Antibodies Flashcards
Immune system
What are antibodies made up of?
A quaternary protein of two pairs of 2 polypeptide chains
What are the polypeptide chains known as?
One pair are long and called the ‘heavy’ chain, the other are shorter and called the ‘light’ chains
What is the structure of an antibody?
A Y shape with two antigen binding sites on the tips of the Y and a receptor binding site at the bottom of the Y
What do the antigen binding sites do on an antibody?
Recognise and bind to specific antigens
What does each binding site consist of?
A sequence of amino acids that form a specific 3-D shape that binds directly to a specific antigen
Where is the variable region?
On the tips of the Y where the antigen binding sites are
Where is the constant region?
The bottom part of the Y shape containing the receptor binding site
Where is the hinge region on an antibody?
At the base of the ‘arms’ of the Y
What does the hinge region allow the antibody to do?
Allows the ‘arms’ of the antibody to move to bind better to antigens
How do antibodies destroy an pathogen?
(two ways)
- Causes the pathogens to agglutinate and stimulate phagocytes to engulf the pathogens they are attached to
- Antitoxins bind to the toxins produced by pathogens and neutralise them
What is a monoclonal antibody?
Antibodies produced from clones of a single plasma cell and therefore are all identical
Why are monoclonal antibodies needed?
Can target cells as they have a high specificity and only bond to one antigen
What is the first step in the process of producing monoclonal antibodies?
Expose mice to a foreign antigen, which makes their B cells produce antibodies
What is the step after the mice B cells produce antibodies in the process of producing monoclonal antibodies?
The antibodies are extracted from the spleen
What is the step after antibodies are extracted from the mice’s spleen in the process of producing monoclonal antibodies?
The antibodies are mixed with cancer cells to ensure they divide rapidly
What happens after the antibodies are mixed with cancer cells in the process of producing monoclonal antibodies?
They are fused together to form hybridoma cells
What is the last step in the process of producing monoclonal antibodies after the hybridoma cells are made?
The hybridoma cells are sorted and the ones producing the required antibody are separated and grown on a larger scale
What are the 4 uses of monoclonal antibodies?
- Treating cancer
- Transplants, anti-rejection
- Immunoassays
- Indirect and direct ELISA tests
How can monoclonal antibodies treat cancer?
They can be shaped to fit only to cancer cells.
The presence of mAbs attached to cells activates cytotoxic drugs.
This is targeted cellular destruction
How can monoclonal antibodies be used as anti-rejection?
- T cells recognise foreign tissue
- Causes rejection
- mAbs made to recognise T cells and ‘knock them out’
What immunoassays can monoclonal antibodies be used in?
- Drug testing kits
- Pregnancy tests
- Detecting AIDS
What is the first step of the process of a direct ELISA test?
The virus sample is placed on the surface
What is the second step of the process of a direct ELISA test after the virus sample is placed on the surface?
An antibody with an enzyme conjugate attaches to the viral antigen
What is the last step of the process of a direct ELISA test after the enzyme conjugate attaches to the viral antigen?
The substrate and enzyme interaction creates a colour change for detection
