1. Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
2. Laboratory of Microbiology, Wageningen University, Wageningen, the Netherlands
3. Institute of Biotechnology, University of Helsinki, Helsinki, Finland
4. Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
5. RPU Immunobiology, Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland