The microenvironment of solid tumor is commonly low in key nutrients such as glucose providing metabolic challenges for tumor infiltrating T lymphocytes (TIL), which upon activation switch to glycolysis to meet their need for energy and effector molecule production. Consequently, TIL become functionally impaired and die unless they can switch their metabolism to alternative pathways such as oxidative phosphorylation catabolizing lipids that are in ample supply within solid tumors. Medicinal interventions that alter the nutrient supply within tumors or that facilitate the TIL’s metabolic switch away from glycolysis have been tested in experimental animals and clinical trials. Some of them were shown to increase TIL functions, prolong their survival and enable them to slow tumor progression.

BACKGROUND:Rabies kills approximately 59 000 people each year. ChAdOx2 RabG, a simian adenovirus-vectored rabies vaccine candidate, has the potential to provide low-cost, single-dose pre-exposure rabies prophylaxis. We aimed to assess the safety and immunogenicity of ChAdOx2 RabG, including in comparison to a currently licensed vaccine. METHODS:We performed a single-centre, age de-escalation, dose-escalation, partly randomised, open-label, phase 1b/2 trial. Healthy adults (18-45 years) and children (2-6 years) who were rabies vaccine-naive and from the semi-urban Bagamoyo area in Tanzania were recruited through a series of community meetings. Adults were first enrolled into a group receiving 2·5 × 1010 virus particles of ChAdOx2 RabG (middle dose); after safety review, adults were randomly assigned (3:1) to receive ChAdOx2 RabG (5 × 1010 virus particles; full dose) on day 0 or an inactivated rabies virus (IRV) vaccine on day 0 (single-visit IRV). Children were first enrolled into a group receiving 1 × 1010 virus particles of ChAdOx2 RabG (low dose), and then into a group receiving the middle dose. After safety review, children were randomly assigned (3:2:2) to receive a full dose of ChAdOx2 RabG on day 0, single-visit IRV, or IRV vaccine on day 0 and day 7 (two-visit IRV). ChAdOx2 RabG was administered intramuscularly at a single anatomical site and IRV intradermally at two anatomical sites. Randomisation was done in blocks by clinical staff using lists generated by an independent statistician. The primary outcome was safety, assessed in the intention-to-treat population. The secondary outcome was rabies virus neutralising antibody (VNA), assessed with a validated assay in participants in the single-visit, full-dose ChAdOx2 RabG groups and the single-visit IRV vaccine groups who attended the nominal 1-year visit. Follow-up is planned for up to 5·5 years after vaccination; here we present data up to 1 year. The trial is registered at ClinicalTrials.gov (NCT04270838). FINDINGS:Between March 3, 2022, and March 9, 2023, 63 adults (three in the middle-dose ChAdOx2 RabG group, 45 in the full-dose ChAdOx2 RabG group, and 15 in the single-visit IRV group) and 111 children (three each in the low-dose and middle-dose ChAdOx2 RabG groups, 45 in the full-dose ChAdOx2 RabG group, 30 in the single-visit IRV group, and 30 in the two-visit IRV group) were enrolled. Participants reported predominantly mild-to-moderate reactogenicity, most commonly injection-site pain or feverishness, and no serious adverse reactions. In adults, geometric mean VNA titres on day 365 were 2·0 (95% CI 1·4-2·9) after single-visit, full-dose ChAdOx2 RabG vaccination and 0·4 (0·2-0·7) after single-visit IRV vaccination (geometric mean ratio 5·1 [95% CI 2·5-10·4]; p<0·0001). In children, geometric mean VNA titres on day 365 were 6·1 (4·5-8·2) after single-visit, full-dose ChAdOx2 RabG vaccination and 0·7 (0·5-1·1) after single-visit IRV vaccination (geometric mean ratio 8·6 [5·4-13·9]; p<0·0001). In a post-hoc analysis, day-365 VNA titres in children who received ChAdOx2 RabG exceeded titres in those who received two-visit IRV (geometric mean 3·0 [95% CI 2·2-4·1]; geometric mean ratio 2·0 [1·3-3·1]; p=0·0028). INTERPRETATION:The ChAdOx2 RabG vaccine was safe and well tolerated in Tanzanian adults and children. It achieved robust attainment and maintenance of VNA responses, with titres at day 365 exceeding the correlate of protection (VNA ≥0·5 IU/mL) and titres in licensed vaccine comparator groups. ChAdOx2 RabG might be an option for lower-cost, easier-to-deliver pre-exposure prophylaxis for people in rabies-endemic areas, extending the range of contexts in which pre-exposure prophylaxis is considered a cost-effective option for rabies prevention. FUNDING:UK Medical Research Council. TRANSLATION:For the Swahili translation of the abstract see Supplementary Materials section.

