White Blood Cell - A special type of cell that works as part of the immune system to defend the body against disease and infection.⏎
Virus - An infectious agent that is only capable of replicating itself inside the living cells of other organisms.⏎
Tissue Culture - The process by which tissues are intentionally grown under controlled conditions.⏎
Strain - A genetic variant or specific subtype of a microorganism, such as a virus or bacteria.⏎