Evaluate Safety and Pharmacokinetics of HLX70 in Healthy Adult Volunteers

Inclusion Criteria: 1. Subjects with voluntary signing of the informed consent form (ICF); 2. Healthy males or females aged ≥ 18 and ≤ 60 years at the time of signing the ICF; 3. Subjects with body weight ≥ 50 kg and body mass index (BMI) must be higher than 18.5 kg/m2 and lower than 30 kg/m2 at screening visit; 4. Subjects who are determined to be in good health according to medical history, normal (site normal ranges to be followed) or abnormal but clinically insignificant physical examination, vital signs, ECG, laboratory test results (including hematology, serum chemistry, coagulation function, urinalysis, etc.), and investigator's clinical judgment (CTCAE grade 1 of triglycerides and uric acid is permitted). One re-test allowed per investigator discretion to confirm result. 5. Subject who agrees that he/she, and his/her spouse or partner, will use reliable contraception (see appendix 1) for 9 months after administration. Exclusion Criteria: 1. Subjects with the lab-confirmed medical history of COVID-19, including nucleic acid (PCR testing of nasopharyngeal samples) tested positive or antibody IgG/IgM tested positive. 2. Subjects with the novel onset of pyrexia/cough/shortness of breath/diarrhea or history of contact with confirmed COVID-19 individuals (positive for SARS-CoV-2 nucleic acid) within the 14 days before randomization. 3. Subjects who are known to have chronic obstructive pulmonary disease (COPD), cirrhosis of liver, cardiac failure or any condition that requires active medical intervention or monitoring to avert serious danger to the participant's health or well-being. 4. Subjects with pneumonia or tuberculosis (TB) suggested by chest X-Ray. 5. Subjects with previous exposure to a mAb or any other biological agents in 6 months before screening. 6. Subjects with previous exposure to vaccines in 3 months before screening, or who plans to receive vaccination during the study period or in 3 months after the study. 7. Subjects with previous participation in clinical trials receiving investigational drug/comparator within the longer of 30 days or 5 half-lives before screening. 8. Subjects who are known to have a history of allergy to any mAb, biological product, protein product, or the ingredient of the IP. 9. Subjects with positive test result(s) for hepatitis B virus (positive for HBsAg or positive for HBcAb and HBV-DNA), hepatitis C virus (HCV) antibodies, human immunodeficiency virus (HIV) antibodies, or treponema pallidum. 10. Subjects who are known to have a history of psychotropic drug abuse, alcoholism, or drug addiction within the last year.