Innate immunity is a non-specific immunity that is activated immediately or within a few hours when a foreign particle enters the body. Adaptive immunity is a specific type of immunity that is developed when a foreign particle or antigen enters the body and acts on the next exposure.

The innate immunity is present in the body already while the adaptive immunity is developed when an antigen or foreign body enters the body for the first time. The innate immunity is due to the physical barriers like skin and the immune cells like white blood cells such as neutrophils, macrophages and mast cells. The adaptive immunity is due to the lymphocytes that include T lymphocytes and B lymphocytes. Antibodies are developed due to adaptive immunity that attacks the antigens. Innate immunity is present in the body since birth while acquired immunity is developed after birth.

Practice Questions

 

Khan Academy 

MCAT Official Prep (AAMC)

Sample Test B/B Section Passage 2 Question 6

Key Points

• Innate immunity is already present in the body since birth and is due to physical barriers like skin and white blood cells including neutrophils and macrophages.

• Acquired immunity is developed when an antigen/ foreign particle enters the body. This is due to T and B lymphocytes that develop antibodies

Key Terms

Lymphocytes: white blood cells involved in adaptive immunity

Antigen: A toxin or foreign particle that activates the immune system of the body

Antibody: Protein produced in the blood to fight against an antigen

Innate immunity: a non-specific immunity always present

Adaptive immunity: a specific type of immunity developed over time

Neutrophils: the most abundant type of white blood cell and an essential part of the innate immune system

Macrophage: is a type of phagocyte, which is a cell responsible for detecting, engulfing and destroying pathogens

Mast cells: mediate the inflammatory response releasing histamines