A Safety and Immunogenicity Study of 3 Doses of Opal Immunotherapy in HIV Infected People

Inclusion Criteria: * Provision of written informed consent * Documented laboratory diagnosis of HIV 1 infection * Documented HIV clade of infection * 18 - 60 years of age, inclusive * Stable antiretroviral therapy (ART) regimen containing at least 3 active ART agents for at least 2 months prior to Baseline * Plasma HIV-Ribonucelc acid (RNA) \<400 copies/millilitre (mL) for 6 months up to and including Screening. Subjects on stable ART with a single value ≥400 copies/mL (i.e. the result is unconfirmed by subsequent testing) within this timeframe may be included at the discretion of the Investigator * CD4+ T-cell count ≥350 cells/cubic millimetres (mm3) at Screening (with nadir ≥100 cells/mm3) * A positive immunogenic response when stimulated with HIV-1 Gag clade C peptides at Screening * Male or female. Women of child-bearing potential must be using two effective methods of contraception and agree to continue to do so from Screening, throughout study medication dosing and for 28 days after the last dose of study medication Exclusion Criteria: * Any serious or active medical or psychiatric illness which, in the opinion of the Investigator, would interfere with treatment, assessment, compliance with the protocol, or subject safety. This would include any active clinically significant renal, cardiac, pulmonary, vascular, or metabolic (thyroid disorders, adrenal disease) illness, or malignancy * Hepatitis B virus surface antigen, or Hepatitis C virus (HCV) antibody and HCV-RNA positive at Screening * Female subjects who are lactating and those of reproductive potential with a positive urine pregnancy test at either Screening or Baseline * A new AIDS-defining condition diagnosed within 42 days prior to Baseline visit * Known or suspected allergy to Dimethyl Sulfoxide * History of allergy or reaction to medications (including peptide or protein containing agents) or history of severe allergy that, in the opinion of the Investigator, might compromise the subject's participation in any way * Moderate or severe asthma, defined as at least chronic moderate symptoms which frequently interfere with daily activities and require anti-asthma/anti-inflammatory agents * Have received immunomodulating agents (including immunosuppressive agents, interferon or other immune or cytokine-based therapies), immunisation, and/or systemic chemotherapeutic agents within 60 days of Screening or expected to receive these agents during the course of the study * Recipient of live attenuated vaccines within 60 days of Screening * Recipient of whole killed, toxoid or sub-unit vaccines (e.g. influenza, pneumococcus, tetanus, hepatitis B) within 42 days prior to Baseline * Ever received an HIV prophylactic or immunotherapeutic vaccine (does not apply to subjects who have written documentation of receiving placebo or adjuvant only) * Recreational and/or therapeutic drug or alcohol use that, in the opinion of the Investigator, might compromise the subject's participation in any way. * Medical or psychiatric condition or occupational responsibilities that may preclude compliance with the protocol * Laboratory blood values: * Haemoglobin \<11.0 grams/decilitre (g/dL) for men and \<10.0 g/dL for women * Neutrophil count \<800/mm3 * Platelet count \<50,000/mm3 * Aspartate aminotransferase or Alanine transaminase \>2.5 times Upper Limit of Normal (ULN) * Lipase \>2.5 times ULN * Amylase \>1.5 times ULN (unless serum lipase is ≤1.5 times ULN) * Subjects with an estimated creatinine clearance of \<80 mL/minute * Recipients of blood products or immunoglobulins within 6 months prior to Screening or loss of 450 mL or more of blood during the three months prior to Screening * Recipients of experimental or investigational agents within 30 days prior to Screening * Previous participation in this study