A Phase 1, Open Label, Dose-escalation Study of the Safety, Pharmacokinetics and Antiretroviral Activity of 3BNC117

Inclusion Criteria: * Group 1 (HIV-uninfected): * Adult males and females, age 18 to 65 * Amenable to HIV risk reduction counseling and agrees to maintaining behavior consistent with low risk of HIV exposure; * If a sexually active male or female, participating in sexual activity that could lead to pregnancy, agrees to use an effective method of contraception throughout the study. * Groups 2-5 (HIV-infected): * Age 18 to 65 * HIV infection confirmed by ELISA and immunoblot * Groups 2A-D - on ART with HIV-1 plasma RNA levels below 100,000 copies/ml, or off ART for at least 8 weeks with HIV-1 plasma RNA level between 2,000-100,000 copies/ml by standard assays on 2 occasions at least 1 week apart; * Group 2E - Untreated HIV-infected (not on ART for at least 8 weeks): HIV-1 RNA plasma levels between 2,000 - 100,000 copies/ml; * Group 3 - Untreated HIV controllers (not on ART for at least 8 weeks): HIV-1 RNA plasma level of \< 2,000 copies/ml by standard assays, on 2 occasions, at least 1 week apart, and ART-naive. * Group 4 - ART treated with HIV-1 RNA plasma level of \> 20 copies/ml by standard assays on 2 occasions, at least 1 week apart, while on combination antiretroviral therapy; * Groups 5A and 5B - ART treated with HIV-1 RNA plasma level of \< 20 copies/ml by standard assays on 2 occasions, at least 1 week apart, while on combination antiretroviral therapy; * Current CD4 cell count \> 300 cells/µl * If sexually active male and female, participating in sexual activity that could lead to pregnancy, agrees to use an effective method of contraception throughout the study. Exclusion criteria: * Group 1 (HIV-uninfected): * Confirmed HIV-1 or HIV-2 infection; * History of immunodeficiency or autoimmune disease; use of systemic corticosteroids, immunosuppressive anti-cancer, or other medications considered significant by the trial physician within the last 6 months; * Any clinically significant acute or chronic medical condition that in the opinion of the investigator would preclude participation; * Within the 12 months prior to enrollment, the volunteer has a history of sexually transmitted disease; * Hepatitis B (surface antigen, HbsAg) or hepatitis C (HCV antibodies); * Laboratory abnormalities in the parameters listed below: * Absolute neutrophil count ≤ 2,000 * Hemoglobin ≤ 12 gm/dL if female; ≤ 13.5 gm/dL if male * Platelet count ≤ 140,000 * ALT ≥ 1.25 x ULN * AST ≥ 1.25 x ULN * Total bilirubin ≥ 1.1 ULN * Creatinine ≥ 1.1 x ULN * Coagulation parameters (PT, PTT, INR) ≥ 1.1 x ULN * Pregnancy or breastfeeding; * Any vaccination within 14 days prior to 3BNC117 administration; * Receipt of any experimental HIV vaccine in the past or monoclonal antibody therapy of any kind in the past; * Participation in another clinical study of an investigational product currently or within past 12 weeks, or expected participation during this study. * Groups 2-5 (HIV-infected): * History of AIDS-defining illness * History of systemic corticosteroids, immunosuppressive anti-cancer, or other medications considered significant by the trial physician within the last 6 months; * Any clinically significant acute or chronic medical condition, other than HIV infection, that in the opinion of the investigator would preclude participation; * Hepatitis B (surface antigen, HbsAg) or hepatitis C (HCV antibodies); * Laboratory abnormalities in the parameters listed below: * Absolute neutrophil count ≤ 1,300 * Hemoglobin ≤ 10 gm/dL * Platelet count ≤ 125,000 * ALT ≥ 2.0 x ULN * AST ≥ 2.0 x ULN * Total bilirubin ≥ 1.1 ULN * Creatinine ≥ 1.1 x ULN * Coagulation parameters ≥ 1.1 x ULN; * Current antiretroviral regimen includes either maraviroc or enfuvirtide; * Pregnancy or breastfeeding; * Any vaccination within 14 days prior to 3BNC117 administration; * Receipt of any experimental HIV vaccine or monoclonal antibody therapy of any kind in the past; * Participation in another clinical study of an investigational product currently or within past 12 weeks, or expected participation during this study.