Delivering HIV Gagp24 to DCIR Induces Strong Antibody Responses In Vivo

PLoS One. 2015 Sep 25;10(9):e0135513. doi: 10.1371/journal.pone.0135513. eCollection 2015.

Abstract

Targeting dendritic cell-specific endocytic receptors using monoclonal antibodies fused to desired antigens is an approach widely used in vaccine development to enhance the poor immunogenicity of protein-based vaccines and to induce immune responses. Here, we engineered an anti-human DCIR recombinant antibody, which cross-reacts with the homologous cynomolgous macaque receptor and was fused via the heavy chain C-terminus to HIV Gagp24 protein (αDCIR.Gagp24). In vitro, αDCIR.Gagp24 expanded multifunctional antigen-specific memory CD4+ T cells recognizing multiple Gagp24 peptides from HIV-infected patient peripheral blood mononuclear cells. In non human primates, priming with αDCIR.Gagp24 without adjuvant elicited a strong anti-Gagp24 antibody response after the second immunization, while in the non-targeted HIV Gagp24 protein control groups the titers were weak. The presence of the double-stranded RNA poly(I:C) adjuvant significantly enhanced the anti-Gagp24 antibody response in all the groups and reduced the discrimination between the different vaccine groups. The avidity of the anti-Gagp24 antibody responses was similar with either αDCIR.Gagp24 or Gagp24 immunization, but increased from medium to high avidity in both groups when poly(I:C) was co-administered. This data provides a comparative analysis of DC-targeted and non-targeted proteins for their capacity to induce antigen-specific antibody responses in vivo. This study supports the further development of DCIR-based DC-targeting vaccines for protective durable antibody induction, especially in the absence of adjuvant.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibody Affinity / immunology
  • Antibody Formation / immunology*
  • Antigen Presentation / immunology
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / metabolism
  • Epitopes, T-Lymphocyte
  • HIV Antibodies / immunology
  • HIV Core Protein p24 / genetics
  • HIV Core Protein p24 / immunology*
  • HIV Infections / immunology
  • HIV Infections / virology
  • HIV-1 / immunology*
  • Humans
  • Immunization
  • Immunization Schedule
  • Immunoglobulin Heavy Chains / genetics
  • Immunoglobulin Heavy Chains / immunology*
  • Lectins, C-Type / immunology*
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / metabolism
  • Leukocytes, Mononuclear / virology
  • Macaca fascicularis
  • Male
  • Membrane Glycoproteins / immunology*
  • Receptors, Immunologic / immunology*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology*
  • T-Cell Antigen Receptor Specificity / immunology

Substances

  • CLEC4A protein, human
  • Epitopes, T-Lymphocyte
  • HIV Antibodies
  • HIV Core Protein p24
  • Immunoglobulin Heavy Chains
  • Lectins, C-Type
  • Membrane Glycoproteins
  • Receptors, Immunologic
  • Recombinant Fusion Proteins
  • p24 protein, Human Immunodeficiency Virus Type 1