This is a single-center, randomized, double-blind, placebo-controlled, dose-escalation, and multiple-dose study to evaluate safety, tolerability, PK and PD of MY008211A Tablets in healthy subjects.

MY008211A Tablets, low/moderate/high dose orally, continually 7 days

Inclusion Criteria:

1. 18≤ age ≤ 45, male or female;
2. Body weight: ≥50 kg for male, ≥45 kg for female; body mass index (BMI): 19.0-26.0 kg/m2 (inclusive);
3. Informed consent will be signed before the trial, and the content, process and possible adverse reactions of the trial will be fully understood;
4. ACYW135 meningococcal vaccine, pneumococcal vaccine were voluntarily administered at least 2 weeks before MY008211A tablet administration
5. The volunteers should be able to communicate well with the researchers and understand and comply with the requirements of the study.

Exclusion Criteria:

1. Participants who were enrolled in a clinical trial or used a study drug within 3 months before administration of the study drug;
2. Patients with chronic or active gastrointestinal diseases such as esophageal disease, gastritis, gastric ulcer, enteritis, active gastrointestinal bleeding, or gastrointestinal surgery within the past three years and still clinically relevant according to the investigator;
3. Patients with definite diseases of the central nervous system, cardiovascular system, digestive system, respiratory system, urinary system, hematological system, metabolic system and other diseases that require medical intervention or are not suitable for clinical trial (such as psychiatric history);
4. History of known or suspected immunodeficiency (e.g., history of frequent recurrent infections), inherited or acquired complement deficiency;
5. Patients had a clear history of capsular microbial infection within 6 months before screening; Including but not limited to: Streptococcus pneumoniae, Bacillus anthracis, Salmonella, Salmonella typhi, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacteroides fragilis, Neisseria meningitidis, Haemophilus influenzae, Legionella pneumophila infection history;
6. Patients with previous or current history of TB infection;
7. Active systemic bacterial, viral, or fungal infection within 14 days before administration of the study drug;
8. Fever (≥ 38 ° C) within 7 days before administration of the study drug;
9. Those who have a history of allergy to the trial preparation and any of its components or related preparations, or to drugs, foods or other substances;
10. Those who cannot tolerate intravenous puncture or have a history of syncope or needle sickness;
11. Patients who underwent surgery within 6 months before the study drug is used, which will be judged by the investigators to affect the absorption, distribution, metabolism, and excretion of the study drug; Surgical procedures within 4 weeks before the use of the study drug; Or planned to undergo a surgical procedure during the trial;
12. Who had taken any medicine (including Chinese herbal medicine, health products, etc.) within 14 days before administration of the study drug;
13. Who received a vaccine or live attenuated vaccine within 14 days before administration of the study drug, or who plan to receive a vaccine during the trial;
14. Who donated blood or lost a large amount of blood (> 400mL) within 3 months before administration of the study drug, received a blood transfusion or use of blood products, or intended to donate blood or blood components during or within 3 months after administration of the study drug;
15. Drug abusers or had used hard drugs (e.g., cocaine, phencyhexidine, etc.) or soft drugs (e.g., cannabis) within 1 year before administration of the study drug;
16. Smokers or had smoked more than 5 cigarettes per day in 3 months before study drug use, or will be unable to stop using any tobacco products during the study;
17. Heavy drinkers, who drink at least twice a day or more than 14 times a week, or are avid binge drinkers (one drink is defined as 125mL of wine, 220mL of beer, or 50mL of liquor; Binge drinking is defined as 5 or more drinks in approximately 2 hours); Or unwillingness to stop drinking alcohol or any alcohol-based product during the trial;
18. Those who have special requirements for diet and cannot abide by the uniform diet;
19. Volunteers (or their partners) who plan to be pregnant or donate sperm or eggs during the trial to 3 months after the end of the trial, or who are unwilling to take one or more non-drug contraceptive measures (such as complete abstinence, condoms, contraceptive rings, surgical sterilization, etc.);
20. Pregnant or lactating women; Or having unprotected sex within 2 weeks before using the study drug; Or oral contraceptive use within 30 days or long-acting estrogen or progestin injectable or implant use within 6 months before use of the study drug;
21. Physical examination, electrocardiogram, chest X-ray, abdominal ultrasound, vital signs, laboratory examination abnormalities were clinically significant (subject to clinician's judgment);
22. With positive uremic screening test;
23. With positive alcohol breath test;
24. Volunteers may not be able to complete the study for other reasons or have other reasons for not participating in the study as judged by the investigator.