determined difference in antibodies between people (can be a small difference in light/heavy chain)

Question 10

Idiotypic difference

Answer 10

Different combinations at the end of the variable region

Question 11

What mediates the rearrangement in TCR

Answer 11

RAG1/RAG2 enzyme complexes (recombinases)

Question 12

Function of papain

Answer 12

Proteolytic cleavage at hinge region -> Fab and Fc separated