Balb canncrl male mice

Wild type C57Bl/6J and Balb/cAnNCrl male mice of 8–10 weeks old were obtained from Charles River (Maastricht, the Netherlands). Mice transgenic for human Interleukin-37 (hIL-37Tg) were created as described previously [5 (link)] and bred and housed under specific pathogen-free conditions in the animal facility of the Radboud university medical center in Nijmegen. Transgenic expression of IL-37 was confirmed by standard genotyping protocols on ear tissue samples. All mice received water and food ad libitum, and only age- and sex-matched mice were included in experiments. All animal experiments were carried out following the guidelines of local and national Animal Ethics Committees and after permission granted by the Animal Ethics Committee of the Radboud University Nijmegen (Permit Number 2011–024). Mice were sacrificed by cervical dislocation.

A group of 10 Balb/cAnNCrl male mice weighing >20 g obtained from Charles River Laboratories were used in this experiment. Each mouse received a biofilm infected implant in one flank and a sterile control in the other flank (the left and right side was randomized) as described previously [14 (link)]. In short, the implants were made by cutting a 5 mm segment of a 7 French polyurethane catheter (Access Technologies, Niles, MI, USA). The infected implants were pre-colonized with the biofilm of a luminescent strain of methicillin-resistant S. aureus, USA300 LAC (AH4802) [19 (link)]. An inoculum of ~10⁷ CFU was used, after which the biofilms were grown for 48 h before implantation. The implantation was performed carefully using a 14-gauge guiding needle through which the catheter implants could be positioned correctly using a K-wire. The implantation of colonized and sterile implants was randomized to the left or right flank of the mouse. Seven mice were successfully injected intravenously in the tail with 50 µg of radiolabeled antibody (7.5 MBq) two days after subcutaneous implantation. Incorrect injections were determined by SPECT/CT scans at 24 h. Three mice showed high uptake (>25% of total activity) in the tail, and thus were injected intramuscularly and were therefore excluded.