Immune system Flashcards
Describe the structure of an antibody. (4 points)
Y shaped glycoproteins called immunoglobulins
Two long identical polypeptide chains (heavy)
Two short identical polypeptide chains (light)
Held together by disulphide bridges
What is the binding site of an antibody?
An area of 110 amino acids on the heavy and light chains called the variable region.
What do antibodies do?
Bind to their specific antigen and trigger an immune response.
What is an opsonin?
A chemical that binds to a pathogen so they can be more easily recognised by phagocytes.
Define an agglutinin
A molecule that causes antibody-antigen complexes to clump together.
What can antibodies do once part of an antibody-antigen complex?
Act as anti-toxins, making them harmless
Prevent pathogens from effectively invading host cells.
Where do B and T Lymphocytes mature?
(B)one Marrow
(T)hymus Gland
What is an interleukin?
A type of cytokine, which stimulate the activity of B cells.
What is the main purpose of B lymphocytes
To provide antibodies that act as cell markers.
What do Plasma cells do?
Provide antibodies to a particular antigen, (about 2000 per second while active)
Are stimulated by interleukins produced by T helper cells.
Which T lymphocyte provides interleukins?
T helper cells
What is the difference between a T and B memory cell?
B- long term immunological memory, programmed to remember a specific antigen.
T- If they meet an antigen a second time, they divide rapidly to produce clones of T killer cells
How are T killer cells used?
Destroy the pathogen by releasing a chemical called perforin which makes holes in the cell membrane.
Describe the process of cell mediated immunity
- macrophages form APC’s
- Receptors of T Helpers fit antigens
- T helpers produce interleukins, producing clones of T cells
