In vivo delivery of engineered synthetic DNA-encoded SARS-CoV-2 monoclonal antibodies for pre-exposure prophylaxis in non-human primates.

COVID-19 remains a major public health concern. Monoclonal antibodies have received emergency use authorization (EUA) for pre-exposure prophylaxis against COVID-19 among high-risk groups for treatment of mild to moderate COVID-19. In addition to recombinant biologics, engineered synthetic DNA-encoded antibodies (DMAb) are an important strategy for direct in vivo delivery of protective mAb. A DMAb cocktail was synthetically engineered to encode the immunoglobulin heavy and light chains of two different two different Fc-engineered anti-SARS-CoV-2 antibodies. The DMAbs were designed to enhance in vivo expression and delivered intramuscularly to cynomolgus and rhesus macaques with a modified in vivo delivery regimen. Serum levels were detected in macaques, along with specific binding to SARS-CoV-2 spike receptor binding domain protein and neutralization of multiple SARS-CoV-2 variants of concern in pseudovirus and authentic live virus assays. Prophylactic administration was protective in rhesus macaques against signs of SARS-CoV-2 (USA-WA1/2020) associated disease in the lungs. Overall, the data support further study of DNA-encoded antibodies as an additional delivery mode for prevention of COVID-19 severe disease. These data have implications for human translation of gene-encoded mAbs for emerging infectious diseases and low dose mAb delivery against COVID-19.

The Inflammatory Contribution of B-Lymphocytes and Neutrophils in Progression to Osteoporosis.

Osteoporosis is a bone disease characterized by structural deterioration and low bone mass, leading to fractures and significant health complications. In this review, we summarize the mechanisms by which B-lymphocytes and neutrophils contribute to the development of osteoporosis and potential therapeutics targeting these immune mediators to reduce the proinflammatory milieu. B-lymphocytes-typically appreciated for their canonical role in adaptive, humoral immunity-have emerged as critical regulators of bone remodeling. B-lymphocytes communicate with osteoclasts and osteoblasts through various cytokines, including IL-7, RANK, and OPG. In inflammatory conditions, B-lymphocytes promote osteoclast activation and differentiation. However, B-lymphocytes also possess immunomodulatory properties, with regulatory B-lymphocytes (Bregs) secreting TGF-ß1 to restrain pathogenic osteoclastogenesis. Neutrophils, the body's most prevalent leukocyte, also contribute to the proinflammatory environment that leads to osteoporotic bone remodeling. In aged individuals, neutrophils display reduced chemotaxis, phagocytosis, and apoptosis. Understanding the delicate interplay between B-lymphocytes and neutrophils in the context of impaired bone metabolism is crucial for targeted therapies for osteoporosis.

Adenosine deaminase augments SARS-CoV-2 specific cellular and humoral responses in aged mouse models of immunization and challenge.

Despite numerous clinically available vaccines and therapeutics, aged patients remain at increased risk for COVID-19 morbidity. Furthermore, various patient populations, including the aged can have suboptimal responses to SARS-CoV-2 vaccine antigens. Here, we characterized vaccine-induced responses to SARS-CoV-2 synthetic DNA vaccine antigens in aged mice. Aged mice exhibited altered cellular responses, including decreased IFNγ secretion and increased TNFα and IL-4 secretion suggestive of TH2-skewed responses. Aged mice exhibited decreased total binding and neutralizing antibodies in their serum but significantly increased TH2-type antigen-specific IgG1 antibody compared to their young counterparts. Strategies to enhance vaccine-induced immune responses are important, especially in aged patient populations. We observed that co-immunization with plasmid-encoded adenosine deaminase (pADA)enhanced immune responses in young animals. Ageing is associated with decreases in ADA function and expression. Here, we report that co-immunization with pADA enhanced IFNγ secretion while decreasing TNFα and IL-4 secretion. pADA expanded the breadth and affinity SARS-CoV-2 spike-specific antibodies while supporting TH1-type humoral responses in aged mice. scRNAseq analysis of aged lymph nodes revealed that pADA co-immunization supported a TH1 gene profile and decreased FoxP3 gene expression. Upon challenge, pADA co-immunization decreased viral loads in aged mice. These data support the use of mice as a model for age-associated decreased vaccine immunogenicity and infection-mediated morbidity and mortality in the context of SARS-CoV-2 vaccines and provide support for the use of adenosine deaminase as a molecular adjuvant in immune-challenged populations.

DNA-delivered antibody cocktail exhibits improved pharmacokinetics and confers prophylactic protection against SARS-CoV-2.

