Immunogenicity of candidate DNA vaccine based on subtype A of human immunodeficiency virus type 1 predominant in Russia

The Increase of the Magnitude of Spontaneous Viral Blips in Some Participants of Phase II Clinical Trial of Therapeutic Optimized HIV DNA Vaccine Candidate

We developed a candidate DNA vaccine called “DNA-4”consisting of 4 plasmid DNAs encoding Nef, Gag, Pol(rt), and gp140 HIV-1 proteins. The vaccine was found to be safe and immunogenic in a phase I clinical trial. Here we present the results of a phase II clinical trial of “DNA-4”. This was a multicenter, double-blind, placebo-controlled clinical trial of safety, and dose selection of “DNA-4” in HIV-1 infected people receiving antiretroviral therapy (ART). Fifty-four patients were randomized into 3 groups (17 patients—group DNA-4 0.25 mg, 17 patients—group DNA-4 0.5 mg, 20 patients—the placebo group). All patients were immunized 4 times on days 0, 7, 11, and 15 followed by a 24-week follow-up period. “DNA-4” was found to be safe and well-tolerated at doses of 0.25 mg and 0.5 mg. We found that the amplitudes of the spontaneous viral load increases in three patients immunized with the candidate DNA vaccine were much higher than that in placebo group—2800, 180,000 and 709 copies/mL, suggesting a possible influence of therapeutic DNA vaccination on viral reservoirs in some patients on ART. We hypothesize that this influence was associated with the reactivation of proviral genomes.

The exon junction complex factor Y14 is dynamic in the nucleus of the beetle Tribolium castaneum during late oogenesis

Background

The oocyte chromosomes of the red flour beetle, Tribolium castaneum, are gathered into a knot, forming a karyosphere at the diplotene stage of meiotic prophase. Chromatin rearrangement, which is a characteristic feature of oocyte maturation, is well documented. The T. castaneum karyosphere is surrounded by a complex extrachromosomal structure termed the karyosphere capsule. The capsule contains the vast majority of oocyte RNA. We have previously shown using a BrUTP assay that oocyte chromosomes in T. castaneum maintain residual transcription up to the very end of oocyte maturation. Karyosphere transcription requires evidently not only transcription factors but also mRNA processing factors, including the components of the exon junction complex with its core component, the splicing factor Y14. We employed a gene engineering approach with injection of mRNA derived from the Myc-tagged Y14 plasmid-based construct in order to monitor the newly synthesized fusion protein in the oocyte nuclei.

Results

Our preliminary data have been presented as a brief correspondence elsewhere. Here, we provide a full-length article including immunoelectron-microscopy localization data on Y14–Myc distribution in the nucleus of previtellogenic and vitellogenic oocytes. The injections of the fusion protein Y14–Myc mRNA into the oocytes showed a dynamic pattern of the protein distribution. At the previtellogenic stage, there are two main locations for the protein: SC35 domains (the analogues of interchromatin granule clusters or nuclear speckles) and the karyosphere capsule. At the vitellogenic stage, SC35 domains were devoid of labels, and Y14–Myc was found in the perichromatin region of the karyosphere, presumably at the places of residual transcription. We show that karyosphere formation is accompanied by the movement of a nuclear protein while the residual transcription occurs during genome inactivation.

Conclusions

Our data indicate that the karyosphere capsule, being a destination site for a protein involved in mRNA splicing and export, is not only a specializes part of nuclear matrix separating the karyosphere from the products of chromosome activity, as believed previously, but represents a special nuclear compartment involved in the processes of gene expression in the case the karyosphere retains residual transcription activity.

Electronic supplementary material

The online version of this article (10.1186/s13039-017-0342-4) contains supplementary material, which is available to authorized users.

Consensus HIV-1 FSU-A integrase gene variants electroporated into mice induce polyfunctional antigen-specific CD4+ and CD8+ T cells

Our objective is to create gene immunogens targeted against drug-resistant HIV-1, focusing on HIV-1 enzymes as critical components in viral replication and drug resistance. Consensus-based gene vaccines are specifically fit for variable pathogens such as HIV-1 and have many advantages over viral genes and their expression-optimized variants. With this in mind, we designed the consensus integrase (IN) of the HIV-1 clade A strain predominant in the territory of the former Soviet Union and its inactivated derivative with and without mutations conferring resistance to elvitegravir. Humanized IN gene was synthesized; and inactivated derivatives (with 64D in the active site mutated to V) with and without elvitegravir-resistance mutations were generated by site-mutagenesis. Activity tests of IN variants expressed in E coli showed the consensus IN to be active, while both D64V-variants were devoid of specific activities. IN genes cloned in the DNA-immunization vector pVax1 (pVaxIN plasmids) were highly expressed in human and murine cell lines (>0.7 ng/cell). Injection of BALB/c mice with pVaxIN plasmids followed by electroporation generated potent IFN-γ and IL-2 responses registered in PBMC by day 15 and in splenocytes by day 23 after immunization. Multiparametric FACS demonstrated that CD8+ and CD4+ T cells of gene-immunized mice stimulated with IN-derived peptides secreted IFN-γ, IL-2, and TNF-α. The multi-cytokine responses of CD8+ and CD4+ T-cells correlated with the loss of in vivo activity of the luciferase reporter gene co-delivered with pVaxIN plasmids. This indicated the capacity of IN-specific CD4+ and CD8+ T-cells to clear IN/reporter co-expressing cells from the injection sites. Thus, the synthetic HIV-1 clade A integrase genes acted as potent immunogens generating polyfunctional Th1-type CD4+ and CD8+ T cells. Generation of such response is highly desirable for an effective HIV-1 vaccine as it offers a possibility to attack virus-infected cells via both MHC class I and II pathways.

The high frequency of HIV type 1-specific cellular immune responses in seronegative individuals with parenteral and/or heterosexual HIV type 1 exposure

Some individuals remain HIV seronegative despite repeated unprotected exposure to the virus. Recent observations led to a concept that acquired immunity plays a role in protection or at least in altered susceptibility to HIV-1 infection in highly exposed seronegative (ESN) individuals. Our aim was to study HIV-specific cellular immune responses induced in parenterally and/or heterosexually ESN individuals. Nine seronegative injection drug users (IDUs), 10 seronegative individuals, and nine of their HIV-positive sexual and/or IDU partners from the cohort of IDUs were included in the study. The discordant couples had unprotected sex, and some of seronegative partners also had parenteral exposure. Cell-mediated responses were measured in peripheral blood mononuclear cells (PBMCs) by ex vivo interferon (IFN)-γ-ELISpot and ICS combining IFN-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-2 after stimulation with four consensus peptide pools (Nef, Gag, RT, Env, subtype A-EE). Thirteen out of 19 (68%) seronegative study subjects had strong Nef peptide pool-specific ELISpot responses, three (16%) subjects responded against the Gag peptide pool, and one subject had an RT peptide pool response. Nef peptide pool responses in ESN were as high as in seropositive subjects. The multiple HIV-specific cytokine production in both CD4(+) and CD8(+) T cells was shown for several ESN subjects. The functional profiles of the immune responses were different between seronegative and HIV-positive study groups. Whether the observed cellular responses have any protective role against HIV needs to be further investigated.