A Chimeric HIV-1 gp120 Fused with Vaccinia Virus 14K (A27) Protein as an HIV Immunogen

PLoS One. 2015 Jul 24;10(7):e0133595. doi: 10.1371/journal.pone.0133595. eCollection 2015.

Abstract

In the HIV vaccine field, there is a need to produce highly immunogenic forms of the Env protein with the capacity to trigger broad B and T-cell responses. Here, we report the generation and characterization of a chimeric HIV-1 gp120 protein (termed gp120-14K) by fusing gp120 from clade B with the vaccinia virus (VACV) 14K oligomeric protein (derived from A27L gene). Stable CHO cell lines expressing HIV-1 gp120-14K protein were generated and the protein purified was characterized by size exclusion chromatography, electron microscopy and binding to anti-Env antibodies. These approaches indicate that gp120-14K protein is oligomeric and reacts with a wide spectrum of HIV-1 neutralizing antibodies. Furthermore, in human monocyte-derived dendritic cells (moDCs), gp120-14K protein upregulates the levels of several proinflammatory cytokines and chemokines associated with Th1 innate immune responses (IL-1β, IFN-γ, IL-6, IL-8, IL-12, RANTES). Moreover, we showed in a murine model, that a heterologous prime/boost immunization protocol consisting of a DNA prime with a plasmid expressing gp120-14K protein followed by a boost with MVA-B [a recombinant modified vaccinia virus Ankara (MVA) expressing HIV-1 gp120, Gag, Pol and Nef antigens from clade B], generates stronger, more polyfunctional, and greater effector memory HIV-1-specific CD4+ and CD8+ T-cell immune responses, than immunization with DNA-gp120/MVA-B. The DNA/MVA protocol was superior to immunization with the combination of protein/MVA and the latter was superior to a prime/boost of MVA/MVA or protein/protein. In addition, these immunization protocols enhanced antibody responses against gp120 of the class IgG2a and IgG3, together favoring a Th1 humoral immune response. These results demonstrate that fusing HIV-1 gp120 with VACV 14K forms an oligomeric protein which is highly antigenic as it activates a Th1 innate immune response in human moDCs, and in vaccinated mice triggers polyfunctional HIV-1-specific adaptive and memory T-cell immune responses, as well as humoral responses. This novel HIV-1 gp120-14K immunogen might be considered as an HIV vaccine candidate for broad T and B-cell immune responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines / genetics
  • AIDS Vaccines / immunology
  • Adaptive Immunity
  • Animals
  • Antibodies, Neutralizing / immunology
  • CD4 Antigens / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / immunology*
  • Cell Line
  • Dendritic Cells / immunology
  • Dendritic Cells / metabolism
  • HIV Antibodies / immunology
  • HIV Antigens / genetics
  • HIV Antigens / immunology*
  • HIV Envelope Protein gp120 / genetics
  • HIV Envelope Protein gp120 / immunology*
  • HIV-1 / genetics
  • HIV-1 / immunology*
  • Humans
  • Immunity, Innate
  • Immunoglobulin G / immunology
  • Immunologic Memory
  • Membrane Proteins
  • Polysaccharides / metabolism
  • Protein Binding
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology*
  • Recombinant Fusion Proteins / isolation & purification
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocyte Subsets / metabolism
  • Th1 Cells / immunology
  • Th1 Cells / metabolism
  • Viral Fusion Proteins / genetics
  • Viral Fusion Proteins / immunology*

Substances

  • A27 protein, vaccinia virus
  • AIDS Vaccines
  • Antibodies, Neutralizing
  • CD4 Antigens
  • Carrier Proteins
  • HIV Antibodies
  • HIV Antigens
  • HIV Envelope Protein gp120
  • Immunoglobulin G
  • Membrane Proteins
  • Polysaccharides
  • Recombinant Fusion Proteins
  • Viral Fusion Proteins

Grants and funding

This investigation was supported by Spanish grants, SAF-2008-02036, SAF-2013-45232-R, RD12/0017/0038 to ME and BFU2011-29038 to JLC. AV and SCR were supported by La CAIXA fellowships.