title: "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: 1 Department of Internal Medicine-Infectious Diseases, The University of Texas Medical Branch , Galveston, Texas.
authors: Lucas S
authors: LS
authors: Blanton
authors: Nicole L
authors: NL
authors: Mendell
authors: David H
authors: DH
authors: Walker
authors: Donald H
authors: DH
authors: Bouyer
mesh_terms: D000818:Animals; D056738:Cross Protection; D006168:Guinea Pigs; D008297:Male; D012281:Rickettsia / Q000276:immunology* / Q000472:pathogenicity; D012282:Rickettsia Infections / Q000276:immunology*; D012284:Rickettsia rickettsii / Q000276:immunology*; D012373:Rocky Mountain Spotted Fever / Q000276:immunology* / Q000517:prevention & control*; D014611:Vaccination
keywords: Cross protection; Rickettsia rickettsia; Rocky Mountain spotted fever; “Rickettsia amblyommii”