Monoclonal antibody therapy has played an important role against SARS-CoV-2. Strategies to deliver functional, antibody-based therapeutics with improved in vivo durability are needed to supplement current efforts and reach underserved populations. Here, we compare recombinant mAbs COV2-2196 and COV2-2130, which compromise clinical cocktail Tixagevimab/Cilgavimab, with optimized nucleic acid-launched forms. Functional profiling of in vivo-expressed, DNA-encoded monoclonal antibodies (DMAbs) demonstrated similar specificity, broad antiviral potency and equivalent protective efficacy in multiple animal challenge models of SARS-CoV-2 prophylaxis compared to protein delivery. In PK studies, DNA-delivery drove significant serum antibody titers that were better maintained compared to protein administration. Furthermore, cryo-EM studies performed on serum-derived DMAbs provide the first high-resolution visualization of in vivo-launched antibodies, revealing new interactions that may promote cooperative binding to trimeric antigen and broad activity against VoC including Omicron lineages. These data support the further study of DMAb technology in the development and delivery of valuable biologics.

Mucosal chemokine adjuvant enhances synDNA vaccine-mediated responses to SARS-CoV-2 and provides heterologous protection in vivo.

The global coronavirus disease 2019 (COVID-19) pandemic has claimed more than 5 million lives. Emerging variants of concern (VOCs) continually challenge viral control. Directing vaccine-induced humoral and cell-mediated responses to mucosal surfaces may enhance vaccine efficacy. Here we investigate the immunogenicity and protective efficacy of optimized synthetic DNA plasmids encoding wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein (pS) co-formulated with the plasmid-encoded mucosal chemokine cutaneous T cell-attracting chemokine (pCTACK; CCL27). pCTACK-co-immunized animals exhibit increased spike-specific antibodies at the mucosal surface and increased frequencies of interferon gamma (IFNγ)+ CD8+ T cells in the respiratory mucosa. pCTACK co-immunization confers 100% protection from heterologous Delta VOC challenge. This study shows that mucosal chemokine adjuvants can direct vaccine-induced responses to specific immunological sites and have significant effects on heterologous challenge. Further study of this unique chemokine-adjuvanted vaccine approach in the context of SARS-CoV-2 vaccines is likely important.

Prime-boost vaccination regimens with INO-4800 and INO-4802 augment and broaden immune responses against SARS-CoV-2 in nonhuman primates.

The enhanced transmissibility and immune evasion associated with emerging SARS-CoV-2 variants demands the development of next-generation vaccines capable of inducing superior protection amid a shifting pandemic landscape. Since a portion of the global population harbors some level of immunity from vaccines based on the original Wuhan-Hu-1 SARS-CoV-2 sequence or natural infection, an important question going forward is whether this immunity can be boosted by next-generation vaccines that target emerging variants while simultaneously maintaining long-term protection against existing strains. Here, we evaluated the immunogenicity of INO-4800, our synthetic DNA vaccine candidate for COVID-19 currently in clinical evaluation, and INO-4802, a next-generation DNA vaccine designed to broadly target emerging SARS-CoV-2 variants, as booster vaccines in nonhuman primates. Rhesus macaques primed over one year prior with the first-generation INO-4800 vaccine were boosted with either INO-4800 or INO-4802 in homologous or heterologous prime-boost regimens. Both boosting schedules led to an expansion of T cells and antibody responses which were characterized by improved neutralizing and ACE2 blocking activity across wild-type SARS-CoV-2 as well as multiple variants of concern. These data illustrate the durability of immunity following vaccination with INO-4800 and additionally support the use of either INO-4800 or INO-4802 in prime-boost regimens.

SARS-CoV-2 DNA Vaccine INO-4800 Induces Durable Immune Responses Capable of Being Boosted in a Phase 1 Open-Label Trial.

BACKGROUND: Additional severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines that are safe and effective as primary vaccines and boosters remain urgently needed to combat the coronavirus disease 2019 (COVID-19) pandemic. We describe safety and durability of immune responses following 2 primary doses and a homologous booster dose of an investigational DNA vaccine (INO-4800) targeting full-length spike antigen. METHODS: Three dosage strengths of INO-4800 (0.5 mg, 1.0 mg, and 2.0 mg) were evaluated in 120 age-stratified healthy adults. Intradermal injection of INO-4800 followed by electroporation at 0 and 4 weeks preceded an optional booster 6-10.5 months after the second dose. RESULTS: INO-4800 appeared well tolerated with no treatment-related serious adverse events. Most adverse events were mild and did not increase in frequency with age and subsequent dosing. A durable antibody response was observed 6 months following the second dose; a homologous booster dose significantly increased immune responses. Cytokine-producing T cells and activated CD8+ T cells with lytic potential were significantly increased in the 2.0-mg dose group. CONCLUSIONS: INO-4800 was well tolerated in a 2-dose primary series and homologous booster in all adults, including elderly participants. These results support further development of INO-4800 for use as primary vaccine and booster. CLINICAL TRIALS REGISTRATION: NCT04336410.

