Answer:
d) The antigen-presenting cell encounters and processes the antigen.
e) With the antigen, the antigen-presenting cell migrates to the nearest lymph node.
b) The antigen-presenting cell displays the antigen to the T cells.
c) The T cells initiate the immune response if the antigens are viral proteins or abnormal antigens.
a) Infected or malignant cells are then destroyed before they can do further harm to the body.
Explanation:
The antigen-presenting cells (e.g., dendritic cells, macrophages) are cells of the immune system that mediate cellular immune responses by processing and presenting antigens (i.e., peptides components of pathogens) to T lymphocytes. The antigen-presenting cells travel through lymphatic vessels from the site of infection to the lymph nodes where they present antigens to naive T cells, i.e., T cells that have matured but have not yet encountered their corresponding antigens. This presentation facilitates the clonal expansion of T cells that are specific for the antigen which acquire effector functions in order to destroy infected cells. This process is known as immune clearance and is associated with the apoptosis of antigen-specific T cells.
