Specific cellular defences against pathogens Flashcards
What are lymphocytes?
White blood cells
What are lymphocytes involved in?
The specific immune response
What does the lymphocytes single type of membrane receptor do?
It’s specific for one antigen
What does antigen binding lead to?
Repeated lymphocytes division resulting in the formation of a clonal population of identical lymphocytes
What are antigens?
Molecules, often proteins located on the surface of cells that trigger a specific response
Where are antigens located?
on the surface of cells that trigger a specific response
What are the two types of lymphocytes?
B lymphocytes and T lymphocytes
What do B lymphocytes produce and what does it lead to ?
Antibodies against antigens and this leads to the destruction of the pathogen
Describe the structure of antibodies
Y shaped proteins
Have receptors binding sites specific to particular antigen on a pathogen
Antibodies become bound to antigens inactivating the pathogen
How can antigen-antibody complex be destroyed?
By pathocytosis
What can B lymphocytes respond to?
Antigens on substances that are harmless to the body eg pollen
What is a hypersensitive response called?
An allergic reaction
What do T lymphocyte destroy?
Infected body cells by recognising antigens of the pathogen on the cell membrane and inducing apoptosis
What is apoptosis?
Is programmed cell death
What does T lymphocytes attach onto?
Infected cells
What do T lymphocytes release
Proteins. These proteins diffuse into the infected cells causing production of self destructive enzymes which cause cell death. The remains of the cell are then removed by phagocytosis
What can T lymphocytes normally distinguish between?
Self antigens on the boy’s own cells and no specific antigens on infected cells
What does failure of the regulation of the immune system lead to?
T lymphocytes responding to self antigens. This causes autoimmune disease
In autoimmunity what do the T lymphocytes attack and the effect?
Body’s own cells .Causes autoimmune diseases such as Type 1 diabetes and rheumatoid arthritis
What do cloned B and T lymphocytes survive as?
long term memory cells
What happens when exposure to the same antigen occurs?
Memory cells rapidly give rise to a new clone of specific lymphocytes. They destroy the invading pathogens before the individual shows symptoms
What happens during secondary response?
antibody production is greater and more rapid than during the primary response
What does HIV attack and destroy?
T lymphocytes.
What does HIV cause?
depletion of T lymphocytes which leads to the development of AIDS
