B Lymphocytes and Humoral Immunity Flashcards
Why is it called humoral immunity
Because it involves antibodies and they are soluble in the blood and tissue fluid of the body. An old fashion word for body fluids is ‘humour’
What is clonal selection
When T helper cells bind to processed antigens and stimulate B cells to divide by mitosis to form a clone of identical B cells, all of which produce the antibody that is specific to the foreign antigen
What happens when an antibody in the surface of a B cell meets a complimentary shaped antigen?
it binds to it forming a antigen antibody complex
What do plasma cells do
They produced antibodies which help destroy the pathogen, they are responsible for the immediate defence of the body against infection.
What do B memory cells so
Remain in the blood so if there is a second exposure then the pathogen rapid mitosis division occurs. It is quicker and a greater number of antibodies are produced
What’s the primary response
When an antigen first enters the body it activates the immune system
This process is slow as there aren’t many B cells that can make the antibody needed to bind to it
Eventually it will produce enough of the right antibody to overcome the disease
Memory B and T cells will remain in the body for a long time, so they will recognise it second time round
What’s the secondary immune response
Same pathogen enters body however immune system produces quicker stronger immune response
Clonal selection happens faster. Members B cells are activated and divide into plasma cells that produce the right antibody to the antigen. Memory T cells are activated and divide into the correct type of T cells to kill the cell carrying the antigen
It gets rid of the pathogen before you show any symptoms
What’s the role of B cells in humoral immunity
1 The surface antigens of an invading pathogen are taken up by a B cell
2 The B cell processes the antigens and presents them on its surface.
3 Helper T cells attach to the processed antigens on the B cell thereby activating the B cell
4 The B cell is now activated to divide by mitosis to give a clone of plasma cells
5 The cloned plasma cells produce and secrete the specific antibody that exactly fits the antigen on the pathogen’s surface.
6 The antibody attaches to antigens on the pathogen and destroys them
7 some B cells develop into memory cells. These can respond to future infections by the same pathogen by dividing rapidly an developing into plasma cells that produce antibodies. This is the secondary immune response.
Contrast the cell mediated and humoral responses to a pathogen
CM involves T cells, H involves mostly B cells
CM has no antibodies, H - anti bodies are produced
CM - first stage of immune response
H- second stage of immune response
CM- effective through cells
H- effective through body fluids
Suggest 3 cell organelles that you might expect to find in large quantities in a plasma cell. Explain why
RER- to make and transport the proteins of the antibodies
Golgi apparatus- sort process and compile the proteins
Mitochondria - release energy for such massive antibody production
