B Lymphocytes And Humoral Immunity Flashcards
What does humoral immunity involve?
This involves antibodies.
What are antibodies soluble in?
Blood and tissue fluid.
Are there lots of types of B cell?
Yes there are many different types of B cells.
What does each B cell start to produce?
It starts to produce a specific antibody that responds to one specific antigen.
Where can antigens be found?
Pathogens Foreign cells Toxins Damaged cells Abnormal cell
What happens when an antigen enters the blood?
There will be one B cell that has an antibody on its surface which will have the exact shape to fit the antigen.
What is meant be complementary?
This is when the antigen and antibody have shapes that allow them to exactly fit into each other.
How does the antigen enter the B cell?
By endocytosis.
What happens when the antigen enters the B cell?
It gets presented on its surface (processes).
What binds to the processed antigens?
T helper cells bind to the processed antigens which stimulates the B cell to divide by mitosis.
What happens when the B cell divides by mitosis?
It produces identical clones that produce the same antibody that is specific to the foreign antigen.
What is clonal selection?
This is where the one type of lymphocyte that has the complementary protein replicates to create enough cells to destroy the pathogen.
What is clonal sélection responsible for?
This is responsible for the body’s ability to respond rapidly to any of a vast number of antigens.
Why is there a time lag between exposure to the pathogen and the body’s defences bringing it under control?
This is because clonal selection does not happen straight away- the right type of cell must be found first.
Do pathogens only have one antigen on their surface?
No, they have many different proteins in their surface which act as antigens.
What does each toxin also act as?
An antigen.
Why do many different B cells make clones?
They all produce their own type of antibody.
Why are these antibodies referred to as monoclonal antibodies?
This is because each clone produces one specific antibody.
In each clone, what do the cells produced develop into?
Plasma cells or memory cells.
What do plasma cells secrete?
They secrete antibodies into the blood plasma.
How long do plasma cells survive for?
A few days but they make lots of antibodies.
What are the plasma cells responsible for?
They are responsible for the immediate defence of the body against infection.
What do the antibodies produced by plasma cells lead to?
They lead to the destruction of the antigen.
What is the production of antibodies and memory cells known as?
The primary immune response.
What are memory cells responsible for?
The secondary immune response.
How long do memory cells live for?
Considerably longer than plasma cells- for decades.
What do memory cells not do?
They don’t produce antibodies directly.
What do memory cells do?
They circulate in the blood and tissue fluid.
What happens when meme pet cells encounter the same pathogen at a later date?
They divide rapidly and develop into more plasma and memory cells.
What type of immunity do memory cells provide?
Long-term immunity.
What ensures them at the new infection can be destroyed before it can cause any harm?
Thanks to the memory cells, a large quantity of antibodies can be secretes faster than in the primary immune response.
What is a monoclonal antibody?
This is an antibody that is produced by a single clone of cells.
Summarise humoral immunity.
The surface antigens of an invading pathogen are taken up by a B cell.
Helper T cells attach to the processed antigens in the B cell which stimulates the B cell to divide by mitosis to create a clone of plasma cells.
The cloned plasma cells produce and secrete a specific antibody that exactly fits the antigen on the pathogen’s surface.
The antibody attaches to antigens on the pathogen and destroys them.
Some B cells develop into memory cells.
