Short-Chain Fatty Acids Alleviate Vancomycin-Caused Humoral Immunity Attenuation in Rabies-Vaccinated Mice by Promoting the Generation of Plasma Cells via Akt-mTOR Pathway.

Mounting evidence suggests that gut microbial composition and its metabolites, including short-chain fatty acids (SCFAs), have beneficial effects in regulating host immunogenicity to vaccines. However, it remains unknown whether and how SCFAs improve the immunogenicity of the rabies vaccine. In this study, we investigated the effect of SCFAs on the immune response to rabies vaccine in vancomycin (Vanco)-treated mice and found that oral gavage with butyrate-producing bacteria (C. butyricum) and butyrate supplementation elevated RABV-specific IgM, IgG, and virus-neutralizing antibodies (VNAs) in Vanco-treated mice. Supplementation with butyrate expanded antigen-specific CD4+ T cells and IFN-γ-secreting cells, augmented germinal center (GC) B cell recruitment, promoted plasma cells (PCs) and RABV-specific antibody-secreting cells (ASCs) generation in Vanco-treated mice. Mechanistically, butyrate enhanced mitochondrial function and activated the Akt-mTOR pathway in primary B cells isolated from Vanco-treated mice, ultimately promoting B lymphocyte-induced maturation protein-1 (Blimp-1) expression and CD138+ PCs generation. These results highlight the important role of butyrate in alleviating Vanco-caused humoral immunity attenuation in rabies-vaccinated mice and maintaining host immune homeostasis. IMPORTANCE The gut microbiome plays many crucial roles in the maintenance of immune homeostasis. Alteration of the gut microbiome and metabolites has been shown to impact vaccine efficacy. SCFAs can act as an energy source for B-cells, thereby promoting both mucosal and systemic immunity in the host by inhibiting HDACs and activation of GPR receptors. This study investigates the impact of orally administered butyrate, an SCFA, on the immunogenicity of rabies vaccines in Vanco-treated mice. The results showed that butyrate ameliorated humoral immunity by facilitating the generation of plasma cells via the Akt-mTOR in Vanco-treated mice. These findings unveil the impact of SCFAs on the immune response of the rabies vaccine and confirm the crucial role of butyrate in regulating immunogenicity to rabies vaccines in antibiotic-treated mice. This study provides a fresh insight into the relationship of microbial metabolites and rabies vaccination.

Rabies post-exposure prophylaxis in the emergency department.

STUDY OBJECTIVES: Rabies is a zoonotic single-stranded RNA lyssavirus that can cause acute infections of the central nervous system (CNS) including encephalomyelitis, encephalitis, and meningoencephalitis that is progressively fatal. Rabies is more common in developing countries, but approximately 23,000 people in the United States (US) are estimated to have been exposed or to have received post exposure prophylaxis (PEP) yearly. Nebraska Medicine follows the Advisory Committee on Immunization Practices (ACIP) guidelines for the vaccination series, as well as the 20 units/kg administration of immunoglobulin (RIG). Nebraska Medicine Medical Center (NMC) and Bellevue Medical Center (BMC) treat the scheduling of the complete rabies vaccine series differently. At both campuses, patients receive their immunoglobulin and first vaccine in the Emergency Department (ED). At NMC, patients are scheduled to receive the remainder of their vaccination series at the outpatient infusion center by the ED pharmacist. At BMC, the subsequent vaccinations are given as "Nurse Only" return visits to the ED. The objective of this study was to compare patient compliance of two different processes for follow-up rabies vaccine series completion. This project's primary aim was to determine the rate of patient compliance for follow up rabies vaccine doses. The secondary aims of this project were to determine if there was a difference in patient follow-up compliance between the two campuses, patient specific factors that impact compliance, and potential cost savings if a dose rounding protocol for RIG was utilized. METHODS: This retrospective chart review was completed as a quality improvement project. Data from patients who had received either rabies immunoglobulin and/or a rabies vaccine, were >18 years of age, and were not admitted were collected for a 3-year period from July 1, 2019, to June 30, 2022. Data were abstracted from the patient's EMR (electronic medical records) using a SQL (Structured query language) query of pre-identified data elements. When unable to abstract with SQL query, data elements were manually abstracted. All data abstracted was collated and descriptive analysis performed. RESULTS: A total of 723 individual encounters were identified during the study period. After combining rabies series for each individual patient, 173 unique patients remained. After exclusions were applied, 143 patients were included: 104 patients from NMC, and 39 from BMC. For the primary outcome, appropriate completion between the two campuses was 78.3%. When comparing the two campuses, completion rates were higher at NMC (82% vs. 69%), although not statistically significant (p = 0.12). Appropriate completion of vaccine series was statistically significant for both payor and exposure type. Application of a dose rounding policy with those >45 kg, rounding to the nearest vial, as well as rounding down if at the midpoint interval, 56 fewer vials would have been used between the two campuses. This would have resulted in a potential cost savings of $57,928.64 over the study period.

