inoculant
/ɪˈnɒkjʊlənt/Definitions
1. noun
An agent or substance capable of inducing immunity to a disease or a microorganism.
“The doctor explained that the vaccine was the inoculant that would protect the child from the deadly virus.”
2. verb
To make (an organism or tissue) immune to a specific disease or agent.
“The researchers inoculated the mice with a weakened form of the virus to test the efficacy of the new treatment.”