Therapeutic Antibodies

Question 1

Monoclonal Antibodies

Answer 1

Laboratory produced molecules that mimic the immune system’s ability to target specific antigens.

Question 2

Discovery of monoclonal antibodies

Answer 2

1975, by Kohler and Milstein.

Question 3

Advantages of Monoclonal Antibodies

Answer 3

1. Highly Specific to target
2. Highly versatile to a range of missions, including carrying payloads, immunotoxins, and radioisotopes.
3. Prolonged half life, IgG can circulate for 8+ weeks
4. Standardized monoclonal antibodies are homogenous
5. Can be produced in large quantities.

Question 4

Limitations of monoclonal antibodies

Answer 4

1. Immunogenicity - immune response, adverse reacions.
2. Costly
3. limited tissue penetration due to ~150kDa size
4. Natural Fc mediated effector functions negatively/have no effect on monoclonal antibodies.

Question 5

Strategies for enhancing monoclonal antibodies.

Answer 5

1. Optimizing affinity
2. Enhancing stability
3. Modifying effector functions

Question 6

Optimizing Affinity

Answer 6

1. Phage display technology
2. Site-Directed mutagenesis
3. Affinity maturation

Question 7

Phage display technology

Answer 7

Bacteriophages can be used to display antibody fragments, which monoclonal antibodies can be tested on in iterative rounds.

Question 8

Site-directed mutagenesis

Answer 8

Amino acid residues in antigen binding site are altered to interaction with target antigen

Question 9

Affinity maturation

Answer 9

Antibody variants are screened for highest binding affinity

Question 10

Example where optimized affinity improved monoclonal antibodies.

Answer 10

HER-2 specific antibodies were optimized for a specific strain of breast cancer

Question 11

Enhancing stability strategies

Answer 11

1. Framework mutations
2. Glycosylation optimization
3. PEGlylation

Question 12

Framework mutations

Answer 12

Mutating the constant region of the antibody increases stability, enhancing antigen binding.

Question 13

Glycosylation

Answer 13

Engineering glycosylation sites in Fc region enhance protease resistance.

Question 14

PEGylation

Answer 14

Attachment of PEG improves antibody solubility into intercellular plasma.

Question 15

Example of enhanced stability

Answer 15

Adalimumab, an anti TNF-a monoclonal antibody is used to treat rheumatoid arthritis and crohns disease.

Question 16

Modifying Effector Functions

Answer 16

1. Fc region engineering
2. Bispecific antibodies
3. Silencing effector functions

Question 17

Fc region engineering

Answer 17

Enhances binding to Fcy receptors improving antibody dependent cellular cytotoxicity (ADCC).

Question 18

Bispecific Engineering

Answer 18

Binding 2 antigens simultaneously for cytotoxic destruction (eg BiTEs - Bispecific T-cell Engangers) kill 2 tumor cells at once)

Question 19

Silencing effector functions

Answer 19

Fc mediated activity is undesirable, eliminating this enhances function.

Question 20

Example of Effector function modified monoclonal antibody

Answer 20

Antibodies targeting PD-1 and PD-L1 has improved checkpoint inhibition in cancer therapy.