The Effects of Endosomal Toll-like Receptor Inhibitors in an EBV DNA-Exacerbated Inflammatory Bowel Disease Mouse Model.

Epstein-Barr virus (EBV), a Herpesviridae family member, is associated with an increased risk of autoimmune disease development in the host. We previously demonstrated that EBV DNA elevates levels of the pro-inflammatory cytokine IL-17A and that inhibiting Toll-like receptor (TLR) 3, 7, or 9 reduces its levels. Moreover, this DNA exacerbated colitis in a mouse model of inflammatory bowel disease (IBD). In the study at hand, we examined whether inhibition of TLR3, 7, or 9 alleviates this exacerbation. Mice were fed 1.5% dextran sulfate sodium (DSS) water and administered EBV DNA. Then, they were treated with a TLR3, 7, or 9 inhibitor or left untreated. We also assessed the additive impact of combined inhibition of all three receptors. Mice that received DSS, EBV DNA, and each inhibitor alone, or a combination of inhibitors, showed significant improvement. They also had a decrease in the numbers of the pathogenic colonic IL-17A+IFN-γ+ foci. Inhibition of all three endosomal TLR receptors offered no additive benefit over administering a single inhibitor. Therefore, inhibition of endosomal TLRs reduces EBV DNA exacerbation of mouse colitis, offering a potential approach for managing IBD patients infected with EBV.

Key Molecular Events in Cervical Cancer Development.

Cervical cancer is the fourth most common cancer among women. Infection by high-risk human papillomavirus (HPV) is the main aetiology for the development of cervical cancer. Infection by high-risk human papillomavirus (HPV) and the integration of the HPV genome into the host chromosome of cervical epithelial cells are key early events in the neoplastic progression of cervical lesions. The viral oncoproteins, mainly E6 and E7, are responsible for the initial changes in epithelial cells. The viral proteins inactivate two main tumour suppressor proteins, p53, and retinoblastoma (pRb). Inactivation of these host proteins disrupts both the DNA repair mechanisms and apoptosis, leading to rapid cell proliferation. Multiple genes involved in DNA repair, cell proliferation, growth factor activity, angiogenesis, as well as mitogenesis genes become highly expressed in cervical intraepithelial neoplasia (CIN) and cancer. This genomic instability encourages HPV-infected cells to progress towards invasive carcinoma. The key molecular events involved in cervical carcinogenesis will be discussed in this review.

A simultaneous oral and intramuscular prime/sublingual boost with a DNA/Modified Vaccinia Ankara viral vector-based vaccine induces simian immunodeficiency virus-specific systemic and mucosal immune responses in juvenile rhesus macaques.

BACKGROUND: A pediatric vaccine to prevent breast milk transmission of human immunodeficiency virus (HIV) may generate greater immune responses at viral entry sites if given by an oral route. METHODS: We compared immune responses induced in juvenile macaques by prime/boosting with simian immunodeficiency virus (SIV)-expressing DNA/modified vaccinia Ankara virus (MVA) by the intramuscular route (IM), the oral (O)/tonsillar routes (T), the O/sublingual (SL) routes, and O+IM/SL routes. RESULTS: O/T or O/SL immunization generated SIV-specific T cells in mucosal tissues but failed to induce SIV-specific IgA in saliva or stool or IgG in plasma. IM/IM or O+IM/SL generated humoral and cellular responses to SIV. IM/IM generated greater frequencies of TFH in spleen, but O+IM/SL animals had higher avidity plasma IgG and more often demonstrated mucosal IgA responses. CONCLUSION: These results suggest that codelivery of HIV DNA/MVA vaccines by the oral and IM routes might be optimal for generating both systemic and mucosal antibodies.

Phase IIb trial of in vivo electroporation mediated dual-plasmid hepatitis B virus DNA vaccine in chronic hepatitis B patients under lamivudine therapy.

