Name any two types of cells which act as 'Cellular barriers' to provide Innate Immunity in humans.

a) Macrophages: Macrophages are irregular shaped phagocytes that are amoeboid in nature and are the most versatile of phagocytes in the body. When pathogens reach the body’s barrier defences, macrophages are the first line of defence.

b) Neutrophils: Neutrophils are the phagocytic cells that are attached via chemotaxis from the bloodstream to infected tissues. These spherical cells are granulocytes. They contain cytoplasmic granules which in turn contain a variety of vasoactive mediator such as histamine.

c)