Please could anyone help me understand what I need to know about humoral immunity for AQA A level biology? I've done a past paper and the markscheme doesn't match my understanding and what I've seen on youtube videos.
My understanding (from my notes):
1. Specific B cell binds to the antigen of the pathogen (on pathogen / antigen presenting cell / free antigen)
2. B cell processes the antigens and presents them on its cell-surface membrane
3. B cell is stimulated to divide by helper T cells which release cytokines
4. B cell is activated to divide by mitosis to produce clones of plasma cells, which produce and secrete the specific antibody complementary to the specific antigen (clonal expansion)
5. Some become B plasma cells which secrete large amounts of monoclonal antibody into the blood, (primary immune response)
6. Some become B memory cells which can respond to future infections by the same pathogen by dividing rapidly and developing into plasma cells that produce the specific antibodies, (secondary response)
1. Helper T cell/TH cell binds to the antigen (on
the antigen-presenting cell/phagocyte);
2. This helper T/TH cell stimulates a specific B
3. B cell clones
B cell divides by mitosis;
4. (Forms) plasma cells that release antibodies;
Basically I thought it was B cells that bind to the antigen on the pathogen but the mark scheme says the T helper cell does this.
Any help could be really appreciated thank you!