AP BIOLOGY

Detailed explanation-1: -Regulatory (suppressor) T cells are white blood cells that help end an immune response. (T lymphocytes) are white blood cells that are involved in acquired immunity.

Detailed explanation-2: -All adaptive immune responses develop in steps, consisting of: antigen recognition; activation of specific lymphocytes to proliferate and differentiate into effector and memory cells; elimination of the antigen; and decline of the response, with memory cells being the long-lived survivors.

Detailed explanation-3: -Neutrophils are considered the first responders of the innate immune system. Neutrophils and macrophages circulate though the blood and reside in tissues watching for potential problems. Both cells can “eat” bacteria, as well as communicate with other immune cells if an issue arises.

Detailed explanation-4: -Memory T and B lymphocytes have an essential role in the immunity against microbial pathogens but are also involved in autoimmunity and maternal-fetal tolerance. Furthermore, the evidence of immunological memory has been established for NK cells.