monoclonal antibodies Flashcards
- What are monoclonal antibodies?
Antibodies that are made by plasma B-cells that have been cloned from a single B-cell that makes complimentary antibody to a specific antigen.
- Explain why antibodies are specific to antigens.
Each antigen has a different tertiary structure; so each antibody has a specific antigen binding site; each antibody only binds to complementary antigen.
- What can monoclonal antibodies by used for?
Targeting therapeutic drugs at specific (cancer) cells; Medical diagnosis through the use of ELISA tests; Pregnancy testing;
- How can an ELISA test be used to identify
specific cells in a patient sample.
Add cells to a well and give time for them to adhere to the binding sites at the bottom of the well. Add antibody specific to an antigen present on the cell; the antibody has an enzyme attached to cells; Wash cells to remove excess unattached antibody; add substrate, if a colour change occurs it shows the enzyme/antibody is present and therefore so are the cells.
- Why is it important to wash the plates before adding the substrate?
To remove any unbound antibodies; so there is no unattached enzyme to change the substrate into a coloured product. This would be a false positive.
- Anti-human antibodies are produced by injecting animals with human antibodies, waiting for an immune response and then collecting a blood sample from the animal to collect the B-cells which produce anti-human antibodies. Evaluate the ethical issues of this process.
Use of animals/harm caused to animals when collecting their blood to collect their B-cells however they are not killed and the benefit is that is can save human suffering/death.
- What are the ethical issues surrounding the use of monoclonal antibodies?
Production of monoclonal antibodies involves the deliberate induction of cancer in mice. Some people have reservations about using animals in this way. There have been some deaths associated with the use of monoclonal antibodies to treat diseases. Patients need to be fully informed before starting these treatments. Drug trials have dangers associated with them. When testing monoclonal antibody treatments, volunteers suffered organ failure. Drug trail conduct was changed following this. The benefits and advantages of new medicines must be balanced with the dangers they might bring.
- Explain how an ELISA test can be used to
detect the presence of antibodies in a human blood sample.
Add the specific antigen to the well and allow time for it to adhere to the bottom of the well. Add patient blood sample to the well and give time for the antibodies to adhere to the antigens. Wash the well. Add antibody from another species that are specific to the constant region of a human antibody, these antibodies have an enzyme attached, Wash cells to remove excess unattached antibody; add substrate, a coloured product is produced which shows the enzyme/antibody is present and therefore so are the cells.
- On an ELISA test strip, what is the difference in the function of immobilised antibodies and mobilised antibodies?
Immobilised antibodies cannot move, they are attached to the surface of the strip so will capture antigen as it diffuses past. Mobilised antibodies have the enzyme attached and bind to the antigen and diffuse with it (they can move).
