WordNet
acquired immunity
n. immunity to a particular disease that is not innate but has been acquired during life; immunity can be acquired by the development of antibodies after an attack of an infectious disease or by a pregnant mother passing antibodies through the placenta to a fetus or by vaccination
Usage examples of "acquired immunity".
They could spread it so freely that every member of their group acquired immunity during infancy.
Melles had acquired immunity to most of the common poisons, but that didn't mean he wouldn't get sick if someone slipped a dose to him.
For him it was healthy, a necessary adjustment to an otherwise intolerable situation, no more pathological than a callus, or an acquired immunity.