Development of HIV-1 immunogens - Development of HIV-1 immunogens
The generation of new immunogens able to elicit strong immune-specific responses remains a major challenge to obtain a vaccine against HIV/AIDS.
Production of HIV immunogens:
- Heat inactivated autologous virus for therapeutic vaccines.
This immunogen is assayed in clinical trials as a new therapeutic HIV-1 vaccine based on monocyte derived dendritic cells (MDDCs) pulsed with heat inactivated autologous HIV-1 viruses. Proyect: HIV immunotherapy with a therapeutic vaccine plus PEG-interferon to modify the viral reservoir and eventually achieve a remission without antirretrovirals (FIS PI15/00641
- New recombinant non-replicative infective viruses.
We have designed and produced a defective recombinant virus based on the HIV-1 genome that generates infectious but non-replicative virions. Taking advantage of the HIV-1 genome, we produce the already patented pNL4.3/?RT vector which carries a deletion in its coding sequence for the retrotranscriptase (?RT).
Production of non-replicative infective HIV-VSV pseudovirions.
Starting with the HIV-1 genomic vector pNL4.3/?RT which carries a deletion in its coding sequence for the retrotranscriptase (?RT), it will be constructed the vector pNL4.3/?RT/?1136env by deleting 1136 bp of the viral envelope coding sequence (?1136env). This vector will be co-transfected with the plasmid encoding for VSV glycoprotein G (VSV-G). The production of pseudoviruses will be achieved by providing additional deleted viral genes from wild type and isolated from HIV1-infected individuals. In addition, this vector will be used to construct chimeric vectors by replacing its gag, gag-pro and nef genes by those from the patients whose immune response will be assayed.
The aim of this strategy consists of enhancing the cellular response against HIV1 to check whether:
- Chimerich pseudoviruses carrying pNL4.3/?RT/?1136env and the endogenous gag, gag-pro and/or nef may affect the immunological response, especially relevant in patients with poor response.
- Pseudoviruses carrying in its envelope cellular molecules like the adhesion molecule ICAM-1, which has been reported to play a role in viral synapses, may also alter the cellular response. This molecule is naturally absent from the easily transfectable 293T cells. To that goal the cotransfection will be performed in 293T cells stably expressing different levels of ICAM-1.
Support in clinical trials and viral pathogenesis studies by quantifying HIV reservoir.
The magnitude of the latent reservoir is highly variable among virally suppressed individuals and is influenced by a variety of factors including the nadir CD4+ T cell count, the CD4/CD8 ratio, the time between infection and initiation of ART and, to a lesser extent, the duration of therapy. Quantifying latently infected cells is critical to evaluate the efficacy of therapeutic strategies aimed at reducing the size of the long-lived viral reservoir, but the owfrequency of these cells makes this very challenging.
The dynamics of HIV-1 infection is evaluated by quantifying the HIV reservoir either by PCR-based methods that measure the frequency of cell harbouring HIV genomes (determining total and integrated HIV DNA) and/or quantitative viral outgrowth asssay in tissue cultures (QVOA, infectious units per million cells, IUPM).