Prime-boost immunization with DNA, recombinant fowlpox virus and VLP(SHIV) elicit both neutralizing antibodies and IFNgamma-producing T cells against the HIV-envelope protein in mice that control env-bearing tumour cells.

Different primings with DNA and fowlpox virus (FP) recombinants or FP alone were used in a pre-clinical trial to evaluate and compare immunogenicity and efficacy against HIV/SHIV. Three immunization regimens were tested in three groups of mice in which the SIV gag/pol and HIV-1 env transgenes were separately expressed by DNA and FP vectors, followed by VLP(SHIV) boosting. All of the protocols were effective in eliciting homologous neutralizing antibodies, although the mice immunized with DNA followed by FP recombinants or DNA+FP recombinants showed both high titres of neutralizing antibodies and high frequencies of env-specific IFNgamma-producing T lymphocytes.

Molecular and biological characterization of simian-human immunodeficiency virus-like particles produced by recombinant fowlpox viruses.

Virus-like particles (VLPs) mimicking the simian-human immunodeficiency virus SHIV89.6P (VLPSHIV) were produced by co-infection of Vero cells with fowlpox SIVgag/pol (FPgag/polSIV) and fowlpox HIV-1env89.6P (FPenv89.

Prior DNA immunization enhances immune response to dominant and subdominant viral epitopes induced by a fowlpox-based SIVmac vaccine in long-term slow-progressor macaques infected with SIVmac251.

A therapeutic vaccine for individuals infected with HIV-1 and treated with antiretroviral therapy (ART) should be able to replenish virus-specific CD4+ T-cells and broaden the virus-specific CD8+ T-cell response in order to maintain CD8+ T-cell function and minimize viral immune escape after ART cessation. Because a combination of DNA and recombinant poxvirus vaccine modalities induces high levels of virus-specific CD4+ T-cell response and broadens the cytolytic activity in naive macaques, we investigated whether the same results could be obtained in SIVmac251-infected macaques. The macaques studied here were long-term nonprogressors that naturally contained viremia but were nevertheless treated with a combination of antiviral drugs to assess more carefully the effect of vaccination in the context of ART.

Comparative analysis of immune responses and cytokine profiles elicited in rabbits by the combined use of recombinant fowlpox viruses, plasmids and virus-like particles in prime-boost vaccination protocols against SHIV.

Three different prime-boost immunization protocols were tested in rabbits and their immune response was evaluated and compared with the final aim of identifying a vaccine strategy that might be able to protect non-human primates from infection with the pathogenic chimera simian/human immunodeficiency virus (SHIV)(89.6P). Protocols were based on priming with two fowlpox (FP) recombinant vectors and two expression plasmids, which express either the simian immunodeficiency virus (SIV)mac(239) gag/pol or the human immunodeficiency virus (HIV-1)env(89.

Evaluation in rabbits of different anti-SHIV vaccine strategies based on DNA/fowlpox priming and virus-like particle boosting.

Two different prime-boost immunization protocols were tested in rabbits and their immune response was evaluated and compared with the final aim of defining a vaccine strategy that might be able to protect non-human primates from infection with the pathogenic simian/human immunodeficiency virus, SHIV(89.6P). The two regimens were based on three priming immunizations with either an expression plasmid plus a fowlpox (FP) recombinant vector or with two FP recombinant vectors, each one expressing either the SIV(mac239) gag/pol or the HIV-1env(89.

Evaluation of poliovirus vaccines for pestivirus contamination: non-specific amplification of poliovirus sequences by pan-pestivirus primers.

Two lots of polyvalent live vaccines for human use against poliovirus were tested by reverse transcriptase (RT) and nested PCR for the presence of contaminating pestivirus RNA. By RT-PCR, samples from both lots showed a band of approximately 450 bp instead of 300 bp for the reference pestivirus strain used as positive control. After nested PCR, the template DNA (450 bp product) was not amplified, suggesting non-specificity of the previous amplification.