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PLoS One. 2017 Oct 24;12(10):e0186602. doi: 10.1371/journal.pone.0186602. eCollection 2017.

Safety and vaccine-induced HIV-1 immune responses in healthy volunteers following a late MVA-B boost 4 years after the last immunization.

Author information

1
Immunopathology and Cellular Immunology, AIDS Research Group, IDIBAPS, Hospital Clínic, University of Barcelona, Barcelona, Spain.
2
Centro Nacional de Biotecnología, CSIC, Madrid, Spain.
3
Infectious Diseases Unit, Hospital Clínic, IDIBAPS, University of Barcelona, Spain.
4
AIDS Immunopathogenesis Unit, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain.
5
Sección Inmunología, Laboratorio InmunoBiología Molecular, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Spanish HIV HGM Biobank, Networking Research Center on Bioengineering, Biomaterials & Nanomedicine (CIBERBBN), Madrid, Spain.

Abstract

BACKGROUND:

We have previously shown that an HIV vaccine regimen including three doses of HIV-modified vaccinia virus Ankara vector expressing HIV-1 antigens from clade B (MVA-B) was safe and elicited moderate and durable (1 year) T-cell and antibody responses in 75% and 95% of HIV-negative volunteers (n = 24), respectively (RISVAC02 study). Here, we describe the long-term durability of vaccine-induced responses and the safety and immunogenicity of an additional MVA-B boost.

METHODS:

13 volunteers from the RISVAC02 trial were recruited to receive a fourth dose of MVA-B 4 years after the last immunization. End-points were safety, cellular and humoral immune responses to HIV-1 and vector antigens assessed by ELISPOT, intracellular cytokine staining (ICS) and ELISA performed before and 2, 4 and 12 weeks after receiving the boost.

RESULTS:

Volunteers reported 64 adverse events (AEs), although none was a vaccine-related serious AE. After 4 years from the 1st dose of the vaccine, only 2 volunteers maintained low HIV-specific T-cell responses. After the late MVA-B boost, a modest increase in IFN-γ T-cell responses, mainly directed against Env, was detected by ELISPOT in 5/13 (38%) volunteers. ICS confirmed similar results with 45% of volunteers showing that CD4+ T-cell responses were mainly directed against Env, whereas CD8+ T cell-responses were similarly distributed against Env, Gag and GPN. In terms of antibody responses, 23.1% of the vaccinees had detectable Env-specific binding antibodies 4 years after the last MVA-B immunization with a mean titer of 96.5. The late MVA-B boost significantly improved both the response rate (92.3%) and the magnitude of the systemic binding antibodies to gp120 (mean titer of 11460). HIV-1 neutralizing antibodies were also enhanced and detected in 77% of volunteers. Moreover, MVA vector-specific T cell and antibody responses were boosted in 80% and 100% of volunteers respectively.

CONCLUSIONS:

One boost of MVA-B four years after receiving 3 doses of the same vaccine was safe, induced moderate increases in HIV-specific T cell responses in 38% of volunteers but significantly boosted the binding and neutralizing antibody responses to HIV-1 and to the MVA vector.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT01923610.

PMID:
29065142
PMCID:
PMC5655491
DOI:
10.1371/journal.pone.0186602
[Indexed for MEDLINE]
Free PMC Article

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