Antibodies Flashcards
What are antibodies?
They are proteins with specific binding sites synthesised by B cells.
Why do antibodies have two specific binding sites?
The antibody binding sites are complementary to a specific antigen.
Describe the four polypeptide chains of antibodies?
Heavy chains and long chains
When an antibody binds to the antigen what is formed?
Antigen-antibody complex, the binding site is called the variable region as it varies form antibody to antibody
Excluding the binding sites, what is the region called?
The constant region
Do antibodies directly destroy antigens?
No they prepare the antigen for destruction.
What Is agglutination?
Bacterial cells are clumped together to make it easier for phagocytes to locate them as they are less spread out within the body.
After agglutination what do antibodies do?
They serve as markers that stimulate phagocytes to engulf the bacterial cells to which they are attached.
What is a monoclonal antibody?
A type of antibody that outside the body can be isolated and cloned.
Describe monoclonal antibody therapy.
Mc antibodies are produced that are specific to antigens on cancer cells
Given to patient and attach to receptors of cancer cells
They attach to the surface of their cancer cells and block chemical signals that stimulate uncontrolled growth
E.g. herceptin.
Name an advantage of monoclonal antibody therapy.
The antibodies are not toxic and are high specific so lead to fewer side effects than other therapies.
What does indirect monoclonal antibody therapy involve?
Attaching a radioactive or cytotoxic drug to the monoclonal antibody, when the antibody attaches to the cell, it kills them.
How does a pregnancy test work?
The placenta produces a hormone called human chorionic gonadotrophin (hCG) that is found in the Urine of the mother, if present it binds to the antibodies and the hCG-antibody-colour complex moves along the strip until it it trapped by a different type of antibody, creating a coloured line.
What are the ethical issues associated with monoclonal antibodies?
The production involves inducing cancer in mice.
Associated with some deaths and side effects.
In a trial in 2006 volunteers suffered organ failure as a result of taking them.
Informed consent is important.
