The assessment of otelixizumab in T1DM subjects will provide safety, tolerability, pharmacodynamic and pharmacokinetic information following subcutaneous administration which will enable the identification of appropriate safe and well-tolerated subcutaneous dosage regimens to be used in subsequent clinical studies. This study will consist of a screening phase, followed by an in-house phase whereby otelixizumab will be administered to cohorts that will be staggered at each dose level. Approximately 6 dose levels, covering up to a 10-fold dose range, will be evaluated. A single subcutaneous dose of otelixizumab will be administered on Day 1 and, serial blood samples will be obtained for clinical laboratory testing, determination of pharmacodynamic markers, serum otelixizumab PK parameters, and immunogenicity. Safety and pharmacodynamic data from the previous dose(s) will be evaluated prior to dose escalation or modification to ensure safety and to achieve target systemic peripheral blood pharmacology. Adverse events, laboratory values, vital signs and ECG's will be monitored closely during this study. All subjects in the study will undergo long-term follow-up out to 48 months to monitor and ensure patient safety.