Vaccination of Fischer 344 rats against pulmonary infections byFrancisella tularensistype A strains

• Published in: Vaccine Vol. 27; no. 34; p. 4684
• Main Authors: Wu, Terry H, Zsemlye, Jason L, Statom, Gloria L, Hutt, Julie A, Schrader, Ronald M, Scrymgeour, Alexandra A, Lyons, C Rick
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Limited 23.07.2009
• Subjects: Animal models; Bacteria; Infections; Infectious diseases; Inhalation; Mortality; Pathogenesis; Rodents; Studies; Tularemia; Vaccines
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2009.05.060

Pneumonic tularemia caused by inhalation of the type A strains ofFrancisella tularensisis associated with high morbidity and mortality in humans. The only vaccine known to protect humans against this disease is the attenuated live vaccine strain (LVS), but it is not currently registered for human use. To develop a new generation of vaccines, multiple animal models are needed that reproduce the human response toF. tularensisinfection and vaccination. We examined the potential use of Fischer 344 rat as such a model. Fischer 344 rats were very sensitive to intratracheal infection with the virulent type A strain SCHU S4 and generally succumbed less than 2 weeks after infection. Similar to humans and non-human primates, Fischer 344 rats vaccinated with LVS by subcutaneous or intradermal routes were protected against a greater range of respiratory SCHU S4 challenge doses than has been reported for LVS vaccinated mice. Intratracheal LVS vaccination also induced effective immunity, but it was less protective when the challenge dose exceeded 105SCHU S4. LVS vaccination did not prevent SCHU S4 infection but rather controlled bacterial growth and pathology, leading to the eventual clearance of the bacteria. Our results suggest that the Fischer 344 rat may be a good model for studying pneumonic tularemia and evaluating potential vaccine candidates.