Expression of Human papillomavirus type 16 major capsid protein in transgenic Nicotiana tabacum cv. Xanthi

 The production of vaccine antigens in plants is a safe and potentially very cost-effective alternative to traditional expression systems. We investigated the possibility of transgenic plant expression of the Human papillomavirus (HPV) type 16 L1 major capsid protein, with and without nuclear localisation signals, in Nicotiana tabacum cv. Xanthi plants. The genes were stably integrated into the N. tabacum genome, and both the expressed proteins were capable of assembling into capsomers and virus-like particles. The proteins in concentrated leaf extracts (L1_Tr) were tested for antigenicity using a panel of characterised monoclonal antibodies (Mabs). Neutralising and conformation-specific Mabs (H16:V5 and H16:E70) were shown to bind to both types of the plant-produced particles. We estimated the L1_Tr product yield to be 2–4 µg per kg of fresh leaf material. Rabbits immunised with small doses of plant-produced particles elicited a weak anti-HPV-16 L1 immune response. Our results support the feasibility of using transgenic plants for the production of HPV vaccines.

Authors and Affiliations

1. Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa, , , , , , ZA

   A. Varsani & E. P. Rybicki

2. Institute for Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa, , , , , , ZA

   A.-L. Williamson & E. P. Rybicki

3. Electron Microscope Unit, University of Cape Town, Cape Town, South Africa, , , , , , ZA

   M. Jaffer

4. National Health Laboratory Service, Groote Schuur Hospital, Observatory, South Africa, , , , , , ZA

   A.-L. Williamson

5. University of Rochester Medical Center, Rochester, New York, U.S.A., , , , , , US

   R. C. Rose

Received December 18, 2002; accpted March 26, 2003 Published online June 2, 2003

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