Chemotherapy Biotherapy Certification ONS Practice Testq

What enhances the body's natural defenses in the fight against cancer?

1. Antigens

2. Monocytes

3. Natural killer cells

4. Chemical barriers

The correct answer is: Natural killer cells

Natural killer cells play a critical role in enhancing the body's natural defenses in the fight against cancer. These specialized lymphocytes are part of the innate immune system and are known for their ability to identify and destroy cancerous cells and virus-infected cells without the need for prior sensitization to specific antigens. Natural killer cells are activated in response to stress signals from damaged or transformed cells, allowing them to shortly engage and eliminate those cells by releasing cytotoxic substances, such as perforin and granzymes. This action not only helps in recognizing and controlling tumor growth but also contributes to the overall immune response, marking them as a vital component in the body's protective mechanisms against cancer. Other options, while they hold significance in the immune response, do not directly enhance defenses against cancer to the same extent. For example, antigens are typically associated with triggering an immune response rather than actively fighting cancer themselves. Monocytes are a type of white blood cell that can differentiate into macrophages and dendritic cells, contributing to immune functions but not primarily enhancing natural defenses against cancer directly. Chemical barriers include physical barriers like skin or stomach acid, which prevent pathogens from entering the body but do not specifically target cancer cells.