Final answer:
The sensitization phase in Canine atopic dermatitis (cAD) is the initial exposure to the antigen that triggers an immune response in dogs. During this phase, the antigen is phagocytosed by antigen-presenting cells, leading to the activation of helper T cells and differentiation into memory T cells. Subsequent exposure to the antigen causes tissue damage.
Step-by-step explanation:
The sensitisation phase in Canine atopic dermatitis (cAD) refers to the initial exposure to the antigen that triggers an immune response in dogs. During this sensitization phase, the antigen is introduced into the skin and phagocytosed by antigen-presenting cells (APCs). The APCs then activate helper T cells, which differentiate into memory T cells. Subsequent exposure to the antigen leads to the release of cytokines by the sensitized memory T cells, activating macrophages and causing tissue damage.