A Study of Anti-HIV Monoclonal Antibody KD-247

Inclusion Criteria: 1. Have HIV-1 infection confirmed by enzyme immunoassay (EIA) and immunoblot. 2. Are male or female subjects, age 18-64 years. 3. Demonstrate an HIV-1 RNA copy number between 1000 and 100,000 copies/mL on 2 measurements at least 2 weeks apart. Measurements taken during screening and/or on a prior non-study related medical visit within 3 to 6 weeks of Study Day 1 may be considered. 4. Have CD4+ T cell count \>350 cells/mm3 on 2 measurements at least 2 weeks apart. Measurements taken during screening and on one prior non-study medical visit within 3 to 6 weeks of Study Day 1 may be considered. 5. Are treatment naïve or have been off antiretroviral drugs for at least 8 weeks prior to screening. 6. By genotyping, have a sequence of the portion of the HIV envelope gene encoding the principal neutralizing determinant that is consistent with neutralization by KD-247. 7. Weigh 45-120 kg. 8. Have an absolute neutrophil count \>1000 cells/uL, hemoglobin (Hgb) \>10 g/dL, and platelets \>100,000/uL. 9. Have serum creatinine ≤1.5 mg/dL and alanine transaminase (ALT) \<2.5 times the upper limit of normal. 10. Have a 12-lead electrocardiogram (ECG) without clinically significant abnormalities in the opinion of the investigator. 11. Female subjects must be: * Women of non-childbearing potential, defined as either surgically sterile or at least 1-year post-menopausal (no menstrual periods for at least 2 years), or * Women of childbearing potential using a highly effective method of contraception, and * Women of childbearing potential with a negative serum beta human chorionic gonadotropin (β-HCG) test result at screening and within the 24 hours prior to administration of study drug. A negative urine pregnancy test within the 24 hours prior to administration of study drug will be acceptable, if the serum pregnancy test result is not yet available. 12. For heterosexual male subjects, the subject and the subject's sexual partner must agree to use acceptable methods of contraception during the entire study. Acceptable methods include, but are not limited to, intrauterine device, diaphragm with spermicide, condoms, or abstinence. Oral contraceptives alone are not an acceptable method of birth control. 13. Be willing and able to provide written informed consent. Exclusion Criteria: 1. Have a history of an acquired immune deficiency syndrome (AIDS)-defining illness or symptomatic HIV disease (i.e., Centers for Disease Control \[CDC\] Class B or C). 2. Have received monoclonal antibody therapy of any kind in the past. 3. Received vaccinations in the past 15 days prior to study entry. 4. Received antihistamines in the 6 weeks prior to study entry. 5. Received non-steroidal anti-inflammatory drugs (NSAIDs) in the 5-6 days prior to skin test. 6. Any history of anaphylaxis, asthma, hypersensitivity reaction to a vaccine or drug infusion, angioedema, or urticaria. 7. Have been treated with any of the following within the 3 months prior to screening: interferons, cytokines, or other immunomodulators; immunoglobulin therapy; systemic corticosteroids; cytotoxic drugs; or ionizing radiation. 8. Have received any investigational agent within 60 days prior to screening. 9. Have any condition which, in the judgment of the investigator, may make the subject's participation in this study too risky; interfere with the collection of or interpretation of PK data; or interfere with the ability of the subject to adhere to and complete the study. Such conditions may include, but are not limited to, cardiovascular, respiratory, gastrointestinal/hepatic, neurologic, and genitourinary disorders. 10. Current alcohol or drug use that, in the judgment of the investigator, will interfere with the subject's ability to comply with the protocol requirements. 11. Have an unexplained positive urine drug screen test for an illicit drug. 12. Have a confirmed positive hepatitis B surface antigen (HBsAg) or antibody to hepatitis C virus (HCV). 13. Have used any prescription within 14 days of study initiation or any over-the-counter (OTC) medication within 3 days of study initiation which, in the judgment of the investigator, would place the individual at risk or interfere with safety, tolerability, or PK data. 14. Have dosages/amounts of drugs that have changed, or are scheduled to use new drugs which, in the judgment of the investigator, would place the individual at risk or interfere with safety, tolerability, or PK data. 15. Have a recent history of major surgery, internal organ biopsy, or major trauma. 16. Females who are pregnant or breast-feeding, or who plan to become pregnant during the study. 17. Have a mental condition rendering the subject unable to understand the nature, scope, and possible consequences of the study. 18. Show a positive reaction to the prick test for KD-247, i.e., ≥3 mm in diameter greater than the negative control.