iHIVARNA phase IIa, a randomized, placebo-controlled, double-blinded trial to evaluate the safety and immunogenicity of iHIVARNA-01 in chronically HIV-infected patients under stable combined antiretroviral therapy

Background: HIV therapeutic vaccination aims to improve the immune responses against HIV in order to control viral replication without the need for combined antiretroviral therapy (cART). iHIVARNA-01 is a novel vaccine combining mRNA delivery and T-cell immunogen (HTI) based on conserved targets of effective antiviral T-cell responses. In addition, it holds adequate stimuli required for activating antigen presenting cells (APC)s and co-activating specific T-cells (TriMix), including human CD40L, constitutively active TLR4 (caTLR4) and CD70. We propose that in-vivo targeting of dendritic cells (DCs) by direct administration of a HIV mRNA encoding these immune modulating proteins might be an attractive alternative to target DCs in vitro. Methods/design: This is a phase-IIa, randomized, double-blinded, placebo-controlled, multicenter study in chronically HIV-1 infected patients under stable cART. One of the three study arms is randomly allocated to subjects. Three vaccinations with either HIVACAT T-cell immunogen (HTI)-TriMix (iHIVARNA-01), TriMix or water for injection (WFI) (weeks 0, 2 and 4) are administered by intranodal injection in the inguinal region. Two weeks after the last immunization (week 6) cART is stopped for 12 weeks. The two primary endpoints are: (1) safety and tolerability of intranodal iHIVARNA-01 vaccination compared with TriMix or WFI and (2) induced immunogenicity, i.e., increase in the frequency of HIV-specific T-cell responses between baseline, week 6 and 12 weeks after treatment interruption in iHIVARNA-01-treated patients as compared to the control groups, immunized with TriMix-mRNA or WFI measured by an IFNγ ELISPOT assay. Secondary endpoints include the evaluation of time to viral rebound, plasma viral load (pVL) at w18, the proportion of patients with control of viral load, induction of T-cell responses to new HIV epitopes, polyfunctionality of HIV-specific T-cells, CD8+ T-cell in-vitro HIV suppressive capacity, the effect on viral reservoir (measured by proviral DNA and cell-associated RNA), assessment of viral immune escape by mutation and mRNA expression profiles of host immune genes. Discussion: This trial aims to direct target DC in situ with mRNA encoding HTI and TriMix for co-stimulation. Intranodal injection circumvents laborious DC isolation and handling in the laboratory. The trial extends on the safety results of a phase-I dose-escalating trial. This candidate vaccine could complement or even replace cART for chronic HIV infection and could be applicable to improve the care and cost of HIV infection

CD40 triggering increases the efficiency of dendritic cells forantitumoralimmunization

Recent studies have shown the importance of triggering CD40 molecules to enhance the efficiency of dendritic cells (DCs) as antigen-presenting cells (APCs). The P198 and P1A tumor antigens, which are expressed by mastocytoma P815, have been assessed for their immunogenicity using different modes of immunization. We measured CTL responses induced in vivo with antigenic peptides P198 and P1A loaded onto bone marrow-derived DCs that had matured as a consequence of CD40-CD40L interactions. CD40L-transfected 3T3 fibroblasts were used as a source of CD40L signal. Our results show that this mode of DC activation considerably improves their ability to induce CTLs against P198 and P1A antigens in vivo as compared to untreated DCs. We also show that immunizations carried out with CD40L-activated DCs loaded with the P1A peptide induce a very efficient protection against a lethal challenge with P815 tumor cells, which express P1A. Our results indicate that the efficiency of DC-based vaccines used in clinical trials of cancer immunotherapy could be increased significantly by triggering DCs via CD40 prior to immunization.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

In vivo depletion of CD4⁺CD25⁺ regulatory T cells enhances the antigen-specific primary and memory CTL response elicited by mature mRNA-electroporated dendritic cells

We previously described mRNA electroporation as an efficient gene delivery method to introduce tumor-antigens (Ag) into murine immature dendritic cells (DC). Here, we further optimize the protocol and evaluate the capacity of mRNA-electroporated DC as a vaccine for immunotherapy. First, the early DC maturation kinetics and the effect of different lipopolysaccha ride incubation periods on the phenotypic maturation profile of DC are determined. Next, we show that either immature or mature DC are equally well electroporated and express and present the transgene at a comparable level after electroporation. We point out that the mRNA electroporation results in a negative effect on the interleukin (IL)-12p70, IL-6, and tumor necrosis factor-alpha secretion after maturation. Nevertheless, mRNA-electroporated DC induce an effective cytotoxic T lymphocyte (CTL) response in vivo. Mature electroporated DC are significantly more potent in eliciting an Ag-specific CD8(+) CTL response compared to their immature electroporated counterparts. In addition, a significant improvement in CTL response is obtained both in the primary and in the memory effector phases when CD4(+)CD25(+) regulatory T cells (Treg) are depleted in vivo prior to immunization. These findings are further substantiated in tumor protection experiments and hold convincing evidence for the merit of Treg cell depletion prior to immunization with mRNA-electroporated DC

CD40 triggering increases the efficiency of dendritic cells for antitumoral immunization.

