5.4 - B Lymphocytes & Humoral Immunity Flashcards
The different types of cells involved in the humoral response The role of B cells in the humoral response The differences between the primary and secondary immune response (27 cards)
What is the humoral response?
2 Key things
- Specific defence mechanisms used to protect the body from disease
- It involves the production of specific antibodies to destroy pathogens
What type of cells are involved in the humoral response?
- B lymphocytes or B cells - produce and are covered in proteins known as antibodies
What are antibodies?
As in what do they do?
Proteins on B cells that bind to antigens
Why is it called the humoral response?
Antibodies are found in body fluids (humors)
What types of cells are involved in the humoral response?
B cells
What do B cells do?
- Have antibodies on their cell-surface membrane that bind to complementary antigens.
- On doing so, they engulf the antigens and display them on their cell-surface to become antigen-presenting cells.
- Once activated, B cells can divide into plasma cells and memory cells.
What do plasma cells do?
Produce and secrete antibodies
What is the lifespan of plasma cells?
A few days
What do memory cells do?
Provide long-term immunity
What is the lifespan of memory cells?
Longer than plasma cells
What do helper T cells do?
Activate B cell division
What are the stages of the humoral response?
6 stages
- A B cell with a complementary antibody binds to the antigens on a pathogen.
- The B cell engulfs the pathogen and presents its antigens on the cell-surface membrane to become an antigen-presenting cell.
- Clonal selection - Activated T helper cells bind to the B cell, causing activation of this B cell.
- Clonal expansion - The activated B cell divides by mitosis to form plasma and memory cell clones.
- The cloned plasma cells produce and secrete the specific antibody which is complementary to the antigen on the pathogen’s surface. These antibodies attach to antigens on pathogens and destroy them.
- The memory cells circulate the blood and tissue fluid, ready to divide if the body is re-infected by the same pathogen.
What is clonal selection?
B cell with correct antibody is selected for cloning
What is clonal expansion?
Division of specific B cells to produce clones (plasma/memory cells)
What are the two types of immune response?
Primary and secondary
What is the primary immune response?
Response to first exposure to a pathogen
What is the secondary immune response?
Response to subsequent exposure
What happens during the primary immune response?
Slow antibody production
What happens during the secondary immune response?
Fast antibody production
What cells are activated in the primary immune response?
B and T cells
What cells are activated in the secondary immune response?
Memory B and T cells
What is the rate of antibody production in the primary response?
Low
What is the rate of antibody production in the secondary response?
High
How many antibodies are produced in the primary response?
Only a few
