Complementary DNA were designed according to the described interleukin-1β sequence of mammals,such as human,murine,equine,bovine,ovine,rabbit. 32 P Labelled DNA probes were made,and were used to detect the IL-1β producing cells of chick brain tissues infected with Avian Encephalomyelitis Virus (AEV)by means of nucleic acid spot hybridization and hybridization in situ.The results indicated that hybridization reactions were positive.