Eligibility Criteria:
"Part1:
Inclusion Criteria:
1. Voluntary written informed consent to participate in the study;
2. Japanese or White men ≥20 and \<45 years at the time of informed consent;
Exclusion Criteria:
1. Current illness requiring treatment;
2. Current respiratory, gastric, renal, or liver disease;
Part2:
Inclusion Criteria:
1. Voluntary written informed consent to participate in the study;
2. Men or women ≥20 years of age at the time of informed consent;
3. Ulcerative colitis diagnosed ≥6 months prior to informed consent;
4. Moderate or more severe ulcerative colitis;
Exclusion Criteria:
1. Definitive diagnosis of bacillary dysentery, amebic colitis, Salmonella enteritis, Campylobacter enteritis, colonic tuberculosis, Chlamydia enteritis, Crohn's disease, radiation colitis, drug-induced colitis, angiolymphoid hyperplasia, ischemic colitis, or intestinal Behcet's disease;
2. Any of the following clinically significant concurrent illnesses:
* Type 1 diabetes
* Poorly controlled type 2 diabetes (HbA1c \>8.5%)
* Congestive heart failure (class II to IV of the New York Heart Association classification)
* Myocardial infarction within 1 year
* Unstable angina pectoris within 1 year
* Poorly controlled hypertension (systolic pressure \>150 mmHg or diastolic pressure \>90 mmHg at screening)
* Severe chronic lung diseases requiring oxygen therapy
* Multiple sclerosis or other demyelinating diseases
* Active malignancies, or onset or a history of treatment of malignancies within 5 years prior to informed consent (except for resected or surgically cured epithelial carcinoma of the uterine cervix, cutaneous basal cell carcinoma, cutaneous squamous cell carcinoma, or ductal carcinoma);
3. Current or past history of clinically significant cardiovascular, liver, renal, respiratory, hematologic, central nervous system, psychiatric, or autoimmune diseases/disorders other than those in 2);
4. Suspected or confirmed symptomatic stenosis of the colon, abdominal abscess, or ischemic colitis based on clinical or radiographic data within 1 year prior to enrollment; suspected or confirmed toxic megacolon or history of toxic megacolon; history of any colonic resection, subtotal or total colectomy, ileostomy, or colostomy; or any previous surgery for ulcerative colitis or an anticipated requirement for surgery for ulcerative colitis;
5. Known colonic dysplasia, adenomas, or polyposis (excluding benign polyposis);
6. Any planned surgical treatment during the study;
7. Clostridium difficile infection within 8 weeks prior to enrollment;
8. Any active infection, including Grade ≥2 localized diseases per Common Terminology Criteria for Adverse Events, version 4.0, Japan Clinical Oncology Group edition (CTCAE v4.0-JCOG), within 4 weeks prior to enrollment;
9. Treatment with 5-aminosalicylic acid (5-ASA) enema, 5-ASA suppository, steroid enema, or steroid suppository within 2 weeks prior to enrollment;
10. Treatment with adalimumab within 2 weeks prior to enrollment or treatment with infliximab within 8 weeks prior to enrollment;