 GSK1070806 is a humanised monoclonal antibody that blocks a protein present in the body called Interleukin-18. The main purpose of this study is to test GSK1070806 in healthy and obese male subjects with normal immune systems to find out how safe this drug is and how long the body takes to get rid of it. The study consists of 2 parts. Part 1 will consist of 6 groups of healthy male subjects and Part 2 will consist of 3 groups of obese male subjects. A total of 89 subjects is planned for this study. Subjects in each group will receive one dose of the study drug or placebo. Dosing in Part 2 will not start until dosing of the first 4 groups is completed in Part 1 and the preliminary safety and pharmacokinetic data from these 4 groups in Part 1 has been reviewed. Both parts will be conducted single-blind and with a placebo control. Within each group, allocation of subjects to placebo or active treatment GSK1070806 will be randomised. 