Specific Defence Flashcards
Name the white blood cells involved in the specific immune response.
Lymphocytes
How many different types of receptor does a lymphocyte have?
one specific to an antigen
What do lymphocytes respond to?
The antigen on the pathogen
When a lymphocyte initially binds to the antigen of a pathogen, what does this lead to?
Repeated lymphocyte division, clonal population of identical lymphocytes
What are antigens usually made from?
Protein
Where are antigens normally located?
On the surface of pathogens
Name the 2 types of lymphocyte.
B and T
Which type of lymphocytes produce antibodies?
B
Name the Y-shaped proteins that have receptor binding sites specific to a particular antigen on a pathogen.
antibodies
What effect do antibodies have on the pathogen?
cause it to be inactive and unable to circulate
What is usually the result of an antigen-antibody complex?
destroyed by phagocytes - yum yum
What do we call it when B lymphocytes respond to antigens on harmless substances?
allergic reaction
Name the cells that bring about apoptosis.
T lymphocytes
What is apoptosis?
programmed cell death
How does a T lymphocyte know which cells to destroy?
The antigens of the pathogen are left on the cell membrane
Describe the 3 main stages of apoptosis.
- T lymphocytes attach onto infected cells and release proteins 2. Proteins diffuse into the infected cell 3. Self-destructive enzymes are produced that cause cell death
Why are the bodies own cells not normally attacked by T lymphocytes?
T lymphocytes can distinguish between self and non-self antigens
What name is given to a disease where failure of the regulation of the immune system leads to T lymphocytes responding to self antigens?
autoimmune disease
Give 2 examples of autoimmune disease.
Rheumatoid arthritis, type 1 diabetes, MS…there are many more
State 2 ways the secondary immune response is different to the primary?
antibody production is quicker and greater
Which cells in the body allow for the secondary immune response?
B and T memory cells
What does the HIV virus attack?
T lymphocytes
Does HIV lead to AIDS or does AIDS lead to HIV?
HIV leads to AIDS
What is the result on the immune system of HIV?
weakened and person more vulnerable to opportunistic infections
How can immunity be developed through vaccinations?
inject antigens from infectious pathogens to create memory cells
State 3 possible antigens used in vaccines.
inactivated pathogen toxins, dead pathogens, parts of pathogens and weakened pathogens
What name is given to a substance which makes the vaccine more effective so enhancing the immune response?
adjuvant
What name is given to the immunity that occurs when a large percentage of the population is immunised?
Herd Immunity
How does Herd immunity protect non-immune individuals?
Less chance of them coming into contact with infected individuals
What is herd immunity threshold?
The number of immune individuals above which the disease may no longer circulate
State 3 factors that can affect the herd immunity threshold.
- type of disease 2. effectiveness of the vaccine 3. density of the population
What are mass vaccination programmes designed to establish?
Herd immunity
Why do we have issues with the influenza virus each year?
The antigens change - antigenic variation
If pathogens change their antigens, what effect does this have?
Means that memory cells are not effective against them
