Heterologous prime-boost regimens using rAd35 and rMVA vectors elicit stronger cellular immune responses to HIV proteins than homologous regimens

PLoS One. 2012;7(9):e45840. doi: 10.1371/journal.pone.0045840. Epub 2012 Sep 26.


We characterized prime-boost vaccine regimens using heterologous and homologous vector and gene inserts. Heterologous regimens offer a promising approach that focuses the cell-mediated immune response on the insert and away from vector-dominated responses. Ad35-GRIN/ENV (Ad35-GE) vaccine is comprised of two vectors containing sequences from HIV-1 subtype A gag, rt, int, nef (Ad35-GRIN) and env (Ad35-ENV). MVA-CMDR (MVA-C), MVA-KEA (MVA-K) and MVA-TZC (MVA-T) vaccines contain gag, env and pol genes from HIV-1 subtypes CRF01_AE, A and C, respectively. Balb/c mice were immunized with different heterologous and homologous vector and insert prime-boost combinations. HIV and vector-specific immune responses were quantified post-boost vaccination. Gag-specific IFN-γ ELISPOT, intracellular cytokine staining (ICS) (CD107a, IFN-γ, TNF-α and IL-2), pentamer staining and T-cell phenotyping were used to differentiate responses to inserts and vectors. Ad35-GE prime followed by boost with any of the recombinant MVA constructs (rMVA) induced CD8+ Gag-specific responses superior to Ad35-GE-Ad35-GE or rMVA-rMVA prime-boost combinations. Notably, there was a shift toward insert-focus responses using heterologous vector prime-boost regimens. Gag-specific central and effector memory T cells were generated more rapidly and in greater numbers in the heterologous compared to the homologous prime-boost regimens. These results suggest that heterologous prime-boost vaccination regimens enhance immunity by increasing the magnitude, onset and multifunctionality of the insert-specific cell-mediated immune response compared to homologous vaccination regimens. This study supports the rationale for testing heterologous prime-boost regimens in humans.

Publication types

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

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • CD8-Positive T-Lymphocytes / cytology
  • Cytokines / metabolism
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Flow Cytometry / methods
  • HIV / metabolism*
  • Histocompatibility Antigens Class I / metabolism
  • Humans
  • Immune System / physiology*
  • Immunity, Cellular
  • Immunologic Memory
  • Interferon-gamma / metabolism
  • Lysosomal-Associated Membrane Protein 1 / biosynthesis
  • Mice
  • Mice, Inbred BALB C
  • Spleen / cytology
  • Spleen / metabolism
  • T-Lymphocytes / cytology
  • Viral Proteins / metabolism*


  • Cytokines
  • Histocompatibility Antigens Class I
  • Lysosomal-Associated Membrane Protein 1
  • Viral Proteins
  • Interferon-gamma

Grants and funding

This work was supported in part by an Interagency Agreement (Y1-AI-2642-12) between the United States Army Medical Research and Materiel Command and the National Institute of Allergy and Infectious Diseases and by a cooperative agreement (W81XWH-07-2-6700-P00001) between the Henry M. Jackson Foundation for the Advancement of Military Medicine and the United States Department of Defense. This study was also partially funded by the International AIDS Vaccine Initiative and its donors, including the generous support of the American people through the United States Agency for International Development (USAID; USAID Cooperative Agreement number GPO-A-00-06-00006-00). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.