ANATOMY

Detailed explanation-1: -After activated cytotoxic T cells attack the pathogen, the memory T cells hang around to mitigate any recurrence. Helper T cells secrete cytokines that help B cells differentiate into plasma cells. These cells also help to activate cytotoxic T cells and macrophages.

Detailed explanation-2: -Cytotoxic T cells kill their targets by programming them to undergo apoptosis (Fig. 8.35). When cytotoxic T cells are mixed with target cells and rapidly brought into contact by centrifugation, they can program antigen-specific target cells to die within 5 minutes, although death may take hours to become fully evident.

Detailed explanation-3: -When helper T-cells detect an infection, they form into one of two subtypes: TH1 helper cells release a molecule that activates a type of cell called a macrophage. Macrophages are specialized cells that help eliminate foreign substances from your body. TH1 cells also activate cytotoxic T-cells.

Detailed explanation-4: -Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.

Detailed explanation-5: -A type of immune cell that can kill certain cells, including foreign cells, cancer cells, and cells infected with a virus. Killer T cells can be separated from other blood cells, grown in the laboratory, and then given to a patient to kill cancer cells.