Modification of the Association Between T-Cell Immune Responses and Human Immunodeficiency Virus Type 1 Infection Risk by Vaccine-Induced Antibody Responses in the HVTN 505 Trial

Background

HVTN 505 was a human immunodeficiency virus type 1 (HIV-1) preventive vaccine efficacy trial of a DNA/recombinant adenovirus serotype 5 (rAd5) vaccine regimen. We assessed antibody responses measured 1 month after final vaccination (month 7) as correlates of HIV-1 acquisition risk.

Methods

Binding antibody responses were quantified in serum samples from 25 primary endpoint vaccine cases (diagnosed with HIV-1 infection between month 7 and month 24) and 125 randomly sampled frequency-matched vaccine controls (HIV-1 negative at month 24). We prespecified for a primary analysis tier 6 antibody response biomarkers that measure immunoglobulin G (IgG) and immunoglobulin A (IgA) binding to Env proteins and 2 previously assessed T-cell response biomarkers.

Results

Envelope-specific IgG responses were significantly correlated with decreased HIV-1 risk. Moreover, the interaction of IgG responses and Env-specific CD8+ T-cell polyfunctionality score had a highly significant association with HIV-1 risk after adjustment for multiple comparisons.

Conclusions

Vaccinees with higher levels of Env IgG have significantly decreased HIV-1 risk when CD8+ T-cell responses are low. Moreover, vaccinees with high CD8+ T-cell responses generally have low risk, and those with low CD8+ T-cell and low Env antibody responses have high risk. These findings suggest the critical importance of inducing a robust IgG Env response when the CD8+ T-cell response is low.

Safety and immunogenicity of an HIV-1 gag DNA vaccine with or without IL-12 and/or IL-15 plasmid cytokine adjuvant in healthy, HIV-1 uninfected adults

Background

DNA vaccines are a promising approach to vaccination since they circumvent the problem of vector-induced immunity. DNA plasmid cytokine adjuvants have been shown to augment immune responses in small animals and in macaques.

Methodology/Principal Findings

We performed two first in human HIV vaccine trials in the US, Brazil and Thailand of an RNA-optimized truncated HIV-1 gag gene (p37) DNA derived from strain HXB2 administered either alone or in combination with dose-escalation of IL-12 or IL-15 plasmid cytokine adjuvants. Vaccinations with both the HIV immunogen and cytokine adjuvant were generally well-tolerated and no significant vaccine-related adverse events were identified. A small number of subjects developed asymptomatic low titer antibodies to IL-12 or IL-15. Cellular immunogenicity following 3 and 4 vaccinations was poor, with response rates to gag of 4.9%/8.7% among vaccinees receiving gag DNA alone, 0%/11.5% among those receiving gag DNA+IL-15, and no responders among those receiving DNA+high dose (1500 ug) IL-12 DNA. However, after three doses, 44.4% (4/9) of vaccinees receiving gag DNA and intermediate dose (500 ug) of IL-12 DNA demonstrated a detectable cellular immune response.

Conclusions/Significance

This combination of HIV gag DNA with plasmid cytokine adjuvants was well tolerated. There were minimal responses to HIV gag DNA alone, and no apparent augmentation with either IL-12 or IL-15 plasmid cytokine adjuvants. Despite the promise of DNA vaccines, newer formulations or methods of delivery will be required to increase their immunogenicity.

Trial Registration

Clinicaltrials.gov NCT00115960NCT00111605

The NOSE study (nasal ointment for Staphylococcus aureus eradication): a randomized controlled trial of monthly mupirocin in HIV-infected individuals

BACKGROUND

HIV-positive patients at HELP/PSI, Inc, an in-patient drug rehabilitation center, had a high baseline prevalence of Staphylococcus aureus colonization (49%) and incidence of infection (17%) in a previous year-long study.

METHODS

A randomized, double-blinded, placebo-controlled study was conducted to determine whether repeated nasal application of mupirocin ointment would decrease the odds of S. aureus nasal colonization in 100 HELP/PSI patients over an 8-month period. A 5-day course of study drug was given monthly, and colonization was assessed at baseline and 1 month after each treatment. S. aureus infection was a secondary outcome.

RESULTS

In repeated-measures analysis, mupirocin reduced the odds of monthly S. aureus nasal colonization by 83% compared with placebo [adjusted odds ratio (ORadj) = 0.17; P < 0.0001]. Subjects colonized at study entry had a 91% reduction in subsequent colonization (ORadj = 0.09; P < 0.0001). Mupirocin also suppressed S. aureus colonization in subjects not colonized at baseline (ORadj = 0.23; P = 0.006). There was no difference in infection rates between the mupirocin and placebo groups (hazard ratio = 0.49, P = 0.29).

CONCLUSIONS

Monthly application of nasal mupirocin significantly decreased S. aureus colonization in HIV patients in residential drug rehabilitation. Monthly mupirocin application has a potential role in long-term care settings or in HIV-positive patients with high rates of S. aureus colonization and infection.