In vaccines, a substance that is added to increase the immune response

 A protein molecule that is produced by B cells in the body in response to contact with a foreign substance termed an antigen. Antibodies neutralize antigens and are an important part of the immune response against infection. Antibodies are also called immunoglobulins.

 A substance that can produce a specific immune response

 Weakened; in vaccines, the weakening of a virus or bacteria to disable its ability to cause disease

 A dose of a vaccine that helps the body maintain immunity against a disease

 An anatomical structure surrounding the body of a bacteria

 Abbreviation of Food and Drug Administration, the U.S. government entity responsible for reviewing drugs and vaccines for effectiveness and safety

 Immunity referring to elements dissolved in the blood or body fluids, such as antibodies in the blood, rather than cells

 A small mesh of tissue that filters, attacks, and destroys harmful microbes. Part of a network of nodes scattered throughout the body to fight infection

 B cells or T cells that help the immune system fight an infection and provide humoral (B cell) or cellular (T cell) immunity