| A | B |
|---|
| Antigen | A foreign invader; bacteria, etc. |
| Antibody | Protein made to attack antigens |
| Skin | First line of defense |
| Macrophages | 2nd line of defense; nonspecific cells |
| Helper T cells | Direct the activities of the other immune system cells |
| Plasma B cells | Makes the antibody |
| Primary immune response | Body's reaction to a first encounter with an antigen |
| Secondary immune response | 2nd ecnounter with the same antigen |
| Inflammatory response | Nonspecific response to injury or infection |
| Killer T cells | Destroy these infected cells |
| Suppressor T cells | Deactivates the Killer T cells |
| Memory B cells | Remembers how to make an antibody |
| Memory T cells | Remembers how to be a killer T cell for that antigen |
