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Background: We conducted a Phase I dose escalation trial of ADVAX, a DNA-based candidate HIV-1 vaccine expressing Clade C/B' env, gag, pol, nef, and tat genes. Sequences were derived from a prevalent circulating recombinant form in Yunnan, China, an area of high HIV-1 incidence. The objective was to evaluate the safety and immunogenicity of ADVAX in human volunteers. Methodology/Principal Findings: ADVAX or placebo was administered intramuscularly at months 0, 1 and 3 to 45 healthy volunteers not at high risk for HIV-1. Three dosage levels [0.2 mg (low), 1.0 mg (mid), and 4.0 mg (high)] were tested. Twelve volunteers in each dosage group were assigned to receive ADVAX and three to receive placebo in a double-blind design. Subjects were followed for local and systemic reactogenicity, adverse events, and clinical laboratory parameters. Study follow up was 18months. Humoral immunogenicity was evaluated by anti-gp120 binding ELISA. Cellular immunogenicity was assessed by a validated IFNc ELISpot assay and intracellular cytokine staining. ADVAX was safe and well-tolerated, with no vaccine-related serious adverse events. Local and systemic reactogenicity events were reported by 64% and 42% of vaccine recipients, respectively. The majority of events were mild. The IFNc ELISpot response rates to any HIV antigen were 0/9 (0%) in the placebo group, 3/12 (25%) in the low-dosage group, 4/12 (33%) in the mid-dosage group, and 2/12 (17%) in the high-dosage group. Overall, responses were generally transient and occurred to each gene product, although volunteers responded to single antigens only. Binding antibodies to gp120 were not detected in any volunteers, and HIV seroconversion did not occur. Conclusions/Significance: ADVAX delivered intramuscularly is safe, well-tolerated, and elicits modest but transient cellular immune responses. Trial Registration: Clinicaltrials.gov NCT00249106. [ABSTRACT FROM AUTHOR]

Background: We conducted a Phase I dose-escalation trial of ADMVA, a Clade-B'/C-based HIV-1 candidate vaccine expressing env, gag, pol, nef, and tat in a modified vaccinia Ankara viral vector. Sequences were derived from a prevalent circulating HIV-1 recombinant form in Yunnan, China, an area of high HIV incidence. The objective was to evaluate the safety and immunogenicity of ADMVA in human volunteers., Methodology/principal Findings: ADMVA or placebo was administered intramuscularly at months 0, 1 and 6 to 50 healthy adult volunteers not at high risk for HIV-1. In each dosage group [1x10(7) (low), 5x10(7) (mid), or 2.5x10(8) pfu (high)] volunteers were randomized in a 3:1 ratio to receive ADMVA or placebo in a double-blinded design. Subjects were followed for local and systemic reactogenicity, adverse events including cardiac adverse events, and clinical laboratory parameters. Study follow up was 18 months. Humoral immunogenicity was evaluated by anti-gp120 binding ELISA, immunoflourescent staining, and HIV-1 neutralization. Cellular immunogenicity was assessed by a validated IFNgamma ELISpot assay and intracellular cytokine staining. Anti-vaccinia binding titers were measured by ELISA. ADMVA was generally well-tolerated, with no vaccine-related serious adverse events or cardiac adverse events. Local or systemic reactogenicity events were reported by 77% and 78% of volunteers, respectively. The majority of events were of mild intensity. The IFNgamma ELISpot response rate to any HIV antigen was 0/12 (0%) in the placebo group, 3/12 (25%) in the low dosage group, 6/12 (50%) in the mid dosage group, and 8/13 (62%) in the high dosage group. Responses were often multigenic and occasionally persisted up to one year post vaccination. Antibodies to gp120 were detected in 0/12 (0%), 8/13 (62%), 6/12 (50%) and 10/13 (77%) in the placebo, low, mid, and high dosage groups, respectively. Antibodies persisted up to 12 months after vaccination, with a trend toward agreement with the ability to neutralize HIV-1 SF162 in vitro. Two volunteers mounted antibodies that were able to neutralize clade-matched viruses., Conclusions/significance: ADMVA was well-tolerated and elicited durable humoral and cellular immune responses., Trial Registration: Clinicaltrials.gov NCT00252148.

The gamma interferon (IFN-gamma) enzyme-linked immunospot (ELISPOT) assay is used routinely to evaluate the potency of human immunodeficiency virus (HIV) vaccine candidates and other vaccine candidates. In order to compare candidates and pool data from multiple trial laboratories, validated standardized methods must be applied across laboratories. Proficiency panels are a key part of a comprehensive quality assurance program to monitor inter- and intralaboratory performance, as well as assay performance, over time. Seven International AIDS Vaccine Initiative-sponsored trial sites participated in the proficiency panels described in this study. At each laboratory, two operators independently processed identical sample sets consisting of frozen peripheral blood mononuclear cell (PBMC) samples from different donors by using four blind stimuli. PBMC recovery and viability after overnight resting and the IFN-gamma ELISPOT assay performance were assessed. All sites demonstrated good performance in PBMC thawing and resting, with a median recovery of 78% and median viability of 95%. The laboratories were able to detect similar antigen-specific T-cell responses, ranging from 50 to >3,000 spot-forming cells per million PBMC. An approximate range of a half log in results from operators within or across sites was seen in comparisons of antigen-specific responses. Consistently low background responses were seen in all laboratories. The results of these proficiency panels demonstrate the ability of seven laboratories, located across three continents, to process PBMC samples and to rank volunteers with differential magnitudes of IFN-gamma ELISPOT responses. These findings also illustrate the ability to standardize the IFN-gamma ELISPOT assay across multiple laboratories when common training methods, reagents such as fetal calf serum, and standard operating procedures are adopted. These results are encouraging for laboratories that are using cell-based immunology assays to test HIV vaccines and other vaccines.