Immunomodulatory Strategies for Parapoxvirus: Current Status and Future Approaches for the Development of Vaccines against Orf Virus Infection

Orf virus (ORFV), the prototype species of the parapoxvirus genus, is the causative agent of contagious ecthyma, an extremely devastating skin disease of sheep, goats, and humans that causes enormous economic losses in livestock production. ORFV is known for its ability to repeatedly infect both previously infected and vaccinated sheep due to several immunomodulatory genes encoded by the virus that temporarily suppress host immunity. Therefore, the development of novel, safe and effective vaccines against ORFV infection is an important priority. Although, the commercially licensed live-attenuated vaccines have provided partial protection against ORFV infections, the attenuated viruses have been associated with major safety concerns. In addition to safety issues, the persistent reinfection of vaccinated animals warrants the need to investigate several factors that may affect vaccine efficacy. Perhaps, the reason for the failure of the vaccine is due to the long-term adaptation of the virus in tissue culture. In recent years, the development of vaccines against ORFV infection has achieved great success due to technological advances in recombinant DNA technologies, which have opened a pathway for the development of vaccine candidates that elicit robust immunity. In this review, we present current knowledge on immune responses elicited by ORFV, with particular attention to the effects of the viral immunomodulators on the host immune system. We also discuss the implications of strain variation for the development of rational vaccines. Finally, the review will also aim to demonstrate future strategies for the development of safe and efficient vaccines against ORFV infections.

Recommendations by the Scientific Department of Neuroimmunology of the Brazilian Academy of Neurology (DCNI/ABN) and the Brazilian Committee for Treatment and Research in Multiple Sclerosis and Neuroimmunological Diseases (BCTRIMS) on vaccination in general and specifically against SARS-CoV-2 for patients with demyelinating diseases of the central nervous system

ABSTRACT The Scientific Department of Neuroimmunology of the Brazilian Academy of Neurology (DCNI/ABN) and Brazilian Committee for Treatment and Research in Multiple Sclerosis and Neuroimmunological Diseases (BCTRIMS) provide recommendations in this document for vaccination of the population with demyelinating diseases of the central nervous system (CNS) against infections in general and against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19. We emphasize the seriousness of the current situation in view of the spread of COVID-19 in our country. Therefore, reference guides on vaccination for clinicians, patients, and public health authorities are particularly important to prevent some infectious diseases. The DCNI/ABN and BCTRIMS recommend that patients with CNS demyelinating diseases (e.g., MS and NMOSD) be continually monitored for updates to their vaccination schedule, especially at the beginning or before a change in treatment with a disease modifying drug (DMD). It is also important to note that vaccines are safe, and physicians should encourage their use in all patients. Clearly, special care should be taken when live attenuated viruses are involved. Finally, it is important for physicians to verify which DMD the patient is receiving and when the last dose was taken, as each drug may affect the induction of immune response differently.

Optimization of translation enhancing element use to increase protein expression in a vaccinia virus system

Since the successful use of vaccinia virus (VACV) in the immunization strategies to eliminate smallpox, research has been focused on the development of recombinant VACV strains expressing proteins from various pathogens. Attempts at decreasing the side effects associated with exposure to recombinant, wild-type viral strains have led to the development of attenuated viruses. Yet while these attenuated VACV’s have improved safety profiles compared to unmodified strains, their clinical use has been hindered due to efficacy issues in stimulating a host immune response. This deficiency has largely been attributed to decreased production of the target protein for immunization. Efforts to increase protein production from attenuated VACV strains has largely centered around modulation of viral factors, while manipulation of the translation of viral mRNAs has been largely unexplored. In this study we evaluate the use of translation enhancing element hTEE-658 to increase recombinant protein production in an attenuated VACV system. Optimization of the use of this motif is also attempted by combining it with strategies that have demonstrated effectiveness in previous research. We show that extension of the 5′ leader sequence containing hTEE-658 does not improve motif function, nor does the combination with other known translation enhancing elements. However, the sole use of hTEE-658 in an attenuated VACV system is shown to increase protein expression levels beyond those of a standard viral promoter when used with a wild-type virus. Taken together these results highlight the potential for hTEE-658 to improve the effectiveness of attenuated VACV vaccine candidates and give insights into the optimal sequence context for its use in vaccine design.

Measles like syndrome after measles and rubella vaccination

National vaccination program (NIS, IAP) provides vaccination for measles and rubella (MR vaccine) for all children below 15 years of age. After vaccination with live attenuated viruses, the virus replicates on a limited scale. Replication may lead to mild symptoms occurring 5-14 days after MR-vaccination including fever, conjunctivitis and rash but sometimes it leads to florid type of severe rashes which are indistinguishable from a wildtype measles infection. A measles like syndrome may occur following MR vaccination, although it seems to be a rare event and therefore as a pediatrician we must take out time to educate and reassurance the parents about this benign nature and so as to avoid unnecessary problems in future. A 14 year old female child was admitted in our hospital with an impressive (florid) rashes, 7 days after MR vaccination in our vaccination clinic. Diagnostic tests were negative for measles and other infections and was discharged after 7 days of nursing and supportive care. Within 14 days after MR vaccination, a child can present with symptoms very similar to a wildtype measles virus infection. The low incidence of wildtype measles infection after MR vaccination, strongly suggests that these symptoms will likely be a reaction to MR vaccination. To elaborate lots of diagnostic procedures may cause the parents a lot of stress and therefore offering nursing care, supportive care and reassurance to parents may be more appropriate and effective in such cases.

