BSCU1 and Immune Function

Inclusion Criteria: Adults * 30 ≤ age ≤ 49 years * BMI ≥ 18.5 and ≤ 25 kg/m2 * In good health as assessed during screening (by questionnaire), and the medical investigator's professional judgment * Non-smoking Elderly * 65 ≤ age ≤ 79 years * BMI ≥ 22.0 and ≤ 28.0 kg/m2 * Generally healthy as assessed during screening (by questionnaire), and the medical investigator's professional judgment * Non-smoking Children * 3 ≤ age ≤ 6 years * Healthy BMI, cut-off points will be used as indicated by JGZ * Generally healthy as assessed during screening (by parental anamnesis), and the study physician's professional judgment Exclusion Criteria: Adults and elderly * Chronic illness (e.g., diabetes mellitus, cardiac insufficiency, respiratory insufficiency, cancer, chronic kidney or liver disease), * Acute infection in the past month * Gastrointestinal disorders (e.g., inflammatory bowel disease), * Acute gastroenteritis in the past 2 months * Any vaccination in the past month or any scheduled vaccination during the study period * Treatment with antibiotics within 2 months before the start of the study and during the study period * Regular use of laxative agents * Immunodeficiency disorder * Use of anti-inflammatory or immunosuppressive drugs (e.g.cyclosporine, azathioprine, systemic corticosteroids, antibodies) * Unexplained weight loss or weight gain of \> 3 kg in the 3 months prior to pre-study screening * Regular consumption of probiotics within 1 month before start of the study * Evidence of current excessive alcohol consumption (\>4 consumptions/day or \>20 consumptions/week) or drug (ab)use * Mental status that is incompatible with the proper conduct of the study Children * Acute respiratory or gastrointestinal infection in the past month * Chronic illness (e.g. chronic infections, systemic or metabolic disease) * Gastrointestinal disorders (e.g., inflammatory bowel disease), * Acute gastroenteritis in the past 2 months * Any vaccination in the past month or any scheduled vaccination during the study period * Treatment with antibiotics within 2 months before the start of the study and during the study period * Immunodeficiency disorder * Use of anti-inflammatory or immunosuppressive drugs (e.g.cyclosporine, azathioprine, systemic corticosteroids, antibodies) * Regular use of laxative agents * Regular consumption of probiotics within 1 month before start of the study