CELLS: Antibodies in Medicine Flashcards
What are monoclonal antibodies?
Antibodies produced from a single group of genetically identical B-cells.
This means they are identical in structure.
Why are monoclonal antibodies useful in medicine?
Because they are very specific (due to their unique tertiary structures) they can be made to bind to anything that you want them to.
Give three examples of how monoclonal antibodies can be used in medicine and healthcare:
- Targeting drugs to a particular cell type - eg, cancer cells.
- Targeting a particular substance for medical diagnosis - eg, pregnancy testing.
- Using an ELISA to test for HIV
Name a way that monoclonal antibodies can be used to target a particular substance for medical diagnosis:
Pregnancy testing.
What hormone do pregnancy tests detect?
Human chorionic gonadotropin (hCG).
This is found in the urine of pregnant women.
Describe how a pregnancy test works:
- Application area contains antibodies for hCG bound to a coloured blue bead.
- When urine is applied any hCG will bind to the antibody on the beads - forming an antigen-antibody complex.
- Urine moves up test strip, carrying beads with it.
- Test strip contains antibodies to hCG that are immobilised in a line.
- If hCG present, the test strip turns blue.
In pregnancy tests, why might the test strip turn blue?
The immobilised antibodies bind to any hCG - this concentrates the hCG-antibody complex with the blue beads attached along the line.
Where is hCG produced?
In the placenta.
Describe direct monoclonal antibody therapy in cancer treatment:
Give an example.
- Monoclonal antibodies produced that are specific to tumour markers on cancer cells.
- Antibodies given to patient and attach themselves to cancer cells.
- Block the chemical signals that stimulate their uncontrolled growth.
Herceptin, used to treat breast cancer.
What is an advantage of direct monoclonal antibody therapy?
Antibodies are not toxic and are highly specific, so have fewer side effects than other treatments as they are less likely to damage healthy cells.
Describe indirect monoclonal antibody therapy in cancer treatment:
- Involves attaching a radioactive or cytotoxic drug to the antibody.
- When antibody attaches to cancer cells, it kills them.
What are the advantages of indirect monoclonal antibody therapy?
- Only required in small doses, so is cheaper.
- Also produces fewer side effects.
ELISA test.
Medical diagnostic test that uses antibodies.
What does ELISA stand for?
Enzyme-linked immunosorbent assay.
8 points
Describe how an indirect ELISA test can be used to see if a patient possesses antibodies to the HIV virus:
- HIV antigen is bound to bottom of well in a well plate.
- Sample of patient’s blood plasma is added to the well.
- Any HIV-specific antibodies will bind to HIV antigen stuck to the bottom of the well.
- Well washed out to remove unbound antibodies.
- Secondary antibody, that has specific enzyme attached, is added to the well.
- Secondary antibody can bind to HIV-specific antibody.
- Well is washed out again to remove any unbound secondary antibody - if there’s no primary antibody in sample then all of secondary antibody will be washed away.
- Solution is added to well, creating a substrate which is able to react with the enzyme attached to secondary antibody and produce a coloured product.
