Which type of immune response is non-specific and acts immediately upon infection?

The innate immune response is the correct answer because it serves as the body’s first line of defense against pathogens. This response is non-specific, meaning it does not target specific pathogens but rather responds to a wide range of invaders, such as bacteria, viruses, and fungi, immediately upon detection.

This type of response includes physical barriers like skin and mucous membranes, as well as various immune cells such as phagocytes (e.g., macrophages and neutrophils) that work quickly to engulf and destroy pathogens. Additionally, components like natural killer cells and the release of cytokines and other signaling molecules are part of this immediate response, helping to orchestrate an effective and rapid reaction to infection.

In contrast, the adaptive immune response relies on the body recognizing specific pathogens and takes longer to activate, typically days to weeks after initial exposure. The cell-mediated immune response and humoral immune response are components of the adaptive immunity, with specific mechanisms that require prior exposure to the pathogen, making them slower to act compared to the innate immune response. This highlights the essential role of the innate immune response in providing immediate defense against infections while the adaptive immune system develops a specific response.