Interleukin-1 Immunoreactive Innervation of the Human Hypothalamus

TLDR

Interleukin‑1 is a cytokine that drives the acute‑phase response and exerts many effects on the central nervous system, yet it had not been recognized as an intrinsic neuronal component of the brain except in glial cells. The study used an anti‑IL‑1β antiserum to immunohistochemically stain human brain tissue for IL‑1β‑like immunoreactive neural elements. IL‑1β‑immunoreactive fibers were found innervating key endocrine and autonomic nuclei that regulate the central acute‑phase response, suggesting IL‑1 functions as an intrinsic neuromodulator in CNS pathways controlling metabolic aspects such as fever.

Abstract

Interleukin-1 (IL-1) is a cytokine that mediates the acute phase reaction. Many of the actions of IL-1 involve direct effects on the central nervous system. However, IL-1 has not previously been identified as an intrinsic component within the brain, except in glial cells. An antiserum directed against human IL-1β was used to stain the human brain immunohistochemically for IL-1β-like immunoreactive neural elements. IL-1β-immunoreactive fibers were found innervating the key endocrine and autonomic cell groups that control the central components of the acute phase reaction. These results indicate that IL-1 may be an intrinsic neuromodulator in central nervous system pathways that mediate various metabolic functions of the acute phase reaction, including the body temperature changes that produce the febrile response.