A novel mRNA rabies vaccine as a promising candidate for rabies post-exposure prophylaxis protects animals from different rabies viruses.

Rabies, caused by the rabies virus (RABV), is the most fatal zoonotic disease. It is a neglected tropical disease which remains a major public health problem, causing approximately 59,000 deaths worldwide annually. Despite the existence of effective vaccines, the high incidence of human rabies is mainly linked to tedious vaccine immunisation procedures and the overall high cost of post-exposure prophylaxis. Therefore, it is necessary to develop an effective vaccine that has a simple procedure and is affordable to prevent rabies infection in humans. RABV belongs to the genus Lyssavirus and family Rhabdoviridae. Previous phylogenetic analyses have identified seven major clades of RABV in China (China I-VII), confirmed by analysing nucleotide sequences from both the G and N proteins. This study evaluated the immunogenicity and protective capacity of SYS6008, an mRNA rabies vaccine expressing rabies virus glycoprotein, in mice and cynomolgus macaques. We demonstrated that SYS6008 induced sufficient levels of rabies neutralising antibody (RVNA) in mice. In addition, SYS6008 elicited strong and durable RVNA responses in vaccinated cynomolgus macaques. In the pre-exposure prophylaxis murine model, one or two injections of SYS6008 at 1/10 or 1/30 of dosage provided protection against a challenge with a 30-fold LD50 of rabies virus (China I and II clades). We also demonstrated that in the post-exposure prophylaxis murine model, which was exposed to lethal rabies virus (China I-VII clades) before vaccination, one or two injections of SYS6008 at both 1/10 and 1/30 dosages provided better protection against rabies virus challenge than the immunization by five injections of commercial vaccines at the same dosage. In addition, we proved that SYS6008-induced RVNAs could neutralise RABV from the China I-VII clades. Finally, 1/10 of the dosage of SYS6008 was able to stimulate significant RABV-G specificity in the T cell response. Furthermore, we found that SYS6008 induced high cellular immunity, including RABV-G-specific T cell responses and memory B cells. Our results imply that the SYS6008 rabies vaccine, with a much simpler vaccination procedure, better immunogenicity, and enhanced protective capacity, could be a candidate vaccine for post-exposure prophylaxis of rabies infections.

Improved Transdermal Delivery of Rabies Vaccine using Iontophoresis Coupled Microneedle Approach.

AIM: This study was aimed to develop rabies vaccine incorporated microneedle (MN) patches and evaluate the immunogenicity of prepared formulations in combination with iontophoresis. METHODS: Patches comprising of polyvinyl pyrrolidone, hyaluronic acid and polyethylene glycol 400 were engineered by vacuum micromolding technique. Physical evaluation of patches included determination of folding endurance, % swelling and morphological features. In vitro release study was performed in skin simulant agarose gel using model drug (methylene blue) loaded patches. In vitro insertion ability was assessed using stratum corneum simulant parafilm. In vivo insertion study was performed in rats. Immunogenicity was evaluated in dogs by determining immunoglobulin G (IgG) and rabies virus neutralizing antibodies (RVNA) titer. RESULTS: Patches displayed uniformly distributed microprojections with pointed tips and smooth surface, ~ 70% swelling, remained intact for ~ 200 foldings and successfully penetrated the parafilm. The area covered by model drug across agarose gel was almost double following treatment with MN-iontophoresis combination (MNdi) compared to MN alone (MNdo). Histological examination of rat skin treated with vaccine laden MN (MNvo) and MN-iontophoresis combination (MNvi) confirmed the formation of grooves in epidermis without any damage to the deep vasculature. A ~ 73% and ~ 206% increase (compared to untreated counterpart) was observed in the IgG titer of MNvo and MNvi treated dogs, respectively. The RVNA titer was increased by ~ 1.2 and ~ 2.2 times (compared to threshold value) after MNvo and MNvi treatment, respectively. CONCLUSION: MN-iontophoresis combination provided relatively potent immunogenic response over the conventional intramuscular injection, hence, can be used for administering vaccines transcutaneously.

Inventory management practices: implications on the pharmaceuticals expenditure of rabies vaccine in public health facilities, Namibia.

