Question

Name various cellular barriers that stop the pathogens. What is their role in innate immunity?

Answer 1

The cellular barriers are:

(i) Monocytes → macrophages: kill microbes by phagocytosis.

(ii) Neutrophils (polymorphonuclear leucocytes): ingest and kill bacteria by phagocytosis and release chemicals that kill nearby bacteria.

(iii) Natural killer cells: kill virus-infected body cells and cancer cells by releasing perforins that form pores in the target cell membrane.

Role:

They form the second line of defence of innate immunity, they act when the first line (anatomical/physiological barriers) is broken and pathogens have entered the body.