Evaluation of relationship between HIV disease progression and viral loads.

<p>CD4 slopes were computed by multilevel regression modelling of six-monthly retrospective participant CD4 counts. The median observation time over which CD4 slopes were calculated was 61 months (minimum 18 and maximum 97) months. Plasma viral load was quantified using Bayer™ bDNA assay according to the manufacturer's protocol; the plasma viral load minimum detection threshold was 50 RNA copies/ml. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g001" target="_blank">Figure 1A</a> illustrates the relationship between CD4 slopes and viral loads, ○denotes RPs, • are NPs; while ⊙are SPs; 1B compares mean viral loads between groups while <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g001" target="_blank">figure 1C</a> compares plasma viral loads in SPs who had HLA alleles known to be protective as previously described and to those who did not. The lines running parallel to the Y and X axis (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g001" target="_blank">figures 1A and 1B</a> respectively) indicate the minimum detection limit for evaluation of plasma viral loads. For purposes of statistical analyses and graphical representation of the data, undetectable plasma viral loads were assumed to equate to 45 RNA copies per ml.</p

Breadth of HIV-induced IFN-γ T-cell recognition.

<p>The peptides sets evaluated were dictated by availability from the NIH AIDS reagent programme; clades A, B, C and D Gag peptides were obtainable while only clade B was available for Nef, Tat, Rev, Vif, Vpr, Pol and Vpu proteins. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g003" target="_blank">Figure 3</a> compares the proportion of participants (%) inducing HIV-specific IFN-γ responses using clade B peptides only, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g003" target="_blank">figure 3A</a>; as opposed to multiple clade Gag peptide sets, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g003" target="_blank">figure 3B</a>.</p

Study population demographics, host genetics and multi-clade gag recognition.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-t002" target="_blank">Table 2</a> illustrates study participant demographics and IFNγ response to clades A, B, C and D gag peptides. CD4+ T –cell slopes were derived from multilevel regression analysis of retrospective 6-monthly CD4+ T-cell counts. Under annual CD4 slope, symbol (−) indicates model-derived decreasing CD4 slopes while (+).indicates decreasing CD4 slopes over time. Under Gag-induced IFN-γ, areas marked + indicate induction of Gag-induced IFN-γ responses to the respective clade of Gag peptides, blank areas indicate lack of IFN-γ response. Clade of the infecting HIV virus was determined from partial sequences of the Gag region, “nd” indicates not done. Bold highlights indicate HLA alleles that have been reported to confer protection from HIV disease.</p

Distribution of Gag T-cell recognition among slow progressors.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g004" target="_blank">Figure 4</a> illustrates the frequency of Gag T-cell recognition across the p17, p24 and p15 Gag region among the slow progressors. The frequency is presented as the proportion of SP individuals with Gag T cell recognition. The horizontal axis represents the peptides recognised.</p

Relationship between multiclade Gag T-cell recognition and HIV disease progression.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g005" target="_blank">Figure 5</a> illustrates the total magnitudes of HIV Gag-induced IFNγ responses evaluated using ELISpot assay. A test was considered positive when response was ≥50 SFU/million PBMCs and at least twice the mean background response (6 wells of cells and media response only). The data is presented as net response; all background values have been subtracted. For purposes of statistical analysis and graphical representation, all negative responses (less than 50 net SFU/million PBMCs) were equated to zero SFU/ml PBMCs. Because the Y axis is presented in log, negative responses are not represented on these graphs. The X-axis represents individual participants. The horizontal dotted lines parallel to the X-axis represent the cutoff for a positive response. Slow progressors (SPs) are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g005" target="_blank">figure 5A</a>; rapid progressors (RPs) are in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g005" target="_blank">figure 5B</a> while normal progressors are in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-g005" target="_blank">figure 5C</a>.</p

Stratification of cohort into HIV-1 disease progression groupings.