Nucleic acid delivery of immune-focused SARS-CoV-2 nanoparticles drives rapid and potent immunogenicity capable of single-dose protection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may target epitopes that reduce durability or increase the potential for escape from vaccine-induced immunity. Using synthetic vaccinology, we have developed rationally immune-focused SARS-CoV-2 Spike-based vaccines. Glycans can be employed to alter antibody responses to infection and vaccines. Utilizing computational modeling and in vitro screening, we have incorporated glycans into the receptor-binding domain (RBD) and assessed antigenic profiles. We demonstrate that glycan-coated RBD immunogens elicit stronger neutralizing antibodies and have engineered seven multivalent configurations. Advanced DNA delivery of engineered nanoparticle vaccines rapidly elicits potent neutralizing antibodies in guinea pigs, hamsters, and multiple mouse models, including human ACE2 and human antibody repertoire transgenics. RBD nanoparticles induce high levels of cross-neutralizing antibodies against variants of concern with durable titers beyond 6 months. Single, low-dose immunization protects against a lethal SARS-CoV-2 challenge. Single-dose coronavirus vaccines via DNA-launched nanoparticles provide a platform for rapid clinical translation of potent and durable coronavirus vaccines.

Epigenetic Plasticity Enables CNS-Trafficking of EBV-infected B Lymphocytes.

Subpopulations of B-lymphocytes traffic to different sites and organs to provide diverse and tissue-specific functions. Here, we provide evidence that epigenetic differences confer a neuroinvasive phenotype. An EBV+ B cell lymphoma cell line (M14) with low frequency trafficking to the CNS was neuroadapted to generate a highly neuroinvasive B-cell population (MUN14). MUN14 B cells efficiently infiltrated the CNS within one week and produced neurological pathologies. We compared the gene expression profiles of viral and cellular genes using RNA-Seq and identified one viral (EBNA1) and several cellular gene candidates, including secreted phosphoprotein 1/osteopontin (SPP1/OPN), neuron navigator 3 (NAV3), CXCR4, and germinal center-associated signaling and motility protein (GCSAM) that were selectively upregulated in MUN14. ATAC-Seq and ChIP-qPCR revealed that these gene expression changes correlated with epigenetic changes at gene regulatory elements. The neuroinvasive phenotype could be attenuated with a neutralizing antibody to OPN, confirming the functional role of this protein in trafficking EBV+ B cells to the CNS. These studies indicate that B-cell trafficking to the CNS can be acquired by epigenetic adaptations and provide a new model to study B-cell neuroinvasion associated CNS lymphoma and autoimmune disease of the CNS, including multiple sclerosis (MS).

EBNA1 inhibitors have potent and selective antitumor activity in xenograft models of Epstein-Barr virus-associated gastric cancer.

BACKGROUND AND AIMS: Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is the most common EBV-associated cancer and accounts for ~ 10% of all gastric cancers (GC). Epstein-Barr virus nuclear antigen 1 (EBNA1), which is critical for the replication and maintenance of the EBV latent genome, is consistently expressed in all EBVaGC tumors. We previously developed small molecule inhibitors of EBNA1. In this study, we investigated the efficacy and selectivity of an EBNA1 inhibitor in cell-based and animal xenograft models of EBV-positive and EBV-negative gastric carcinoma. METHODS: We tested the potency of an EBNA1 inhibitor, VK-1727, in vitro and in xenograft studies, using EBV-positive (SNU719 and YCCEL1) and EBV-negative (AGS and MKN74) GC cell lines. After treatment, we analyzed cell viability, proliferation, and RNA expression of EBV genes by RT-qPCR. RESULTS: Treatment with VK-1727 selectively inhibits cell cycle progression and proliferation in vitro. In animal studies, treatment with an EBNA1 inhibitor resulted in a significant dose-dependent decrease in tumor growth in EBVaGC xenograft models, but not in EBV-negative GC xenograft studies. Gene expression analysis revealed that short term treatment in cell culture tended towards viral gene activation, while long-term treatment in animal xenografts showed a significant decrease in viral gene expression. CONCLUSIONS: EBNA1 inhibitors are potent and selective inhibitors of cell growth in tissue culture and animal models of EBV-positive GC. Long-term treatment with EBNA1 inhibitors may lead to loss of EBV in mouse xenografts. These results suggest that pharmacological targeting of EBNA1 may be an effective strategy to treat patients with EBVaGC.