BACKGROUND: To achieve well-regulated distribution, storage, and utilization of the rabies vaccine, health facilities should adhere to standard operating procedures. In Namibia, information on inventory management, utilization, monitoring, and reporting of rabies vaccine adherence to standard operating procedures in public healthcare facilities is insufficient. The aim of this study was to assess adherence to rabies vaccine standard operating procedures and inventory management and to compare rabies vaccine expenditure to the number of patients who received rabies vaccination at the Ministry of Health and Social Services' public healthcare facilities from 2018 to 2020. METHODS: A cross-sectional, web-based questionnaire consisting of closed-ended questions was sent to 147 pharmacy staff and warehouse managers working in the 14 regions of Namibia during the period of May 1, 2021, to June 2, 2021. The overall expenditure and the total number of patients vaccinated from 2018 to 2020 were obtained from national-level logistic and vaccination program coordinators. Data were coded and transcribed into Microsoft® Excel® 2013 and analyzed using SPSS® version 27. RESULTS: One hundred and thirty-three completed questionnaires were received from sixty-nine public health centers and hospitals. The group of respondents consisted of pharmacist assistants (50%), pharmacy technicians (12%), pharmacists (36.8%), senior pharmacists (0.8%), and chief pharmacists (1.5%). Overall, adherence to standard operating procedures was poor (27.1%). Rabies vaccine distributed to public health facilities from 2018 to 2020 was worth N$75,381,419.91 (~ US$4,074,671.46) and was expected to vaccinate 87,269 patients; however, only 95 cases of both rabies and rabid dog-bite patients were reported. The major inventory management challenges for public healthcare facilities include an inadequate number of pharmacy staff, poor adherence to standardized pharmaceutical warehousing, lack of regular supervision, and inadequate staff training. CONCLUSION: Inventory management practices in public healthcare facilities were not in compliance with standard operating procedures. There is a significant discrepancy between rabies vaccine expenditure and the number of patients that were vaccinated. Therefore, there is a need for adequate staff training on inventory management and regular facility supervision to enforce optimal rabies vaccine inventory management practices.

Immune Response of Inactivated Rabies Vaccine Inoculated via Intraperitoneal, Intramuscular, Subcutaneous and Needle-Free Injection Technology-Based Intradermal Routes in Mice.

Inoculation routes may significantly affect vaccine performance due to the local microenvironment, antigen localization and presentation, and, therefore, final immune responses. In this study, we conducted a head-to-head comparison of immune response and safety of inactivated rabies vaccine inoculated via intraperitoneal (IP), intramuscular (IM), subcutaneous (SC) and needle-free injection technology-based intradermal (ID) routes in ICR mice. Immune response was assessed in terms of antigen-specific antibodies, antibody subtypes and neutralizing antibodies for up to 28 weeks. A live rabies virus challenge was also carried out to evaluate vaccine potency. The dynamics of inflammatory cell infiltration at the skin and muscle levels were determined via histopathological examination. The kinetics and distribution of a model antigen were also determined by using in vivo fluorescence imaging. Evidence is presented that the vaccine inoculated via the ID route resulted in the highest antigen-specific antibody and neutralizing antibody titers among all administration routes, while IP and IM routes were comparable, followed by the SC route. Antibody subtype analysis shows that the IP route elicited a Th1-biased immune response, while SC and IM administration elicited a prominent Th2-type immune response. Unexpectedly, the ID route leads to a balanced Th1 and Th2 immune response. In addition, the ID route conferred effective protection against lethal challenge with 40 LD50 of the rabies CVS strain, which was followed by IP and IM routes. Moreover, a one-third dose of the vaccine inoculated via the ID route provided comparable or higher efficacy to a full dose of the vaccine via the other three routes. The superior performance of ID inoculation over other routes is related to longer local retention at injection sites and higher lymphatic drainage. Histopathology examination reveals a transient inflammatory cell infiltration at ID and IM injection sites which peaked at 48 h and 24 h, respectively, after immunization, with all side effects disappearing within one week. These results suggest that needle-free injection technology-based ID inoculation is a promising strategy for rabies vaccination in regard to safety and efficacy.

Dog bite management practices by general practitioners; where are we standing in ASIA; a narrative review.

Rabies is an infectious viral disease endemic worldwide and is fatal after the onset of clinical symptoms. In 99% of cases, dogs contribute to infectious viral transmission in humans. It causes approximately 10,000 deaths per year, mainly in Asia and Africa, with 95% of deaths occurring in Asia alone. Currently, the number of dog bite cases reported in Pakistan is alarming. Such cases are first seen mostly by general practitioners. The current narrative review was planned to assess the knowledge, attitude and practices of general practitioners as reported in the literature from different countries published between July 2016 and February 2021 regarding dog bite management. Articles were searched using Google, Google Scholar, Ovid, Eric and PubMed databases. Keywords used included rabies, dog bite, general practitioners, medical officers, knowledge, attitude and practices. A total of 7 studies comprising 875 participants were included. Because of the increasing human population, a growing number of dogs and a lack of concerted efforts for the control of disease, the burden of human deaths as a result of rabies will continue to escalate.

Development of an efficient veterinary rabies vaccine production process in the avian suspension cell line AGE1.CR.pIX.

