C57bl 6j mice

Young (2–3 months) male and female C57BL/6J mice were purchased from Janvier (Le Genest-Saint-Isle, France). Furthermore, middle-aged (16 months) and old (23–24 months) male and female C57BL/6J mice (initially obtained from Janvier) were obtained from our in-house breeding colonies (SFB 1506 “Aging at interfaces”; project Z02) at the Tierforschungszentrum of Ulm University. Mice were routinely housed in our animal facility under standardized pathogen-free (SPF) conditions. Aging mice were routinely checked for overall appearance, and only healthy aged mice were used in the described experiments.

Behavior and biochemistry: Male C57BL/6J mice (postnatal day, PD, 56) were purchased from Janvier (Barcelona, Spain) and maintained in the animal facility (UBIOMEX, PRBB) in a 12 h light–dark cycle. Mice were housed at a stable temperature (22 °C ± 2) and humidity (55% ± 10%), with food and water ad libitum. They were allowed to acclimatize to the new environmental conditions for at least five days prior to experimentation. Animal care and experimental protocols were approved by the Barcelona Biomedical Research Park – Universitat Pompeu Fabra Ethical Committee for Animal Research (CEEA-PRBB-UPF).
Electrophysiology: Male C57BL/6J mice (PD60) were purchased from Janvier (Le Genest-Saint-Isle, France) and maintained in the animal facility in a 12 h light–dark cycle. Mice were housed at stable temperature (20 ± 1 °C) and humidity (60%), with food and water ad libitum. They were allowed to acclimatize to the new environmental conditions for at least one week prior to experimentation. All experiments were performed on male C57BL/6J mice between PD70 and PD110. The French Ethical committee authorized this project (APAFIS#3279-2015121715284829 v5).
In all the studies, animals were treated in compliance with the European Communities Council Directive (86/609/EEC) and the ARRIVE guidelines for the care and use of laboratory animals.

Female Balb/c mice were obtained from Janvier Laboratories (Le Genest Saint Isle, France) and maintained under acidified water upon arrival. Donor cells were from specific pathogen free (SPF) C57BL/6J mice (from Janvier laboratories), congenic CD45.1⁺ C57BL/6J, Actin-GFP knock-in (KI) C57BL/6J, IFN-γ deficient C57BL/6J mice, all raised in our accredited animal facility at Institut Necker Enfants Malades under pathogen-free conditions. All mice were backcrossed for at least ten generations.

Animal work was carried out under UK Home Office guidelines and the approval of the Regional Animal Ethics Committee of Northern Stockholm, Sweden. Mice were housed in a specific pathogen-free animal facility, provided with food and water ad libitum, and maintained on a 12-hour light-dark cycle at 21°C. Genotyping was performed with DNA from ear biopsies using commercial Transnetyx qPCR assays. C57Bl/6J mice were purchased from Janvier Labs. Donor TCR transgenic OT-1 mice (JAX 003831, The Jackson Laboratory) were crossed with mice bearing the CD45.1 congenic marker (JAX 002014, The Jackson Laboratory). All mice were backcrossed over ten generations to the C57BL/6J background. Male and female animals >6 weeks of age were used in experiments. Groups were assigned randomly for mouse experiments and the investigator was blinded to group assignment. No statistical methods were used to pre-determine sample size.