Genetic engineering, expression, and activity of a fusion protein of a human neurotrophin and a molecular Trojan horse for delivery across the human blood–brain barrier
Article first published online: 7 FEB 2007
Copyright © 2007 Wiley Periodicals, Inc.
Biotechnology and Bioengineering
Volume 97, Issue 6, pages 1376–1386, 15 August 2007
How to Cite
Boado, R. J., Zhang, Y., Zhang, Y. and Pardridge, W. M. (2007), Genetic engineering, expression, and activity of a fusion protein of a human neurotrophin and a molecular Trojan horse for delivery across the human blood–brain barrier. Biotechnol. Bioeng., 97: 1376–1386. doi: 10.1002/bit.21369
- Issue published online: 27 JUN 2007
- Article first published online: 7 FEB 2007
- Manuscript Accepted: 23 JAN 2007
- Manuscript Received: 2 JAN 2007
- blood–brain barrier;
- drug targeting;
- drug delivery;
Neurotrophins, such as brain derived neurotrophic factor (BDNF), do not cross the blood–brain barrier (BBB). Certain monoclonal antibodies (MAb) to the human insulin receptor (HIR) do cross the BBB via receptor-mediated transport, and can act as a molecular Trojan horse to ferry across the BBB an attached drug. A genetically engineered fusion protein was produced whereby the amino terminus of human BDNF is fused to the carboxyl terminus of the heavy chain of a chimeric HIRMAb. The HIRMAb-BDNF fusion protein reacted equally with antibodies to human IgG and BDNF. The bi-functionality of the fusion protein was retained as the affinity of the fusion protein for the HIR was identical to that of the chimeric HIRMAb, and the affinity of the fusion protein for the trkB receptor was identical to that of BDNF. The fusion protein was equi-potent with BDNF in a neuroprotection assay in human neural cells. The pharmacokinetics (PK) of the fusion protein was examined in the adult Rhesus monkey. The mean residence time (MRT) of the fusion protein in blood was >100-fold longer than the MRT of BDNF. Therapeutic levels of BDNF were produced in primate brain following the intravenous administration of the fusion protein. A fusion protein tandem vector was engineered that allowed for isolation of a CHO cell line that produced the fusion protein at high levels in serum free medium. Neurotrophins, such as BDNF, can be re-formulated to enable these molecules to cross the human BBB, and such fusion proteins represent a new class of human neurotherapeutics. Biotechnol. Bioneg. 2007;97: 1376–1386. © 2007 Wiley Periodicals, Inc.