If you have a high enough antibody level to protect you against a particular infection, you are immune.
This is when the body is activated and produces the antibodies needed to fight an infection.
Active immunity is:
The primary response when a microorganism enters the body is described as natural active immunity.
Vaccines provide artificial active immunity.
This is when ready-made antibodies, from another source, are introduced to the body.
Passive immunity is:
Breastfeeding provides a baby with natural passive immunity.
Anti-venom provides artificial passive immunity after a poisonous bite.