Week 8: Modern Antibody Therapy Flashcards
What is polyclonal antibodies?
- Bind to various epitopes on a specific antigen
- From many B cells
- Obtained from donation of blood products
What is monoclonal antibodies?
- Produced by one B cell clone
2.
What is monoclonal antibodies?
- Produced by one B cell clone
- Bind to a specific epitope on a given antigen
- Same antigen binding site
- More expensive
- No batch to batch variability
What secret polyclonal antibodies?
Multiple clones of antigen specific B cells
How is polyclonal antibodies derived?
- An experimental animal or human subject is immunized with Ag one or more times
- Subject is bled and Ab is purified from serum
What are the pros of polyclonal?
A mixture of Ab directed toward a variety of epitopes are formed, good for agglutination and immunoprecipitation
What are the cons of polyclonal?
- May produce cross-reactivities against other Ag
- Different bleed points may yield different degrees of affinity
What produces monoclonal antibodies?
Product of a single stimulated B cell
What produces monoclonal antibodies?
Product of a single stimulated B cell
How is monoclonal antibodies derived?
- Fusion of B cells and immortalized myeloma cell
- Technique includes HAT selection medium for fused cells
- Produces mass quantities of single specificity Ab
What is passable polyclonal antibodies?
Antibodies being passed from one host to another
What is convalescent plasma CCP?
- Plasma is obtained from recovered individual by plasmapheresis
- Plasma is collected at 14 days past infection who meet strict criteria for donating blood
- Polyclonal antibodies neutralize pathogen
What is plasmapheresis?
The process of separating plasma from whole blood components
What does convalescent plasma CCP treat?
- H1N1 influenza
- 2003 SARS CoV 1
- 2012 MERS CoV
- COVID 19
What is intravenous immunoglobin (IVIG) used for?
- Mostly IgG and varying IgA
- Provides passive immunity through the transfer of antibodies from one host to another
- Cna neutralize a wide range of antigens and superantigens
- Can provide immunoregulatory effects by suppressing functions of effector cells
What are therapeutic proteins?
- Monoclonal antibodies
- ANtibodies
- Hormones
- Cytokines
- Enzymes
How are the characteristics monoclonal antibody production?
- mAb’s are large complex proteins
- Contain multiple disulfide bonds
- Glycosylated (post-translational modification)
- Require eukaryotic machinery to produce active form of protein
- Hybridoma technology was developed in 1975
How are monoclonal antibodies produced?
- Immunize animal with an antigen we want to target.
- Isolate B cells from the spleen of the immunized animal.
- Fuse immunized B cells with myeloma cells (tumor plasma cells) to form a hybridoma which will produce antibodies forever.
- Grow up the cells in a special media that will kill myeloma cells and B cells but will allow hybridoma cells to grow.
- A hybridoma will produce identical antibodies of a single specificity-monoclonal antibodies.
What are the approaches of therapeutic antibody development?
- Mouse hydridoma
- Phage display
- Transgenic mouse
- Single B cell
What are the monoclonal antibody structures?
- Murine
- Chimeric
- Humanized
- Fully
What is murine mABs?
Fully derived from mice
What is chimeric mABs?
Murine variable region is spiced into the human constant region (70% human)
What is humanized mAbs?
Murine hypervariable regions (CDRs) spliced into a human antibody (80-95% human)
What is fully human mABs?
Completely derived from human sequence
What is the suffix -cept?
Fab portion has be replaced with a receptor protein sequence
What is guidance for industry?
FDS’s nonproprietary naming of biological products
How are biologics named?
- Monoclonal antibody core name
- Distinguishing, nonproprietary suffix
- Devoid of meaning
- 4 lowercase letters
What are the limiting factors of therapeutic antibodies?
- Immunogenicity
- Ability to reach the target tissue and with sufficient concentration
- Ability to trigger a particular biological effect that would modify a disease process
What is immunogenicity?
Ability of a substance to induce an immune response
What is immunogenicity good for?
- An infection but bad for therapeutic antibodies
- Leads to the production of anti drug antibodies (ADAs) that bind to and neutralize the therapeutic mAB thereby increasing clearance and decreasing efficacy
What are immunogenicity?
Contain epitopes that induce an immune response and are also targets of this immune resposne
What is reaching target tissue with sufficient concentration?
- Specificity for the target
- Antibody affintiy