B lymphocytes and humoral immunity

Question 1

Humoral immunity
Endocytosis
Mono Clonal Antibody

Answer 1

+Called this due the antibodies involved are soluble in the blood and tissue fluid (Humour)
+Different types of B cells means there is one responds to a certain antigen and produces the antibody.
+This antibody is complementary to a specific antigen.
+The antigen enters the B cell through endocytosis and gets presented on its surface.
+ Helper T cells attach to these antigens and stimulate the B cells to divide to form clones. (clonal selection).
+A typical pathogen has different antibodies on its surface and some produce toxins which also have antigens.
+As each clone produces one antibody = Monoclonal antibody

Question 2

Plasma cells

Answer 2

+Secrete antibodies in to blood plasma
+Cells only survive for only a few days
+Make 2000 antibodies every second
+Lead to the destruction of the antigen
+Immediate defence of the body
+Primary immune response

Question 3

Memory cells

Answer 3

Responsible for the secondary immune response.
+Live longer than plasma cells
+They do not produce antibodies directly but but circulate in the blood.
+When they encounter their specific antigen, they divide rapidly into memory and plasm cells.
+The created plasma cells produce antibodies while the memory cells circulate for future infections.

Question 4

Process of B cells in humoral immunity

Answer 4

1.Surface antigens 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 destroy them
7. Some develop into memory cells for a future infection.