Bone Forming Gene Therapy (Immune Animal Model in Ex Vivo Gene Therapy for Spinal Fusion with Type 5 Adenoviral Delivery of the LIM Mineralization Protein-1 cDNA) / 대한척추외과학회지

ABSTRACT

STUDY DESIGN: In vivo study to determine the immune effects to adenoviral vector encoding LMP-1 cDNA in rabbit. OBJECTIVE: To quantify the immune effect of Ad5-LMP-1 in the rabbit during the therapeutic gene transfer. SUMMARY OF LITERATURE REVIEW One of the major limitations in the use of adenoviral vector for gene therapy is the immune response and it made the poor transduction efficiency when re-administrated. Adenoviral antigen plus those derived from transgene expression in transduced cell contribute to cellular, humoral and non-specific immune response constitutes barriers to successful gene therapy. Therefore, the animal immune model will be mandatory to study the immune impact. MATERIALS AND METHOD: We i.v. injected Ad5-betaGal to total 24adult NZW rabbits; 1x108, 1x109, 1x1010, 1x1011v.p. to each 6 rabbits allowed them to develop immune response. Six non-immunized animals were used as control. Adenovirus antibodies were measured at 0, 4, 8, 16, 20 weeks. Group I. 6 control rabbit underwent spinal arthrodesis at 4 weeks (n=3) and 16 weeks (n=3) with 4 million cells and MOI of 4. Group II. 6 rabbit underwent spinal arthrodesis at 4 weeks after injection of 108 p.f.u virus (n=3) and 16 weeks (n=3). Group III. six 109 immunized rabbits, Group IV. six 1010 immunized rabbits, Group V. six 1011 immunized rabbits, underwent spinal arthrodesis at 4 and 16 weeks after injection. Total anti-Ad Ig and neutralizing antibody titer was measured on the 0. 4. 8, 16, 20 weeks after injection. RESULTS: Group I. All 6 non-immunized rabbits had solid spine fusions at 4 and 16 weeks. Group II. All 3immunized rabbits had not spine fusions at 4 weeks and all three had solid spine fusion at 16 weeks. Group III. None of them (n=6) immunized rabbits had spine fusion at 4 and 16weeks, but some bone formation was observed at 16 weeks. Group IV, V. None of them immunized rabbits had bone formation. The anti-Ad5 Ig and neutralizing Ab were detected and peaked at the 4weeks and significantly dropped off 16 weeks after injection. CONCLUSION: This experiment revealed that a small dose of adenovirus elicited an enough immune response that inhibited the bone formation. Because majority of human posses the Ab against adenovirus, it will be mandatory to overcome immune response in adenoviral vector gene therapy.