Monoclonal Antibody

Question 1

How many chains make up Ig?

Answer 1

4

Question 2

What does the immunoglobulin fold result in?

Answer 2

strongest structure in protein biology

Question 3

What does IgG have?

Answer 3

Sugar that is glycosylated making it a glycoprotein

Question 4

What is long-term immunity down to>

Answer 4

Antibody production & secretion

Question 5

What type of response occurs due to infection?

Answer 5

Polyclonal response

Question 6

What is the polyclonal response?

Answer 6

Antigen cross-linking by multiple antibodies

Question 7

Can you mimic the polyclonal response and why?

Answer 7

No - we need to find one monoclonal antibody that recognizes one epitope

Question 8

For clinical treatment what do we need the monoclonal antibody to be?

Answer 8

Specific
High binding affinity for target

Question 9

What is the immunoglobulin structure?

Answer 9

Tetrameric - 4 peptide chains joined by disulfide bonds

Question 10

What region of the Ab is the antigen binding site?

Answer 10

Fab

Question 11

What section is critical for pharmacokinetics?

Answer 11

Fc - trunk

Question 12

What are characteristics of the finger part of the Ab?

Answer 12

hyper variable - short gene segments any combination of aa
Binds antigens

Question 13

Define clinical pharmacokinetics?

Answer 13

Application of pharmacokinetic principles to the safe & effective therapeutic management of drugs in an individual patient

Question 14

What part of the antibody is the PK profile relevant to?

Answer 14

Fc portion

Question 15

What are 4 desirable characteristics of antibody drugs?

Answer 15

Good stability & solubility
long persistence
high selectivity & specificity
low risk for bioconversion to toxic metabolites

Question 16

What is half life?

Answer 16

Time taken for serum conc. of drug to decrease by half its steady state conc

Question 17

What is difference between selectivity & specificty?

Answer 17

Selectivity - breast cancer tissue
specificity - receptor on breast cancer cell

Question 18

What does CDR stand for?

Answer 18

complementary determining regions

Question 19

What is a paratope?

Answer 19

sequences of Ab making contact with antigen?

Question 20

What is the epitope?

Answer 20

Sequence of antigen making contact with Ab

Question 21

What is the CDR responsible for?

Answer 21

Aa in CDR have right chemistry & folded in right way for interface for epitope & paratope bonding

Question 22

What is the half-life of Abs down to?

Answer 22

Salvage from lysosomal pathway by FcRn

Question 23

What is the MoA of salvaging Ab?

Answer 23

Fc gamma receptor binds to Fc portion ->
Internalized in early endosome -> pH in endosome drops ->
Antibody stops recognizing each other -> new receptor takes over (FcRn) -> rescues Ab ->
Returns to surface and is let go

Question 24

What gives pH control in IgG and FcRn recognition?

Answer 24

Glycoprotein

Question 25

What are 4 downfalls of IgG?

Answer 25

Not orally available incomplete absorption following IM or SC admin nonlinear distribution/elimination leads to endogenous antibody response - alter efficacy

Question 26

Who were the first to produce the first murine mAbs from hybridomas?

Answer 26

Kohler & Milstein

Question 27

What were 4 downfalls of murine mAbs?

Answer 27

Allergic reaction induction of anti-drug antibodies short half life poor recruiters of effector function ADCC & CDC

Question 28

What is muromonab-CD3?

Answer 28

immunosuppressant drug reducing acute rejection in organ transplants

Question 29

What does muromonab-CD£ target?

Answer 29

CD3 receptor on T cells

Question 30

What was developed to overcome downfalls of murine Ab?

Answer 30

Chimeric mouse-human antibodies were developed (ximab)

Question 31

How was ximab made?

Answer 31

grafting antigen-specific variable domain of mouse (35%) onto constant domains of human Ab (65%)

Question 32

What was the final engineered mAb?

Answer 32

humanized (zumab) developed

Question 33

What is the zumab?

Answer 33

Murine hypervariable regions (CDR) onto human Ab framework (95% human)

Question 34

What four thing does targeted cancer therapies do?

Answer 34

interferer with cell growth signaling or tumors blood vessel development promote cancer cell death stimulate immune system to destroy specific cancer cells deliver toxic drugs

Question 35

What are 4 targets for cancer biology?

Answer 35

VEGF EGFR CD19 immune checkpoints

Question 36

What is HER2?

Answer 36

receptor tyrosine kinase essential for cell division & proliferation eg. Cardiac myocytes

Question 37

What are tyrosine kinase domains activated by?

Answer 37

Homodimerization & heterodimerization generally induced by ligand binding

Question 38

What happens when receptor overexpression or mutation occurs?

Answer 38

Induce dimerization - promote cellular proliferation & survival

Question 39

What does HER2 signalling promote cell growth through?

Answer 39

RAS-MAPK pathway

Question 40

What does HER2 signalling inhibit cell death through?

Answer 40

PIK3 AKT (target of mTOR) inhibits apoptosis

Question 41

What does trastuzumab target?

Answer 41

juxtamembrane (epitope) portion of EC domain of HER2 receptor -> prevents tyrosine kinase activation

Question 42

What doe preclinical models of Trastuzumab suggest?

Answer 42

recruits immune effector cells responsible for antibody-dependent cytotoxicity

Question 43

What is the loading dose of trastuzumab?

Answer 43

8mg per kg given IV

Question 44

What is a side effect of trastuzumab?

Answer 44

5% had cardiotoxic effects

Question 45

Why are people primarily resistant to trastuzumab?

Answer 45

Breaking of EC domain leaving P95 has already occurred - patients have already lost EC before treatment - epitope is gone

Question 46

What % of patients develop secondary resistance to Trastuzumab?

Answer 46

70%

Question 47

Which 2 proteins play are role in primary/acquire resistance to trastuzumb?

Answer 47

PTEN Src