Vaccination

Question 1

how do lymphocytes prevent the body being infected by the same pathogen again?

Answer 1

they produce memory cells - these cells can remain in our circulatory system for a lifetime

Question 2

what does it mean to say we have gained immunity?

Answer 2

• when the body encounters the same pathogen, the memory cells react to the pathogen very quickly, producing lots of antibodies much earlier than the first time
• this kills the pathogen before we feel ill and so prevents us being infected twice by the same pathogen

Question 3

how does vaccination work?

Answer 3

• the body is given a vaccine, which is a dose of the pathogen, normally by injection
• the dose is either the dead pathogen or parts of the pathogen’s cell surface
• the stops the pathogen from causing a disease
• the lymphocytes generate antibodies against the pathogen and more importantly, make memory cells - this way, vaccines can give us immunity