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Infection and Immunity, May 2007, p. 2476-2483, Vol. 75, No. 5
0019-9567/07/$08.00+0 doi:10.1128/IAI.01908-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Immunization of Pigs To Prevent Disease in Humans: Construction and Protective Efficacy of a Salmonella enterica Serovar Typhimurium Live Negative-Marker Vaccine
,
Martin Selke,1
Jochen Meens,1
Sven Springer,2
Ronald Frank,3 and
Gerald-F. Gerlach1*
Institute for Microbiology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Hannover, Germany,1 Impfstoffwerk Dessau-Tornau GmbH, PSF 214, Rodleben OT Tornau, Germany,2 Department of Chemical Biology, Helmholtz Centre for Infection Research (HZI), Mascheroder Weg 1, D-38124 Braunschweig, Germany3
Received 4 December 2006/ Returned for modification 21 January 2007/ Accepted 4 February 2007
Zoonotic infections caused by Salmonella enterica serovar Typhimurium pose a constant threat to consumer health, with the pig being a particularly major source of multidrug-resistant isolates. Vaccination, as a promising approach to reduce colonization and shedding, has been scarcely used, as it interferes with current control programs relying on serology as a means of herd classification. In order to overcome this problem, we set out to develop a negative-marker vaccine allowing the differentiation of infected from vaccinated animals (DIVA). Applying an immunoproteomic approach with two-dimensional gel electrophoresis, Western blot, and quadrupole time-of-flight tandem mass spectrometry, we identified the OmpD protein as a suitable negative marker. Using allelic exchange, we generated an isogenic mutant of the licensed live vaccine strain Salmoporc and showed that virulence of Salmoporc and that of the mutant strain, Salmoporc
ompD, were indistinguishable in BALB/c mice. In a pig infection experiment including two oral immunizations with SalmoporcompD and challenge with a multiresistant S. enterica serovar Typhimurium DT104 clinical isolate, we confirmed the protective efficacy of SalmoporcompD in pigs, showing a significant reduction of both clinical symptoms and colonization of lymph nodes and intestinal tract. OmpD immunogenic epitopes were determined by peptide spot array analyses. Upon testing of several 9-mer peptides, each including an immunogenic epitope, one peptide (positions F100 to Y108) that facilitated the detection of infected animals independent of their vaccination status (DIVA function) was identified. The approach described overcomes the problems currently limiting the use of bacterial live vaccines and holds considerable potential for future developments in the field.
* Corresponding author. Mailing address: Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule Hannover, Bischofsholer Damm 15, 30173 Hannover, Germany. Phone: 49 511 856 7598. Fax: 49 511 856 7697. E-mail: gfgerlach{at}gmx.de
Published ahead of print on 12 February 2007.
Supplemental material for this article may be found at http://iai.asm.org/.
Infection and Immunity, May 2007, p. 2476-2483, Vol. 75, No. 5
0019-9567/07/$08.00+0 doi:10.1128/IAI.01908-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
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