Monoclonal Antibodies Flashcards
What is a monoclonal antibody?
An antibody from a white blood cell is extracted and cloned, theyre produced from a single clone of cells
Which WBC’s are used to produce monoclonal antibodies?
Ones that produce antibodies known as B-lymphocytes
Why are monoclonal antibodies important?
- if you know the type of antibody that the body needs to fight a pathogen, being able to isolate and do this, you can produce many of them
- they can be injected into a person with the disease
How do monoclonal antibodies work?
1) . They’re specific to one antigen and can attach to it, helping the pathogen to be destroyed
2) . Some MA are able to bind to receptor sites on chemical eg toxins by bacteria
3) . They are extracted from the lymphocyte and are copied many times
4) . They can be injected into patient with a needle
How are monoclonal antibodies made?
1) . mouse lymphocytes are stimulated to make a particular antibody
2) . they are then combined with a tumour cell in a combination called Hybridoma
3) . Hybridoma can then divide and make the antibody 4). single hybridoma cells are cloned and produce identical antibodies, they are collected and purified
5) . They are then injected
Why are B-Lymphocyte and tumour cells used together?
B-lymphocytes dont divide easily (mitosis) and are then hard to obtain
Tumour cells divide easily and can be grown easily in a lab. They dont produce antibodies
Why do cancerous cells have different antigens to healthy body cells?
Mutations in their DNA
What can monoclonal antibodies do for cancerous cells?
they target specific cells ie the cancer cells as they only bind to the tumour markers, so the drug kills the cancer cells and leaves normal cells alone
How do monoclonal antibodies work in cancer?
an anti cancer drug can be attached to these MA, it may be a radioactive substance, a toxic drug or a chemical which stops cancer cells growing or diving
What does a pregnant woman produce?
A hormone called HCG in her urine
What do pregnancy tests contain?
A monoclonal antibody which binds to the hormone, the antibodies have blue beads attached to it
How do pregnancy sticks work?
1) . Woman urinates in the stick with the antibodies in it
2) . Hormone HCG binds to the antibodies with the blue beads
3) . The urine travels up the stick carrying the antibodies and beads
4) . The hormone/bead/antibody bind to more antibodies which are attached to the strip in the pregnancy stick
5) . The blue beads get stuck to the strip, turning it blue
What happens if you are not pregnant?
Urine still travels up the stick with the blue beads but there is nothing to stick the blue beads to the test strip so it doesnt turn blue
What are the advantages of monoclonal antibodies?
- they leave healthy cells alone
- cancer treatment
- are cheaper to use as you can have a smaller dose
- have fewer side effects than chemotherapy or radiotherapy, as they leave normal cells alone
What are the disadvantages of monoclonal antibodies?
- side effects such as fever, vomiting
- have more side effect than initially expected so they are not widely used as treatments as scientists had originally hoped
What is a drug?
A chemical that changes the way the body works
What happens in stage 1 of laboratory testing?
Drugs are tested on computer stimulation models or human cells/tissue grown in the lab
Why do many substances fail stage 1 of laboratory testing?
They damage the cells or do not work
What limitations does stage 1 of laboratory testing have?
Cannot show the effect of the drug on an entire organism, as the drugs may have side effects for other organs
What happens in stage 2 of laboratory testing?
- The substances are tested in animals
- animals are given a certain amount of the substance and the side effects are monitored
What does the law in UK say about testing?
All new drugs must be tested on two mammals before given to people
What happens in stage 2 part 2 of laboratory testing?
Tested for three things:-
- efficacy of the drug, does it work
- toxicity of drug, how harmful is it
- does, what concentration should be given
What are the pros of animal testing?
- able to see what drugs work for certain illnesses
- safest way to see if the drug is dangerous
- see if there are any side effects
What are the cons of animal testing?
- ethical concerns ic welfare of animals
- have to go through multiple trials especially if 1st one fails
- time consuming and expensive
- not that accurate as humans and animals are not going to get identical results
What happens in phase 1 of clinical testing?
If they pass stage 2 of lab testing, substances are tested on human volunteers
Why do the human volunteers have to be healthy?
- if we tested on a ill person the symptoms of the condition will make drug side effects difficult to see
- if the drug is toxic an unhealthy person may not be able to recover
Why are clinical tests done?
To see whether they are safe for humans to use, allows us to find out whether the drug has any harmful side effects on a normally functioning body
What happens in clinical testing part 2?
If they’re safe, the drugs are tested on people who have the condition or disease
What is the purpose of phase 2 clinical testing?
To find out if the drug actually works and enables the researchers to find the optimum dose
What two groups are patients randomly put into?
- patients given the drug
- patients who are given a placebo
What is a placebo?
A inactive drug that does not work
What is the placebo effect?
When a patient is given the drug, they psychologically begin to feel better as they expect the drug to work
They report fewer symptoms even though the drug isnt working
What does having a control and placebo group allow scientists to do?
To see the actual difference that the drug makes
What are clinical test blind trails? Who knows the difference?
Volunteers do not know whether they are taking the new drug or a placebo.
Researchers know the difference and this van lead to the give away of clues making the test unfair
What is a double blind trial? What does it remove?
Neither the volunteer nor the researcher knows which is the placebo and which isnt.
Removes bias and risk of doctors subconsciously influencing the results
What is peer review? And what does it mean?
If a drug passes all of the previous stages it must be peer reviewed, ie other scientists must check that the work is valid and that the tests are carried accurately
What happens if the drug passes peer review?
Results can be published in a scientific journal
How are monoclonal antibodies used in research?
- bind to hormones and other chemicals in blood to measure levels
- test blood samples
- locate specific molecules in a cell or tissue
what are plants physical defences?
- leaves and stems have waxy cuticles which act as barriers
- cell walls
- layers of dead cells around their stems
what are plants chemical defences?
- antibacterial chemicals which kill bacteria
- produces poisons which deter herbivores
what are plants mechanical defences?
- thorns and hairs
- leaves that droop or curl, when something touches
- some plants mimic other organisms
