What is a common cause of fever during an infection?

• A. Release of histamine by mast cells
• B. Toxins from bacteria triggering macrophages to release interleukin 1
• C. Direct infection of the hypothalamus
• D. Increase in white blood cell count

Answer: (B)

The common cause of fever during an infection is the release of toxins from bacteria that trigger macrophages to release interleukin-1. When pathogens invade the body, macrophages, which are a type of immune cell, recognize the presence of bacteria and other pathogens. In response, they release cytokines, including interleukin-1.

Interleukin-1 serves as a signaling molecule that communicates with the hypothalamus in the brain, which is responsible for regulating body temperature. When interleukin-1 interacts with the hypothalamus, it induces the release of prostaglandins, leading to an increase in the body’s set point temperature. This results in a fever, which is a natural immune response intended to create an environment less favorable for the pathogens and to enhance the efficiency of the immune system in fighting off the infection.

In summary, the path from bacterial toxins to the activation of macrophages, and subsequently to the release of interleukin-1, is a crucial mechanism through which the body develops fever as part of its defense strategy during an infection.