1<p>CD4+ T cell decline without adjusting for first CD4 count and age of the participant.</p>2<p>CD4+ T cell decline after adjusting for first CD4 count and age of the participant.</p><p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004188#pone-0004188-t001" target="_blank">Table 1</a> illustrates the stratification of 110 chronically HIV-1 adults into distinct progression groups. Six-monthly retrospective CD4 counts were used in a multilevel regression model to derive individual participant CD4 slopes. The slopes were calculated over a median observation time of 610 months (minimum-maximum 18–97 months). Annual CD4+ T-cell changes are expressed as medians with interquartile ranges. Positive (+) symbols indicate increasing CD4+ counts while (−) indicates decreasing CD4+ counts over time. Individuals in the extreme stratification group 1 were selected as rapid progressors (RP, n = 7) while those in group 5 were selected as slow progressors (SP, n = 14). Groups 2, 4and 4 were categorised as normal progressors (NP, n = 89). Normal progressors were those with CD4 slopes between −91/year to +10/year; RPs had CD4 slopes <−91/year while SPs had CD4 slopes >+10/year.</p

Priming with a Simplified Intradermal HIV-1 DNA Vaccine Regimen followed by Boosting with Recombinant HIV-1 MVA Vaccine Is Safe and Immunogenic: A Phase IIa Randomized Clinical Trial

<div><p>Background</p><p>Intradermal priming with HIV-1 DNA plasmids followed by HIV-1MVA boosting induces strong and broad cellular and humoral immune responses. In our previous HIVIS-03 trial, we used 5 injections with 2 pools of HIV-DNA at separate sites for each priming immunization. The present study explores whether HIV-DNA priming can be simplified by reducing the number of DNA injections and administration of combined versus separated plasmid pools.</p><p>Methods</p><p>In this phase IIa, randomized trial, priming was performed using 5 injections of HIV-DNA, 1000 μg total dose, (3 Env and 2 Gag encoding plasmids) compared to two “simplified” regimens of 2 injections of HIV-DNA, 600 μg total dose, of Env- and Gag-encoding plasmid pools with each pool either administered separately or combined. HIV-DNA immunizations were given intradermally at weeks 0, 4, and 12. Boosting was performed intramuscularly with 10⁸ pfu HIV-MVA at weeks 30 and 46.</p><p>Results</p><p>129 healthy Tanzanian participants were enrolled. There were no differences in adverse events between the groups. The proportion of IFN-γ ELISpot responders to Gag and/or Env peptides after the second HIV-MVA boost did not differ significantly between the groups primed with 2 injections of combined HIV-DNA pools, 2 injections with separated pools, and 5 injections with separated pools (90%, 97% and 97%). There were no significant differences in the magnitude of Gag and/or Env IFN-γ ELISpot responses, in CD4+ and CD8+ T cell responses measured as IFN-γ/IL-2 production by intracellular cytokine staining (ICS) or in response rates and median titers for binding antibodies to Env gp160 between study groups.</p><p>Conclusions</p><p>A simplified intradermal vaccination regimen with 2 injections of a total of 600 μg with combined HIV-DNA plasmids primed cellular responses as efficiently as the standard regimen of 5 injections of a total of 1000 μg with separated plasmid pools after boosting twice with HIV-MVA.</p><p>Trial Registration</p><p>World Health Organization International Clinical Trials Registry Platform <a href="http://apps.who.int/trialsearch/Trial2.aspx?TrialID=PACTR2010050002122368" target="_blank">PACTR2010050002122368</a></p></div

Number of individuals screened, randomized and allocated to the three vaccination groups and withdrawn from the trial.

<p>Number of individuals screened, randomized and allocated to the three vaccination groups and withdrawn from the trial.</p

Antibody endpoint titers.

<p>Antibody endpoint titers to native HIV-1_IIIB subtype B gp160 one month after the second HIV-MVA vaccination. Data is shown for each of the HIV-DNA priming groups. The dashed line shows a titer of 100, corresponding to a 1:100 serum dilution, the lowest dilution used in the assay.</p

The proportion of ICS responders to Gag or Env peptide pools two weeks after the first and second HIV-MVA vaccination in each of the HIV-DNA primed groups.

<p>The proportion of ICS responders to Gag or Env peptide pools two weeks after the first and second HIV-MVA vaccination in each of the HIV-DNA primed groups.</p