Abstract: Objective The antibody targeted technical combined with siRNA was used to produce a bispecific complex scFv-9R-siRNA, which is a highly efficient delivery system. The delivery system would specifically transport the specific siRNAs of MAG, OMgp and NogoA to the injuried nerve cells through anti-Omgp scFv to inhibit the expression of these three axon-inhibitors, improve the local micro-environment after spinal cord injury, block the inhibition of these myelin-related inhibitors on axonal regeneration, and establish solid foundation for the subsequent rat model experiment. Methods (1) Single-chain antibody scFv (OMgp) was constructed with monoclonal anti-OMgp by recombinant DNA technology, and then, scFv (OMgp)-9R-siRNA was non-covalent synthesized for the genes of MAG, OMgp, NogoA; (2) Effects identification of scFv (OMgp)-9R-siRNA complex in vitro: mRNA and protein expression levels of MAG, OMgp and NogoA were identified in nerve cells comparing with non-nerve cells at the same time, to discover the cell-targeting specificity of scFv. Results (1) Rat OMgp monoclonal antibody E811 was successfully prepared, then specificity and sensitivity of that were idendified with ELISA and Western blotting. Finally we successfully got the scFv (OMgp)-9R-siRNA complex; (2) In vitro experiments confirmed that: scFv (OMgp)-9R-siRNA complexes simultaneously decreased the expression of MAG, OMgp and Nogo A specifically. Conclusion Single chain antibody technology resolved the specific import problems of siRNAs, and provided the foundation for the further study which is transporting the specific siRNA to damaged neurons in vivo and made axonal regeneration on the condition of spinal cord injury.

Key words: Monoclonal antibodies, Single chain antibody, RNA interference