Evaluate the Safety Pharmacokinetics of a Human Monoclonal Antibody S315 Against Diphtheria Toxin in Healthy Subjects

Exclusion Criteria

• •1\. Previous receipt of humanized or human monoclonal antibody whether licensed or investigational.
• •2\. History of or any current medical condition that could compromise the safety of the participant in the study, as determined by the Investigator.
• •3\. History of suicidal behavior within 12 months prior to screening.
• •4\. Donated blood or plasma within 60 days prior to dosing.
• •5\. Clinically significant gastrointestinal, cardiovascular, neurologic, psychiatric, substance abuse, metabolic, renal, hepatic, respiratory, inflammatory, or infectious disease, as determined by the Investigator.
• •6\. Drug or alcohol abuse within previous 12 months or a positive test at screening and at Day -1 within 24 hours of study product administration.
• •7\. History of a previous severe allergic reaction with generalized urticaria, angioedema or anaphylaxis.
• •8\. Physical finding on examination considered clinically significant such as murmur (other than functional), hepatosplenomegaly, lymphadenopathy or focal neurological deficit.
• •9\. Urinalysis positive for \> trace protein, \> 5 Red Blood Cell (RBC)/hpf or \> 5 WBC/hpf.
• •10\. Positive serology for HIV antibody, Hepatitis C Virus (HCV) antibody or Hepatitis B surface antigen at screening.
• •11\. Positive serum pregnancy test during screening or within 24 hours of study product administration, or an unwillingness to undergo pregnancy testing.
• •12\. Pregnant within 6 months or breast-feeding within 3 months prior to screening.
• •13\. Receipt of licensed vaccine containing diphtheria toxoid (Td, Tdap, pneumococcal conjugate vaccines, meningococcal conjugate vaccines) within the last year.
• •14\. Treatment with another investigational drug or other intervention within 30 days from screening.
• •15\. Any other condition that in the opinion of the investigator would jeopardize the safety or rights of the subject participating in the study.
• •16\. Safety laboratory abnormalities at Screening or Day -1, which are clinically significant as determined by the Investigator.
• •17\. Tobacco, e-cigarettes, and/or nicotine use within 30 days prior to screening confirmed by urine cotinine test.