Mice were used for obtaining peptone-elicited peritoneal macrophages, resident peritoneal macrophages and bone marrow-derived macrophages. Animal experiments were performed in accordance with protocols approved by the Animal Experimentation Ethics Committee of the Institut Pasteur (permit #03-49) and following Austrian law in accordance with protocols approved by the Ethics Committee of the University of Veterinary Medicine, Vienna (#GZ680 205/67-BrGt/2003).