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Define the term 'immunity'
Is the ability for the body to resistant disease.
What is RESISTANT to DISEASE?
It is the ability of the body to protect against itself from the pathogen and protect the body from infection.
How is immunity achieved?
The majority of lymphocytes induced (made) for eliminating the pathogen dies by apoptosis.
Although the life of the lymphocyte is short lived it also generates long-lived memory cells.
Memory cells respond faster and more effectively against the antigen than do naïve cells. Therefore to achieve immunity the most important goal is to develop MEMORY CELLS.
Define the term ' active immunity'
Is protection provided by an individual's own adaptive immune response. This type of immunity takes time to develop, but the memory B and T lymphocytes result in immunological memory. - LONG-TERM IMMMUNITY
Describe the process of the adaptive immune response following a natural infection.
Responding to a natural infection is without medical intervention and means if exposed to the same antigen again (secondary response), the response will be faster and stronger than the primary immune response. Therefore making you RESISTANT TO DISEASE.
'Natural' develops from the adaptive immune response to a NATURAL INFECTION without medical intervention.
'Active' - This means if exposed to the same antigen again (secondary response), the response will be faster and stronger than the primary immune response. Therefore making you RESISTANT TO DISEASE
Define ''vaccinations,' and role.
Artificially inducing the active immunity to produce memory cells for the disease.
Vaccines administrate a small dosage of antigens.
- Weaken live Pathogens
- Killed pathogens
Advanatage and disavantage of Live Attenuated Vaccines
Involves administrated live pathogen that has been weakened.
Advantage is that a single-dose provides a long-lasting immunity because it induces a strong adaptive immune response.
Disadvantage is that the vaccine may lead to disease people with a weaken immune system
Advanatage and disavantage of inactivated Vaccines
Contain microbes that have been inactivated (killed). The advantage of inactivated vaccines is that you can administrate a lot more antigens leading to greater immunity to different diseases.
Advantage - Can be used by people with weaken immune system/
Disadvantage - Stimulates a weak immune response compared to live attenuated vaccines. You will need a booster shot to achieve long-term immunity by generating more memory cells.
Mode of action of vaccination. - 1.PRIMARY IMMUNE RESPONSE
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1.PRIMARY IMMUNE RESPONSE After a person receives their first vaccination, there is a delay in the adaptive immune system's response. This is because the adaptive immune response is relatively slow - it takes time for antigen-presenting cells to find T and B cells complementary to the vaccine's antigen and for the process of clonal selection to occur. Eventually a primary immune response takes place in which a moderate number of antibodies and memory cells are formed, however these quickly diminish over time.
Mode of action of vaccination. - 1.PRIMARY IMMUNE RESPONSE
1.SECONDARY IMMUNE RESPONSE (RE-EXPOSURE TO SAME PATHOGEN)Upon receiving a second vaccination, the memory cells created by the first vaccine quickly recognise the SAME antigen in the vaccine and mount a rapid, large secondary immune response. This results in the generation of a large number of antibodies and memory cells that go on to create long-lasting immunity.
Herd Immunity
For immunisation program to be successful there must be herd immunity.
The more people who are vaccinated, the less chance there is an infectious pathogen spreading throughout the population.
Herd immunity is important to protect those with weaken immune system, newborn babies and the elderly who cannot be vaccinated.
Natural Passive immunity
Involves the passive transfer of antibodies from the mother to foetus. The maternal (from mum) antibodies provide protection to the baby for weeks or months, while its own immune system is developing.
Artificial passive immunity
Involves receiving an injection of antiserum (antibodies produced by another organism.
The antiserum is a serum that contains specific antibodies. When these antibodies are injected to the person it binds to the antigens on the pathogen or toxin, they form an antigen-antibody complex that inhibits the pathogen or toxin before it does too much damage.
Active immunity
active - •Adaptive immune response to antigen takes place in the individual.
•Immunity takes time to progress (weeks).
•The individuals immune system is activated against the antigen.
•Therefore, receives immunological memory because of the memory B & T lymphocytes.