Rabies claims the lives of over 55,000 humans each year. It is a disease that is mainly transmitted by dogs and, to a lesser extent, by other domestic and wildlife animals. Vaccines for immunization of humans given before or after exposure to rabies virus (RABV) and animals are available, but they remain underutilized. This chapter describes the different types of vaccines and methods for their production and quality control.

Self-replicating RNA (srRNA) technology, in comparison to mRNA vaccines, has shown dose-sparing by approximately 10-fold and more durable immune responses. However, no improvements are observed in the adverse events profile. Here, we develop an srRNA vaccine platform with optimized non-coding regions and demonstrate immunogenicity and safety in preclinical and clinical development. Optimized srRNA vaccines generate protective immunity (according to the WHO defined thresholds) at doses up to 1,000,000-fold lower than mRNA in female mouse models of influenza and rabies. Clinically, safety and immunogenicity of RBI-4000, an srRNA vector encoding the rabies glycoprotein, was evaluated in a Phase I study (NCT06048770). RBI-4000 was able to elicit de novo protective immunity in the majority of healthy participants when administered at a dose of 0.1, 1, or 10 microgram (71%, 94%, 100%, respectively) in a prime-boost schedule. Similarly, we observe immunity above the WHO benchmark of protection following a single administration in most participants at both 1 and 10 microgram doses. There are no serious adverse events reported across all cohorts. These data establish the high therapeutic index of optimized srRNA vectors, demonstrating feasibility of both low dose and single dose approaches for vaccine applications.

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.

Adeno-associated virus (AAV)-mediated gene therapy has made significant progress in the last few decades. Nevertheless, challenges imposed by the immune system remain. The very high doses of AAV vectors used for some disorders have resulted in serious adverse events (SAEs) or even deaths, demonstrating that AAV vector doses that can safely be injected into patients are limited and for some indications below the therapeutic dose. Currently used immunosuppressive drugs have not prevented the SAEs, indicating that it may be prudent to treat patients with repeated transfer of moderate doses rather than a single injection of high doses of AAV vectors. The former approach has been avoided as AAV vectors elicit neutralizing antibodies that prevent successful reapplication of serologically crossreactive vectors. Immunosuppressive regimens that block B cell responses to AAV vectors or treatments that remove AAV neutralizing antibodies thus need to be developed to allow for a shift from toxic single-dose injections of AAV vectors to repeated treatments with more moderate and safe doses. Preventing or blocking antibody responses would also allow for redosing of patients with declining transgene product expression, or for effective AAV-mediated gene transfer into patients with the pre-existing neutralizing antibodies.

The objective of this study was to conduct preclinical immunogenicity and efficacy studies with several therapeutic vaccines for human papillomavirus (HPV)-16-associated cancers expressing the early antigens E5, E6, and E7 with or without E2. The viral oncoproteins were either expressed by themselves as fusion proteins or the fusion proteins were inserted genetically into herpes simplex virus (HSV)-1 glycoprotein D (gD) which, upon binding to the herpes virus entry mediator (HVEM), inhibits an early T cell checkpoint mediated by the B and T cell mediator (BTLA). This, in turn, lowers the threshold for T cell activation and augments and broadens CD8+ T cell responses to the antigens. The fusion antigens were expressed by chimpanzee adenovirus (AdC) vectors. Expression of the HPV antigens within gD was essential for vaccine immunogenicity and efficacy against challenge with TC-1 cells, which express E7 and E6 of HPV-16 but neither E5 nor E2. Unexpectedly, inclusion of E2 increased both CD8+ T cell responses to the other oncoproteins of HPV-16 and the effectiveness of the vaccines to cause the regression of sizable TC-1 tumors.

