Biopharmaceutical products ic5 and Hba1c, Insulin IC6 Flashcards
2 purification techniques for antiserum
1) Protein A/G purification
2) Immunoaffinity column chromatography
Differences between Mouse MAB, Chimeric MAB, Humanised MAB, Recombinant Human MAB (structure, % human, immunogenicity)
Murine (mouse) MAB
Produced by 1 B cell clone from mouse, hence have the same CDRs → recognise 1 epitope
High specificity → used for immunoaffinity chromatography of polyclonal antibodies (prev point)
High homogeneity → Result is highly reproducible
Therapeutic molecule with less side effect
Diagnostic test kit
Limitations
Immunogenic → Have short half life
Develop antibodies against monoclonal antibodies
Chimeric MAB
Variable (Vh, Vl): Mouse
Constant: Human
Still retains antigen selectivity and affinity
75% human → less immunogenicity
Humanised MAB
Mouse: Hypervariable CDR domains in Vh, Vl
> 90% human
CDR binds to epitope
Recombinant Human MAB
Using culture human cells
Fully human
High cost
What are antibody derivatives and Why are antibody derivatives created
Antibody derivatives dont have Fc region compared to antibodies
Inhibit enzymes, bind to active site
Neutralise receptor ligands eg. hormones, cytokines
Overproduction of cytokines (cytokine storm)
Neutralise snake venom
What is the Fc domain for?
Fc domain binds to Fc receptor of first line innate immunity (effector cells) eg. macrophages, NK cells
Ig conjugate is a full length antibody. How can it be an antibody derivative?
Ig conjugate tagged to cytokine, radioisotope, toxin
When antibody binds to cell receptor to form complex, complex is taken up by cell
Cytokine / Radioisotope / Toxin exerts lethal effect on cell
Which enzymes cleaves to form Fab2 VS Fab
Fab2: pepsin
Fab: papain
What does fucose do
Fucose reduces binding affinity for Fc domain to bind to activating Fc receptor on effector cells eg. Macrophage, Neutrophils
What is Fc domain in Triomab used for?
Fc receptor needed to mediate Complement-dependent cytotoxicity (CDC) and Antibody-dependent cellular cytotoxicity (ADCC)
Describe TIL therapy (indication, process, advantages and limitations)
For solid tumours
Tumour infiltrating Lymphocytes are autologous, isolated from tumour masses and expanded by REP (Rapid Expansion Process). Then infused back into patient
Advantage: generally safe, because autologous (belong to patient)
Limitations: Low quantities of TIL, expanded T cells possess various antigen specificities, may not be specific enough, May not possess high affinity
Describe TCR therapy (indication, process, advantages and limitations)
For blood tumours
Genetically modify gene encoding for Va and Vb of TCR to create tumour antigen specific cells
Describe CAR-T therapy (indication, process, advantages and limitations)
Chimeric Antigen Receptor
ScFv region, bonded to signalling domains
Advantages of TCR and CAR-T therapy
TCR:
Context: TCR has full TCR complex. This allows them to:
1) Effective for both solid and blood tumours
2) Be activated at low antigen quantities -> TCR complex allows signal transduction and amplification
3) slower onset but longer killing
CAR:
1) Faster onset
2) ScFv only binds to cell surface antigens -> hence can only target blood tumours
3) Not limited to MHC binding, can bind to antigen without MHC
Disadvantages of TCR and CAR
Both:
Cytokine storm (CAR more than TCR)
On target off tumour toxicity
Off target toxicity
TCR:
1) Low specificity to MHC as MHC is polygenic and polymorphic
2) less safe than TIL therapy
CAR:
1) Activated only at higher antigen levels
2) Faster onset but less extended killing
3) Antigen independent mechanism
What form does B cells in pancreas produce insulin
Pre-proinsulin
What is removed in conversion from pre-proinsulin to proinsulin
Signal peptide (23 amino acid)
