Ciliary neurotrophic factor is an endogenous pyrogen

Area of Science:

• Neuroscience
• Immunology
• Physiology

Background:

• Fever results from endogenous pyrogens elevating the hypothalamic thermoregulatory set point.
• Ciliary neurotrophic factor (CNTF) is known for its role in neuronal support.
• The pyrogenic potential of CNTF has not been previously established.

Purpose of the Study:

• To investigate the intrinsic pyrogenic activity of Ciliary neurotrophic factor (CNTF).
• To determine the mechanism and characteristics of CNTF-induced fever.
• To explore the relationship between CNTF and other endogenous pyrogens.

Main Methods:

• Intravenous injection of CNTF in rabbits.
• Administration of indomethacin as a pretreatment.
• Analysis of plasma for endogenous pyrogen activity post-injection.
• In vitro assessment of CNTF's effect on interleukin 1, tumor necrosis factor, and interleukin 6 production.

Main Results:

• CNTF induced a rapid, monophasic fever in rabbits, independent of endotoxins.
• Indomethacin pretreatment blocked the fever response to CNTF.
• Higher CNTF doses prolonged the fever, suggesting secondary pyrogenic activity.
• Plasma transfer from CNTF-treated rabbits did not transfer pyrogenic activity; CNTF did not induce IL-1, TNF, or IL-6 in vitro.

Conclusions:

• CNTF possesses intrinsic pyrogenic activity, directly inducing fever.
• CNTF-induced fever is mediated by prostaglandin synthesis and potentially involves central nervous system mechanisms.
• CNTF shares the gp130 signal-transduction pathway with interleukin 6 for its pyrogenic effects.