Format

Send to

Choose Destination
Vaccine. 2011 Sep 16;29(40):6941-7. doi: 10.1016/j.vaccine.2011.07.075. Epub 2011 Jul 29.

Identification of Francisella tularensis outer membrane protein A (FopA) as a protective antigen for tularemia.

Author information

1
Albany Medical College, Center for Immunology and Microbial Disease, Albany, NY 12208, USA.

Abstract

Francisella tularensis is a highly pathogenic gram negative bacterium that infects multiple sites in a host, including the skin and the respiratory tract, which can lead to the onset of a deadly disease with a 50% mortality rate. The live vaccine strain (LVS) of F. tularensis, while attenuated in humans but still virulent in mice, is not an option for vaccine use in the United States due to safety concerns, and currently no FDA approved vaccine exists. The purpose of the present work was to assess the ability of recombinant Francisella outer membrane protein A (FopA) to induce a protective response in mice. The gene encoding FopA from F. tularensis LVS was cloned and expressed in Escherichia coli. The resulting recombinant protein was affinity-purified from the E. coli outer membrane, incorporated into liposomes and administered to mice via multiple routes. FopA-immunized mice produced FopA-specific antibodies and were protected against both lethal intradermal and intranasal challenges with F. tularensis LVS. The vaccinated mice had reduced bacterial numbers in their lungs, livers and spleens during infection, and complete bacterial clearance was observed by day 28 post infection. Passive transfer of FopA-immune serum protected naïve mice against lethal F. tularensis LVS challenge, showing that humoral immunity played an important role in vaccine efficacy. FopA-immunization was unable to protect against challenge with the fully virulent SchuS4 strain of F. tularensis; however, the findings demonstrate proof of principle that an immune response generated against a component of a subunit vaccine is protective against lethal respiratory and intradermal tularemia.

PMID:
21803089
PMCID:
PMC3428214
DOI:
10.1016/j.vaccine.2011.07.075
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center