Humoral Immunity

Question 1

what are monoclonal antibodies?

Answer 1

• each toxin molecule produced by a pathogen acts as an antigens which means many different B cells make clones which produces its own type of antibody
• each clone produces one specific antibody which is referred to as a monoclonal antibody

Question 2

what are plasma cells?

Answer 2

• secrete antibodies into the blood stream
• they only survive for a few days but each can make around 2000 antibodies every second during its brief lifespan
• these antibodies lead to the destruction of the antigen
• the plasma cells are therefore responsible for the immediate defence of the body against infection
• the production of antibodies and memory cells is known as the primary immune response

Question 3

what are memory cells?

Answer 3

• these are responsible for the secondary immune response
• memory cells live longer than plasma cells usually for decades
• they don’t produce antibodies directly but circulate in the blood and tissue fluid
• when they encounter the same antigen again the divide rapidly and develop into plasma cells and more memory cells
• the plasma cells produce the antibodies needed to destroy the pathogen while the new memory cells circulates ready for another infection
• this provides long term immunity as an increased quantity of antibodies is secreted at a faster rate than the primary immune response to insure an infection is destroyed before it causes harm

Question 4

what are B cells role in immunity?

Answer 4

• the surface antigens of an invading pathogen are taken up by a B cell
• the B cell processes the antigens and presents them on the surface
• helper T cells attach to the processed antigens on the B cell thereby activating the B cell
• the B cell is now activated to divide by mitosis to give a clone of the plasma cells
• the cloned plasma cells produce and secrete the specific antibody that exactly fits the antigen on the pathogens surface
• the antibody attaches to antigens on the pathogen and destroys them
• some B cells develop into memory cells which can respond to future infections by the same pathogen by dividing rapidly and developing into plasma cells that produce antibodies which is the secondary immune response

Question 5

how is humoral immunity provoked?

Answer 5

• the first phase of the specific response to infection is the mitotic division of the specific T cells to form a clone of the relevant T cells to build up their numbers
• some T cells produce factors that stimulate B cells to divide which are then used in the next phase of the immune response

Question 6

how did humoral immunity get its name?

Answer 6

• it involves antibodies and antibodies are soluble in the blood and tissue fluid of body
• humour used to mean body fluids

Question 7

what is humoral immunity?

Answer 7

• when an antigen enters the blood stream or tissue fluid there will be one B cell that has an antibody on its surface that fits the antigen if they are complementary
• the antigen attaches to this complementary antigen which enters the B cell by endocytosis and gets presented on its surface
• T helper cells bind to these presented antigens and stimulate this B cell 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

Question 8

what is clonal selection?

Answer 8

-cloning B cells to produce the antibodies required for the body’s ability to respond rapidly to any vast number of antigens