Development of lung and muscle protein factories to deliver therapeutic monoclonal antibodies

Monoclonal antibodies (mAbs), which represent the largest market of any protein therapeutic, are used in the treatment of conditions such as cancer and autoimmune diseases, and prophylaxis of infections. The complexity of manufacture of mAbs translates to a high cost compared with small-molecule drugs, and their use may be restricted as a result. Gene transfer for direct production of mAbs in vivo could offer an alternative to parenteral administration, with the added benefit of easing patient burden caused by repeated injections or infusions. Studies presented in this thesis investigated the possibility of using gene transfer agents for expression of mAbs in the lung lumen and circulation. Using the secreted reporter protein Gaussia luciferase, delivery of the lentiviral vector recombinant simian immunodeficiency virus, pseudotyped with F and HN proteins from Sendai virus (rSIV.F/HN) for targeting of pulmonary epithelium, was identified as an efficient means of gene transfer to the murine lung, with transgene expression in the lung lumen lasting for at least 12 months in BALB/c mice. The recombinant adeno-associated viral vector serotype 8 (rAAV2/8) injected into the muscle directed robust expression of the reporter protein into the circulation and lung lumen of mice for at least 12 months. Two model applications were used to assess the effectiveness of these vectors for mAb gene transfer: respiratory syncytial virus (RSV) infection and rheumatoid arthritis. Both rSIV.F/HN and rAAV2/8 vectors expressing the anti-RSV mAb palivizumab protected mice from weight loss upon RSV infection. Recombinant AAV2/8 delivered intramuscularly was also used to express the anti-tumour necrosis factor alpha (TNFa) biologics infliximab and etanercept for at least 6 months and 56 days, respectively. Due to the immunosuppressive nature of TNFα antagonists, constitutive expression is undesirable and small molecule-assisted shutoff (SMASh) was investigated as a possible method of regulation of etanercept production. In conclusion, viral vectormediated mAb gene transfer to the muscle and lung could be a feasible alternative to parenteral administration provided that an effective method of regulation of expression following vector delivery can be developed.