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Flashcards in Vaccinations Deck (15):

Define antibodies?

Antibodies are proteins made from four polypeptide chains. The binding site is formed from the tertiary structure. Similarly to an enzyme the active site of an antibody binding site is specific to a single antigen and when the two bind together they form an antibody-antigen complex. Antibodies lead to the destruction of the antigen by neutralising the toxins and agglutination.


What are polyclonal antibodies?

A collection of many different types of antibodies.


What are monoclonal antibodies?

A collection of a single type of antibody which is isolate and cloned.


Why are cancer cells used?

As they divide rapidly.


Why do they use monoclonal antibodies?

As they can be used to target specific antigens, they can be directed and minimise damage.


How is a vaccine created?

A lymphocyte can divide several times to make clones of itself, but once it starts to make antibodies it becomes a B lymphocyte and can't divide anymore to get around this problem in a lab a B lymphocyte is fused with a cancer cell creating a hybridoma. A detergent is added to the plasma and tumour cell mixture to break down the cell-surface membrane of both cells to help them fuse. To create vaccines the cells are taken from animals such as mice. The fused cells are separated and cultured to form a group. Those which produce the required antibody are grown on a large scale and the antibodies are extracted from the growth medium. These antibodies are extracted from the growth medium. These antibodies have come from cells cloned from a single cell and are called monoclonal antibodies.


What are the uses of monoclonal antibodies?

-drugs targeting
-pregnancy tests
-diagnostic tools e.g. ELISA
-targeting cancer cells


What are the risks of monoclonal antibodies?

They would be recognised as non-self causing our own antibodies to attack them. Genetic engineering is used to overcome the problem of monoclonal antibodies manufactured from mouse cells triggering an immune response. It also 'humanises' hybridoma's by replacing much of the antibody with the corresponding human structure.


Define vaccine?

An antigenic substance prepared from the causative of a disease or synthetic substitute used to provide immunity against one or several diseases.


What makes a good vaccine?

-means of availability
-ease of administering
-no/not extreme side effects


Why don't vaccines always work?

- some are defective and don't produce an immune response in everyone.
- you may develop the disease directly after the vaccine.
- some pathogens hide from the body e.g. Cholera
- religious, ethical and medical objections e.g. MMR
- antigenic variation, some pathogens e.g. flu, mutate regularly changing the antigens on the surface, so the memory cells are no longer effective as the new antigens are not complementary to the receptors.


Ethical issues towards vaccines?

- the production involves the use of animals and deliberately inducing cancer in them.
- the issues surrounding genetic engineering and playing God.
- there has been some deaths associated with their use.
- trials for them can result in health people dying.
- balancing treatment and side effects.
- is it cost effective? Would it be detrimental to the NHS?


Why are booster vaccines given?

Booster vaccines can be given several years later to ensure memory cells are still being produced.


During the primary response of your immune system the B-cells are dividing to deal with the pathogen, as this takes time you suffer from the disease. Vaccines help to avoid this, how?

Vaccines contain antigens that cause your body to produce memory cells against a specific pathogen, when a vaccine is given a dead or attenuated pathogen is injected, since the pathogen is dead it does not cause the disease. The vaccine always contains antigens which are free or attached to the pathogen. Vaccines may be taken orally or by injection.


What might happen if a vaccine is given orally?

If taken orally it may be broken down by enzymes or not absorbed into the blood as the molecules are too big.