Exam 32: Innate Immunity

Correct Answer:

Answered by Examlex AI Copilot

Natural killer (NK) cells are a type of white blood cell that plays a critical role in the immune system. They are part of the body's innate immune response, meaning they are always ready to attack and destroy abnormal cells, such as virus-infected cells or cancer cells, without needing prior exposure to them.

NK cells function by releasing toxic chemicals, such as perforin and granzymes, that directly kill the target cells. They can also induce apoptosis, or programmed cell death, in the abnormal cells. Additionally, NK cells can release cytokines, which are signaling molecules that help regulate the immune response and recruit other immune cells to the site of infection or inflammation.

The functioning of NK cells is tightly regulated to prevent them from attacking healthy cells. They have a balance of activating and inhibitory receptors on their surface, which allows them to distinguish between normal and abnormal cells. When an NK cell encounters a potential target, it assesses the balance of signals it receives from these receptors to determine whether to initiate an attack.

Overall, natural killer cells are an important component of the immune system's defense against infections and cancer. Their ability to quickly recognize and eliminate abnormal cells makes them a crucial part of the body's immune surveillance and response.