Annually, vaccines against infectious agents prevent countless cases of human misery and death. One of the first vaccines that was developed and tested in humans was against rabies, an infectious disease which causes a fatal encephalitis in unvaccinated, exposed humans. The initial vaccine, first used successfully during 1885 in a child by Pasteur and colleagues in France, was derived from nerve tissue of experimentally infected rabbits. Shortly afterwards, such products were produced globally, including in the New World, throughout the early twentieth century. Although they protected humans who had been exposed to a rabid animal, most commonly a dog, these biologics were not only poorly immunogenic (requiring multiple, painful injections), but also caused serious neurological adverse events in a sizable fraction of recipients. Early attempts at improvement included the use of different animal species for viral propagation, and various physical and chemical alterations, to help inactivate rabies virus and lessen the risk of serious adverse events, including vaccine-associated rabies. Upon the development of techniques to maintain and expand embryonal cells in culture, modern methods for rabies vaccine propagation were developed. Cell culture-derived, inactivated rabies vaccines were more immunogenic and importantly, they were safe and replaced the need for nerve tissue-derived rabies vaccines. By the mid-twentieth century, rabies immune globulin (RIG) was added to the postexposure prophylaxis (PEP) protocol for humans after severe exposure to rabies virus, as a means of providing passive immunity, in the period before the active induction of virus neutralizing antibodies. Concomitant with the development of human cell culture-derived rabies vaccines, preexposure (PrEP) vaccination programs expanded for companion animals, most notably dogs. These biologics reduced or even eliminated canine rabies. Nevertheless, human rabies vaccines and RIG are costly and continue to be underutilized. Furthermore, rapid PEP is essential to prevent disease, which is often not possible in remote areas with limited access to health care. The use of currently available vaccines for more wide-spread PrEP rabies vaccination, which would reduce the human death toll due to rabies, is not considered cost-effective, necessitating the development of less expensive vaccines that induce protective immune responses after a single dose. Several next generation vaccines that may allow for greater dose-sparing and less costly vaccine regimens are in development.

Background Checkpoint inhibitors (CPI) that target activated, impaired T cells, have revolutionized cancer treatments. However, there are limited data on CPIs that affect T cell activation. HSV-1 glycoprotein D (gD) binds to the herpes virus entry mediator (HVEM) on dendritic cells and blocks BTLA-HVEM inhibitory signaling during early CD8+ T cell activation. Inhibition of BTLA signaling allows for co-stimulation through LIGHT, which binds to a different domain on HVEM, and enhances and broadens CD8+ T cell responses to the target antigen(s). Here, we report the immunogenicity and efficacy of a chimpanzee adenoviral (AdC) vector expressing sequences of early (E) antigens 2, 5, 6, and 7 of HPV-16, fused into gD (AdC-gDE7652). Methods Studies were performed in C57/Bl6 mice (n=5–10/group). Frequencies of HPV-16 specific CD8+ T-cells was assessed by intracellular cytokine staining 14 days after a single intramuscular (i.m.) vaccination with AdC vectors encoding HPV-16 E7652 oncoproteins expressed with or without gD. Efficacy was tested in TC-1 challenge studies (5x10^4 to 1x10^6 cells) in mice injected with a single i.m. dose of 1x10^10 vp of AdC-gDE7652, AdC-E7652, or control antigens fused with gD 3 or 9 days after tumor cell transplantation. In some studies, mice were followed for up to 176 days. In mice with growing tumors, T cell functions (granzyme B, perforin, IFN-gamma) and exhaustion markers (PD1, TIM3, LAG3, CTLA4), in spleens and tumors were assessed. Results The addition of gD increased HPV-16-specific CD8+ T-cell frequencies approximately 10- to 15-fold. In mice vaccinated with AdC-gDE7652, 3 days post TC-1 transplantation, 25/25 (100%) cleared their tumors and remained tumor free, while all (20/20; 100%) of the control-vaccinated mice showed rapid tumor progression. When mice were vaccinated 9 days after TC-1 challenge, the addition of gD doubled the survival time over controls or AdC-E7652-vaccinated animals (60 vs 30 days); T cells within spleens and tumors of AdC-gDE7652 vaccinated animals were polyfunctional and expressed lower levels of exhaustion markers than those of AdC-E7652 or control-vaccinated mice. In 8 mice that previously cleared their tumors, all remained tumor free, upon rechallenge. Conclusions The addition of gD, an early checkpoint modifier, that provides both checkpoint inhibition and co-stimulation of T cell activation, to an oncogenic target within a vaccine, markedly improves immunogenicity, promotes activation of polyfunctional T cells and enhances tumor clearance and survival with continued protection against rechallenge. A clinical trial evaluating a gD-based vaccine for advanced solid tumors is in development.

