This is a clinical study to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamic and immunogenicity of SHR-1139 injection in healthy subjects who receive a single subcutaneous injection or intravenous infusion of SHR-1139 injection, and in patients with moderate - to - severe plaque psoriasis who receive multiple subcutaneous injections of SHR-1139 injection.

Inclusion Criteria:

1. Subjects who fully understand the trial procedures, voluntarily agree to participate, and sign a written informed consent form.
2. Age between 18 and 55 years old (inclusive).
3. Vital signs, physical examinations, laboratory tests, and other assessments are normal or show abnormalities without clinical significance.

Exclusion Criteria:

1. Subjects with any clinical disease in the circulatory, endocrine, nervous, digestive, respiratory, hematological, immunological, psychiatric systems, or metabolic abnormalities; or any other disease that may interfere with trial results.
2. History of malignant tumor.
3. Opportunistic infection within 6 months prior to screening.
4. Acute infection with systemic symptoms requiring systemic intravenous or oral anti-infective treatment within 4 weeks before baseline.
5. Participation in any drug or medical device clinical trial within 3 months prior to screening.