Vaccine 30 (2012) 998–1008 Contents lists available at SciVerse ScienceDirect Vaccine j ourna l ho me pag e: www.elsevier.com/locate/vaccine Peptide vaccination is superior to genetic vaccination using a recombineered bacteriophage  subunit vaccine Brad S. Thomas a,b,∗ , Sandra Nishikawa a , Kenichi Ito a,b , Puja Chopra a , Navneet Sharma a , David H. Evans b , D. Lorne J. Tyrrell b , Oliver F. Bathe a,c , Derrick E. Rancourt a a Southern Alberta Cancer Research Institute, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary. Calgary, AB, Canada b Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada c Departments of Surgery and Oncology, University of Calgary, Calgary, AB, Canada a r t i c l e i n f o Article history: Received 29 April 2011 Received in revised form 12 December 2011 Accepted 14 December 2011 Available online 28 December 2011 Keywords: Bacteriophage  Phage display Recombineering Subunit vaccine Th1 response Peptide vaccination Peptide immunization a b s t r a c t Genetic immunization holds promise as a vaccination method, but has so far proven ineffective in large primate and human trials. Herein, we examined the relative merits of genetic immunization and peptide immunization using bacteriophage . Bacteriophage  has proven effective in immune challenge models using both immunization methods, but there has never been a direct comparison of efficacy and of the quality of immune response. In the current study, this vector was produced using a combination of cis and trans phage display. When antibody titers were measured from immunized animals together with IL-2, IL-4 and IFN production from splenocytes in vitro, we found that proteins displayed on  were superior at eliciting an immune response in comparison to genetic immunization with . We also found that the antibodies produced in response to immunization with  displayed proteins bound more epitopes than those produced in response to genetic immunization. Finally, the general immune response to  inoculation, whether peptide or genetic, was dominated by a Th1 response, as determined by IFN and IL-4 concentration, or by a higher concentration of IgG2a antibodies. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction With the advent of recombinant DNA technology, the speed at which vaccines can be produced has improved, but still lags the speed at which viruses may adapt. It therefore remains a challenge to rapidly produce new vaccines in response to epidemics. To this end, we have been interested in bacteriophage lambda () as a subunit vaccine platform, as it has several advantageous charac- teristics. Bacteriophage have been used for therapeutics in humans Abbreviations: , bacteriophage lambda; (-wt) or (wt), wildtype bac- teriophage lambda; (TLR), toll-like receptor; (IFN), interferon gamma; (PRR), pattern-recognition receptor; (PAMP), pathogen associated molecular pattern; (gfp10), bacteriophage lambda gt10 with EGFP cloned into the EcoRI site; (gfp10- TAT), bacteriophage lambda with EGFP cloned into the EcoRI site displaying gpD-TAT; (gfp10-GFP-TAT), bacteriophage lambda with EGFP cloned into the EcoRI site displaying gpD-TAT and gpD-GFP; (pDE), pBluescript containing gpD to gpE in the MCS; (IP), intra peritoneal; (Th), T helper cell; (MHC), major histocompatibility complex. ∗ Corresponding author at: Li Ka Shing Institute of Virology, Department of Medi- cal Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Canada. Tel.: +1 780 492 9819; fax: +1 780 492 5304. E-mail address: brad.thomas@ualberta.ca (B.S. Thomas). since their discovery nearly a century ago [1]. They are inexpen- sive, are stable at room temperature, can be produced quickly in large quantities, and can also be genetically engineered with ease, which is a boon where vaccines must be quickly generated against evolving or emerging pathogens. Phage display was developed as a technique to clone proteins recognized by antibodies, and it remains a technique widely used in vaccine studies [2,3]. Filamentous bacteriophage (M13/fd) was first used for phage display, [3] and it is still the predominant phage strain, as no simple methods are available to display pro- teins on . However, filamentous phage display is not efficient at displaying large fusion proteins or libraries of complex cDNAs [4].  is superior to other bacteriophage for protein display, as it has been proven to stably display fusion proteins larger than a few amino acids on its capsid, with copies per virion that are two to three orders of magnitude higher than other phage dis- play vectors [4–10]. For example, with , it is possible to display large functional proteins off all 420 copies of the gpD capsid. Func- tional proteins such as -lactamase [11–13], luciferase (a 61 kDa protein) [14], or even -galactosidase (a 465 kDa protein) [11,12] have all been displayed on  with negligible effects on morphol- ogy and viability. In comparison, large proteins can be displayed on M13 bacteriophage, but only off the pIII capsid protein, which 0264-410X/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2011.12.070