BACKGROUND: Mass vaccination of dogs as important rabies reservoir is proposed to most effectively reduce and eliminate rabies also in humans. However, a minimum coverage of 70% needs to be achieved for control of the disease in zoonotic regions. In numerous developing countries, dog vaccination rate is still dangerously low because of economic constraints and due to a high turnover in dog populations. Improved vaccine production processes may help to alleviate cost and supply limitations. In this work, we studied and optimized the replication and vaccine potency of PV rabies virus strain in the muscovy-duck derived AGE1.CR and AGE1.CR.pIX suspension cell lines. RESULTS: The BHK-21-adapted PV rabies virus strain replicated efficiently in the avian cell lines without requirement for prior passaging. CR.pIX was previously shown to augment heat shock responses and supported slightly higher infectious titers compared to the parental CR cell line. Both cell lines allowed replication of rabies virus also in absence of recombinant IGF, the only complex component of the chemically defined medium that was developed for the two cell lines. After scale-up from optimization experiments in shake flask to production in 7-l bioreactors peak virus titers of 2.4 × 108 FFU/ml were obtained. The potency of inactivated rabies virus harvest according to the NIH test was 3.5 IU/ml. Perfusion with the chemically defined medium during the virus replication phase improved the potency of the vaccine twofold, and increased the number of doses 9.6 fold. CONCLUSION: This study demonstrates that a rabies vaccine for animal vaccination can be produced efficiently in the AGE1.CR.pIX suspension cell line in a scalable process in chemically defined medium.

Colloidal Manganese Salt Improves the Efficacy of Rabies Vaccines in Mice, Cats, and Dogs.

Rabies, caused by rabies virus (RABV), remains a serious threat to public health in most countries worldwide. At present, the administration of rabies vaccines has been the most effective strategy to control rabies. Herein, we evaluate the effect of colloidal manganese salt (Mn jelly [MnJ]) as an adjuvant of rabies vaccine in mice, cats, and dogs. The results showed that MnJ promoted type I interferon (IFN-I) and cytokine production in vitro and the maturation of dendritic cells (DCs) in vitro and in vivo. Besides, MnJ serving as an adjuvant for rabies vaccines could significantly facilitate the generation of T follicular helper (Tfh) cells, germinal center (GC) B cells, plasma cells (PCs), and RABV-specific antibody-secreting cells (ASCs), consequently improve the immunogenicity of rabies vaccines, and provide better protection against virulent RABV challenge. Similarly, MnJ enhanced the humoral immune response in cats and dogs as well. Collectively, our results suggest that MnJ can facilitate the maturation of DCs during rabies vaccination, which can be a promising adjuvant candidate for rabies vaccines. IMPORTANCE Extending the humoral immune response by using adjuvants is an important strategy for vaccine development. In this study, a novel adjuvant, MnJ, supplemented in rabies vaccines was evaluated in mice, cats, and dogs. Our results in the mouse model revealed that MnJ increased the numbers of mature DCs, Tfh cells, GC B cells, PCs, and RABV-specific ASCs, resulting in enhanced immunogenicity and protection rate of rabies vaccines. We further found that MnJ had the same stimulative effect in cats and dogs. Our study provides the first evidence that MnJ serving as a novel adjuvant of rabies vaccines can boost the immune response in both a mouse and pet model.

Virus-Like Vesicles Based on Semliki Forest Virus-Containing Rabies Virus Glycoprotein Make a Safe and Efficacious Rabies Vaccine Candidate in a Mouse Model.

Rabies is a fatal zoonosis that causes encephalitis in mammals, and vaccination is the most effective method to control and eliminate rabies. Virus-like vesicles (VLVs), which are characterized as infectious, self-propagating membrane-enveloped particles composed of only Semliki Forest virus (SFV) replicase and vesicular stomatitis virus glycoprotein (VSV-G), have been proven safe and efficient as vaccine candidates. However, previous studies showed that VLVs containing rabies virus glycoprotein (RABV-G) grew at relatively low titers in cells, impeding their potential use as a rabies vaccine. In this study, we constructed novel VLVs by transfection of a mutant SFV RNA replicon encoding RABV-G. We found that these VLVs could self-propagate efficiently in cell culture and could evolve to high titers (approximately 108 focus-forming units [FFU]/ml) by extensive passaging 25 times in BHK-21 cells. Furthermore, we found that the evolved amino acid changes in SFV nonstructural protein 1 (nsP1) at positions 470 and 482 was critical for this high-titer phenotype. Remarkably, VLVs could induce robust type I interferon (IFN) expression in BV2 cells and were highly sensitive to IFN-α. We found that direct inoculation of VLVs into the mouse brain caused reduced body weight loss, mortality, and neuroinflammation compared with the RABV vaccine strain. Finally, it could induce increased generation of germinal center (GC) B cells, plasma cells (PCs), and virus-neutralizing antibodies (VNAs), as well as provide protection against virulent RABV challenge in immunized mice. This study demonstrated that VLVs containing RABV-G could proliferate in cells and were highly evolvable, revealing the feasibility of developing an economic, safe, and efficacious rabies vaccine. IMPORTANCE VLVs have been shown to represent a more versatile and superior vaccine platform. In previous studies, VLVs containing the Semliki Forest virus replicase (SFV nsP1 to nsP4) and rabies virus glycoprotein (RABV-G) grew to relatively low titers in cells. In our study, we not only succeeded in generating VLVs that proliferate in cells and stably express RABV-G, but the VLVs that evolved grew to higher titers, reaching 108 FFU/ml. We also found that nucleic acid changes at positions 470 and 482 in nsP1 were vital for this high-titer phenotype. Moreover, the VLVs that evolved in our studies were highly attenuated in mice, induced potent immunity, and protected mice from lethal RABV infection. Collectively, our study showed that high titers of VLVs containing RABV-G were achieved, demonstrating that these VLVs could be an economical, safe, and efficacious rabies vaccine candidate.

