Herpes Simplex Virus Research Articles

Phase I Dose Volume Escalation of Rectally Administered PC-1005 to Assess Safety, Pharmacokinetics, and Antiviral Pharmacodynamics as a Multipurpose Prevention Technology (MTN-037)

Background: On demand, topical PrEP is desired by those preferring episodic, nonsystemic PrEP. PC-1005 gel (MIV-150, zinc, and carrageenan) exhibits in vitro antiviral HIV-1, human papillomavirus (HPV), and herpes simplex virus type 2 (HSV-2) activity, attractive for a multipurpose prevention technology candidate. We evaluated the safety, pharmacokinetics, and antiviral effect of rectally applied PC-1005. Methods: HIV-uninfected adults received a series of 3 rectal PC-1005 doses—4, 16, and 32 mL separated by 2-week washout periods. Following each dose, plasma, rectal fluid and tissue, and vaginal fluid were collected over 48 hours. Results: Thirteen adults enrolled; 12 completed all 3 doses. All 13 adverse events reported were grade 1 or 2; 5 were judged study drug related. Plasma MIV-150 peaked 1–2 h after dosing with a median peak concentrations range of 0.07–0.23 ng/mL and median half-life range of 4.9–7.4 hours across dose volumes; median concentrations were below assay quantitation limits (BLQ) 24 hours after dosing. Rectal tissue MIV-150 peaked 0.5–1 hours after dosing at 1.4 ng/g (ng/mL) (0.8, 1.9), 46.0 (30.7, 831.0), and 79.7 (11.9, 116.0), respectively, after each dose volume; median tissue concentrations were BLQ beyond 5 hours for all doses. All vaginal fluid samples were BLQ. Ex vivo antiviral assays showed 5 hours of antiviral HPV and HSV effects but no anti-HIV activity. Conclusions: MIV-150 rectal tissue concentrations were below the 100 ng/g target concentration and transient. Ex vivo assays demonstrated antiviral HSV and HPV effects but not against HIV. PC-1005 requires a more potent antiviral and longer-lasting formulation for further consideration as a multipurpose prevention technology candidate. Clinical Trials: NCT03408899.

Pediatric MOG-Ab-Associated Encephalitis: Supporting Early Recognition and Treatment.

Antibodies to myelin oligodendrocyte glycoprotein (MOG-Ab) have recently been reported in patients with encephalitis who do not fulfill criteria for acute disseminated encephalomyelitis (ADEM). We evaluated a cohort of these children and compared them with children with ADEM. This retrospective, multicenter cohort study comprised consecutive patients <18 years of age with MOG-Ab who fulfilled criteria for autoimmune encephalitis. These patients were stratified into (1) children not fulfilling criteria for ADEM (encephalitis phenotype) and (2) children with ADEM. Clinical/paraclinical data were extracted from the electronic records. Comparisons were made using the Mann-Whitney U test and χ2 Fisher exact test for statistical analysis. From 235 patients with positive MOG-Ab, we identified 33 (14%) with encephalitis and 74 (31%) with ADEM. The most common presenting symptoms in children with encephalitis were headache (88%), seizures (73%), and fever (67%). Infective meningoencephalitis was the initial diagnosis in 67%. CSF pleocytosis was seen in 79%. Initial MRI brain was normal in 8/33 (24%) patients. When abnormal, multifocal cortical changes were seen in 66% and unilateral cortical changes in 18%. Restricted diffusion was demonstrated in 43%. Intra-attack new lesions were seen in 7/13 (54%). When comparing with children with ADEM, children with encephalitis were older (median 8.9 vs 5.7 years, p = 0.005), were more likely to be admitted to intensive care (14/34 vs 4/74, p < 0.0001), were given steroid later (median 16.6 vs 9.6 days, p = 0.04), and were more likely to be diagnosed with epilepsy at last follow-up (6/33 vs 1/74, p = 0.003). MOG-Ab should be tested in all patients with suspected encephalitis even in the context of initially normal brain MRI. Although exclusion of infections should be part of the diagnostic process of any child with encephalitis, in immunocompetent children, when herpes simplex virus CSF PCR and gram stains are negative, these features do not preclude the diagnosis of immune mediated disease and should not delay initiation of first-line immunosuppression (steroids, IVIG, plasma exchange), even while awaiting the antibody results.