•Defense can last for many years, possibly even a lifetime. LONG TERM
Passive immunity
passive Adaptive immune response takes place in another organism which is exposed to the antigen and then its antibodies are given to a recipient.
•Immunity progress is immediate.
•Recipients immune system is not activated against the antigen.
•Therefore doesn't receive immunological memory.
•SHORT-TERM
Causes of autoimmune diseases
Failure of clonal deletion - a process that occurs in the development and maturation of B and T lymphocytes. During maturation the lymphocytes are presented with self-antigens. If they respond to the self-antigen they are destroyed (Clonal Deletion).
In autoimmune disease, these lymphocytes that are autoreactive to self antigen is not destroyed during maturation
B cells in autoimmune disease
B cells in Autoimmune diseases involve the production of autoantibodies which directly bind to cells displaying self antigens that destroy them
T cells in autoimmune diseases
T cells in autoimmune disease can be autoreactive. Autoreactive cytotoxic T cells can release toxic proteins to destroy self cell showing self antigen because it recognises it as foreign.
Allergic Reactions
Allergic reaction due to the rapid and overreaction of the immune system to antigens that would be harmless.
These antigens are called 'Allergens'
Depending on the reaction it can be life threatening leading to
'anaphylaxis'.
Histamine - the signalling molecule
Histamine binds to specific receptors on certain cells which causes
•Blood vessel dilation
•Decrease in blood pressure
•Increase in the permeability of blood vessels to immune cells (makes immune cells easier to come into contact with the antigen)
•Contraction of smooth muscles lining the airway to prevent breathing
•Activation of fluid-secreting cells
Management of allergic reactions
Avoidance of allergens - don't go outside or wear a face mask
Management of symptoms - if they have a severe allergic reaction (anaphylaxis) inject them with adrenaline (EpiPen). Adrenaline has the opposite effect. If muscles are constricting (difficulty in breathing) give them Ventolin.
Reduction of the allergic response - Use antihistamines. These bind to histamine receptors in the body and prevent histamine being released by the mast cell.
Define immunotheraphy
Immunotherapy is treatment that uses a person's own immune system to fight cancer. A treatment that involves helping the immune response to perform correctly (either increasing or decreasing in response).
There are two main forms of immunotherapy:
activation immunotherapies - which aim to increase or amplify an immune response
suppression immunotherapies - which aim to prevent or reduce an immune response
we will discuss one type of immunotherapy called monoclonal antibodies.
Monoclonal antibodies
Monoclonal antibodies (mAbs) are one form of immunotherapy. mAbs are made in the laboratory to bind to a specific antigen.
Antibodies that have been grown in culture (clones) from a single B lymphocyte.
Used to treat cancer by targeting specific antigens present on cancer cells.
Can also be used to target specific cells in the immune system to direct the immune response.
Steps to creating monoclonal antibodies
1. Scientists identify and isolate an antigen that is present on a desired target cell. This cell will typically be one that is responsible for causing the disease that scientists want to treat
2. Scientists vaccinate an animal, usually mice, with an antigen. A vaccination stimulates an immune response against the antigen and results in the selection and proliferation of a B lymphocyte that matches the antigen.
3 Scientists extract these B lymphocytes from the spleen of the mice.
4 The extracted B lymphocytes are fused with rapidly-dividing cancerous human plasma cells known as myeloma cells. The products of this fusion are called hybridomas. The reason these myeloma cells are chosen to fuse with the B lymphocytes is because B lymphocytes do not grow well in vitro (in the petri dish), whereas myeloma cells can grow indefinitely and produce large quantities of antibodies.
5 Hybridomas are screened so that only the cells with the appropriate antibody are selected. The hybridomas that produce the specific antibody are cloned, which results in the mass production of these antibodies.
6 Antibodies are then collected and purified before being administered to a patient
How do they treat cancer?
•Identifies cancer cells as foreign so that the immune system cells destroy them
•Deliver radiation or chemotherapy treatment by exploiting their ability to connect with cancer cells.
