The immunogenicity of viral haemorragic septicaemia rhabdovirus (VHSV) DNA vaccines can depend on plasmid regulatory sequences.
A plasmid DNA encoding the viral hemorrhagic septicaemia virus (VHSV)-G glycoprotein under the control of 5' sequences (enhancer/promoter sequence plus both non-coding 1st exon and 1st intron sequences) from carp beta-actin gene (pAE6-G(VHSV)) was compared to the vaccine plasmid usually described the gene expression is regulated by the human cytomegalovirus (CMV) immediate-early promoter (pMCV1.4-G(VHSV)). We observed that these two plasmids produced a markedly different profile in the level and time of expression of the encoded-antigen, and this may have a direct effect upon the intensity and suitability of the in vivo immune response. Thus, fish genetic immunisation assays were carried out to study the immune response of both plasmids. A significantly enhanced specific-antibody response against the viral glycoprotein was found in the fish immunised with pAE6-G(VHSV). However, the protective efficacy against VHSV challenge conferred by both plasmids was similar. Later analysis of the transcription profile of a set of representative immune-related genes in the DNA immunized fish suggested that depending on the plasmid-related regulatory sequences controlling its expression, the plasmid might activate distinct patterns of the immune system. All together, the results from this study mainly point out that the selection of a determinate encoded-antigen/vector combination for genetic immunisation is of extraordinary importance in designing optimised DNA vaccines that, when required for inducing protective immune response, could elicit responses biased to antigen-specific antibodies or cytotoxic T cells generation.
IBMC, Miguel Hernández University, 03202 Elche, Spain.
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V
Chico
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M
Ortega-Villaizan
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A
Falco
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C
Tafalla
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L
Perez
J M
JM
Coll
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Estepa
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D000917:Antibody Formation; D005399:Fishes / Q000235:genetics / Q000276:immunology* / Q000821:virology; D015870:Gene Expression; D031941:Hemorrhagic Septicemia, Viral / Q000276:immunology / Q000517:prevention & control*; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D029141:Novirhabdovirus / Q000276:immunology*; D014611:Vaccination / Q000379:methods; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
D000914:Antibodies, Viral; C096089:G protein, viral hemorrhagic septicemia virus; D007075:Immunoglobulin M; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D014765:Viral Vaccines