|the immunity produced by exposure of an organism to antigens, which stimulates the production of antibodies|
|a chattering or flighty, light-headed person.|
|a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison.|
acquired immunity n.
Immunity obtained either from the development of antibodies in response to exposure to an antigen, as from vaccination or an attack of an infectious disease, or from the transmission of antibodies, as from mother to fetus through the placenta or the injection of antiserum.
Immunity that is not inherited. Acquired immunity can be active or passive. ◇ Active immunity results from the development of antibodies in response to an antigen, as from exposure to an infectious disease or through vaccination. ◇ Passive immunity results from the transmission of antibodies, as from mother to fetus through the placenta or by the injection of antiserum.