Enhanced mucosal immune responses induced by a combined candidate mucosal vaccine based on Hepatitis A virus and Hepatitis E virus structural proteins linked to tuftsin

PLoS One. 2015 Apr 13;10(4):e0123400. doi: 10.1371/journal.pone.0123400. eCollection 2015.

Abstract

Hepatitis A virus (HAV) and Hepatitis E virus (HEV) are the most common causes of infectious hepatitis. These viruses are spread largely by the fecal-oral route and lead to clinically important disease in developing countries. To evaluate the potential of targeting hepatitis A and E infection simultaneously, a combined mucosal candidate vaccine was developed with the partial open reading frame 2 (ORF2) sequence (aa 368-607) of HEV (HE-ORF2) and partial virus protein 1 (VP1) sequence (aa 1-198) of HAV (HA-VP1), which included the viral neutralization epitopes. Tuftsin is an immunostimulatory peptide which can enhance the immunogenicity of a protein by targeting it to macrophages and dendritic cells. Here, we developed a novel combined protein vaccine by conjugating tuftsin to HE-ORF2 and HA-VP1 and used synthetic CpG oligodeoxynucleotides (ODNs) as the adjuvant. Subsequent experiments in BALB/c mice demonstrated that tuftsin enhanced the serum-specific IgG and IgA antibodies against HEV and HAV at the intestinal, vaginal and pulmonary interface when delivered intranasally. Moreover, mice from the intranasally immunized tuftsin group (HE-ORF2-tuftsin + HA-VP1-tuftsin + CpG) showed higher levels of IFN-γ-secreting splenocytes (Th1 response) and ratio of CD4+/CD8+ T cells than those of the no-tuftsin group (HE-ORF2 + HA-VP1 + CpG). Thus, the tuftsin group generated stronger humoral and cellular immune responses compared with the no-tuftsin group. Moreover, enhanced responses to the combined protein vaccine were obtained by intranasal immunization compared with intramuscular injection. By integrating HE-ORF2, HA-VP1 and tuftsin in a vaccine, this study validated an important concept for further development of a combined mucosal vaccine against hepatitis A and E infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Female
  • Hepatitis A virus / genetics
  • Hepatitis A virus / immunology*
  • Hepatitis Antibodies / immunology
  • Hepatitis E / genetics
  • Hepatitis E / immunology*
  • Immunity, Mucosal*
  • Immunoglobulin A / blood
  • Immunoglobulin A / immunology
  • Immunoglobulin A, Secretory / immunology
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Mice
  • Mucous Membrane / immunology*
  • Recombinant Fusion Proteins / immunology
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocytes / immunology
  • Tuftsin / genetics
  • Tuftsin / immunology*
  • Vaccines, Combined / immunology*
  • Viral Hepatitis Vaccines / immunology*
  • Viral Structural Proteins / genetics
  • Viral Structural Proteins / immunology*

Substances

  • Hepatitis Antibodies
  • Immunoglobulin A
  • Immunoglobulin A, Secretory
  • Immunoglobulin G
  • Recombinant Fusion Proteins
  • Vaccines, Combined
  • Viral Hepatitis Vaccines
  • Viral Structural Proteins
  • Tuftsin

Grants and funding

This study was supported by a grant from the Chinese Ministry of Science and Technology Program for Important Infectious Diseases Control and Prevention (2012ZX10002-001). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.