The primary objective of this study is to assess the safety and tolerability of a single dose and multiple doses of BIIB033 administered to healthy adult Japanese participants. The secondary objectives of this study are to evaluate the pharmacokinetics (PK) profile of BIIB033 administered as single and multiple doses in healthy adult Japanese participants and to assess the single-dose and multiple-dose immunogenicity of BIIB033.

Key Inclusion Criteria:

• Japanese subjects must have been born in Japan, and their biological parents and grandparents must all have been of Japanese origin.
• Subjects who have lived out of Japan for more than 5 years must not have significantly modified their diets since leaving Japan.
• Must be a nonsmoker or light smoker (<10 cigarettes per day) and be willing to abstain from using tobacco and tobacco-containing products during the Inpatient Period and for at least 48 hours prior to Day -1, Day 14 (for Cohort 3), and all outpatient visits.
• Must have a body mass index of 18 to 32 kg/m2, inclusive.

Key Exclusion Criteria:

• History of any clinically significant cardiac, endocrine, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, renal, or other major disease, as determined by the Investigator.
• Serious infection (e.g., pneumonia, septicemia) as determined by the Investigator within the 3 months prior to Day -1.
• Fever or bacterial or viral infection (including upper respiratory tract infection) within 2 weeks prior to Day -1.
• History of severe allergic or anaphylactic reactions.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.