TJ003234RAR101 is a first-in-human (FIH), single-center, randomized, double-blind, placebo-controlled, single ascending dose study of TJ003234 in healthy adults to determine whether TJ003234 is safe and tolerated when administered as an intravenous (IV) infusion and to determine the maximum dose tolerated (MTD).

Inclusion Criteria:

• Able to understand and willing to sign the informed consent form (ICF)
• Healthy subjects 18-70 years of age
• If of childbearing potential, agree to use protocol-specified contraception
• Body mass index (BMI) 19.0-32.0 kg/m^2
• Blood pressure ≤ 139/89 mm Hg
• Subjects are able to follow the study protocol and complete the trial

Exclusion Criteria:

• Current use of tobacco or nicotine-containing products or illicit drug use
• History of severe allergic or anaphylactic reaction to a therapeutic drug or severe seasonal allergies
• Any known pulmonary disease
• Use of any prescription, investigational drugs, herbal supplements, or nonprescription drugs within 1 month or 5 half-lives (whichever is longer) prior to study drug administration, or dietary supplements within 1 week prior to study drug administration, unless, in the opinion of the Investigator and Sponsor, the medication will not interfere with the study
• Abnormal hematological and chemistry laboratory values >10% above upper limit of normal (ULN) or >10% below the lower limit of normal (LLN). Absolute neutrophil count (ANC) ≤ 1000 cells/mm^3
• Use of any biologic drugs in the last 120 days prior to dosing.
• Immunization with a live or attenuated vaccine within 4 weeks prior to study drug administration
• Prior treatment with any biologic anti-GM-CSF or GM-CSF receptor antagonists
• ADA screening positive
• Subjects who have a history of documented autoimmune disease, even if not clinically severe or never treated with systemic steroids or immunosuppressive agents
• A positive alcohol test and/or urine drug screen for substance of abuse at screening or upon check-in to the clinical site