Avoidable emergency department visits for rabies vaccination.

BACKGROUND: Administering subsequent doses of rabies vaccine is not a medical emergency and does not require access to emergency department (ED) services. This study reviewed ED visits for rabies postexposure prophylaxis (PEP) to identify avoidable ED visits for subsequent rabies vaccination. METHODS: This retrospective study included patients who received human rabies immune globulin (HRIG) or rabies vaccine at 15 EDs of a multi-hospital health system from 2016 to 2018. All ED visits were classified as initial or non-initial healthcare visits after animal exposure. Emergency department visits for non-initial healthcare were classified as necessary (HRIG administration, worsening symptoms, other emergent conditions, or vaccination during a natural disaster) or avoidable (rabies vaccination only). RESULTS: This study included 145 patients with 203 ED visits (113 initial and 90 non-initial healthcare visits). Avoidable ED visits were identified for 19% (28 of 145) of patients and 66% (59 of 90) of ED visits for non-initial healthcare. Contributing factors for avoidable ED visits were suboptimal ED discharge instructions to return to the ED for vaccination (n = 20 visits) and patients' inability to coordinate outpatient follow-up (n = 17 visits). Patients with previous avoidable ED visits had a 73% probability for unnecessarily returning to the ED for vaccination. The average number of avoidable ED visits observed per patient was 0.41 (95% CI = 0.25 to 0.56). Since the Centers for Disease Control and Prevention reports that 30,000 to 60,000 Americans initiates rabies PEP each year, we estimate that 7500 to 33,600 avoidable ED visits occur for rabies vaccination in the US each year. CONCLUSIONS: One of 5 patients who received rabies PEP in the ED had avoidable ED visits for subsequent rabies vaccination. This study highlights systemic lack of coordination following ED discharge and barriers to accessing rabies vaccine.

Development of an assay for detecting the residual viable virus in inactivated rabies vaccine by enzyme-linked immunosorbent assay.

Rabies is a zoonotic disease that can be prevented by vaccination. The confirmation of rabies virus inactivation is a critical step during the vaccine quality test; however, the current protocol conducted in Japan requires a large number of mice. The development and introduction of animal-free alternative assays are essential from the perspective of the 3Rs (reduction, refinement, and replacement) of animal testing. Here, we propose a novel inactivation assay for confirming the complete inactivation of the viable rabies virus using cultured Neuro-2a cells and an enzyme-linked immunosorbent assay (ELISA). The detection ability of ELISA was similar to that of a direct immunofluorescence assay, with the detection limit of ELISA being as low as 0.014 focus forming units/test. These results suggest that the assay could be used as a viral inactivation test. In comparison with a traditional in vivo assay, this assay has a higher detection ability, an objective interpretation, and would shorten the test duration from 25 days to 8 days.

Re-exposure animal bite management among incident animal bite cases in a secondary care Hospital in Delhi, India.

Complete postexposure prophylaxis with 4 doses of anti-rabies vaccine (ARV) in a previously vaccinated (nonnaïve) individual results in administration of two extra ARV doses resulting in wastages of precious resources comprising vaccine logistics, human resources, physician, and patient time. This cross-sectional study conducted in a secondary care hospital in Delhi among 175 incident animal bite cases observed 39 (22.3%) had an animal-bite history within the previous 5 years. A total of 19 (10.8%) cases reported a history of complete ARV vaccination during a previous animal-bite exposure. However, in the absence of supportive patient medical documentation, all the animal bite cases without exception were prescribed a full course of ARV irrespective of their previous exposure status. Rabies immunoglobulins (anti rabies serum) were also re-administered in 13 (81.2%) cases. National guidelines for rabies prophylaxis should, therefore, consider the inclusion of an explicit decision-making algorithmic mechanism when the health-care provider is confronted with this situation carrying the potential for hidden vaccine wastage.