Supplementary Tables 1-5 from Considerations for the Clinical Application of Chimeric Antigen Receptor T Cells: Observations from a Recombinant DNA Advisory Committee Symposium Held June 15, 2010

Viral-vectored vaccines are highly amenable for respiratory mucosal delivery as a means of inducing much-needed mucosal immunity at the point of pathogen entry. Unfortunately, current monovalent viral-vectored tuberculosis (TB) vaccine candidates have failed to demonstrate satisfactory clinical protective efficacy. As such, there is a need to develop next-generation viral-vectored TB vaccine strategies which incorporate both vaccine antigen design and delivery route. In this study, we have developed a trivalent chimpanzee adenoviral-vectored vaccine to provide protective immunity against pulmonary TB through targeting antigens linked to the three different growth phases (acute/chronic/dormancy) of Mycobacterium tuberculosis (M.tb) by expressing an acute replication-associated antigen, Ag85A, a chronically expressed virulence-associated antigen, TB10.4, and a dormancy/resuscitation-associated antigen, RpfB. Single-dose respiratory mucosal immunization with our trivalent vaccine induced robust, sustained tissue-resident multifunctional CD4+ and CD8+ T-cell responses within the lung tissues and airways, which were further quantitatively and qualitatively improved following boosting of subcutaneously BCG-primed hosts. Prophylactic and therapeutic immunization with this multivalent trivalent vaccine in conventional BALB/c mice provided significant protection against not only actively replicating M.tb bacilli but also dormant, non-replicating persisters. Importantly, when used as a booster, it also provided marked protection in the highly susceptible C3HeB/FeJ mice, and a single respiratory mucosal inoculation was capable of significant protection in a humanized mouse model. Our findings indicate the great potential of this next-generation TB vaccine strategy and support its further clinical development for both prophylactic and therapeutic applications.

The cartoon describes the experimental set-up used to generate the results shown in Figure 1. Groups of mice were injected with B16BrafV600E cells. Starting 6 or 8 days later mice were treated daily for 3 weeks with fenofibrate (FF) or diluent. Tumor sizes were recorded over time.