Next-generation 3D printed multipurpose prevention intravaginal ring for prevention of HIV, HSV-2, and unintended pregnancy

Globally, nearly half of all pregnancies are unintended, ∼1.3 million new human immunodeficiency virus (HIV) infections are reported every year, and more than 500 million people are estimated to have a genital herpes simplex virus (HSV-2) infection. Here we report the first 3D printed multipurpose prevention technology (MPT) intravaginal ring (IVR) for prevention of HIV, HSV-2, and unintended pregnancy. The IVRs were fabricated using state-of-the-art Continuous Liquid Interface Production (CLIP™) 3D printing technology using a biocompatible silicone-urethane based resin. Anti-HIV drug (Dapivirine, DPV), anti-herpes drug (Pritelivir, PTV) and a contraceptive drug (Levonorgestrel, LNG) were loaded in a macaque size IVR (25 mm outer diameter, OD; 6.0 mm cross-section, CS) allometrically scaled from the human size (54 mm OD; 7.6 mm CS) IVR analogue. All three active pharmaceutical ingredients (APIs) were loaded in the IVR using a single-step drug loading process driven by absorption. DPV, PTV, and LNG elicited zero-order release kinetics in vitro in simulated vaginal fluid (SVF) at pH 4 and pH 8 relevant to human and macaque vaginal pH respectively. CLIP 3D printed MPT IVRs remained stable after 6 months of storage at 4 °C with no change in physical, dimensional, or mechanical properties and no change in drug concentration and absence of drug degradation byproducts. The MPT IVRs elicited sustained release of all three APIs in macaques for 28 days with median plasma concentrations of 138 pg/mL (DPV), 18,700 pg/mL (PTV), and 335 pg/mL (LNG). Safety studies demonstrated that the MPT IVRs were safe and well tolerated in the macaques with no observed change or abnormalities in vaginal pH and no significant changes in any of the 22 mucosal cytokines and chemokines tested including pro-inflammatory (IL-1β, IL-6, IL-8, IFN-γ, TNF-α, IL-17, IL-18) and anti-inflammatory (IL-10, IL-12) cytokines while the MPT IVR was in place or after its removal. Additionally, MPT IVRs elicited no observed alterations in systemic CD4+ and CD8+ T cells during the entire study. Collectively, the proposed MPT IVR has potential to expand preventative choices for young women and girls against unintended pregnancy and two highly prevalent sexually transmitted infections (STIs).

Parenteral aciclovir for suspected herpes simplex virus infection in children: 0–18 years

Abstract Background Variations in neonatal aciclovir prescribing for suspected herpes simplex virus (HSV) disease are well-known, but there are limited data describing aciclovir prescribing in older children. Methods Medical records of neonates (≤28 days) and children (29 days to 18 years) prescribed intravenous aciclovir for suspected HSV disease (1 January 2019–12 December 2019) in eight Australian and New Zealand hospitals were reviewed. Prescribing indication, HSV testing, aciclovir prescription details, adverse events and discharge diagnosis were recorded. Results 1426 received empirical aciclovir. For neonates (n = 425), the median duration was 1 day (IQR 1–3), 411/425 underwent HSV investigations and 13/425 had HSV disease (two with disseminated encephalitis, four with encephalitis and seven with skin, eye, mouth disease). Of the 1001 children, 906 were immunocompetent. 136/906 suspected of mucocutaneous disease received aciclovir for a median of 2 days (1–2), 121/136 underwent HSV testing, and 69/136 had proven disease. 770/906 received aciclovir for suspected disseminated disease or encephalitis for a median of 1 day (1–2), 556/770 underwent HSV testing, and 5/770 had disseminated disease or encephalitis. Among 95 immunocompromised children, 53/58 with suspected mucocutaneous disease had HSV testing and this was confirmed in 22. Disseminated disease or encephalitis was suspected in 37/95, HSV testing conducted in 23/37 and detected in one. The median aciclovir duration was 3 (2–7) days for immunocompromised children. Nephrotoxicity occurred in 7/1426 and 24/1426 had an extravasation injury. Conclusion Frequent and often unnecessary intravenous aciclovir prescribing for suspected HSV encephalitis or disseminated disease occurred in children, as evidenced by incomplete HSV investigations and only 5/770 older children having the diagnosis confirmed.

