B-lymphocytes and Humoral Immunity

Question 1

What is the role of B cells (Lymphocytes) in humoral immunity?

Answer 1

-B cell takes up the surface antigens of an invading pathogen
-B cell processes and presents antigens on its surface
-Helper T cells attach to the processed antigens on the B cell, activating it
-Clonal expansion to produce plasma cells
-Cloned plasma cells produce and secrete the specific antibody that exactly fits the antigen on the pathogen’s surface
-Antibody attaches to and destroys pathogen
-Certain B cells develop into memory cells and can respond to future infections by the same pathogen by dividing rapidly and developing into plasma cells that produce antibodies (Secondary immune response)

Question 2

How does antigenic variation affect the body’s response to infection?

Answer 2

Increased antigenic variation causes a slower response to infection, and can even enable re-infection of hosts.