Recent studies have shown the importance of triggering CD40 molecules to enhance the efficiency of dendritic cells (DCs) as antigen-presenting cells (APCs). The P198 and P1A tumor antigens, which are expressed by mastocytoma P815, have been assessed for their immunogenicity using different modes of immunization. We measured CTL responses induced in vivo with antigenic peptides P198 and P1A loaded onto bone marrow-derived DCs that had matured as a consequence of CD40-CD40L interactions. CD40L-transfected 3T3 fibroblasts were used as a source of CD40L signal. Our results show that this mode of DC activation considerably improves their ability to induce CTLs against P198 and P1A antigens in vivo as compared to untreated DCs. We also show that immunizations carried out with CD40L-activated DCs loaded with the P1A peptide induce a very efficient protection against a lethal challenge with P815 tumor cells, which express P1A. Our results indicate that the efficiency of DC-based vaccines used in clinical trials of cancer immunotherapy could be increased significantly by triggering DCs via CD40 prior to immunization

Dendritic cells transduced with viral interleukin 10 or Fas ligand: no evidence for induction of allotolerance in vivo.

Dendritic cells (DC) are the most potent presenters of alloantigens and therefore are responsible for the induction of allograft rejection. Genetic modifications of DC allowing the expression of a tolerogenic molecule may render them immunosuppressive. We transduced bone marrow-derived DC with recombinant MFG retrovirus encoding either viral interleukin (vIL)-10 or Fas ligand (FasL) to induce transplantation tolerance. Up to 10 ng/ml of bioactive vIL-10 was produced by DC after transfer of the corresponding gene. Although the inhibitory properties of vIL-10-transduced DC were revealed in vitro in a mixed lymphocyte culture, no clear down-regulation of the allogeneic response was observed in vivo after single or multiple injections of those DC overexpressing vIL-10. When we transduced wild-type bone marrow-derived DC with recombinant MFG retrovirus encoding murine FasL, cells quickly died, probably because of suicidal or fratricidal Fas-dependent death. Indeed, only DC from Fas-deficient lpr mice survived to FasL gene transfer. Those FasL-transduced lpr DC exhibited a strong cytotoxic activity against Fas-positive targets in vitro. DC overexpressing FasL did not behave as immunosuppressive DC in vivo. The subcutaneous injection of FasL+ lpr DC in MHC class II-disparate mice hyperactivated the allospecific proliferation of T cells in the draining lymph nodes compared with mice treated with control-transduced DC. These results argue against the development of FasL+ DC or vIL-10-secreting DC as immunosuppressive tools in vivo. The alternative pathways of T-cell activation triggered by these genetically modified DC need to be investigated.Journal ArticleReviewinfo:eu-repo/semantics/publishe

Retrovirally transduced bone marrow-derived dendritic cells require CD4+ T cell help to elicit protective and therapeutic antitumor immunity

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

In vivo retargeting of T cell effector function by recombinant bispecific single chain Fv (anti-CD3 x anti-idiotype) induces long-term survival in the murine BCL1 lymphoma model.

As demonstrated in several preclinical models, bispecific Abs are attractive immunotherapeutic agents for tumor treatment. We have previously reported that a bacterially produced anti-CD3 x antitumor bispecific single chain variable fragment of Ab fragment (BsscFv), which is capable of retargeting CTLs toward BCL1 tumor cells, exhibits antitumor activity in vitro. To further facilitate BsscFv production, the coding sequence was subcloned in a eukaryotic expression vector and introduced into Chinese hamster ovary cells for large-scale production. In this report, we have determined the serum stability and the clearance rate from the circulation of BsscFv. Most important, we prove here the therapeutic value of BsscFv in the treatment of BCL1 lymphoma, a murine model for human non-Hodgkin's lymphoma. Tumor-bearing mice that were treated with rscFv in combination with staphylococcal enterotoxin B superantigen, human rIL-2, or murine rIL-12 showed long-term survival, whereas untreated mice all died. This is the first report of the successful in vivo use of BsscFv as an immunotherapeutic agent. Furthermore, long-term survival was the result of complete tumor removal and was not due to the induction of dormancy.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Side-by-side comparison of lentivirally transduced and mRNA-electroporated dendritic cells: implications for cancer immunotherapy protocols

The use of tumor antigen-loaded dendritic cells (DC) is one of the most promising approaches to inducing a tumor-specific immune response. We compared electroporation of mRNA to lentiviral transduction for the delivery of tumor antigens to human monocyte-derived and murine bone marrow-derived DC. Both lentiviral transduction and mRNA electroporation induced eGFP expression in on average 81% of human DC. For murine DC, eGFP mRNA electroporation (62%) proved to be more efficient than lentiviral transduction (47%). When we used tNGFR as a transgene we observed lentiviral pseudotransduction that overestimated lentiviral efficiency. Neither gene transfer method had an adverse effect on viability, phenotype, or allostimulatory capacity of either human or murine DC. Yet, the mRNA-electroporated DC showed a reduced production of IL-12p70 compared to their lentivirally transduced and unmodified counterparts. Human li80MAGE-A3-modified DC and murine li80tOVA-modified DC were able to present antigenic epitopes in the context of MHC class I and class II. Both types of modified murine DC were able to induce OVA-specific cytotoxic T cells in vivo; however, the mRNA-electroporated DC were less potent. Our data indicate that this may be related to their impaired IL-12 production