Breaching the Barrier: Investigating Initial Herpes Simplex Viral Infection and Spread in Human Skin and Mucosa

Herpes simplex virus (HSV) is sexually transmitted via the anogenital mucosa where it initially infects epidermal keratinocytes and mononuclear phagocytes (MNPs). It then spreads to the dorsal root ganglion via sensory nerve endings, to remain latent for life with periodic reactivation. Currently, there is no cure or vaccine. Initial or recurrent HSV infection can produce serious complications and mediate acquisition of HIV. This review outlines the initial events after the HSV infection of human anogenital mucosa to determine the optimal window to target the virus before it becomes latent. After infection, HSV spreads rapidly within the mid-layers of epidermal keratinocytes in the explanted human inner foreskin. Infected cells produce chemokines, which modulate nectin-1 distribution on the surface of adjacent keratinocytes, facilitating viral spread. Epidermal Langerhans cells and dendritic cells become infected with HSV followed by a “viral relay” to dermal MNPs, which then present viral antigen to T cells in the dermis or lymph nodes. These data indicate the need for interruption of spread within 24 h by diffusible vaccine-induced mediators such as antiviral cytokines from resident immune cells or antibodies. Intradermal/mucosal vaccines would need to target the relevant dermal MNPs to induce HSV-specific CD4+ and CD8+ T cells.

Interest and Expectations for a Herpes Vaccine Among People Diagnosed with Genital HSV 1-2 Infection: Results from an Italian Survey

Genital herpes simplex virus (HSV) is associated with a reduction in quality of life and adverse outcomes. The aim of this study is to assess the interest and expectations for a therapeutic HSV vaccine among individuals diagnosed with genital herpes in Italy. A retrospective survey was conducted at the Infectious Diseases Unit of the IRCCS San Raffaele Scientific Institute, Milan, Italy. The study collected data on demographics, clinical history and interest in HSV vaccination. The results showed that 87.5% of participants were interested in a therapeutic vaccine, with interest higher among younger people and those with frequent genital herpes recurrences. Participants most expected the vaccine to reduce the pain associated with outbreaks, followed by a reduction in the frequency and duration of recurrences. These findings underscore the strong demand for a therapeutic HSV vaccine, especially among those who experience recurrent outbreaks, and highlight the importance of considering patient expectations when developing preventive and therapeutic strategies for genital herpes.

Control of HSV-1 Infection: Directions for the Development of CRISPR/Cas-Based Therapeutics and Diagnostics

It is estimated that nearly all individuals have been infected with herpesviruses, with herpes simplex virus type 1 (HSV-1) representing the most prevalent virus. In most cases, HSV-1 causes non-life-threatening skin damage in adults. However, in patients with compromised immune systems, it can cause serious diseases, including death. The situation is further complicated by the emergence of strains that are resistant to both traditional and novel antiviral drugs. It is, therefore, imperative that new methods of combating HSV-1 and other herpesviruses be developed without delay. CRISPR/Cas systems may prove an effective means of controlling herpesvirus infections. This review presents the current understanding of the underlying molecular mechanisms of HSV-1 infection and discusses four potential applications of CRISPR/Cas systems in the fight against HSV-1 infections. These include the search for viral and cellular genes that may serve as effective targets, the optimization of anti-HSV-1 activity of CRISPR/Cas systems in vivo, the development of CRISPR/Cas-based HSV-1 diagnostics, and the validation of HSV-1 drug resistance mutations.

Innate immunodeficiencies: a group of primary immunodeficiencies predisposing exclusively to common diseases

Abstract Background Innate immune deficiencies can impair both cellular and humoral immune responses. In contrast, other immune functions may appear normal, leading to increased susceptibility to specific pathogens, such as severe viral infections or Mendelian Susceptibility to Mycobacterial Disease (MSMD). Studying these deficiencies is essential for understanding the pathophysiology of these infectious diseases. Main body While primary immunodeficiencies (PIDs) generally cause vulnerability to multiple infections, innate immunodeficiencies increase susceptibility to specific pathogens, despite normal immune responses to others. Patients with these deficiencies show normal immunoglobulins and lymphocyte subpopulations, complicating diagnosis. This review highlights genetic susceptibility to mycobacteria, pneumococci, herpes simplex virus, and candidiasis, emphasizing recognizing this subset of PIDs. Conclusion This review highlights the diverse spectrum of genetic mutations contributing to defects in innate and intrinsic immunity, including Mendelian susceptibility to mycobacterial disease (MSMD), chronic mucocutaneous candidiasis, and predispositions to invasive bacterial and viral infections. Identifying key mutations in pathprovideh such as TLR3, IFN signaling, and IL-17A/F immunity provides valuable insights into the pathogenesis of these conditions. Our findings underscore the need for early genetic diagnosis and targeted interventions, particularly in regions with high undiagnosed cases, to reduce the morbidity and mortality associated with defects in innate and intrinsic immunity.