COVID-19 and Standardized Vaccines Development: A Brief Review

The severe acute respiratory syndrome coronavirus disease (COVID-19) pandemic brings a global emergency affecting all civilizations. After the initial spread from Wuhan City atypical form of pneumonia to other areas of the world led the world health organization to look after it as a pandemic situation. The clinical coronavirus now spread all over the globe and brutally affected almost all countries including community transmission. The current capital of coronavirus cases in the US, trailed by India and Brazil, respectively. The most common symptoms were mild to moderate respiratory discomfort. Lung was the main targeting organ for COVID-19 infection resulting in severe pneumonia. Furthermore, severe acute respiratory distress syndrome (ARDS), acute cardiac injury, along with pathological features such as RNAaemia with shared ground-glass opacities that may be a cause for death in patients. The surface glycoproteins may be responsible for this garnishing of the virus belonging to the Coronaviridae family. Vaccines work to enhance the immune system of the body by training and making it ready to fight a specific pathogenic agent. At present there over 50 COVID-19 vaccine candidates are in trials, some of which are now ready to deliver via emergency use authorization (EUA). The vast majority of viral vaccines currently licensed for humans can be categorized as inactivated or live-attenuated viruses and protein-based subunit vaccines. Hence, we hereby review the significance of certain genotypic vaccines that are currently subjected for development such as non-replicating viral vectors, mRNA vaccine, self-amplifying mRNA vaccine, DNA vaccine, whole-virus inactivated vaccine, and a subunit vaccine. The current review also explores the mode of pathogenesis and invasion of COVID-19 virus to host cell that would be well-comprised data for future studies in the concerned area of interest.

The SARS-Coronavirus Infection Cycle: A Survey of Viral Membrane Proteins, Their Functional Interactions and Pathogenesis

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a novel epidemic strain of Betacoronavirus that is responsible for the current viral pandemic, coronavirus disease 2019 (COVID-19), a global health crisis. Other epidemic Betacoronaviruses include the 2003 SARS-CoV-1 and the 2009 Middle East Respiratory Syndrome Coronavirus (MERS-CoV), the genomes of which, particularly that of SARS-CoV-1, are similar to that of the 2019 SARS-CoV-2. In this extensive review, we document the most recent information on Coronavirus proteins, with emphasis on the membrane proteins in the Coronaviridae family. We include information on their structures, functions, and participation in pathogenesis. While the shared proteins among the different coronaviruses may vary in structure and function, they all seem to be multifunctional, a common theme interconnecting these viruses. Many transmembrane proteins encoded within the SARS-CoV-2 genome play important roles in the infection cycle while others have functions yet to be understood. We compare the various structural and nonstructural proteins within the Coronaviridae family to elucidate potential overlaps and parallels in function, focusing primarily on the transmembrane proteins and their influences on host membrane arrangements, secretory pathways, cellular growth inhibition, cell death and immune responses during the viral replication cycle. We also offer bioinformatic analyses of potential viroporin activities of the membrane proteins and their sequence similarities to the Envelope (E) protein. In the last major part of the review, we discuss complement, stimulation of inflammation, and immune evasion/suppression that leads to CoV-derived severe disease and mortality. The overall pathogenesis and disease progression of CoVs is put into perspective by indicating several stages in the resulting infection process in which both host and antiviral therapies could be targeted to block the viral cycle. Lastly, we discuss the development of adaptive immunity against various structural proteins, indicating specific vulnerable regions in the proteins. We discuss current CoV vaccine development approaches with purified proteins, attenuated viruses and DNA vaccines.

Mechanisms of Attenuation by Genetic Recoding of Viruses

ABSTRACT The development of safe and effective vaccines against viruses is central to disease control. With advancements in DNA synthesis technology, the production of synthetic viral genomes has fueled many research efforts that aim to generate attenuated viruses by introducing synonymous mutations. Elucidation of the mechanisms underlying virus attenuation through synonymous mutagenesis is revealing interesting new biology that can be exploited for vaccine development. Here, we review recent advancements in this field of synthetic virology and focus on the molecular mechanisms of attenuation by genetic recoding of viruses. We highlight the action of the zinc finger antiviral protein (ZAP) and RNase L, two proteins involved in the inhibition of viruses enriched for CpG and UpA dinucleotides, that are often the products of virus recoding algorithms. Additionally, we discuss current challenges in the field as well as studies that may illuminate how other host functions, such as translation, are potentially involved in the attenuation of recoded viruses.