Rabies post-exposure prophylactic vaccination for returning travelers to Japan.

BACKGROUND: Rabies post-exposure prophylaxis (PEP) in Japan is administered using 6 subcutaneous doses (on days 0, 3, 7, 14, 30, and 90), which is not in line with international recommendations of 4 or 5 intramuscular doses. For reducing dose frequency, we evaluate the immunogenicity of PEP with a regimen of 6 subcutaneous doses. METHOD: This prospective single-center cross-sectional study was performed between September 2013 and December 2014. We included patients underwent rabies PEP by purified chick embryo-cultured rabies vaccine Kaketsuken (PCEC-K) at our clinic, and excluded patients with a history of pre-exposure prophylaxis or PEP using rabies immunoglobulin. The rabies virus-neutralizing antibody tests were performed at the first visit to our office (doses 1-4) and at the fifth and sixth doses. RESULTS: Data were available for 43 of 59 enrolled patients. Thirty-two patients did not start PEP within 48 h after exposure to animals. The seroprotection rates (≥0.5 IU/mL) were 90.7% and 75.7%, at days 30 and 90, respectively. Despite receiving a fifth dose, 85.3% of the patients exhibited decreasing antibody titers during days 30-90 (p < 0.001). CONCLUSIONS: The seroprotection rates of PCEC-K induced subcutaneously were insufficient to prevent rabies at day 30 and 90.

Potency test to discriminate between differentially over-inactivated rabies vaccines: Agreement between the NIH assay and a G-protein based ELISA.

The NIH assay is used to assess the potency of rabies vaccine and is currently a key measure required for vaccine release. As this test involves immunization of mice and subsequent viral challenge, efforts are being made to develop alternative analytical methods that do not rely on animal testing. Sanofi Pasteur has reported the development of a G-protein specific ELISA assay that has shown agreement with the NIH test. In this study we have generated several non-conform vaccine lots by an excessive inactivation with ß-propiolactone (BPL) and assessed the capacity of both tests to detect the corresponding consequences. Excessive BPL inactivation causes G-protein unfolding, altering in turn viral morphology and the continuity of the G-protein layer in the viral particle. Both the NIH and the ELISA tests were able to monitor the consequences of excessive inactivation in a similar manner. Of note, the experimental error of the ELISA test was well below that of the NIH test. These results increase the prospect that the ELISA test could be considered a suitable candidate for the replacement of the NIH test.

Achieving scientific and regulatory success in implementing non-animal approaches to human and veterinary rabies vaccine testing: A NICEATM and IABS workshop report.

This two-day workshop, co-sponsored by NICEATM and IABS-NA, brought together over 60 international scientists from government, academia, and industry to advance alternative methods for human and veterinary Rabies Virus Vaccine (RVV) potency testing. On day one, workshop presentations focused on regulatory perspectives related to in vitro potency testing, including recent additions to the European Pharmacopoeia (5.2.14) that provide a scientific rationale for why in vivo methods may be less suitable for vaccine quality control than appropriately designed in vitro methods. Further presentations reviewed the role of the consistency approach to manufacturing and vaccine batch comparison to provide supportive data for the substitution of existing animal-based methods with in vitro assays. In addition, updates from research programs evaluating and validating RVV glycoprotein (G) quantitation by ELISA as an in vitro potency test were presented. On the second day, RVV stakeholders participated in separate human and veterinary vaccine discussion groups focused on identifying potential obstacles or additional requirements for successful implementation of non-animal alternatives to the in vivo potency test. Workshop outcomes and proposed follow up activities are discussed herein.

DROSOPHILA S2 cell culture in a WAVE Bioreactor: potential for scaling up the production of the recombinant rabies virus glycoprotein.

The transmembrane rabies virus glycoprotein (RVGP) is the main antigen of vaccine formulations used around the world to prevent rabies, the most lethal preventable infectious disease known. The objective of this work was to evaluate the potential of a bioreactor using wave-induced agitation in the initial steps of scaling up the rRVGP production process by a Drosophila melanogaster S2 cell line to produce rRVGP in sufficient quantities for immunization and characterization studies. Taking advantage of some remarkable features recognized in Drosophila S2 cells for scaling the culture process, a robust recombinant lineage (S2MtRVGPH-His) engineered by our group for the expression of rRVGP using a copper-inducible promoter was used in the bioreactor cultures. The WAVE Bioreactor was chosen because it represents an innovative approach to the cultivation of animal cells using single-use technology. For that purpose, we firstly established a procedure for culturing the S2MtRVGPH-His lineage in 100 mL Schott flasks. Using an inoculum of 5 × 105 cells/mL in culture medium (Sf900-III) induced with solution of CuSO4 (0.7 mM) and a convenient pH range (6.2-7.0), optimal parameter values such as time of induction (72 h) and temperature (28 °C) to increase rRVGP production could be defined. This procedure was reproduced in culture experiments conducted in a WAVE Bioreactor™ 2/10 using a 2 L Cellbag. The results in Schott flasks and in WAVE Bioreactor™ were very similar, yielding a maximum titer of rRVGP above of 1 mg.L-1. The immunization study showed that the rRVGP produced in the bioreactor was of high immunogenic quality.