Minimally Invasive Transthoracic Intramyocardial Cellular Transplantation Under Echocardiographic Guidance for Myocardial Impairment

Abstract Objective: To explore the approach of minimally invasive transthoracic intramyocardial cellular transplantation under echocardiographic guidance to promote ischemic myocardial repair in a preclinical big-animal study. Methods: Female Guangxi Bama miniature pigs (weight: 25–30 kg) were randomly allocated into the sham group, untreated myocardial infarction (MI) group (MI group), the MI and surgical intramyocardial injection (SIM) group (MI-SIM group), and the MI and transthoracic echocardiography-guided percutaneous intramyocardial injection (TTEPIM) group (MI-TTEPIM group) (n = 4 each) using a lottery method. A swine MI model was established in the 3 groups excluding the sham group, and human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CM) labeled with the herpes simplex virus type-1 thymidine kinase reporter gene (hiPS-CMTK+) were transplanted by SIM in MI-SIM group and TTEPIM in MI-TTEPIM group. The operation time, postoperative recovery time of animals and volume of blood loss were collected for comparison between MI-SIM group and MI-TTEPIM group. 9-(4-[18F] fluoro-3-(hydroxymethyl) butyl) guanine positron emission tomography/computed tomography imaging was performed to track the hiPS-CMTK+ in vivo. Cardiac function and morphology were evaluated by echocardiography. Results: The operation time and postoperative recovery time of MI-TTEPIM group were significantly shorter than those of MI-SIM group ((28.3 ± 3.6) min vs. (97.0 ± 6.7) min, P &lt; 0.001; (1.3 ± 0.3) d vs. (7.5 ± 0.9) d, P &lt; 0.001). MI-TTEPIM also showed significantly lesser volume of blood loss during cell transplantation than MI-SIM group ((4.3 ± 0.8) mL vs. (47.0 ± 4.1) mL, P &lt; 0.001). The transplanted cells could be traced more accurately in vivo in MI-TTEPIM than in MI-SIM. The circumferential strain of intervention region in the MI-TTEPIM group (–25.07% ± 0.27%) was significantly higher than that of the MI-SIM (–20.39% ± 0.67%) and MI groups (–19.68% ± 0.67%), respectively (P &lt; 0.01). Conclusion: A minimally invasive TTEPIM protocol with stem cells for treating the ischemic myocardium was established in this study. Transplantation of hiPS-CMTK+ with this method could promote the recovery of the circumferential strain of the ischemic myocardium. The findings of this study lay a foundation for the clinical transformation of this auxiliary means of treatment in the future.

Non-replicative herpes simplex virus genomic and amplicon vectors for gene therapy - an update.

Two major types of defective vectors have been derived from herpes simplex virus type 1 (HSV-1), non-replicative genomic vectors (nrHSV-1), and amplicon vectors. This review recapitulates the main features of both vector types and summarizes recent improvements in our understanding of virus/vector biology, particularly with regard to the critical role played by the overpowering of antiviral cellular defenses and the epigenetic control of viral gene expression. Over the past years, significant breakthroughs in vector design, genetic engineering, and HSV-1 biology have accelerated the development of nrHSV-1 vectors. The low immunogenicity and enhanced safety profiles allowed the successful translation of these vectors into several clinical trials, with some being approved by the FDA. Regarding amplicons, despite their advantage in carrying very large or multiple transgenes, and their potential to avoid genome dilution in dividing cells, the absence of production procedures capable of generating large amounts of helper-free amplicons at reasonable cost with GMP compliance, still limits the translation of these outstanding vectors to clinical trials.

