Antibodies in Medicine Flashcards
How are monoclonal antibodies produced?
Monoclonal antibodies are produced from a single group of genetically identical B-cells (plasma cells). This means they’re identical in structure
Can you make monoclonal antibodies?
You can make monoclonal antibodies to bind to anything you want
How can you target drugs to cancer cells?
- Different cells in the body have different surface antigens
- Cancer cells have antigens called tumour markers that are not found on normal body cells
- Monoclonal antibodies can be made that will bind to the tumour markers - anti-cancer drugs are attached to the antibodies
- When the antibody comes into contact with the cancer cells they will bind to the tumour markers
- This means the drug will only accumulate in the body where there are cancer cells
- The side-effects of an antibody-based drugs are lower than other drugs because they only accumulate near specific cells
What hormone do pregnancy tests detect?
The human chorionic gonadotropin (hCG) hormone found in the urine of pregnant women
How do pregnancy tests work?
- The application area contains antibodies for hCG bound to a coloured bead (blue)
- When urine is applied to the application area any hCG will bind to the antibody on the beads, forming an antigen-antibody complex
- The urine moves up the stick to the test strip, carrying any beads with it
- The test strip contains antibodies to hCG that are stuck in place (immobilised)
- If there is hCG present the test strip turns blue because the immobilised antibody binds to any hCG - concentrating the hCG-antibody complex with blue beads attached. If no hCG is present, the beads will pass through the test area without binding to anything, so it won’t go blue
What is the ELISA test?
The enzyme-linked immunosorbent assay (ELISA) allows you see if any patient has any antibodies to a certain antigen or any antigen to a certain antibody
What can the ELIZA test be used to test for?
It can be used to test for pathogenic infections, allergies and anything you can make an antibody for
What happens in an ELIZA test?
In an ELIZA test, an antibody is used which has en enzyme attached to it. This enzyme can react with a substrate to produce a coloured product. This causes the solution in the reaction vessel to change colour. If there’s a colour change, it means that the antigen or antibody in interest is present
In an ELIZA test what does the intensity of the colour change mean?
In some ELIZA tests, the quantity antigen/antibody can be worked out from the intensity of the colour change
What are the two types of ELIZA test?
- Direct ELIZA - this uses a single antibody that is complimentary to the antigen you’re testing for
- Indirect ELIZA - this uses two different antibodies that is complimentary to the antigen you’re testing for
What type of ELIZA test is used to detect for antibodies to the HIV virus?
Indirect ELIZA
Explain how an indirect ELIZA test is used to test for antibodies to the HIV virus
HIV antigen is bound to the bottom of the well in a well plate
A sample of blood plasma is added to the well. If there are any HIV-specific antibodies these will bind to the HIV antigen stuck to the bottom of the well. The well is washed out to remove any unbound antibodies
A secondary antibody, that has a specific enzyme attached, is added to the well. This secondary antibody can bind to the HIV-specific antibody. The well is washed out again to remove any unbound secondary antibody. If there’s no primary antibody in the sample, all of the secondary antibody will be washed away
A solution is added to the well that contains a substrate which can react with the enzyme attached to the secondary antibody to produce a coloured product. If the solution changes colour, it indicates the patient has HIV-specific antibodies in their blood and is therefore infected with HIV
