Temporal magnitudes of vaccine stimulated T cell and Ab responses.

<p>Panels A-D: medians with interquartile ranges for Gag-stimulated T cell responses scored using ICS. IFNγ (panel A) and IFNγ + IL-2 co-producing (Panel B) CD8+ cells as % of total CD8+ T cells. IFNγ (Panel C) and IFNγ + IL-2 (Panel D) co-producing CD4+ cells as % of total CD4+ T cells. Panels E and F: gp120 and gp41 Ab (μg/ml). Data are for the vaccination, treatment interruption (indicated in grey) and treatment reinstitution phases of the trial. Dotted lines indicate the timing of DNA (D) and MVA (M) immunizations. All 9 participants are included in T cell data through the 1^st MVA inoculation after which data are for the 8 participants that completed the trial. The Ab data are for the 8 participants that completed the trial.</p

DNA/MVA Vaccination of HIV-1 Infected Participants with Viral Suppression on Antiretroviral Therapy, followed by Treatment Interruption: Elicitation of Immune Responses without Control of Re-Emergent Virus

<div><p>GV-TH-01, a Phase 1 open-label trial of a DNA prime—Modified Vaccinia Ankara (MVA) boost vaccine (GOVX-B11), was undertaken in HIV infected participants on antiretroviral treatment (ART) to evaluate safety and vaccine-elicited T cell responses, and explore the ability of elicited CD8+ T cells to control viral rebound during analytical treatment interruption (TI). Nine men who began antiretroviral therapy (ART) within 18 months of seroconversion and had sustained plasma HIV-1 RNA <50 copies/mL for at least 6 months were enrolled. Median age was 38 years, median pre-ART HIV-1 RNA was 140,000 copies/ml and mean baseline CD4 count was 755/μl. Two DNA, followed by 2 MVA, inoculations were given 8 weeks apart. Eight subjects completed all vaccinations and TI. Clinical and laboratory adverse events were generally mild, with no serious or grade 4 events. Only reactogenicity events were considered related to study drug. No treatment emergent viral resistance was seen. The vaccinations did not reduce viral reservoirs and virus re-emerged in all participants during TI, with a median time to re-emergence of 4 weeks. Eight of 9 participants had CD8+ T cells that could be stimulated by vaccine-matched Gag peptides prior to vaccination. Vaccinations boosted these responses as well as eliciting previously undetected CD8+ responses. Elicited T cells did not display signs of exhaustion. During TI, temporal patterns of viral re-emergence and Gag-specific CD8+ T cell expansion suggested that vaccine-specific CD8+ T cells had been stimulated by re-emergent virus in only 2 of 8 participants. In these 2, transient decreases in viremia were associated with Gag selection in known CD8+ T cell epitopes. We hypothesize that escape mutations, already archived in the viral reservoir, plus a poor ability of CD8+ T cells to traffic to and control virus at sites of re-emergence, limited the therapeutic efficacy of the DNA/MVA vaccine.</p><p>Trial Registration</p><p>clinicaltrials.gov <a href="https://clinicaltrials.gov/ct2/show/NCT01378156" target="_blank">NCT01378156</a></p></div

Temporal Levels of Absolute CD4+ and CD8+ T Cells Throughout the Study.

<p>All data are means with the error bars indicating standard deviations. Panels A and B present absolute CD4+ and CD8+ T cell counts as cells/μl. Panels C and D present activated cells as a percent of total CD4+ and CD8+ T cells respectively. Cells displaying CD38+ and HLA-DR surface markers are considered activated T cells.</p

Sequence changes consistent with CD8+ T cell selection of re-emergent virus in 01–4 and 01–8.

<p>Sequence changes consistent with CD8+ T cell selection of re-emergent virus in 01–4 and 01–8.</p

Temporal viral RNA and responding T Cells.

<p>Panels show data for the 8 participants in the trial who completed the study ordered from the individual who delayed treatment re-institution (01–1) and then participants with increasing levels of viral RNA during the TI phase (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163164#pone.0163164.t002" target="_blank">Table 2</a>, measured by area under the curve). The red bar at the left side of each panel indicates pre-ART levels of viral RNA. Red lines indicate temporal levels of viral RNA and black lines, temporal levels of Gag-specific IFNγ expressing CD8+ T cells. DNA and MVA immunizations are indicated by dashed black vertical lines designated D and M respectively. The initiation of an efavirenz washout is indicated by a dashed vertical blue line, W. Levels of HIV-1 RNA < 50 copies/mL are plotted as 20 copies/ml. In 01–3, a low CD8 ICS response at TI3 reflected high background at this time point.</p

Timing and Height of Re-emergent Virus and Viral Reservoirs.

<p>Panel A. presents weeks to re-emergent virus and panel B presents temporal levels of viral RNA throughout the study. Temporal levels of viral RNA are given as medians and interquartile ranges. In panel B, the median pre-ART level of viral RNA is indicated with a square symbol. Panel C shows the frequency of circulating CD4+ T cells harboring integrated HIV DNA. Panel D shows the number of CD4+ cells with inducible Tat/ Rev mRNA as measured by TILDA. Insets in C and D give the medians and interquartile ranges for all participants. Participants are listed in the same order in A, C, and D. Participant 01–7 is not included in reservoir analyses because pre-vaccination cells were not available. Pre designates the day of vaccination and TI-1, the day of treatment interruption. Samples with HIV-1 RNA <50 copies/mL are plotted at 10 copies per ml.</p

Response rates.

<p>Response rates are for (A) vaccine enhanced CD8+ and CD4+ T cells scored by ICS and (B) vaccine enhanced Ab to gp120 and gp41 scored by ELISA.</p

HIV-1 RNA, Area Under the Curve (AUC) During TI.

<p>HIV-1 RNA, Area Under the Curve (AUC) During TI.</p

Demographics and History of HIV Seroconversion and Antiretroviral Therapy.

<p>Demographics and History of HIV Seroconversion and Antiretroviral Therapy.</p

Ratio of Absolute CD4+ to Absolute CD8+ T cell Counts¹.

<p>Ratio of Absolute CD4+ to Absolute CD8+ T cell Counts¹.</p