Transient expression of hepatitis B virus surface antigen (HBsAg) and human erythropoietin (hEPO) genes in milk after direct introduction into ewe

摘要

The ability to deliver nonviral DNA directly into animals would provide major practical and economic benefits. To pursue this potential, as a preliminary approach, the expression in mammary epithelial cells with nonviral DNA encoding HBsAg and hEPO was investigated by in vivo delivery directly into mammary gland. Either the bovine alpha s1-casein-HBsAg or the WAP-hEPO gene construct was introduced into mammary glands of dose by mammary artery injection A single injection of 10~(11) copies of DNA construct was implemented for a doe. Transient expression of the constructs in milk collected from milk letdown by induction up to 19 d after injection was measured with an hEPO ELISA kit from Boehringer Mannheim (Cat, No 1 693 417) for rhEPO, and a HBsAg-ELISA kit (Abbott Lab, USA) for rHBsAg The treated animals showed mean concentration of recombinant molecules at 16 mu g/L for rHBsAg, and 2 mg/L for rhEPO in milk.