PFOS: Male C57BL/6 (H-2b) mice (6–8 weeks old at the beginning of each experiment) were obtained from B&K (Solna, Sweden). This mouse strain was chosen because of its wide use and paradigmatic status in immunological research. Animals were housed in the animal facilities at the Wenner–Gren Institute, Stockholm University, at 22 °C with a 12-h light/12-h dark cycle, 50% humidity and access to the diets indicated below and tap water ad libitum. Upon arrival, 4 mice were placed in each cage (for group monitoring of food intake) and allowed to acclimatize to this environment for 7 days before starting dietary exposure to PFOA or PFOS. In order to mitigate the stress and fighting associated with group-housing of male mice, each cage was provided with nesting materials, e.g., white paper towels and toilet paper rolls. All of the experiments performed on these animals were preapproved by the Northern Stockholm Ethical Committee for Animal Experimentation (approval number N150/07).

PFOA: Male C57BL/6 (H-2b) mice (6–8 weeks old at the beginning of each experiment) were obtained from B&K (Solna, Sweden). This mouse strain was chosen because of its wide use and paradigmatic status in immunological research. Animals were housed in the animal facilities at the Wenner–Gren Institute, Stockholm University, at 22 °C with a 12-h light/12-h dark cycle, 50% humidity and access to the diets indicated below and tap water ad libitum. Upon arrival, 4 mice were placed in each cage (for group monitoring of food intake) and allowed to acclimatize to this environment for 7 days before starting dietary exposure to PFOA or PFOS. In order to mitigate the stress and fighting associated with group-housing of male mice, each cage was provided with nesting materials, e.g., white paper towels and toilet paper rolls. All of the experiments performed on these animals were preapproved by the Northern Stockholm Ethical Committee for Animal Experimentation (approval number N150/07).