Abstract: Many scientists have abstracted the tumor necrosis factor(TNF) from the mammals and avians, and studied its physiological, chemical properties and biological activity at different level, since the first abstraction of the TNF from the animal in 1975. But until now, there are no records of the incressiong and decreasing of TNF and the correlation between the inclusion body hepatitis virus-induced TNF and IBH.The paper was about using chicken inclusion body hepatitis virus to infect SPF chicken and abstract the TNF from the blood and different age and study its immue activity(killing rate to the L₉₂₉ cells).We furthermore studied the increasing and decressing of TNF and the correlation between the TNF and virus.The chicken inclusion body hepatitis virus could induce SPF chicken to synthesize TNF with the infection by mouth.Moreover the TNF activities at different age show decreasing and increasing which verity that virus are closely related to the synthesis and activity of TNF.

Key words: chicken; inclusion body hepatitis virus; tumor necrosis factor; increasing and decreasing