Safety and immunogenicity of INO-4800 DNA vaccine against SARS-CoV-2: A preliminary report of an open-label, Phase 1 clinical trial.

BACKGROUND: A vaccine against SARS-CoV-2 is of high urgency. Here the safety and immunogenicity induced by a DNA vaccine (INO-4800) targeting the full length spike antigen of SARS-CoV-2 are described. METHODS: INO-4800 was evaluated in two groups of 20 participants, receiving either 1.0 mg or 2.0 mg of vaccine intradermally followed by CELLECTRA® EP at 0 and 4 weeks. Thirty-nine subjects completed both doses; one subject in the 2.0 mg group discontinued trial participation prior to receiving the second dose. ClinicalTrials.gov identifier: NCT04336410. FINDINGS: The median age was 34.5, 55% (22/40) were men and 82.5% (33/40) white. Through week 8, only 6 related Grade 1 adverse events in 5 subjects were observed. None of these increased in frequency with the second administration. No serious adverse events were reported. All 38 subjects evaluable for immunogenicity had cellular and/or humoral immune responses following the second dose of INO-4800. By week 6, 95% (36/38) of the participants seroconverted based on their responses by generating binding (ELISA) and/or neutralizing antibodies (PRNT IC50), with responder geometric mean binding antibody titers of 655.5 [95% CI (255.6, 1681.0)] and 994.2 [95% CI (395.3, 2500.3)] in the 1.0 mg and 2.0 mg groups, respectively. For neutralizing antibody, 78% (14/18) and 84% (16/19) generated a response with corresponding geometric mean titers of 102.3 [95% CI (37.4, 280.3)] and 63.5 [95% CI (39.6, 101.8)], in the respective groups. By week 8, 74% (14/19) and 100% (19/19) of subjects generated T cell responses by IFN-É£ ELISpot assay with the median SFU per 106 PBMC of 46 [95% CI (21.1, 142.2)] and 71 [95% CI (32.2, 194.4)] in the 1.0 mg and 2.0 mg groups, respectively. Flow cytometry demonstrated a T cell response, dominated by CD8+ T cells co-producing IFN-É£ and TNF-α, without increase in IL-4. INTERPRETATION: INO-4800 demonstrated excellent safety and tolerability and was immunogenic in 100% (38/38) of the vaccinated subjects by eliciting either or both humoral or cellular immune responses. FUNDING: Coalition for Epidemic Preparedness Innovations (CEPI).

Identification of Mubritinib (TAK 165) as an inhibitor of KSHV driven primary effusion lymphoma via disruption of mitochondrial OXPHOS metabolism.

KSHV-associated cancers have poor prognoses and lack therapeutics that selectively target viral gene functions. We developed a screening campaign to identify known drugs that could be repurposed for the treatment of KSHV-associated cancers. We focused on primary effusion lymphoma (PEL), which has particularly poor treatment outcomes. We developed a luciferase reporter assay to test the ability of drugs to inhibit DNA binding of the KSHV LANA DNA binding domain (DBD). In parallel, we screened drugs for selective inhibition of a KSHV+ PEL cells. While potent hits were identified in each assay, only one hit, Mubritinib, was found to score in both assays. Mubritinib caused PEL cells to undergo cell cycle arrest with accumulation of sub-G1 population and Annexin V. Mubritinib inhibited LANA binding to KSHV terminal repeat (TR) DNA in KSHV+ PEL cells, but did not lead to KSHV lytic cycle reactivation. Mubritinib was originally identified as a receptor tyrosine kinase (RTK) inhibitor selective for HER2/ErbB2. But recent studies have revealed that Mubritinib can also inhibit the electron transport chain (ETC) complex at nanomolar concentrations. We found that other related ETC complex inhibitors (Rotenone and Deguelin) exhibited PEL cell growth inhibition while RTK inhibitors failed. Seahorse analysis demonstrated that Mubritinib selectively inhibits the maximal oxygen consumption (OCR) in PEL cells and metabolomics revealed changes in ATP/ADP and ATP/AMP ratios. These findings indicate that PEL cells are selectively sensitive to ETC complex inhibitors and provide a rationale for repurposing Mubritinib for selective treatment of PEL.