Asthmatic and healthy children Asthma GF C57BL/622,23 GF C57BL/6N24 GF Swiss Webster N/A: not applicable; GF: germ-free; GM: gut microbiota. Cancer patients GF Swiss Webster Healthy infants Oncology GF Swiss Webster GF overexpressing a-synuclein mice GF C57BL/6 GF C57BL/6J Ten bacterial species selected from healthy GM Healthy adults Parkinson's disease patients Multiple sclerosis patients GF C57BL/6J GF BALB/c GF C3H/He Healthy adult Not specified Healthy adult GF C57BL/6 Healthy adults Neurodegenerative Nutritional Infectious Metabolome Not specified GF Swiss Webster Obese children and adolescents Healthy adults GF Swiss Webster and C57BL/6J Antibiotic-treated A/J GF C57BL/6J Obese adult twins Obesity Recipient Human Donor Research area Tumor engraftment and checkpoint inhibitor therapy Ovalbumin-induced lung inflammation Immunization with glycoprotein to induce experimental autoimmune encephalomyelitis Dietary intervention by infant formula ingredients Genetic susceptibility Dietary prebiotic intervention Antibiotic disruption of GM and Clostridium difficile infection Challenge with Salmonella typhimurium Challenge with enterotoxigenic Escherichia coli and ovalbumin Dietary intervention by switch from low-fat to high-fat diet Dietary intervention by feeding refined macronutrients Dietary intervention by polysaccharidedeficient diet N/A N/A N/A Model induction Table 1. Examples of human-to-mouse GM transfer studies and relevant model features. Phenotype transfer of Parkinson's disease traits42 Phenotype transfer of CNS-specific autoimmunity13 Mice with patient and healthy control GM displayed different induction of regulatory T cells13 Phenotype transfer of drug efficacy towards checkpoint inhibitor therapy22-24 Measurable inflammation in the model, though lower compared to mice with mouse GM16 Mice with GM from different humans exhibited different responses to the dietary intervention41 Responsiveness to dietary intervention7 Responsiveness to dietary intervention40 Phenotype transfer of adiposity and obesityassociated metabolic features12 Phenotype transfer of adiposity and increased fasting insulin18 Majority of metabolic features of donors were reflected in mice with the donor GM39 GM from different donors resulted in different cecal metabolite profiles in recipient mice5 Susceptibility to disease induction in the same way as SPF mice9 Colonization resistance toward infection11 Protection against abrogation of oral tolerance, but only when born with microbiota21 Rapid responsiveness to dietary intervention28 Model features 246 Laboratory Animals 53(3)