Evaluation of a Killed Phase I 'Coxiella burnettii' Vaccine in Cynomolgus-Monkeys.

摘要

The protective efficacy of a killed, purified phase I Coxiella burnettii vaccine was tested in cynomolgus monkeys. Monkeys vaccinated once with 30 microgram of the antigen were challenged 6 or 12 months later with virulent phase I rickettsiae administered in small-particle aerosols. The vaccine provided only partial protection since come of the monkeys developed a febrile response, tachypnea, anorexia, and rickettsmeia. Thoracic radiographs revealed no discernible pulmonary changes in any of the vaccinated animals, whereas, nonvaccinated control monkeys developed severe interstitial pneumonia following challenge. Control monkeys demonstrated an absolute neutrophilia and lymphopenia, increased alkaline phosphatase, total bilirubin, and SGOT; these parameters remained normal in vaccinated monkeys. Although rickettsiae were isolated from peripheral blood in vaccinated monkeys, the rickettsemia persisted for only one to two days; whereas, organisms were recovered from nonvaccinated animals for six to seven days. One hundred times more rickettsiae were isolated from the nonvaccinated group than the vaccinated group. All vaccinated animals had circulating microagglutinating antibodies to phase I and phase II antigens 6 and 12 months after vaccination. A rapid anamnestic response was demonstrated following challenge. (Author)