[Objective] The research aimed to carry out the cloning,identification and differential expression analysis of carp interleukin-1β （IL-1β） cDNA. [Method] By using DD-RTPCR method,the differential expression cDNA fragments were gained. The cDNA library of carp peripheral blood leucocytes which was stimulated by the mitogen was screened,and the full length cDNA of carp IL-1β was cloned. Moreover,the sequence analysis and differential expression analysis were carried out. [Result] The positive clone which had a whole ORF that encoded 276 amino acids was obtained. The cluster analysis showed that the amino acid sequence of carp IL-1β and Japanese carp closely gathered as a branch,and the homoeology of amino acid sequence reached 95%. The clustering order was the carassius,zebra fish,pig,cattle,horse,human and mouse in turn. The differential expression analysis showed that the expression of IL-1β in the leucocytes significantly increased in the prior period （4 h） after the mitogen stimulated. But as the time went by （12 and 24 h）,it didn＇t increase in the same period. The total trend of expression amount presented the peak type. [Conclusion] The research laid the foundation for further studying the expression manner,function characteristic,regulation mechanism of IL-1β in vivo and its action mechanisms in the inflammatory reaction,emergency reaction and immune response.
