A Study of Possibility of Using Regulatory T Cells(VT301) for Treatment of Alzheimer's Disease

Inclusion Criteria: 1. Male or female 79≥ aged ≥50 years at the time of signing Informed Consent Form. 2. Patients (or their legally acceptable representative) can understand and provide informed consent to participate in the study. 3. Diagnosis of mild-to-moderate AD according to National Institute of Aging and Alzheimer Association (NIA-AA) diagnostic guidelines. 4. Mild-to-moderate AD with MMSE ≥ 10 points and CDR Global Score (CDR-GS) of 0.5 to 2.0 points at Screening. 5. Have ≥1 identified adult caregiver (study partner) who is able to read, understand, and speak the designated language at the study site; either lives with the subject or sees the subject for ≥8 hours/week; and agrees to accompany the subject to each study visit and participate in clinical assessments. Exclusion Criteria: 1. A medical history of any of the following: 1. Stroke, transient ischemic attack (TIA), or unexpected loss of consciousness within one year at Screening. 2. Clinically significant cerebral hemorrhage, bleeding lesion, or cerebrovascular abnormality. 3. Malignant tumor within 5 years at Screening (no time limit for stable non-metastatic prostate cancer or completely resected non-melanoma skin cancer of 6 months or longer). 4. Unable to perform MRI tests by enthesis/transplantation of metallic substances (metallic bone fixings, heart devices, etc.) in the body. 5. Allergic or hypersensitive to the treatment of regulatory T cell components. 2. Patients who have any of the following accompanying diseases/symptoms: 1. Medical conditions or neurological/neural degenerative disease (excluding AD) considered to cause cognitive impairment or to affect the evaluation of clinical trials (discontinuation, nonconformity, interference, etc.) in the judgment of the investigator. 2. History of clinically significant gastrointestinal, endocrine, inflammatory or cardiovascular disease that is not controlled by drug/non-drug treatment. 3. History of mental illness (e.g., schizophrenia, major depression disorder, bipolar disorder, delirium, etc.) that is considered to affect participation in clinical trials under the judgment of the investigator. 4. History of alcohol or drug abuse or dependence (except caffeine or nicotine). 5. Vision, hearing, or mobility (behavior) has deteriorated to a degree that interferes with or is unable to perform clinical trial procedures. 6. Hypersensitive to bee venom. 7. High blood pressure who are not controlled by drug/non-drug treatment (SBP \> 165 mmHg or DBP \> 96 mmHg). 8. Hypersensitive to gentamycin. 3. Patients who have any of the following abnormal lab values at Screening: 1. Urine Drug Screening Test: positive. 2. Hepatitis B virus surface Antigen (HBsAg): positive. 3. Anti-Hepatitis C Virus (Anti-HCV): positive. 4. Anti- Human Immunodeficiency Virus (Anti-HIV): positive. 5. Sensitization test for bee venom: positive. 6. Serious renal dysfunction: Serum Creatinine ≥ 1.7 mg/dL. 7. Clinically significant hepatic dysfunction (one or more of the following):. * Serum Alanine Transaminase (ALT) ≥ 2 x upper limit of normal (ULN) * Serum Aspartate Transaminase (AST) ≥ 2 x ULN * Serum Bilirubin ≥ organ ULN x 2 4. The person with the following drug or need to be administered during the clinical trial period: 1. Acetylcholine Esterase(AChE) inhibitor, N-methyl-D-aspartate(NMDA) receptor antagonist, or a co-administration of these two drugs (Except if the dose was started more than 90 days before the date of the acquisition of the consent form and can be maintained reliably during administration and clinical trials without changing the dose for more than 60 days). * However, the drug corresponding to (a) shall not be duplicated in (b). 2. Drugs affecting the central nervous system (However, the dose was administered stably 30 days prior to the date of the acquisition of the consent form, except if it can be maintained during the clinical trial period). 3. Drugs that are not properly administered during the clinical trial period as determined by the other investigator's. 5. The person with the following one or more applicable: 1. A female subject who is pregnant or breast-feeding. 2. Fertile female@ subjects who have plans for pregnancy or do not use effective contraception method# during clinical trials period. 3. A male subject who does not undergo surgical sterilization procedures or surgery without effective contraception method# (with a Fertile female@ partner). * A fertile women is a women whose menopause has not occurred since the first menstrual and who has not undergone surgical sterilization procedures or surgery. Non-fertile women are defined as having one or more of the following: * 12 months of natural menopause. * For natural menopause for 6 months, the concentration of hCG(human Chorionic Gonadotropin) in the blood is 0 to 5 mIU/mL. * In case of surgical sterilization procedures or surgery (bilateral ovariectomy, bilateral tubal ligation, etc.) * Effective contraception methods recognized in this clinical trial are as follows: * Combining either hormonal contraceptives(subdermal implant agents, injections, oral contraceptive, etc.) or spermicide with physical barrier method(condom, contraceptive vaginal diaphragm, vaginal sponge, cervical cap). * Transplantation of intrauterine device(IUD) or intrauterine system(copper-loop, hormone-containing intrauterine system). * Both male(condom) and female(contraceptive vaginal diaphragm, vaginal sponge, or cervical cap) use physical barrier method. * surgical sterilization procedures or surgery (bilateral ovariectomy, bilateral tubal ligation, etc.) 6. A person who has blood donation within 30 days of the date of the acquisition of the consent form. 7. A person who has participated in another clinical trial within 60 days from the time of the acquisition of the consent form and has been given a investigational product(IP) or applied a clinical trial medical instrument. 8. Other persons who are not qualified to participate in clinical trials under the judgment of the investigator's.