Multiple evanescent white dot syndrome following rabies vaccination: a case report.

BACKGROUND: To report a case of multiple evanescent white dot syndrome (MEWDS) following simultaneous rabies vaccination. CASE PRESENTATION: Review of the clinical, laboratory, photographic, optical coherence tomographic (OCT), fundus autofluorescent, angiographic, electrophysiologic, and perimetric records of a patient suffering from MEWDS. RESULTS: A healthy 33-year-old Chinese female suffering from rapidly progressive visual loss of her left eye associated with photopsia and a para-central scotoma, seven days after receiving simultaneous rabies vaccination. Both anterior segments and fundus examination were unremarkable. The findings on OCT, electrophysiology, and perimetry were pathognomonic for MEWDS. CONCLUSIONS: The clinical presentation and the benign course were consistent with the diagnosis of MEWDS. No other events could be identified as a cause, other than the rabies vaccination. This case may suggest an autoimmune basis for MEWDS in predisposed patients.

New developments in rabies vaccination.

Current rabies vaccines are safe and, when administered properly, they are highly effective. In addition, they elicit long-lasting immunity, with virus-neutralising antibody titres persisting for years after vaccination. However, current regimens require multiple doses to achieve high neutralising titres and they are costly, which means that it is difficult for developing countries, where rabies deaths are highest, to implement widespread vaccination. New innovations are the only way to reduce rabies disease to acceptable rates. Numerous preclinical and clinical studies are under way, testing novel vaccines, adjuvants and injection methods. Research into the use of live vaccines and alternative vaccine vectors is ongoing, while attempts to develop DNA vaccines have so far failed to match the immunogenicity and neutralising capability of traditional vaccines. The development of molecular adjuvants that induce faster, stronger immune responses with less antigen has yielded exciting preclinical results and appears to edge us closer to a better rabies vaccine. However, steep challenges remain: molecular adjuvants require administration with live vaccines, and differences in species specificity of immune molecules complicate development. Over all, the array of research undertaken over the past decade is impressive and encouraging, but most new vaccines have yet to be tested in clinical trials, and the viability of such experimental vaccines in the global market remains to be seen. Only a vaccine that outperforms currently available vaccines in every area will have a chance at widespread adoption. Nevertheless, the authors are confident that some vaccine candidates will meet these criteria.

Les vaccins actuels contre la rage sont sûrs et très efficaces lorsqu'ils sont administrés correctement. En outre, ils confèrent une immunité durable, avec le maintien de titres neutralisants d'anticorps plusieurs années après la vaccination. Néanmoins, les régimes actuels nécessitent l'administration de plusieurs doses pour obtenir des titres élevés d'anticorps neutralisants et ils sont onéreux, de sorte que la vaccination à grande échelle est difficile à mettre en oeuvre dans les pays en développement, pourtant les plus touchés par la mortalité par rage. Seule l'adoption de solutions innovantes permettra de ramener l'incidence de la rage à un niveau acceptable. De nombreuses études précliniques et cliniques sont en cours, visant à tester les innovations en matière de vaccins, de modes d'injection et d'adjuvants. La recherche sur l'utilisation de vaccins à virus vivant et sur de nouveaux vecteurs vaccinaux se poursuit, alors que les tentatives de développement de vaccins à ADN n'ont pas réussi jusqu'à présent à obtenir un effet immunogène ou des capacités de neutralisation virale équivalents à ceux des vaccins traditionnels. Les résultats d'essais précliniques sur de nouveaux adjuvants moléculaires induisant une réponse immune plus rapide et plus puissante avec moins d'antigène sont extrêmement prometteurs et semblent annoncer l'imminence de meilleurs vaccins contre la rage. Il subsiste toutefois d'importantes difficultés : les adjuvants moléculaires ne peuvent être administrés qu'avec des vaccins vivants et les différences de spécificité d'espèce des molécules immunes rendent le développement plus complexe. Globalement, les efforts déployés depuis une décennie par la recherche sont impressionnants et encourageants mais la plupart des nouveaux vaccins doivent encore être soumis à des essais cliniques ; d'autre part la viabilité de ces vaccins expérimentaux dans le marché mondial reste à démontrer. Seul un vaccin capable de surpasser les performances des vaccins actuels dans chaque domaine aura une chance d'être largement adopté. Les auteurs estiment cependant que certains vaccins candidats pourront satisfaire à ces exigences.

