A Shot That Trains Defences

In the picture

1. 1A syringe holding clear liquid: one small dose is given.
2. 2A harmless germ particle: the antigen the immune system studies.
3. 3A white blood cell releasing Y-shaped antibodies that grip the antigen.
4. 4A memory cell that stays in the body after the first meeting.
5. 5The same germ wrapped in many antibodies: a fast second response.

Examples

• A tetanus shot after a cut from a rusty nail.
• A flu shot each year before winter.

Quiz: A Shot That Trains Defences (Age 14)

1. 1

   What does a vaccine use to train the immune system without causing the illness?

   • A ready-made memory cell from another person
   • A harmless antigen from the germ
   • A harmful dose of the real pathogen
2. 2

   What advantage do memory cells give after vaccination?

   • They stop the body from ever making antibodies again
   • They turn the harmless antigen into the real pathogen
   • They make the next response faster and stronger
3. 3

   When the real germ is met again after vaccination, what does the card say happens?

   • It causes the original illness before memory cells form
   • It is ignored because the vaccine already removed all germs
   • It is wrapped in many antibodies in a fast second response

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.