AIM: To assess the efficacy and safety of in vivo electroporation (EP)-mediated dual-plasmid hepatitis B virus (HBV) DNA vaccine vs placebo for sequential combination therapy with lamivudine (LAM) in patients with chronic hepatitis B. METHODS: Two hundred and twenty-five patients were randomized to receive either LAM + vaccine (vaccine group, n = 109) or LAM + placebo (control group, n = 116). LAM treatment lasted 72 wk. Patients received the DNA vaccine or placebo by intramuscular injection mediated by EP at weeks 12 (start of treatment with vaccine or placebo, SOT), 16, 24, and 36 (end of treatment with vaccine or placebo, EOT). RESULTS: In the modified intent-to-treat population, more patients had a decrease in HBV DNA > 2 log10 IU/mL in the vaccine group at week 12 after EOT compared with the control group. A trend toward a difference in the number of patients with undetectable HBV DNA at week 28 after EOT was obtained. Adverse events were similar. In the dynamic per-protocol set, which excluded adefovir (ADV) add-on cases at each time point instantly after ADV administration due to LAM antiviral failure, more patients had a decrease in HBV DNA > 2 log10 IU/mL in the vaccine group at week 12 and 28 after EOT compared with the control group. More patients with undetectable HBV DNA at week 28 after EOT in the vaccine group were also observed. Among patients with a viral load < 1000 copies/mL at week 12, more patients achieved HBeAg seroconversion in the vaccine group than among controls at week 36 after EOT, as well as less virological breakthrough and YMDD mutations. CONCLUSION: The primary endpoint was not achieved using the HBV DNA vaccine. The HBV DNA vaccine could only be beneficial in subjects that have achieved initial virological response under LAM chemotherapy.

A Phase I Double Blind, Placebo-Controlled, Randomized Study of the Safety and Immunogenicity of Electroporated HIV DNA with or without Interleukin 12 in Prime-Boost Combinations with an Ad35 HIV Vaccine in Healthy HIV-Seronegative African Adults.

BACKGROUND: Strategies to enhance the immunogenicity of DNA vaccines in humans include i) co-administration of molecular adjuvants, ii) intramuscular administration followed by in vivo electroporation (IM/EP) and/or iii) boosting with a different vaccine. Combining these strategies provided protection of macaques challenged with SIV; this clinical trial was designed to mimic the vaccine regimen in the SIV study. METHODS: Seventy five healthy, HIV-seronegative adults were enrolled into a phase 1, randomized, double-blind, placebo-controlled trial. Multi-antigenic HIV (HIVMAG) plasmid DNA (pDNA) vaccine alone or co-administered with pDNA encoding human Interleukin 12 (IL-12) (GENEVAX IL-12) given by IM/EP using the TriGrid Delivery System was tested in different prime-boost regimens with recombinant Ad35 HIV vaccine given IM. RESULTS: All local reactions but one were mild or moderate. Systemic reactions and unsolicited adverse events including laboratory abnormalities did not differ between vaccine and placebo recipients. No serious adverse events (SAEs) were reported. T cell and antibody response rates after HIVMAG (x3) prime-Ad35 (x1) boost were independent of IL-12, while the magnitude of interferon gamma (IFN-γ) ELISPOT responses was highest after HIVMAG (x3) without IL-12. The quality and phenotype of T cell responses shown by intracellular cytokine staining (ICS) were similar between groups. Inhibition of HIV replication by autologous T cells was demonstrated after HIVMAG (x3) prime and was boosted after Ad35. HIV specific antibodies were detected only after Ad35 boost, although there was a priming effect with 3 doses of HIVMAG with or without IL-12. No anti-IL-12 antibodies were detected. CONCLUSION: The vaccines were safe, well tolerated and moderately immunogenic. Repeated administration IM/EP was well accepted. An adjuvant effect of co-administered plasmid IL-12 was not detected. TRIAL REGISTRATION: ClinicalTrials.gov NCT01496989.

Structural determinants in human DNA polymerase gamma account for mitochondrial toxicity from nucleoside analogs.

Although antiviral nucleoside analog therapy successfully delays progression of HIV infection to AIDS, these drugs cause unwelcome side-effects by inducing mitochondrial toxicity. We and others have demonstrated that the mitochondrial polymerase, DNA polymerase gamma (pol gamma), participates in mitochondrial toxicity by incorporating these chain-terminating antiviral nucleotide analogs into DNA. Here, we explore the role of three highly conserved amino acid residues in the active site of human pol gamma that modulate selection of nucleotide analogs as substrates for incorporation. Sequence alignments, crystal structures and mutagenesis studies of family A DNA polymerases led us to change Tyr951 and Tyr955 in polymerase motif B to Phe and Ala, and Glu895 in polymerase motif A was changed to Ala. The mutant polymerases were tested for their ability to incorporate natural nucleotides and the five antiviral nucleoside analogs currently approved for antiviral therapy: AZT, ddC, D4T, 3TC and carbovir. Steady-state kinetic analysis of the pol gamma derivatives with the normal and antiviral nucleotides demonstrated that Tyr951 is largely responsible for the ability of pol gamma to incorporate dideoxynucleotides and D4T-MP. Mutation of Tyr951 to Phe renders the enzyme resistant to dideoxynucleotides and D4T-TP without compromising the activity of the polymerase. Alteration of Glu895 and Tyr955 to Ala had the largest effect on overall polymerase activity with normal nucleotides, producing dramatic increases in K(m(dNTP)) and large decreases in k(cat). Mutation of Tyr955 in pol gamma causes the degenerative disease progressive external ophthalmoplegia in humans, and we show that this residue partially accounts for the ability of pol gamma to incorporate D4T-MP and carbovir. Alteration of Glu895 to Ala slightly increased discrimination against dideoxynucleotides and D4T-TP. The mechanisms by which pol gamma selects certain nucleotide analogs are discussed.

