IMMUNOLOGY

Detailed explanation-1: -There are two main classes of T cells-cytotoxic T cells and helper T cells. Effector cytotoxic T cells directly kill cells that are infected with a virus or some other intracellular pathogen.

Detailed explanation-2: -The T cell, for example, might kill a virus-infected host cell that has viral antigens on its surface, thereby eliminating the infected cell before the virus has had a chance to replicate (see Figure 24-2).

Detailed explanation-3: -Dendritic cells, macrophages, and B cells are the principal antigen-presenting cells for T cells, whereas follicular dendritic cells are the main antigen-presenting cells for B cells. The immune system contains three types of antigen-presenting cells, i.e., macrophages, dendritic cells, and B cells.

Detailed explanation-4: -Dendritic cells are immune cells that process antigen material; they are present in the skin (Langerhans cells) and the lining of the nose, lungs, stomach, and intestines. Sometimes a dendritic cell presents on the surface of other cells to induce an immune response, thus functioning as an antigen-presenting cell.

Detailed explanation-5: -Cytotoxic T-cells are a type of immune cell. They destroy cells infected with viruses. Another name for cytotoxic T-cells is killer T-cells. Cytotoxic T-cells are one of the three main types of cells developed in your thymus.