ANATOMY

Detailed explanation-1: -These include dendritic cells, which initially activate helper T cells, as well as the targets of effector helper T cells, such as macrophages and B cells. Because dendritic cells express both class I and class II MHC proteins, they can activate both cytotoxic and helper T cells.

Detailed explanation-2: -MHC class II molecules sense when there’s an infection or foreign substance in your body. The CD4 receptor and MHC class II molecules activate the helper T-cells. The helper T-cells release molecules called cytokines. Cytokines send messages to other immune cells to start an immune response.

Detailed explanation-3: -Having MHC class II molecules present proper peptides that are bound stably is essential for overall immune function. Because class II MHC is loaded with extracellular proteins, it is mainly concerned with presentation of extracellular pathogens (for example, bacteria that might be infecting a wound or the blood).