| Virus | Particle made up of hereditary material and protein. |
| Immune System | System used to defend the body from disease. |
| White Blood Cell | A cell that destroys micoorganisms that are not part of the body. |
| Interferon | Prevents viruses from reproducing. |
| Antibodies | Sticks to viruses preventing them from sticking to cells and flagging them for destruction. |
| Complement | Destroys cells flagged with antibodies. |
| Vaccine | A weakened version of a virus to build immunity. |
| AIDS | Acquired Immune Deficiency Syndrome |
| HIV | A virus causing AIDS |
| Smallpox | A disease that causes small pus-filled sores and a high fever. |