Vigorous hepatitis C virus-specific CD4+ and CD8+ T cell responses induced by protein immunization in the presence of Montanide ISA720 plus synthetic oligodeoxynucleotides containing immunostimulatory cytosine-guanine dinucleotide motifs.
BACKGROUND
A prophylactic vaccine for hepatitis C virus (HCV) requires generation of strong humoral as well as CD4(+) and CD8(+) T cell responses.


METHODS
The immunomodulatory effects of the combination of 2 adjuvants, synthetic oligodeoxynucleotides containing immunostimulatory cytosine-guanine dinucleotide motifs emulsified with Montanide ISA720 (M-ISA720/CpG), were investigated using the murine model.


RESULTS
Administration of recombinant HCV (rHCV) nonstructural (NS) 3 and NS5B proteins plus M-ISA720/CpG (hereafter, "M-ISA720/CpG/rHCV protein") induced high anti-NS3 and anti-NS5B immunoglobulin (Ig) G titers, with the IgG2a isotype being predominant. NS3- and NS5B-specific interferon (IFN)- gamma - and interleukin-2-producing CD4(+) T cell responses, as assessed by enzyme-linked immunospot assay, were significantly more vigorous in mice immunized with M-ISA720/CpG/rHCV protein than in control mice immunized without adjuvant. NS3- and NS5B-specific IFN- gamma -producing CD8(+) T cell percentages, as measured by direct ex vivo intracellular cytokine staining assay, were, respectively, a mean+/-SD of 0.14% +/- 0.04% and 0.15% +/- 0.05% in mice immunized with M-ISA720/CpG/rHCV protein. Furthermore, boosting with recombinant NS3 expression plasmid DNA after priming with M-ISA720/CpG-adjuvanted rNS3 strikingly enhanced both CD4(+) and CD8(+) T cell responses.


CONCLUSIONS
Immunization with M-ISA720/CpG/rHCV protein is capable of inducing potent humoral as well as HCV-specific T helper type 1-biased CD4(+) and CD8(+) T cell responses. A DNA boost after a protein prime--a reversal of the conventional approach--may provide an alternative path to the development of an effective HCV vaccine.
Sugauchi
Fuminaka
F
Department of Transfusion Medicine, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
Wang
Richard Y-H
RY
Qiu
Qi
Q
Jin
Bo
B
Alter
Harvey J
HJ
Shih
J Wai-Kuo
JW
D000276:Adjuvants, Immunologic; D000818:Animals; D020029:Base Pairing; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D015226:Dinucleoside Phosphates / Q000008:administration & dosage / Q000737:chemistry; D016174:Hepacivirus / Q000276:immunology; D008353:Mannitol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D051379:Mice; D009829:Oleic Acids / Q000008:administration & dosage*; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage* / Q000737:chemistry; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000008:administration & dosage* / Q000276:immunology
D000276:Adjuvants, Immunologic; D015226:Dinucleoside Phosphates; D008353:Mannitol; D009829:Oleic Acids; D009838:Oligodeoxyribonucleotides; D014614:Vaccines, Synthetic; D014761:Viral Hepatitis Vaccines; C408982:CPG-oligonucleotide; C015772:CpG dinucleotide; C001681:mannide monooleate