What is an example of innate immunity? Group of answer choices T cells natural killer cells B cells antibodies
The correct answer and explanation is:
Correct Answer: Natural killer cells
Explanation:
Innate immunity is the body’s first line of defense against pathogens. It provides a quick, non-specific response to invaders such as bacteria, viruses, and other harmful organisms. Unlike adaptive immunity, innate immunity does not require previous exposure to a pathogen in order to act. It responds the same way every time a pathogen is detected.
Natural killer (NK) cells are a key component of the innate immune system. They are a type of white blood cell that targets and destroys infected or cancerous cells. NK cells do not need prior activation or sensitization to recognize threats. They patrol the body, identifying cells that are abnormal because they are missing “self” proteins (like MHC I) or displaying stress signals. Once they identify a target, they release chemicals such as perforin and granzymes to kill the affected cells.
In contrast, T cells and B cells belong to the adaptive immune system. T cells identify and destroy infected cells but require activation through antigen presentation. B cells produce antibodies in response to specific antigens but also need activation and memory formation to become effective. Antibodies themselves are proteins made by B cells and are part of the adaptive immune response. They recognize specific pathogens and help neutralize or mark them for destruction.
Therefore, among the choices provided, only natural killer cells are directly involved in innate immunity. Their ability to react quickly without prior exposure makes them crucial in controlling infections during the early stages before the adaptive immune system becomes fully active. This immediate response is essential in containing pathogens and preventing the spread of infection in the body.