"Rickettsia amblyommii" induces cross protection against lethal Rocky Mountain spotted fever in a guinea pig model.

Abstract

Rocky Mountain spotted fever (RMSF) is a severe illness caused by Rickettsia rickettsii for which there is no available vaccine. We hypothesize that exposure to the highly prevalent, relatively nonpathogenic "Rickettsia amblyommii" protects against R. rickettsii challenge. To test this hypothesis, guinea pigs were inoculated with "R. amblyommii." After inoculation, the animals showed no signs of illness. When later challenged with lethal doses of R. rickettsii, those previously exposed to "R. amblyommii" remained well, whereas unimmunized controls developed severe illness and died. We conclude that "R. amblyommii" induces an immune response that protects from illness and death in the guinea pig model of RMSF. These results provide a basis for exploring the use of low-virulence rickettsiae as a platform to develop live attenuated vaccine candidates to prevent severe rickettsioses.

• Authors: Lucas S Blanton, Nicole L Mendell, David H Walker, Donald H Bouyer
• Journal: Vector borne and zoonotic diseases (Larchmont, N.Y.) (Vector Borne Zoonotic Dis) Vol. 14 Issue 8 Pg. 557-62 (Aug 2014) ISSN: 1557-7759 [Electronic] United States
• PMID: 25072985 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Animals
• Cross Protection
• Guinea Pigs
• Male
• Rickettsia (immunology, pathogenicity)
• Rickettsia Infections (immunology)
• Rickettsia rickettsii (immunology)
• Rocky Mountain Spotted Fever (immunology, prevention & control)
• Vaccination