Las actuales vacunas antirrábicas son seguras y, si se administran debidamente, muy eficaces. Además, inducen inmunidad duradera, con títulos de anticuerpos neutralizantes que subsisten años después de la vacunación. Sin embargo, los regímenes actuales resultan costosos y exigen dosis múltiples para lograr títulos de neutralización elevados, lo que dificulta a los países en desarrollo, que son los más golpeados por la rabia, la implantación generalizada de la vacunación. El único camino para reducir la rabia a niveles aceptables pasa por la innovación. Están en marcha numerosos estudios preclínicos y clínicos en los que se ensayan vacunas, adyuvantes y métodos de inyección novedosos. También sigue adelante la investigación sobre el uso de vacunas vivas y vectores vacunales alternativos, mientras que ninguna de las tentativas realizadas hasta la fecha con vacunas de ADN ha deparado niveles de inmunogenicidad y capacidad de neutralización equiparables a los de las vacunas tradicionales. La obtención de adyuvantes moleculares que inducen una respuesta inmunitaria más rápida y vigorosa en presencia de menos cantidad de antígeno ha dado resultados preclínicos muy interesantes y poco a poco parece acercarnos al logro de una mejor vacuna antirrábica. Subsisten, empero, arduas dificultades: los adyuvantes moleculares solo funcionan si se administran con vacunas vivas, y las diferencias existentes entre las especies en cuanto a la especificidad de las moléculas inmunitarias complican las labores de desarrollo. Globalmente, el conjunto de investigaciones emprendidas en el último decenio es impresionante y alentador, pero la mayoría de las nuevas vacunas aún deben pasar por la fase de ensayo clínico, y está por ver qué viabilidad tienen estas vacunas experimentales en el mercado mundial. Solo una vacuna que supere a las actuales en todos los aspectos tiene posibilidades de ser adoptada a gran escala. Pese a todo, los autores expresan su confianza en que algunas de las vacunas candidatas cumplan estos criterios.

Human immune responses to traditional and novel rabies vaccines.

Traditional rabies vaccines given preventatively or after exposure to the virus induce cluster of differentiation 4+ (CD4+) T cell responses that promote the induction of long-lived memory B cells and neutralising antibody-secreting plasma cells. The high cost of rabies vaccines, combined with the complexity of immunisation protocols, is partially to blame for their under-use in exposed individuals and prevents the vaccines' widespread use in preventative childhood immunisation programmes in areas where rabies remains common. Novel vaccines or vaccine adjuvants that reduce the cost of rabies vaccination and afford protective immunity, as well as sustained immunological memory, after a single dose are being developed and may very well reduce the human death toll of rabies.

Les vaccins antirabiques classiques administrés préventivement ou suite à une exposition virale déclenchent une réponse cellulaire des lymphocytes T CD4+ induisant l'activation des lymphocytes B mémoire à longue durée de vie et des plasmocytes sécréteurs d'anticorps neutralisants. Le coût élevé des vaccins contre la rage et la complexité des protocoles de vaccination se traduisent par une sous-utilisation chez les individus exposés et font obstacle à l'emploi généralisé de ces vaccins dans les programmes d'immunisation préventive des enfants dans les régions où la rage est endémique. Des vaccins ou adjuvants innovants sont en cours de développement, qui pourraient réduire les coûts de la vaccination antirabique tout en conférant une immunité protectrice et en renforçant la mémoire immunitaire après l'administration d'une dose unique, ce qui contribuerait à réduire considérablement le tribut en vies humaines payé à la rage.

Las vacunas antirrábicas tradicionales, administradas con fines preventivos o tras la exposición al virus, inducen, en linfocitos T que expresan el cúmulo de diferenciación 4 (linfocitos CD4+), una respuesta que promueve la inducción de células B de memoria de larga vida y células plasmáticas secretoras de anticuerpos neutralizantes. El hecho de que las vacunas antirrábicas se utilicen menos de lo debido en personas expuestas se explica en parte por su elevado costo, que, sumado a la complejidad de los protocolos de inmunización, obstaculiza su empleo generalizado para programas preventivos de inmunización infantil en zonas donde la rabia sigue siendo frecuente. Ahora se están obteniendo adyuvantes o vacunas de nuevo cuño que reducen el costo de la vacunación antirrábica, ofrecen inmunidad protectora y confieren una memoria inmunológica duradera tras una sola dosis, lo que muy bien podría aligerar el duro tributo que se cobra la rabia en vidas humanas.