Abstract 4137845: A single-cell lung atlas of human pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a disaster disease characterized by obliterative vascular remodeling and persistent increase of vascular resistance, leading to right heart failure and premature death. Understanding the cellular and molecular mechanisms will help develop novel therapeutic approaches for PAH patients. Hypothesis: We hypothesis that single-cell RNA sequencing analysis can help understand the cellular and molecular mechanisms that drive the disease initiation and progression. Methods: 10 healthy donors, 10 idiopathic PAH, 10 drug and toxin induced PAH, 10 systemic and pulmonary shunting induced PAH patients from both male and female, and different ethical groups and races, and ages were obtained from PHBI. Lung tissue specimens were processed for fixed scRNA-seq. The cell proportion change, gene expression, and pathway analysis were evaluated between different disease subclasses, sex, age on different cell types. Results: Our analysis reveals 317,414 cells, 33 clusters and 9 major cell types, including endothelial cells (ECs), alveolar cells, fibroblast, smooth muscle cells (SMCs), pericytes, myeloid cells, lymphocytes, airway epithelial cells, platelet. Cell proportion analysis demonstrated an increase in the proportions of venous ECs, adventitial fibroblasts and myofibroblasts, alveolar macrophages, B cells, plasma cells and a reduction in capillary ECs 2 and pericytes in PAH lungs. KEGG Pathway analysis showed that upregulated pathways related Herpes simplex virus 1 infection, ECM-receptor interaction, Complement and coagulation cascades, Hedgehog signaling, TGF-beta signaling pathway, and downregulated pathways related to IL-17 signaling, TNF signaling, MAPK signaling pathway were enriched in the PAH patients. Female PAH patients exhibit an increase of myofibroblasts and platelets proportion compared to male PAH patients. MsigDB Hallmark Pathway analysis showed that p53 pathway was upregulated, whereas Inflammatory Response, Hypoxia, Epithelial Mesenchymal Transition were downregulated in female PAH patients. PAH patients older than 21 years exhibit an increase in the cell proportion of Platelet, SMCs, Arterial ECs and Venous ECs, and alveolar macrophages and a reduction of B cells and plasma cells. Conclusions: Our integrated analysis of human PAH lung atlas dataset provides a comprehensive understanding of lung cell populations and molecular signature in PAH patients with different sex, age and subclasses

Physiological oxygen concentration during sympathetic primary neuron culture improves neuronal health and reduces HSV-1 reactivation.

Herpes simplex virus-1 (HSV-1) establishes a latent infection in peripheral neurons and periodically reactivates in response to a stimulus to permit transmission. In vitro models using primary neurons are invaluable to studying latent infection because they use bona fide neurons that have undergone differentiation and maturation in vivo. However, culture conditions in vitro should remain as close to those in vivo as possible. This is especially important when considering minimizing cell stress, as it is a well-known trigger of HSV reactivation. We recently developed an HSV-1 model system that requires neurons to be cultured for extended lengths of time. Therefore, we sought to refine culture conditions to optimize neuronal health and minimize secondary effects on latency and reactivation. Here, we demonstrate that culturing primary neurons under conditions closer to physiological oxygen concentrations (5% oxygen) results in cultures with features consistent with reduced stress. Furthermore, culture in these lower oxygen conditions diminishes the progression to full HSV-1 reactivation despite minimal impacts on latency establishment and earlier stages of HSV-1 reactivation. We anticipate that our findings will be useful for the broader microbiology community as they highlight the importance of considering physiological oxygen concentration in studying host-pathogen interactions.IMPORTANCEEstablishing models to investigate host-pathogen interactions requires mimicking physiological conditions as closely as possible. One consideration is the oxygen concentration used for in vitro tissue culture experiments. Standard incubators do not regulate oxygen levels, exposing cells to oxygen concentrations of approximately 18%. However, cells within the body are exposed to much lower oxygen concentrations, with physiological oxygen concentrations in the brain being 0.55%-8% oxygen. Here, we describe a model for herpes simplex virus 1 (HSV-1) latent infection using neurons cultured in 5% oxygen. We show that culturing neurons in more physiological oxygen concentrations improves neuronal health to permit long-term studies of virus-cell interactions and the impact on reactivation.

