It is the foundation of therapy of hepatitis b . the gene of scfv was cloned into the expression vector pet32a ( + ) and subsequently expressed in escherichia coll . the expressed scfv fused with the 109 aa trx - tag thioredoxin protein was above 30 % total cell protein in the shaking flask cultures 融合硫氧还蛋白的单链抗体在大肠杆菌bl21 ( de3 )中以包涵体的形式得到高效表达,单链抗体表达量达占30的总蛋白以上。