*2.2.2 Response of phagocytic cells (monocytes, macrophages and granulocytes)*

Phagocytic cells such as the granulocytes and monocytes play an important role in cell-mediated immunity (T-cells and phagocytic cells such as monocytes, granulocytes) and so attacks the killed *C. albicans* in similar mechanism as though it is viable and infectious cells. These cells are the first line defense mechanism and are recruited in large quantity in the first few days of injection of the killed *C. albicans*

to the Wister rats. Granulocytes being components of white blood cells are recruited as innate immune response to engulf the killed *C. albicans* [29]. However, viable *C. albicans* have the ability of switching or morphogenesis which allows them to escape phagocytosis by piercing of phagocytes and subsequent killing of phagocytic cells, leading to a decrease in circulating granulocytes in blood [30]. Consequently, contributing to a large extent the impeding factor for availability of an effective vaccine.

### *2.2.3 Delayed-type hypersensitivity*

Delayed-Type Hypersensitivity reaction is initiated when antigens are presented by antigen presenting cells (i.e. langerhans cells) to sensitized memory T cells. The antigen presentation and subsequent T cell activation elicit an influx of macrophages, monocytes and lymphocytes at the site of antigen exposure. At the onset of delayed-type hypersensitivity reaction, verso-permeability is increased so that additional cellular components migrate into the local site of antigen presentation [31] and this explains the swelling at the site of injection of killed *C. albicans*. Therefore, inactivated *C. albicans* have an immune-stimulatory property.