CNSC-20. MONOSYNAPTIC TRACING DEFINES BRAIN-WIDE CIRCUIT CONNECTIVITY OF HUMAN GLIOBLASTOMA

Abstract Glioblastoma (GBM), a deadly brain cancer, infiltrates the brain and can be synaptically innervated by neurons. Synaptic inputs onto GBM cells identified so far are largely short-range and glutamatergic in nature. The extent of integration of GBM cells into the brain-wide neuronal circuitry is therefore not well understood. We report the application of transsynaptic viral tracing approaches to study the neuronal connectome of GBM. We applied rabies virus-mediated retrograde tracing and herpes simplex virus (HSV)-mediated anterograde tracing approaches to characterize presynaptic partners in vivo in the adult mouse brain and ex vivo with iPSC-derived neurons, cortical organoid-GBM assembloids, and human surgical specimens. After transplantation into adult mice, GBM cells derived from multiple patients rapidly integrated into brain-wide neuronal circuits. GBM exhibited increased connectivity rates compared to transplanted neural progenitor cells, highlighting functional connectivity as a hallmark of malignant cells. Beyond glutamatergic inputs, we identified neuromodulatory inputs across the brain, including cholinergic inputs from the basal forebrain. We validated these long-range cholinergic neuron-to-glioma synapses signaling through the metabotropic CHRM3 receptor by high-resolution microscopy, anterograde monosynaptic HSV tracing, calcium imaging, and patch-clamp electrophysiology. To interrogate the functional effects of acetylcholine (ACh) on GBM, we performed calcium imaging and RNA sequencing analyses, which showed that ACh stimulation induced sustained calcium oscillations and long-lasting transcriptional reprogramming of GBM cells into a more invasive state via CHRM3. Importantly, CHRM3 activation promoted GBM cell invasion, whereas CHRM3 downregulation suppressed GBM cell invasion in vitro and in vivo, suggesting CHRM3 as a potential therapeutic target for this disease. Together, these results reveal the capacity of human GBM cells to robustly integrate into anatomically and molecularly diverse neuronal circuitry in the adult brain. They also support a model wherein rapid synapse formation onto GBM cells may promote a long-lasting increase in tumor cell fitness.

DDDR-37. OHSV AND RADIATION THERAPIES SENSITIZE GLIOBLASTOMA TO IGF1R-TARGETED THERAPY AND SYNERGIZE IN TRIPLE COMBINATION THERAPY

Abstract Glioblastoma (GBM) continues to have a dismal prognosis despite remarkable advances in the field due to both tumor-intrinsic factors (i.e., IDH1 or EGFRvIII mutations) and extrinsic factors (i.e., relating to the tumor microenvironment (TME)), necessitating therapeutic innovation. Oncolytic herpes simplex virus-1 (oHSV) is an FDA-approved therapy that has shown promising results in clinical trials; however, therapeutic efficacy is limited to a small subset of patients. Thus, elucidating both the tumor-TME interplay and feedback/feedforward tumor-cell signaling in the context of viro-immunotherapy is essential in augmenting therapeutic outcomes. We recently discovered a novel mechanism of resistance to oHSVs, in which infection increases secretion of Insulin-like growth factor 2 (IGF2), activating the Insulin-like Growth Factor-1 Receptor (IGF1R). Upregulation of the IGF1R signaling pathway in GBM is correlated with poor prognosis and has been implicated in resistance to conventional therapies including radiotherapy (RTx). Herein, we further elucidate the impact of oHSVs on IGF1R activation, demonstrating a dose-dependent enhancement of downstream signaling. While IGF1R targeting therapies (e.g., OSI-966, Picropodophyllin (PPP)) have displayed limited efficacy in clinical trials, they significantly increased oHSV-induced cytotoxicity in all tested primary GBM cells compared to either agent alone in vitro and in vivo, resulting in a dose-dependent increase in PARP and caspase 3 activity by western blot and immunohistochemistry. We further found that RTx-induced IGF1 secretion and subsequent IGF1R activation were enhanced when combined with oHSV treatment. Triple combination therapy with oHSV, IGF1R inhibition, and RTx significantly increased tumor cell killing in vitro and improved survival of orthotopic GBM tumor-bearing mice. Collectively, our study provides preclinical evidence of enhanced therapeutic efficacy of oHSVs and RTx in combination with IGF1R blockade, supporting future use of IGF1R inhibitors in combination with the standard of care and FDA-approved oHSV therapies in patients with GBM.

TMIC-61. DEVELOPMENT OF A NOVEL NOTCH-TARGETING ONCOLYTIC HSV FOR GBM TUMORS

Abstract Glioblastoma (GBM) is the most aggressive brain malignancy, which despite continuing worldwide efforts to develop new therapies, remains a deadly disease with limited treatment options. The NOTCH signaling pathway is often hyperactive in GBM tumors, and its activity contributes to tumor progression and resistance to treatment. The role of NOTCH signaling in tumor growth and resistance is well studied, but the significance of this pathway for immunotherapy of GBM is not very well understood. We have recently shown that NOTCH activation following virotherapy contributes to tumor regrowth and induces recruitment of monocytic MDSC cells into the tumor, which limit optimal immune activation to kill tumor cells. For this study, we have discovered a NOTCH interfering intracellular ligand (NIIL) that blocks NOTCH activation from inside glioma cells. RNA sequencing shows the expression of NIIL downregulates NOTCH signaling in vitro. To evaluate the effect of NIIL on virotherapy, we generated an oncolytic herpes simplex virus (oHSV) that also encodes for NIIL. This virus showed a slower spread in vitro but improved therapeutic efficacy in vivo in multiple models of intracranial tumors. In immune competent mice there was a significant improvement in the survival of mice treated with the NIIL-encoding virus, with a fraction of mice showing a complete response after a single treatment. Single-cell RNA sequencing analysis of immune infiltrates is ongoing to understand how NIIL impacts tumor microenvironment and anti-tumor immune therapy.

