Final answer:
Fever, a systemic sign of acute inflammation, is primarily induced by cytokines such as interleukin 1, which acts as a pyrogen to elevate body temperature and stimulate the immune response.
Step-by-step explanation:
One systemic manifestation of the acute inflammatory response is fever, which can be triggered by a variety of mediators. Fever acts as a system-wide sign of inflammation, elevating body temperature to stimulate the immune response. The mediators responsible for inducing fever include cytokines like interleukin 1 (IL-1), which is part of a group of fever-producing molecules known as pyrogens. While other mediators like histamine, leukotrienes, and prostaglandins play key roles in promoting inflammation by causing vasodilation and increasing blood flow and capillary permeability, it is the release of cytokines, particularly interleukin 1, that is crucial for the development of fever.
Therefore, the correct answer to the question about which mediator induces fever during an acute inflammatory response is interleukin 1.