Construction and cellular immune response induction of HA-based alphavirus replicon vaccines against human-avian influenza (H5N1).
Several approaches are being taken worldwide to develop vaccines against H5N1 viruses; most of them, however, pose both practical and immunological challenges. One potential strategy for improving the immunogenicity of vaccines involves the use of alphavirus replicons and VP22, a herpes simplex type 1 (HSV-1) protein. In this study, we analysed the antigenic peptides and homogeneity of the HA sequences (human isolates of the H5N1 subtype, from 1997 to 2003) and explored a novel alphavirus replicon system of VP22 fused with HA, to assess whether the immunogenicity of an HA-based replicon vaccine could be induced and augmented via fusion with VP22. Further, replicon particles expressing VP22, and enhanced green fluorescent protein (EGFP) were individually used as controls. Cellular immune responses in mice immunised with replicons were evaluated by identifying specific intracellular cytokine production with flow cytometry (FCM). Animal-based experimentation indicated that both the IL-4 expression of CD4(+) T cells and the IFN-gamma expression of CD8(+) T cells were significantly increased in mice immunised with VPR-HA and VPR-VP22/HA. A dose titration effect vis-à-vis both IL-4 expression and IFN-gamma expression were observed in VPR-HA- and VPR-VP22/HA-vaccinated mice. Our results revealed that both VPR-VP22/HA and VPR-HA replicon particles presented a promising approach for developing vaccines against human-avian influenza, and VP22 could enhance the immunogenicity of the HA antigens to which it is fused.
Yang
Shi-gui
SG
State Key Laboratory for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China.
Wo
Jian-er
JE
Li
Min-wei
MW
Mi
Fen-fang
FF
Yu
Cheng-bo
CB
Lv
Guo-liang
GL
Cao
Hong-Cui
HC
Lu
Hai-feng
HF
Wang
Bao-hong
BH
Zhu
Hanping
H
Li
Lan-Juan
LJ
D000524:Alphavirus / Q000276:immunology*; D000818:Animals; D001717:Birds; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology; D007252:Influenza Vaccines / Q000096:biosynthesis / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010802:Phylogeny; D010957:Plasmids; D012093:Replicon / Q000276:immunology; D015678:Viral Structural Proteins / Q000276:immunology*
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D015678:Viral Structural Proteins; C073413:herpes simplex virus type 1 protein VP22; D015847:Interleukin-4; D007371:Interferon-gamma