Specific pathogen free swiss female of1 mice

The spleens from mice infected with C. burnetii 602 and NM strains were used as in vivo model to study bacterial gene expressions. Animal experiments were conducted using 7 week old Specific-Pathogen-Free Swiss female OF1 mice (Charles River, l’Arbresle). The mice were housed under sterile conditions in biosecurity level 3 facilities. After a week of acclimatization, infections were performed with 3 Swiss OF1 mice per strain. The mice were inoculated intraperitoneally with 0.2 ml PBS suspension of C. burnetii (grown in BGM cell culture) with each mouse receiving a dose of 10⁷ genome copy equivalents as determined by quantitative PCR [20 (link)]. Twenty days after inoculation the mice were euthanized, spleens were harvested aseptically and immediately frozen in liquid nitrogen and then at −80 °C for RNA isolation. Animal experiments were approved by the animal experiment commission of the Central Veterinary Institute part of Wageningen UR, and conducted in accordance with the Dutch regulations on animal experimentation.

Two independent animal experiments were conducted using Specific-Pathogen-Free Swiss female OF1 mice (Charles River, l’Arbresle, France). For Experiment 1 (E1) and Experiment 2 (E2), 6 and 7 week old mice were used respectively. The mice were housed under sterile conditions in biosafety level 3 facilities and acclimatized for one week before experimental infection. Each group was housed separately and consisted of 10 mice.