Subjects with active UC on either 5-ASA,corticosteroids,azathioprine(AZA) and or/6-mercaptopurine(6-MP);

Mayo score of 6 to 10 points with moderate to severe disease on endoscopy

Subjects on the following medications;

1. prednisolone ≤ 20 mg daily (or equivalent) (dose must be stable for at least 2 weeks prior to study drug administration)

2. 5-ASA (dose must be stable for at least 4 weeks prior to study drug administration)

3. AZA or 6-MP (dose must be stable for at least 3 months prior to study drug administration)

4. Rectal steroids or 5-ASA (must have been stable for at least 4 weeks prior to study drug)

A Study of MDX-1100 in Subjects With Active Ulcerative Colitis