Objective:To obtain the clone and gene of light chain on human antibody against HBs.Methods:The phage displaying library was subjected to three rounds panning of “adherence-elution-amplification” with HBsAg coated in solid phase and help phage.The positive clone against HBsAg was characterized by ELISA assay and its P/N value was 2.415.The recombinant plasmid vectors from the positive clone was amplified by PCR with designed oligonucleotide primers of κ light chain.The κ chain PCR fragment was subcloned into plasmid pUC18 and sequenced.Results:The phage antibody against HBsAg was screened from a human immunoglouin phage displaying library.The pUC18-κ recombinant plasmid was constructed and sequenced.The gene size of κ chain is 643bp including variable region and constant region.Conclusion:According to the sequenceing and ELISA assay

we suggest that κ chain is a human anti-HBs-κ immunoglobuin.