Different types of immunity
Your immune system consists broadly of three levels of defence. The innate immune system which you are born with and an adaptive immune system that evolves with exposure to microorganisms and the chemicals they release.
Your innate immune system consists of-
- The physical barrier offered by the skin and mucous membranes
- Protection offered by the immune system cells (defense cells) and proteins
Your adaptive immune system, also called “acquired immunity” changes with exposure to microorganisms. The adaptive immune system protects us based on its past “experience”. This is why, after being infected with something and getting better, we are no longer (at least for some time) susceptible to the same infection.