The Safety and Immunogenicity of GTU®MultiHIV DNA Vaccine Delivered by Transcutaneous and Intramuscular Injection With or Without Electroporation in HIV-1 Positive Subjects on Suppressive ART.

Previous studies have shown targeting different tissues via the transcutaneous (TC) and intramuscular injection (IM) with or without electroporation (EP) has the potential to trigger immune responses to DNA vaccination. The CUTHIVTHER 001 Phase I/II randomized controlled clinical trial was designed to determine whether the mode of DNA vaccination delivery (TC+IM or EP+IM) could influence the quality and function of induced cellular immune responses compared to placebo, in an HIV positive clade B cohort on antiretroviral therapy (ART). The GTU®MultiHIV B DNA vaccine DNA vaccine encoded a MultiHIV B clade fusion protein to target the cellular response. Overall the vaccine and regimens were safe and well-tolerated. There were robust pre-vaccination IFN-γ responses with no measurable change following vaccination compared to placebo. However, modest intracellular cytokine staining (ICS) responses were seen in the TC+IM group. A high proportion of individuals demonstrated potent viral inhibition at baseline that was not improved by vaccination. These results show that HIV positive subjects with nadir CD4+ counts ≥250 on suppressive ART display potent levels of cellular immunity and viral inhibition, and that DNA vaccination alone is insufficient to improve such responses. These data suggest that more potent prime-boost vaccination strategies are likely needed to improve pre-existing responses in similar HIV-1 cohorts (This study has been registered at http://ClinicalTrials.gov under registration no. NCT02457689).

Comparative Immunogenicity of HIV-1 gp140 Vaccine Delivered by Parenteral, and Mucosal Routes in Female Volunteers; MUCOVAC2, A Randomized Two Centre Study.

BACKGROUND: Defining optimal routes for induction of mucosal immunity represents an important research priority for the HIV-1 vaccine field. In particular, it remains unclear whether mucosal routes of immunization can improve mucosal immune responses. METHODS: In this randomized two center phase I clinical trial we evaluated the systemic and mucosal immune response to a candidate HIV-1 Clade C CN54gp140 envelope glycoprotein vaccine administered by intramuscular (IM), intranasal (IN) and intravaginal (IVAG) routes of administration in HIV negative female volunteers. IM immunizations were co-administered with Glucopyranosyl Lipid Adjuvant (GLA), IN immunizations with 0.5% chitosan and IVAG immunizations were administered in an aqueous gel. RESULTS: Three IM immunizations of CN54 gp140 at either 20 or 100 µg elicited significantly greater systemic and mucosal antibodies than either IN or IVAG immunizations. Following additional intramuscular boosting we observed an anamnestic antibody response in nasally primed subjects. Modest neutralizing responses were detected against closely matched tier 1 clade C virus in the IM groups. Interestingly, the strongest CD4 T-cell responses were detected after IN and not IM immunization. CONCLUSIONS: These data show that parenteral immunization elicits systemic and mucosal antibodies in women. Interestingly IN immunization was an effective prime for IM boost, while IVAG administration had no detectable impact on systemic or mucosal responses despite IM priming. CLINICAL TRIALS REGISTRATION: EudraCT 2010-019103-27 and the UK Clinical Research Network (UKCRN) Number 11679.

The majority of HIV type 1 DNA in circulating CD4+ T lymphocytes is present in non-gut-homing resting memory CD4+ T cells.

Memory CD4(+) T lymphocytes in peripheral blood that express integrins α4ß7 preferentially recirculate through gut-associated lymphoid tissue (GALT), a proposed site of significant HIV-1 replication. Tregs and activated CD4(+) T cells in GALT could also be particularly susceptible to infection. We therefore hypothesized that infection of these subsets of memory CD4(+) T cells may contribute disproportionately to the HIV-1 reservoir. A cross-sectional study of CD4(+) T cell subsets of memory CD45RO(+) cells in peripheral blood mononuclear cells (PBMCs) was conducted using leukapheresis from eight subjects with untreated chronic HIV-1 infection. Real-time polymerase chain reaction (PCR) was used to quantify total and integrated HIV-1 DNA levels from memory CD4(+) T cells sorted into integrin ß7(+) vs. ß7(-), CD25(+)CD127(low) Treg vs. CD127(high), and activated CD38(+) vs. CD38(-). More than 80% of total HIV-1 DNA was found to reside in the integrin ß7-negative non-gut-homing subset of CD45RO(+) memory CD4(+) T cells. Less than 10% was found in highly purified Tregs or CD38(+) activated memory cells. Similarly, integrated HIV-1 DNA copies were found to be more abundant in resting non-gut-homing memory CD4(+) T cells (76%) than in their activated counterparts (23%). Our investigations showed that the majority of both total and integrated HIV-1 DNA was found within non-gut-homing resting CD4(+) T cells.

Lack of correlation between three commercial platforms for the evaluation of human immunodeficiency virus type 1 (HIV-1) viral load at the clinically critical lower limit of quantification.

BACKGROUND: Concordance in plasma HIV-1 viral load quantification at the lower limit of quantification (LLOQ) is crucial for current commercial assays. OBJECTIVE: To compare the performance of three commercial viral load assays and carry out a correlation study with the Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 test, the Roche Cobas Amplicor HIV-1 MONITOR test, and the Abbott RealTime HIV-1 assay. STUDY DESIGN: Assay agreement was analyzed using linear regression and Bland-Altman plots. Concordance near the clinically critical LLOQ was measured by Cohen's kappa statistics. Intra-assay precision was assessed, and assay reproducibility was measured at 50copies/mL across all three platforms. RESULTS: While good overall correlation was observed between the assays (r≥0.93), quantitative differences exceeded 0.5log(10)copies/mL among paired results in 3.7 to 8.3% of specimens. The degree of concordance between the assays near the LLOQ was unsatisfactory, with Cohen's kappa ranging from 0.14 to 0.38. The intra-assay precision of the Abbott RealTime HIV-1 assay ranged from 0.04 to 0.15 (SD log(10)) and 1.34% to 8.37% (CV). Reproducibility at 50copies/mL for RealTime HIV-1, TaqMan, and Amplicor was 10.05, 11.04 and 5.07 (% CV), respectively. CONCLUSION: Although good correlation was observed between the assays across their linear range, their concordance at the clinically critical LLOQ was poor. The accurate quantification of low-level viremia remains elusive, and the lack of correlation of these assays presents a challenge to the interpretation of such results and in the clinical management of HIV-infected patients.