5.5 Antibodies Flashcards
What is an antibody?
A highly specific protein that is produced by B cells and secreted by plasma cells that bind onto an antigen to destroy it.
How many identical binding sites to antibodies have?
2
How many polypeptide chains are antibodies a made up of?
4
What are the two chains in antibodies called?
Heavy chains
Light chains
The specific binding site on an antibody that fits very precisely onto a specific antigen to form what is known as an _______-________ _______.
Antigen-antibody complex
What part of the antibody is different in different antibodies?
Variable region
What is the region called that is the same on all antibody’s?
Constant region
How do antibodies assist in the destruction on a bacterial cell? (2 ways)
- cause agglutination of bacterial cells, clumps of bacterial cells are formed, making it easier for phagocytes to locate them.
- serve as markers that stimulate phagocytes to engulf the bacterial cells to which to which they are attached.
How are monoclonal antibodies used to treat cancer?
Monoclonal antibodies are specific to antigens on cancer cells, attach to the surface of the cancer cells and block chemical signals that stimulate their uncontrolled growth.
What is the advantage to using direct monoclonal antibody therapy?
Antibodies aren’t toxic and are highly specific, lead to fewer side effects than other forms of therapy.
Another method of treating cancer is indirect monoclonal antibody therapy, how does this work?
Involves attaching a radioactive or cytotoxic drug to the monoclonal antibody, and when it attaches, it kills the cancer cell.
How does a pregnancy test kit work?
If a pregnant lady urinates on the strip, and her urine contains the hormone hCG, the antibody will bind onto the hCG and move up the strip until it reaches another antibody where it will cause a coloured line.
How does the ELISA test work?
- antibodies bound to bottom of container, solution added and if complementary antigen is present they will bind together
- secondary antibody attached to an enzyme is added, if first antibody has bound onto an antigen, the secondary antibody will too
- a substrate is added and a colour change will be present if the enzymes react with it
How are monoclonal antibodies produced?
Inactive antigen injected into a rat, this produces a B lymphocyte which is then fused together with a tumour cell to form a hybridoma. Monoclonal antibody is now formed.
What bond holds the 4 polypeptide chains together in an antibody?
Disulfide bridge
