[High-level expression of anti-interleukin-6 single chain variable fragment through plastid transformation technology].

Interleukin-6 (IL-6) is a pleiotropic cytokine which participates in the pathogenesis of a variety of clinical disorders, including many kinds of cancers. Anti-IL-6 antibody was proved to be useful for the immunotherapy of various inflammatory diseases. Plants are low-cost platforms for producing specific proteins of therapeutic interest. Two dependent transplastomic tobacco lines expressing murine anti-IL-6 single chain variable fragment (scFv) were generated after bombardment and regeneration, homoplasmy was then verified by Southern blotting analysis. The anti-IL-6 scFv gene was successfully expressed at both transcriptional and translational levels in transplastomic tobacco plants. Functional anti-IL-6 scFv accumulated to 1% of total soluble proteins, namely 41 mg/kg fresh weight. There was no obvious phenotypic difference between the wild-type and the transplastomic tobacco plants, including the growth rate, the height of mature plants and the number of siliques. The high-level expression of anti-IL-6 scFv indicates the potential for cost-effective production of scFV using transplastomic plants.