Monoclonal Antibodies - 19/12/23 Flashcards
What are monoclonal antibodies?
A single type of antibody that’s been cloned after being released from a B cell.
What are the Useful Functions of Monoclonal Antibodes?
- Direct therapy
- Medical Diagnosis
- Pregnancy Testing
- Indirect Therapy
What is an example of indirect monoclonal antibody therapy?
Attaching a radioactive/cytotoxic drug (something that’ll kill the cell) to a monoclonal antibody that’ll bind to a specific antigen
Explain how you can target medications to specific cell types.
[3]
- Radioactive or cytotoxic drugs are attached to an monoclonal antibody
- Antibody is used to direct the drug towards cells with a certain antigen (cancer cells with tumour markers)
- This attaches to antigen, and targets specific cell - the drug takes place
What are some Strengths of Indirect therapy?
[3]
- It’s specific - less side effects
- Only low doses needed
- Cheaper
Why is indirect therapy called ‘indirect’?
Because it’s not the monoclonal antibody that actually kills a cell - it only targets it
What is a real life example of Indirect therapy of monoclonal antibody?
Herceptin targetting breast cancer cells
What happens in Direct therapy?
[4]
- Monoclonal antibodies that are specific to antigens found on surface of cancerous cells can be used
- It can bind to receptors on cancer cells
- And blocks chemical signals that stimulate uncontrolled cell growth
- This destroys the cells
What are strengths of Direct therapy?
[2]
- Specific and non-toxic
- Fewer side effects
What does ELISA stand for?
Enzyme-Linked Immunosorbent Assay
What is ELISA and what’s it used to identify?
[2]
- ELISA are monoclonal antibodies are used to detect prescence and concentration of specific protein
- Detects prescence and quantity of antigen found on HIV
How can ELISA detect low levels of a certain antigen?
It’s very sensitive
Describe how a direct ELISA test tests for prescence of HIV.
[7]
- A direct ELISA uses a single antibody that’s complementary to HIV antigen
- HIV antigen are bound to inside well of well plate
- A detection antibody with attached enzyme that’s complementary to HIV antigen added
- If HIV antigen is present the detection antibody will bind to it
- Well is washed out to remove any unbound antibody
- Substrate solution added
- If detection antibody is present, enzyme reacts with substrate to give colour change
Describe how an Indirect ELISA test might detect HIV.
[5]
- Monoclonal antibody complementary to HIV antigen bound to well of test plate
- Blood from patient added. Only HIV antigen binds - other antigens don’t
- Enzyme linked antibody added. Only binds if antigen-antibody complex present
- Well is washed out to remove antibodies
- Colourless substrate for enzyme is added
- Enzyme converts substrate to coloured product that can be detected
Describe how pregnancy tests work with the help of monoclonal antibodies.
[6]
- Application area of stick contains antibodies that are complementary to the HCG protein, bound to blue coloured bead
- When urine applied, any HCG binds to antibody on beads, forming antibody-antigen complex
- Urine moves up stick to test strip, carrying any beads with it
- The test strip contains antibodies to HCG that’s stuck in place (immobilised)
- If any HCG present, test strip turns blue because immobilised antibody binds to any HCG present with antibody with blue beads attached
- If no HCG attached, beads move through test area without binding to anything, and so it first part isn’t blue
