monoclonal antibodies (topic 3). Flashcards
what is an antibody (2)
- a protein molecule
- made by the immune system
- destroys pathogens
scientists are using mice to make the antibodies against heroin, describe how monoclonal antibodies against heroin can be produced in a laboratory (6)
- inject heroin/drug into mice
- lymphocytes are made and collected
- lymphocytes are fused with tumour/myeloma cells
- fusion of lymphocytes and myeloma cells produces hybridoma cells
- hybridoma cells make antibodies against heroin
- antibodies are collected and purified
explain why these antibodies would not work against another drug such as cannabis (1)
antibodies are specific (antibodies only bind to one drug/type of pathogen/antigen)
drug companies have developed new drugs to treat ebola, explain what testing must be done before the drugs can be used to treat people (4)
pre-clinical trials:
- on cells
- test toxicity, dosage and efficacy
clinical trials:
- clinical trials test on healthy volunteers and patients at very low doses
- monitor for side effects + safety
clinical trials - double blind trials:
- only then do trials to find the optimum dosage and test for efficacy
- placebo does not contain the new drug
peer-reviewing of data:
- data is peer-reviewed
- prevents false claims
there are currently two treatments approved to treat ebola in adults and children, one of the drugs, ebanga, is made of monoclonal antibodies, describe how scientists produce monoclonal antibodies (3)
- inject the antigen into a mouse
- combine lymphocytes with tumour (myeloma) cells to make hybridoma cells
- find a hybridoma which makes a monoclonal antibody specific to the ebola virus
- the scientist clones the hybridoma to produce many cells to make the antibody
explain how monoclonal antibodies can be used to help diagnose some diseases (3)
- monoclonal antibodies bind to antigens
- antigens are found on specific pathogens
- the monoclonal antibodies carry a marker
- the marker enables the disease to be identified
why are lymphocytes combined with tumour cells to produce hybridoma cells (2)
- lymphocytes have a limited life (but produce antibodies)
- tumour cells are immortal (but do not produce antibodies)
- hybridoma cells produce antibodies AND can divide indefinitely
explain how the pregnancy test strip works to show a positive result (4)
- as urine passes through the reaction zone
- if present, hCG hormone binds to the mobile hCG antibody in the reaction zone
- if present, hCG hormone moves up the test and binds to the immobilised hCG antibodies in the result window
- the other antibodies which do not attach to hCG bind to antibodies in the control window
- blue dye appears in both the control and the result zones to show positive result
give two more uses of monoclonal antibodies in medicine, other than pregnancy tests (2)
- identify specific molecules
- find blood clots
- diagnose some cancers
- treat some cancers
fire blight is a bacterial disease that affects many species of plants, including apple and pear trees, scientists have made monoclonal antibodies that recognise the bacteria that cause fire blight, describe how scientists make monoclonal antibodies (4)
- collect sample of bacteria from tree
- extract/isolate antigen from bacteria
- inject the bacteria/antigen into an animal/mouse
- take antibody-producing cells from the animal/mouse
- identify/isolate the cell that is making antibodies against the bacteria/antigen
- grow/clone this cell (in culture)
give one advantage and one disadvantage of using monoclonal antibodies (2)
- mAbs are specific (or allow accurate detection of pathogens)
- mAbs are sensitive
- mAbs can be produced in large quantities
- mAbs can be modified with other molecules for visual identification
_ - making mAbs is complex
- making mAbs is expensive
- mAbs are derived from animals, so there might be ethical considerations
mAbs are a mixture of different types of antibodies
scientists have produced a monoclonal antibody to treat pancreatic cancer, explain how the monoclonal antibody works to treat pancreatic cancer (3)
- monoclonal antibody is attached to radioactive substance (or toxin or drug or chemical)
- monoclonal antibody will only attach to antigen on cancer cells
- so radioactive substance (or toxin or drug or chemical) will bind to cancer cells and stop them growing
scientists have used human lymphocytes to make monoclonal antibodies to some types of cancer cells, suggest one reason why these mAbs have been more successful in treating diseases in humans than mAbs made using mice (1)
- the body will not reject the mAbs
- mouse mAbs are more likely to be rejected
- the human lymphocytes have already responded to that cancer cell so they are known to work against the disease
