A Study of GW856553X For the Treatment of Depression

Inclusion Criteria: * Male or female = 18 years of age and \< 60 years, * routine laboratory results within normal ranges, * Body Mass Index within the range 18.5-35.0 kg/m2 inclusive. * Subject must have had at least one previous major depressive episode with a diagnosis of MDD in his/her history, and had a successful pharmacological treatment of that episode, and is currently experiencing a recurrence of MDD presently un-medicated. * Subjects must met the diagnosis of an episode of Major Depressive Disorder in the past 12 weeks but not greater than 24 months. Exclusion Criteria: * The subject has any history of liver disease. * The subject has significant cardiac, pulmonary, metabolic, renal, hepatic or gastrointestinal conditions that, in the opinion of the investigator and/or GSK medical monitor, places the subject at an unacceptable risk as a participant in this trial. * The subject has a history of autoimmune diseases. * The subject has any active infectious diseases, including active tuberculosis or a history of active tuberculosis. * The subject has a history of malignancy, except for surgically cured basal cell carcinoma or females with cured cervical carcinoma (\> 2 yrs prior). * The subject has a history of HIV or other immunosuppressive disease. * The subject has uncontrolled diabetes. * The subject is pregnant or nursing. * Subject has no contact with an adult on a daily basis (i.e., subjects who are not living with at least one other adult or subjects who do …