Anionic Polyelectrolyte Hydrogel as an Adjuvant for Vaccine Development

Vaccination is one of the main methods for the specific prevention of infectious diseases. The disadvantage of vaccination is the use of pathogens (live or attenuated viruses and bacteria) that can lead to the development of a disease. Recombinant technologies are capable of producing specific DNA or protein molecules that possess antigenic properties and do not cause disease. However, individual antigen molecules are low-immunogenic, and therefore, require conjugation with a compound possessing stronger immunogenic properties. In this study, we examined the immunogenic properties of the new anionic copolymer consisting of glycidyl methacrylate, butyl acrylate, triethylene glycol dimethacrylate, and acrylic acid, in mice. The experimental polymer induced a stronger immunogenic response than aluminum hydroxide. The histological studies have established that immunization both with aluminum hydroxide and the polymer studied does not cause damage to the liver, kidneys, or the spleen. No negative side effects were observed. It has been concluded that the new synthetic anionic polyelectrolyte hydrogel (PHG) has a potential as an adjuvant for vaccine development.

846 Neospora caninum – an immunotherapeutic protozoan against solid cancers

BackgroundImmunotherapy induces, provides, and/or reactivates anti-tumor immune responses. Some microorganisms also can initiate response that lyzes infected tumor and/or stimulates systemic immunity. Attenuated viruses or bacteria are well studied as oncotherapeutics, but not protozoa except Toxoplasma gondii.1 We assessed the effect on tumors of other protozoa that were naturally non-pathogenic to humans. Thus, we discovered the ability to use Neospora caninum (Nc) in a manner and form that demonstrated a synergistic array of pertinent immunotherapeutic characteristics against solid cancers. Our first Article on Neospora as Onco-immunotherapeutic is currently under revision after review by the JITC. We report on the most recent data notably from Nc engineered to secrete human IL-15 within the tumor.MethodsIn vitro, the immunostimulatory properties of Nc strains wildtype and engineered to secrete human IL-15 were studied. In vivo experiments of treatment with of Nc tachyzoites2 administered locally (intra and peri tumoral) or remotely (subcutaneous) in a murine thymoma EG7 tumor and in human Merkel cell carcinoma (MCC).ResultsWe demonstrated that the treatment of thymoma EG7 by Nc strongly inhibited tumor development. Analysis of immune responses and interactions between Nc and tumor cells showed that Nc had the ability to lyze infected cancer cells, reactivated immune competence within the Tumor Microenvironment (TME), and activated the systemic immune system by promoting the recruitment of immune cells to the site of tumor. We also established in a NOD/SCID mouse model that Nc was able to induce a strong regression of human MCC. Recently, to further enhance oncotherapeutic effect, we engineered an Nc strain to secrete human IL-15 (cross reactive with mouse cells), associated with alpha subunit of IL-15 receptor, increasing its stability.3 This strain induced proliferation of human PBMCs and their secretion of IFN-γ. In the EG7 model, human IL-15 secreting Nc showed greater protection against tumor development, confirming enhancement of immunotherapy by engineering Nc to deliver/secrete IL-15.ConclusionsThese results highlight Neospora caninum as a potentially extremely efficient, and non-toxic anti-cancer agent, capable of being engineered to express at its surface or to secrete bio-drugs, like human IL-15 cytokine. Our work has identified the broad clinical possibilities of using N. caninum as an oncolytic protozoan in human medicine capable of vectoring molecular therapy, overcoming TME defenses.ReferencesFox BA, Butler KL, Guevara RB, Bzik DJ. Cancer therapy in a microbial bottle: Uncorking the novel biology of the protozoan Toxoplasma gondii. PLoS Pathog 2017;13(9):e1006523. https://doi.org/10.1371/journal.ppat.1006523Bjerkas I, Jenkins MC, Dubey JP. Identification and characterization of Neospora caninum tachyzoite antigens useful for diagnosis of neosporosis. Clin Diagn Lab Immunol 1994;1(2):214-221.Article for publication in the Journal of Immunotherapy of Cancer, under revision on September 20, 2020.

Using the Past to Maximize the Success Probability of Future Anti-Viral Vaccines

Rapid obtaining of safe, effective, anti-viral vaccines has recently risen to the top of the international agenda. To maximize the success probability of future anti-viral vaccines, the anti-viral vaccines successful in the past are summarized here by virus type and vaccine type. The primary focus is on viruses with both single-stranded RNA genomes and a membrane envelope, given the pandemic past of influenza viruses and coronaviruses. The following conclusion is reached, assuming that success of future strategies is positively correlated with strategies successful in the past. The primary strategy, especially for emerging pandemic viruses, should be development of vaccine antigens that are live-attenuated viruses; the secondary strategy should be development of vaccine antigens that are inactivated virus particles. Support for this conclusion comes from the complexity of immune systems. These conclusions imply the need for a revision in current strategic planning.