Human Gene TherapyVol. 34, No. 13-14 AnnouncementFree AccessRosalind Franklin Society Proudly Announces the 2022 Award Recipient for Human Gene TherapyHildegund ErtlHildegund ErtlThe Wistar Institute, Philadelphia, PA, USASearch for more papers by this authorPublished Online:17 Jul 2023https://doi.org/10.1089/hum.2023.29249.rfs2022AboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail The Rosalind Franklin Society (RFS), in partnership with Mary Ann Liebert, Inc., publishers, enthusiastically congratulate our distinguished recipient of the 2022 annualRFS Award in Sciencefor this journal, which recognizes the outstanding research and published work of women and underrepresented minority scientists, physicians, and engineers.Zhiquan Xiang, Klaudia Kuranda, William Quinn, Areski Chekaoui, Robert Ambrose, Mohadeseh Hasanpourghai, Mikhail Novikov, Dakota Newman, Christina Cole, Xiangyang Zhou, Federico Mingozzi, and Hildegund C.J. Ertl, “The Effect of Rapamycin and Ibrutinib on Antibody Responses to Adeno-Associated Virus Vector-Mediated Gene Transfer,” Human Gene Therapy 33, no. 11–12 (June 2022): 614–624, http://doi.org/10.1089/hum.2021.258.AbstractAdeno-associated virus (AAV) vector-mediated gene transfer is lessening the impact of monogenetic disorders. Human AAV gene therapy recipients commonly mount immune responses to AAV or the encoded therapeutic protein, which requires transient immunosuppression. Most efforts to date have focused on blunting AAV capsid-specific T cell responses, which have been implicated in elimination of AAV-transduced cells. Here, we explore the use of immunosuppressants, rapamycin given alone or in combination with ibrutinib to inhibit AAV vector- or transgene product-specific antibody responses. Our results show that rapamycin or ibrutinib given alone reduces primary antibody responses against AAV capsid, but the combination of rapamycin and ibrutinib is more effective, blunts recall responses, and reduces numbers of circulating antibody-secreting plasma cells. The drugs fail to lower B cell memory formation or to reduce the inhibitory effects of pre-existing AAV capsid-specific antibodies on transduction efficiency.BiosketchHildegund Ertl came to The Wistar Institute as an associate professor in 1987. A native of Germany, she received her medical degree from the University of Göttingen. While in medical school, she began her scientific training as a student in the Max Planck Institute of Experimental Medicine. After research fellowships at the Australian National University and the University of Minnesota, Ertl joined the faculty of Harvard University before transitioning to Wistar. She became a full professor at Wistar in 1996 and holds professorships at the University of Pennsylvania School of Medicine and The Children's Hospital of Philadelphia.Dr. Ertl's research centers on two areas of investigation: immune responses to gene transfer vehicles that impede long-term successes of gene therapy, and developing vaccines for an array of diseases and conditions (including AIDS, chronic viral infections, COVID-19, and some forms of cancer) not typically considered to be treated using this approach. These vaccines aim to protect against future infections and look to create new therapies for diseases already affecting people.FiguresReferencesRelatedDetails Volume 34Issue 13-14Jul 2023 InformationCopyright 2023, Mary Ann Liebert, Inc., publishersTo cite this article:Hildegund Ertl.Rosalind Franklin Society Proudly Announces the 2022 Award Recipient for Human Gene Therapy.Human Gene Therapy.Jul 2023.587-587.http://doi.org/10.1089/hum.2023.29249.rfs2022Published in Volume: 34 Issue 13-14: July 17, 2023PDF download

Abstract Reducing metabolic stress within the tumor microenvironment (TME) could be essential for improving the efficacy of cancer immunotherapy. Using a mouse model of melanoma, we show here that appropriately timed treatment with the PPARα agonist fenofibrate improves the ability of a T cell–inducing cancer vaccine to delay tumor progression. Fenofibrate reduced the use of glucose by tumor and stromal cells in the TME and promoted the use of fatty acids for their metabolic needs. The glucose within the TME was in turn available for use by vaccine-induced tumor-infiltrating CD8+ T cells, which improved their ability to slow tumor progression. Early fenofibrate treatment 3 days after vaccination improved functions of circulating CD8+ T cells but failed to significantly affect tumor-infiltrating lymphocyte (TIL) metabolism or decrease tumor progression. In contrast, delaying treatment until day 5 after vaccination modified TIL metabolism and augmented the vaccine's ability to slow tumor progression. In summary, our findings reveal that a PPARα agonist can increase the efficacy of a cancer vaccine by reprogramming cells within tumors to increase fatty acid metabolism, providing T cells access to glucose in the TME. Significance: These findings suggest that metabolic manipulations using already approved drugs may offer an easy pathway to increase the efficacy of vaccines against solid tumors.

A The cartoon describes the experimental set-up. B shows frequencies of Trp-1-tet+ CD8+ in spleens and tumors. To better compare cells from naïve and vaccinated mice we gated on naïve cells (CD62Lhi), recently activated cells (PD1high,CD62Llow), tetramer+CD8+ T cells over all CD8 T cells or tetramer+ CD8+ T cells over all recently activated PD1high,CD62Llow CD8+ T cells. C shows phenotypes of percentages of marker positive cells.

The cartoon describes the experimental set-up used to generate the results shown in Figure 2. Groups of mice were vaccinated with AdC68-gDMelapoly. 3, 5 or 7 days later fenofibrate or diluent treatment was started and continued daily till day 17. One day after the last group finished treatment mice were euthanized and their splenic CD44+CD8+ cells were analyzed.