Chemotherapy Biotherapy Certification ONS Practice Testq

What is the primary role of natural killer cells?

1. Produce antibodies

2. Regulate immune responses

3. Enhance inflammation

4. Kill infected or cancerous cells

The correct answer is: Kill infected or cancerous cells

Natural killer (NK) cells play a crucial role in the innate immune system, primarily tasked with identifying and eliminating cells that are infected by viruses or have become cancerous. These cells possess the ability to recognize stressed cells in the absence of antibodies and major histocompatibility complex (MHC) molecules, allowing them to act quickly in response to threats. Their method of attack involves the release of cytotoxic granules that induce apoptosis (programmed cell death) in target cells, thus preventing the proliferation of infected or malignant cells. This direct killing mechanism is vital for controlling the spread of infections and for immune surveillance against tumors. While other immune cells are responsible for producing antibodies, regulating immune responses, and enhancing inflammation, the specific function of natural killer cells distinctly centers on their cytotoxic capabilities, solidifying their importance in the defense against tumors and viral infections.