Abstract: Objective   To clone and express the arginine kinase （AK） gene of Blattella germanica and analyze its immune activity.   Methods   The cDNA of AK was cloned using specific primers from the total RNA of Blattella germanica. The open reading frame （ORF） of AK was cloned into pET-28A vector, and expressed in Escherichia coli BL21（DE3） with IPTG induction. The recombinant protein was purified by Ni²⁺ chelating affinity chromatography. The recombinant protein was detected by SDS-PAGE， and its immune activity was analyzed by Western blotting.  Results   The cloned cDNA ORF sequence （GenBank accession No. FJ514482） contained 1 071 bp and encoded 356 amino acids. Its sequence homology with the published one （GenBank accession No. EU429466） was 97.2% at nucleotide level. The recombinant containing recombinant plasmid pET-28a-AK expressed a soluble protein of AK （M_r 45 000） after being induced with IPTG. The recombinant AK protein was recognized by sera of allergic patients, indicating that the recombinant AK protein has an adequete response activity.  Conclusion   The AK gene of Blattella germanica has been cloned and the recombinant AK protein has been confirmed with immune activity.

Key words: Blattella germanica, Arginine kinase, Allergen, Clone