• The immune system defends the body against foreign material, including bacteria and viruses.
  • It consists of two parts - the innate and adaptive immune system - which differ in the speed and specificity of the reaction.
  • The innate system consists of physical barriers and a range of cells and chemical responses that provide non-specific immediate defence mechanisms.
  • Adaptive immunity consists of antigen-specific reactions via T- and B-cells. It is precise but takes several days or weeks to develop.
  • The adaptive response has memory, so subsequent exposure results in a more vigorous and rapid response.

This chapter outlines the basics of innate and adaptive immune responses, and introduces how immunology is applied to vaccinology.