EXTH-75. IMMUNOVIROTHERAPY WITH PP2A AND PD-1 INHIBITION IN PEDIATRIC HIGH-GRADE GLIOMA

Abstract Pediatric high-grade gliomas (HGGs) represent a significant clinical challenge with poor survival rates. Engineered oncolytic herpes simplex virus (oHSV) has shown potential in several clinical trials at targeting HGGs through their direct lytic effect and induction of an immune response. We have learned from our clinical trial experience (NCT02457845) that a critical barrier to more durable response is augmenting and sustaining the anti-tumor immune response generated by oHSV. LB-100, a protein phosphatase 2A (PP2A) inhibitor, is known to enhance T-cell activity. We hypothesized that LB-100 with anti-PD-1 therapy would overcome the immunosuppressive barriers, enhancing the immunotherapeutic effects of oHSV and improve survival in an immunocompetent murine model. We investigated the therapeutic impact of clinically available, next-generation oHSV, M002, which expresses murine interleukin-12, combined with LB-100 and PD-1 inhibition compared to M002 with LB-100 or anti-PD-1 antibody, each therapy alone, or control by measuring median survival and changes in the tumor immune microenvironment. The triple combination of M002, LB-100, and anti-PD-1 antibody significantly extended median survival compared to control (45 days vs 22.5 days, P=0.001) or each treatment alone, and compared to M002 and LB-100 (44 days vs 28 days, P=0.017) or M002 and anti-PD-1 (45.5 days vs 41 days, P=0.023). This increase in survival was correlated with a robust increase in CD45+ immune cell infiltration and a reduction in T-regulatory cells. We will further investigate the changes in the tumor microenvironment to better understand the specific contributions of different immune cell populations. These data support the hypothesis that LB-100 enhances the efficacy of oHSV by amplifying T-cell-mediated immune responses against tumor cells. This combination therapy demonstrates a promising strategy that warrants further exploration and potential clinical application, emphasizing the critical role of targeting multiple aspects of immune regulation to enhance the efficacy of oncolytic virotherapy in pediatric tumors.

TMIC-58. LEVERAGING VIRO-IMMUNOTHERAPY BY TARGETING IGF2-IGF1R SIGNALING

Abstract While an FDA-approved oncolytic herpes simplex-1 virus (oHSV) has shown therapeutic promise with superior safety, accumulating clinical data revealed that its therapeutic efficacy is observed in a small subset of patients. Here, we show that NFκB-mediated Insulin-like Growth Factor 2 (IGF2)/Insulin-like Growth Factor-1 Receptor (IGF1R) signaling pathway as a key modulator for oHSV therapy-mediated tumor resistance. RNA sequencing on the oHSV-infected primary glioblastoma (GBM) and breast cancer (BC) cells identified IGF2 as one of the top 10 upregulated secretomes. Transcriptomic analysis also revealed significant upregulation/enrichment of genes related to IGF2-IGF1R-MAPK pathway in oHSV-treated tumor cells. Infection with oHSV in GBM and BC cells up-regulated IGF2 transcription via direct binding of NFκB in the IGF2 promoter 3. Compromising the IGF2-IGF1R signaling pathway using IGF2 neutralizing antibody significantly increased oHSV-mediated tumor cell killing in vitro and mice survival in vivo. To circumvent this and promptly translate our findings in clinical settings, we have developed a novel oHSV, oHSV-D11mt, by incorporating modified IGF2R domain 11 into the parental oHSV genome to function as IGF2 decoy receptor as a single-agent modality. oHSV-D11mt specifically bind to IGF2 not IGF1, blocks oHSV-induced IGF2-IGF1R signaling, increases tumor cell killing, decreases oHSV-induced neutrophils/PMN-MDSCs infiltration, immune suppressive/proangiogenic cytokine secretion, and increases CD8+ cytotoxic T lymphocytes (CTLs) activation, resulting in increased virus propagation and mice survival. These findings suggest that IGF2-IGF1R signaling is a novel target to overcome oHSV therapy resistance and oHSV-D11mt could be used for improved viro-immunotherapy.

