Wild-type C57BL/6J and 129P2/OlaHsd mice were obtained from Jackson Laboratories (Bar Harbor, USA) and Harlan UK (Bicester, UK), respectively. All mice were housed in individually ventilated cages in a specific pathogen-free environment with a 12 h light-dark cycle and were fed a regular unrestricted diet. The GBF's routine surveillance program screened for selected pathogens. The Ptdsrtm1Gbf mutant was crossed to C57BL/6J mice to establish the co-isogenic C57BL/6J-Ptdsrtm1Gbf mouse line. All studies were approved by the appropriate authorities.