1. What cell is most important in humoral immunity? Where do these cells come from?
2. What happens when humoral immunity is activated?
1. B lymphocytes, from the liver and bone marrow.
2. Each B lymphocyte makes a single type of antibody (immunoglobulin) which it displays on its membrane.
Next, antibody recognizes antigen and binds to antigen; macrophages consume antigen and display antigenic determinants on their membrane.
If B lymphocyte antibody contacts a matching antigen presented by a macrophage, it will differentiate (w/ help of Helper T cells) into plasma cells and memory cells.
Plasma cells synthesize free antibodies and release them into blood.
If antibodies bind to antigen again, they will mark antigen for phagocytosis by macrophages and natural killer cells, may cause antigenic substances to agglutinate, or may block its chemically active portion..