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

Abstract

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.

Fig 1. CONSORT Flow diagram.

Numbers of participants recruited into the trial “Analysis 1”is the original protocol schedule to week 20 incorporating the planned main analysis. Five from IM100 and 3 from the IN group also received additional boost vaccinations following an amendment to the protocol, and these individuals were included in the exploratory “Boost Analysis -2”.

Fig 2. Participant response rates in systemic and mucosal compartments;

Panel a) shows the numbers of participants with a CN54gp140 IgG antibodies in serum according to vaccination group and timepoint from randomisation. Panel b) shows the numbers of participants with CN54gp140 IgG antibodies in mucosal samples by vaccination group. Filled bars show the number of participants with detectable CN54 IgG, open bars show the number of participants with no CN54gp140 IgG antibodies.

Fig 3. Magnitude of serum CN54gp140 IgG antibody responses for the two intramuscular vaccination groups by timepoint from randomisation.

Panel a) Serum CN54gp140 IgG levels measured by ELISA expressed as μg/ml in either IM20 group (red circles) or IM100 group (black squares) at weeks 5, 8 12, 16 and 20. The black arrows indicate immunizations administered at weeks 0, 4 and 8 weeks. Panel b) Serum IgG responses measured in the 8 participants that received boost immunizations at weeks 32 and 34 (shown as arrows). Black symbols/lines indicate the 5 participants from the IM100 group, red symbols/lines indicate 3 participants from the IN prime group.

Fig 4. Peptide binding array analysis against gp120 peptides in serum samples from participants that developed a serum CN54gp140 IgG antibody response.

Panel a) shows mean binding intensities against consensus clades; Panel b) shows mean binding intensities against a variety of HIV-1 vaccine strains. Panel c) Details the maximum binding intensities are shown according to participant at peak serum IgG response for the two groups that received intramuscular immunizations.

Fig 5. Serum neutralizing antibody titres, analysed by TZM-bl assay.

Data expressed as ID50 against a variety of viruses at (a) week 0, b) week 12, c) week 20, and following additional boost in panel d).

Fig 6. T cell ICS analysis.

The graphs display background corrected magnitude of T cell response for each cytokine and T cell subset by visit as percentage staining shown as box plots. Here, cohort 1 = IM20, cohort 2 = IM100, cohort 3 = IN and cohort 4 = IVAG. Responders are colored red and non-responders blue. Box plots based upon data from responders only are superimposed on the distributions, mid-line denotes median,ends of the box denote 25^th and 75^th percentiles and where whiskers that extend from the top and bottom are the extreme data points. Panel a) shows staining of CN54gp140 specific live CD3+/CD4+ CD154+ cells, b) CD3+/CD4+ IL-2+, c) CD3+/CD4+ TNF-α+ according to vaccination group at weeks 0, 12 and 24.