Question

What is innate immunity? List the four type of barriers which protect the body from the entry of the foreign agent.

Answer 1

Innate immunity or naturally active immunity or non-specific immunity is present at the time of birth and passed down genetically from parents to children. Innate immunity consists of following barriers:

1. Physical barriers- skin and mucous membrane prevent the entry of foreign organisms into the body.

2. Physiological barriers- Body temperature, pH of body fluids and other secretions of the body like HCl , Bile, Ear wax , prevent the growth of several disease causing microorganisms.

3. Cellular barriers- Certain types of blood cells called leucocytes (WBC) like Polymorpho-Nuclear Leucocytes (PMNLs) or neutrophils and monocytes, natural killer cells (type of lymphocytes) as well as the macrophages are most important phagocytes.

4. Cytokine barriers- Certain kinds of cells when infected with a virus, release interferons which make the cells resistant to viral infections.