A phase I study of Onyx-015, an E1B attenuated adenovirus, administered intratumorally to patients with recurrent head and neck cancer.

An E1B 55 kDa gene-deleted adenovirus, Onyx-015, which reportedly selectively replicates in and lyses p53-deficient cells, was administered by a single intratumoral injection to a total of 22 patients with recurrent head and neck cancer. The objectives of this Phase I study were to determine the safety, feasibility, and efficacy of this therapy and determine any correlation to p53 status. Six cohorts were investigated with a dose escalation from 10(7)-10(11) plaque-forming units. Toxicity was assessed using NCIC criteria. Tumor response was assessed by clinical and radiological measurement. Blood samples were taken to detect adenovirus DNA and neutralizing antibody to adenovirus. Tumor biopsies were taken to detect adenovirus by in situ hybridization. Treatment was well tolerated, with the main toxicity being grade 1/2 flu-like symptoms. Dose-limiting toxicity was not reached at the highest dose of 10(11) plaque-forming units. Twenty-one of the 22 patients treated showed an increase in neutralizing antibody to adenovirus. In situ hybridization showed viral replication in 4 of 22 patients treated, all of whom had mutant p53 tumors. Using conventional response criteria, no objective responses were observed. However, magnetic resonance imaging scans were suggestive of tumor necrosis at the site of viral injection in five patients, three of whom were classified using nonconventional criteria as partial responders, and two of whom were classified using nonconventional criteria as minor responders. Of these five cases, four had mutant p53 tumors. The response duration for the three partial responders was 4, 8, and 12 weeks. An additional eight patients had stable disease in the injected tumors lasting from 4-8 weeks. These preliminary results show that intratumoral administration of Onyx-015 is feasible, well tolerated, and associated with biological activity. Further investigation of Onyx-015, particularly with a more frequent injection protocol and in combination with systemic chemotherapy, is warranted.

Phase 1 safety and immune response studies of a DNA vaccine encoding hepatitis B surface antigen delivered by a gene delivery device.

This study was designed to determine the safety and immunogenicity in volunteers of a DNA vaccine consisting of a plasmid encoding hepatitis B surface antigen delivered by the PowderJect XR1 gene delivery system into human skin. Seven healthy adult volunteers received two immunizations at one of three forces of delivery on day 0 and 56. The vaccine was well tolerated. One of six seronegative volunteers developed high titers of persistent HBsAb after a single immunization. In retrospect, this volunteer may have had previous exposure to hepatitis B. Our study suggests that the hepatitis B DNA vaccine given by this gene delivery system may induce a booster response, but the vaccine at the extremely low DNA dose used (0.25 microg) did not induce primary immune responses.

Safety of viral DNA in biological products.

Data from studies of the infectivity of DNA injected directly into laboratory animals are used to estimate the potential infectivity risk of residual DNA in biological products. The potential for some novel products to contain infectious quantities of residual cellular DNA is discussed, and further study of this subject is suggested.

Safety of intrapleurally administered recombinant adenovirus carrying herpes simplex thymidine kinase DNA followed by ganciclovir therapy in nonhuman primates.

Preclinical safety and toxicity studies of intrapleural administration of recombinant adenovirus carrying the herpes simplex thymidine kinase gene (H5.010RSVtk) were performed. Previously reported experimental evidence has demonstrated the efficacy of this approach in animal models of a localized thoracic cancer, malignant mesothelioma. H5.010RSVtk was delivered at high dose (10(12) pfu) into the pleural cavity of three non-human primates followed by systemic administration of ganciclovir. No clinical toxicity was noted. Although an inflammatory reaction observable by microscopy was noted in the serosal spaces of the chest cavity, these changes were reversible and were not associated with radiographic sequelae. Extrathoracic viral dissemination was minimal and detectable only by sensitive polymerase chain reaction techniques. This low level of viral dissemination was not associated with detectable clinical, biochemical, or pathologic abnormalities.