Paper I
Question
State six differences between active and passive immunity.
Answer
Six differences between active and passive immunity
| Feature | Active immunity | Passive immunity |
|---|---|---|
| Source of antibody | Produced by the individual’s own immune system | Pre-formed antibody transferred from an outside source |
| Onset | Slow (days to weeks) | Immediate |
| Duration | Long-lasting (months to years) | Short-lived (weeks) |
| Immunological memory | Generated | Not generated |
| Response on re-exposure | Faster, stronger secondary response | No improvement |
| Natural example | Immunity following actual infection | Maternal IgG across placenta; IgA via colostrum |
| Artificial example | Vaccination | Immunoglobulin/antitoxin injection |
| Use | Long-term prevention (vaccination programmes) | Immediate protection after high-risk exposure |
| Antigen requirement | Requires antigen exposure to stimulate response | No antigen exposure needed |