Combined effect of basic antiherpetic drugs with a new inhibitor of the terminase complex of herpes simplex virus type 1 in Vero cell culture

More than 90% of the world’s population are carriers of herpes simplex virus type 1 (HSV-1). The infection manifests itself in the formation of blisters and ulcers on the face or genitals, and can cause blindness, encephalitis, and generalized infection. All modern first- and second-line antiherpetic drugs selectively inhibit viral DNA-polymerase. The purine-benzoxazine conjugate LAS-131 [(S)-4-[6-(purin-6-yl)aminohexanoyl]-7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine], which we described earlier, uses the large subunit of the HSV-1 terminase complex as a biotarget and selectively inhibits its reproduction in vitro. For the first time, we have obtained fundamentally new results on the combined effect of LAS-131 on human herpesvirus infection with practically significant antiviral compounds – nucleoside analogues (acyclovir [ACV], penciclovir [PCV], ganciclovir [GCV], brivudine [BVDU], iododeoxyuridine [IDU], adenine arabinoside [Ara-A], as well as a nucleoside phosphonate analogue (cidofovir [CDV]) and a pirophosphate analogue (foscarnet [FOS]). Using a inhibition assay of cytopathic effect (CPE) induced by a virus, it was shown that when combined with LAS-131, the concentrations of the compounds in combinations providing inhibition of HSV-1-induced CPE by 50%, decreased by 2 times (additive effect, FOS) or more (synergistic effect, ACV, PCV, GCV, IDU, BVDU, Ara-A, CDV). Reducing the concentrations of agents creates non-permissive conditions for the reproduction of HSV-1 and opens up new real possibilities for controlling human herpesvirus infection.

Zebrafish (Danio rerio) as a Model System to Investigate the Role of the Innate Immune Response in Human Infectious Diseases

The zebrafish (Danio rerio) has emerged as a valuable model for studying host-pathogen interactions due to its unique combination of characteristics. These include extensive sequence and functional conservation with the human genome, optical transparency in larvae that allows for high-resolution visualization of host cell-microbe interactions, a fully sequenced and annotated genome, advanced forward and reverse genetic tools, and suitability for chemical screening studies. Despite anatomical differences with humans, the zebrafish model has proven instrumental in investigating immune responses and human infectious diseases. Notably, zebrafish larvae rely exclusively on innate immune responses during the early stages of development, as the adaptive immune system becomes fully functional only after 4–6 weeks post-fertilization. This window provides a unique opportunity to isolate and examine infection and inflammation mechanisms driven by the innate immune response without the confounding effects of adaptive immunity. In this review, we highlight the strengths and limitations of using zebrafish as a powerful vertebrate model to study innate immune responses in infectious diseases. We will particularly focus on host-pathogen interactions in human infections caused by various bacteria (Clostridioides difficile, Staphylococcus aureus, and Pseudomonas aeruginosa), viruses (herpes simplex virus 1, SARS-CoV-2), and fungi (Aspergillus fumigatus and Candida albicans).

A therapeutic HBV vaccine containing a checkpoint modifier enhances CD8+ T cell and antiviral responses.

In patients who progress from acute hepatitis B virus (HBV) infection to a chronic HBV (CHB) infection, CD8+ T cells fail to eliminate the virus and become impaired. A functional cure of CHB likely requires CD8+ T cell responses different from those induced by the infection. Here we report preclinical immunogenicity and efficacy of an HBV therapeutic vaccine that includes herpes simplex virus (HSV) glycoprotein D (gD), a checkpoint modifier of early T cell activation, that augments CD8+ T cell responses. The vaccine is based on a chimpanzee adenovirus serotype 6 (AdC6) vector, called AdC6-gDHBV2, which targets conserved and highly immunogenic regions of the viral polymerase and core antigens fused to HSV gD. The vaccine was tested with and without gD in mice for immunogenicity, and in an AAV8-1.3HBV vector model of antiviral efficacy. The vaccine encoding the HBV antigens within gD stimulates potent and broad CD8+ T cell responses. In a surrogate model of HBV infection, a single intramuscular injection achieved pronounced and sustained declines of circulating HBV DNA copies and HBV surface antigen; both inversely correlated with HBV-specific CD8+ T cell frequencies in spleen and liver.