Allergic Diseases

Question: How does humoral immunity work?


Humoral immunity involves antibodies, produced by B cells. Terminally differentiated B cells, called plasma cells, produce most of the antibodies. Humoral immune responses defend the host against extracellular bacteria and toxins. Blocking antibodies can prevent the adherence of bacteria, viruses, or toxins to host cells. Antibodies can activate complement through the classical pathway and lyse cells. Complement activation also generates chemotactic fragments that activate mast cells and phagocytes and chemotactically attract phagocytic cells into sites of inflammation. NK cells can bind to antibody-coated targets and lyse them in antibody-mediated cytotoxicity. Antibodies can also opsonize; in other words, their binding facilitates uptake of the antigen by phagocytic cells.


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