Immunity Flashcards
Origin of phagocytes
Bone marrow.
Types of phagocytes
Macrophages and neutrophils.
Mode of action of phagocytes
When phagocytes come into contact with bacteria, the receptors on the phagocyte’s surface will bind to them. This binding will lead to the engulfing of the bacteria by the phagocyte. Some phagocytes kill the ingested pathogen with oxidants and nitric oxide.
Types of lymphocytes
B-lymphocytes and T-lymphocytes.
Mode of action of B-lymphocytes
A B-lymphocyte places some of its specific receptor molecules in its cell surface membrane. If it encounters an antigen that binds with this receptor, the B-lymphocyte is activated. It divides repeatedly by mitosis to produce a clone of genetically identical plasma cells.
Mode of action of T-lymphocytes
T-lymphocytes include T helper cells and T killer cells. Both of these types of cell place their specific receptors in their cell surface membranes. These stimulate B-lymphocytes to produce plasma cells, and stimulate monocytes and macrophages to attack and destroy pathogens.
Significance of the increase in white
blood cell count in humans with infectious diseases and leukaemias
A high white blood cell count may indicate that the immune system is working to destroy an infection.
What is an immune response?
A reaction which occurs within an organism for the purpose of defending against foreign invaders.
Role of memory cells in long-term immunity
Memory cells record information for your immune system about how to fight and destroy viruses and the like that plague the body. When a disease strikes the body the memory cells instruct the body on how to produce antibodies. Once created, these antibodies are released into the bloodstream.
Why does the immune
system sometimes fails to distinguish between self and nonself?
If you have an infection that destroys important white blood cells, this weakens the immune system and might fail in recognition.
Molecular structure of antibodies and functions
Each antibody consists of four polypeptides– two heavy chains and two light chains joined to form a “Y” shaped molecule. The amino acid sequence in the tips of the “Y” varies greatly among different antibodies. This variable region, composed of 110-130 amino acids, give the antibody its specificity for binding antigen.
Hybridoma method for the production of
monoclonal antibodies
Hybridoma technology is a well-established method to produce monoclonal antibodies (mAbs) specific to antigens of interest. Hybridoma cell lines are formed via fusion between a short-lived antibody-producing B cell and an immortal myeloma cell.
The use of monoclonal antibodies in the diagnosis of
disease and in the treatment of disease
Eg. cancer. When injected into a person’s body, the monoclonal antibodies will bind with these cancer cells and clump them together. This makes it easier to identify a cancerous tumour , which can then be treated or removed.
Difference between active and passive immunity
A prominent difference between active and passive immunity is that active immunity is developed due to the production of antibodies in one’s own body, while passive immunity is developed by antibodies that are produced outside and then introduced into the body.
Difference between natural and artificial immunity
Natural immunity occurs through contact with a disease causing agent, when the contact was not deliberate, where as artificial immunity develops only through deliberate actions of exposure.
