J-LEAPS vaccines initiate murine Th1 responses by activating dendritic cells

Vaccine. 2010 Aug 2;28(34):5533-42. doi: 10.1016/j.vaccine.2010.06.043. Epub 2010 Jun 25.


The Ligand Epitope Antigen Presentation System (LEAPS) converts a peptide containing a T cell epitope as small as 8 amino acids into an immunogen and directs the nature of the subsequent response. Tandem synthesis of the J peptide (a peptide from the beta-2-microglobulin) with peptides of 15 or 30 amino acids from HSV-1 or HIV made them immunogenic and promoted Th1 immune responses. Immunization of A/J or C57BL/6 mice with J-LEAPS heteroconjugates containing an epitope from the HSV-1 glycoprotein D (JgD) or an epitope from the HIV gag protein (JH) emulsified with Seppic ISA51 induced increased levels of IL-12p70 by day 3 and increased levels of interferon gamma (IFN-gamma) on days 10 and 24. Interestingly, levels of IL-10, TNF-alpha, and IL-6 did not change. Neither the H nor the gD peptides alone elicited responses and only weak responses followed immunization with the J peptide. Bone marrow (BM) cells became CD86 and CD11c positive within 48 h of treatment with JgD or JH. JH or JgD treatment promoted IL-12p70 production and expression of CD8 denoting the maturation and activation of a subclass of myeloid DCs. Pure cultures of immature myeloid DCs also responded to JgD treatment, forming clusters, developing dendrites, and producing IL-12p70 within 24 h. The JH or JgD treated bone marrow cells (JgD-DC) were necessary and sufficient to activate splenic T cells to produce IFN-gamma and the JgD-DC provided an antigen specific booster response to T cells from JgD immunized mice. Adoptive transfer of JgD-DC was also sufficient to initiate protective antigen specific immunity from lethal challenge with HSV-1. The J-LEAPS vaccines appear to act as an adjuvant and immunogen on DC precursors in a unique manner to promote activation and maturation into IL-12p70 producing DCs which then can initiate sufficient Th1 immune responses to elicit protection without production of acute phase cytokines.

MeSH terms

  • Adoptive Transfer
  • Animals
  • Antigen Presentation*
  • Cells, Cultured
  • Dendritic Cells / immunology*
  • Epitopes, T-Lymphocyte / immunology
  • Female
  • Herpes Simplex / immunology
  • Herpes Simplex / prevention & control
  • Herpesvirus 1, Human / immunology
  • Interferon-gamma / immunology
  • Interleukin-12 / immunology
  • Mice
  • Mice, Inbred A
  • Mice, Inbred C57BL
  • Th1 Cells / immunology*
  • Viral Envelope Proteins / immunology
  • Viral Vaccines / immunology*
  • gag Gene Products, Human Immunodeficiency Virus / immunology


  • Epitopes, T-Lymphocyte
  • Viral Envelope Proteins
  • Viral Vaccines
  • gag Gene Products, Human Immunodeficiency Virus
  • glycoprotein D, Human herpesvirus 1
  • Interleukin-12
  • Interferon-gamma