Inactivation of Chikungunya virus by 1,5 iodonapthyl azide

A Review on Chikungunya Virus Epidemiology, Pathogenesis and Current Vaccine Development

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that recently re-emerged in many parts of the world causing large-scale outbreaks. CHIKV infection presents as a febrile illness known as chikungunya fever (CHIKF). Infection is self-limited and characterized mainly by severe joint pain and myalgia that can last for weeks or months; however, severe disease presentation can also occur in a minor proportion of infections. Among the atypical CHIKV manifestations that have been described, severe arthralgia and neurological complications, such as encephalitis, meningitis, and Guillain–Barré Syndrome, are now reported in many outbreaks. Moreover, death cases were also reported, placing CHIKV as a relevant public health disease. Virus evolution, globalization, and climate change may have contributed to CHIKV spread. In addition to this, the lack of preventive vaccines and approved antiviral treatments is turning CHIKV into a major global health threat. In this review, we discuss the current knowledge about CHIKV pathogenesis, with a focus on atypical disease manifestations, such as persistent arthralgia and neurologic disease presentation. We also bring an up-to-date review of the current CHIKV vaccine development. Altogether, these topics highlight some of the most recent advances in our understanding of CHIKV pathogenesis and also provide important insights into the current development and clinical trials of CHIKV potential vaccine candidates.

Methods of Inactivation of Highly Pathogenic Viruses for Molecular, Serology or Vaccine Development Purposes

The handling of highly pathogenic viruses, whether for diagnostic or research purposes, often requires an inactivation step. This article reviews available inactivation techniques published in peer-reviewed journals and their benefits and limitations in relation to the intended application. The bulk of highly pathogenic viruses are represented by enveloped RNA viruses belonging to the Togaviridae, Flaviviridae, Filoviridae, Arenaviridae, Hantaviridae, Peribunyaviridae, Phenuiviridae, Nairoviridae and Orthomyxoviridae families. Here, we summarize inactivation methods for these virus families that allow for subsequent molecular and serological analysis or vaccine development. The techniques identified here include: treatment with guanidium-based chaotropic salts, heat inactivation, photoactive compounds such as psoralens or 1.5-iodonaphtyl azide, detergents, fixing with aldehydes, UV-radiation, gamma irradiation, aromatic disulfides, beta-propiolacton and hydrogen peroxide. The combination of simple techniques such as heat or UV-radiation and detergents such as Tween-20, Triton X-100 or Sodium dodecyl sulfate are often sufficient for virus inactivation, but the efficiency may be affected by influencing factors including quantity of infectious particles, matrix constitution, pH, salt- and protein content. Residual infectivity of the inactivated virus could have disastrous consequences for both laboratory/healthcare personnel and patients. Therefore, the development of inactivation protocols requires careful considerations which we review here.

Inactivation of Zika Virus by Photoactive Iodonaphthyl Azide Preserves Immunogenic Potential of the Virus

Zika virus's (ZIKV) emergence as a pathogen of significant public health importance has accelerated efforts to develop a ZIKV vaccine. To date, the need for an effective ZIKV vaccine is unmet. In this study, we report inactivation of ZIKV using a hydrophobic photoactive compound: 1, 5 iodonaphthyl azide (INA). 50 and 100 µM of INA completely inactivated ZIKV (INA-ZIKV). Western blot and ELISA analysis show some loss of the binding capacity of INA-iZIKV to anti-ZIKV monoclonal antibodies; however, immunization of mice with INA-iZIKV demonstrated seroconversion and ZIKV-neutralizing antibody response. RNA isolated from INA-iZIKV did not induce productive infection in Vero cells, suggesting inactivation of ZIKV RNA. These results suggest that in the absence of an approved ZIKV vaccine, INA-iZIKV can be pursued as a viable ZIKV vaccine candidate.

Beyond Fever and Pain: Diagnostic Methods for Chikungunya Virus

Chikungunya virus (CHIKV) is an alphavirus that is primarily transmitted by Aedes species mosquitoes. Though reports of an illness consistent with chikungunya date back over 200 years, CHIKV only gained worldwide attention during a massive pandemic that began in East Africa in 2004. Chikungunya, the clinical illness caused by CHIKV, is characterized by a rapid onset of high fever and debilitating joint pain, though in practice, etiologic confirmation of CHIKV requires the availability and use of specific laboratory diagnostics. Similar to infections caused by other arboviruses, CHIKV infections are most commonly detected with a combination of molecular and serological methods, though cell culture and antigen detection are reported. This review provides an overview of available CHIKV diagnostics and highlights aspects of basic virology and epidemiology that pertain to viral detection. Although the number of chikungunya cases has decreased since 2014, CHIKV has become endemic in countries across the tropics and will continue to cause sporadic outbreaks in naive individuals. Consistent access to accurate diagnostics is needed to detect individual cases and initiate timely responses to new outbreaks.

A scoping review of Chikungunya virus infection: epidemiology, clinical characteristics, viral co-circulation complications, and control

Chikungunya fever is a mosquito-borne viral illness characterized by a sudden onset of fever associated with joint pains. It was first described in the 1950s during a Chikungunya virus (CHIKV) outbreak in southern Tanzania and has since (re-) emerged and spread to several other geographical areas, reaching large populations and causing massive epidemics. In recent years, CHIKV has gained considerable attention due to its quick spread to the Caribbean and then in the Americas, with many cases reported between 2014 and 2017. CHIKV has further garnered attention due to the clinical diagnostic difficulties when Zika (ZIKV) and dengue (DENV) viruses are simultaneously present. In this review, topical CHIKV-related issues, such as epidemiology and transmission, are examined. The different manifestations of infection (acute, chronic and atypical) are described and a particular focus is placed upon the diagnostic handling in the case of ZIKV and DENV co-circulating. Natural and synthetic compounds under evaluation for treatment of chikungunya disease, including drugs already licensed for other purposes, are also discussed. Finally, previous and current vaccine strategies, as well as the control of the CHIKV transmission through an integrated vector management, are reviewed in some detail.

Whole-Inactivated and Virus-Like Particle Vaccine Strategies for Chikungunya Virus

Chikungunya virus (CHIKV) is a global public health threat, having been identified in >60 countries in Asia, Africa, Europe, and the Americas. There is no cure for or licensed vaccine against CHIKV infection. Initial attempts at CHIKV vaccine development began in the early 1960s. Whole-inactivated and virus-like particle (VLP) vaccines are 2 of the current approaches being evaluated. Success of these approaches is dependent on a safe, well-tolerated vaccine that is immunogenic and deployable in regard to manufacturing, stability, and delivery characteristics.

1,5-Iodonaphthyl azide-inactivated V3526 protects against aerosol challenge with virulent venezuelan equine encephalitis virus

Venezuelan equine encephalitis virus (VEEV) is a New World alphavirus. VEEV is highly infectious in aerosolized form and has been identified as a bio-terrorism agent. There is no licensed vaccine for prophylaxis against VEEV. The current IND vaccine is poorly immunogenic and does not protect against an aerosol challenge with virulent VEEV. We have previously shown that VEEV inactivated by 1,5-iodonaphthyl azide (INA) protects against footpad challenge with virulent VEEV. In this study, we inactivated an attenuated strain of VEEV, V3526, with INA and evaluated its protective efficacy against aerosol challenge with wild type VEEV. We demonstrated that among three routes of immunization, intramuscular immunization with INA-inactivate V3526 (INA-iV3526) provided complete protection against aerosol challenge with virulent VEEV. Our data suggests that INA-iV3526 can be explored further for development as an effective vaccine candidate against aerosol challenge of virulent VEEV.

Application of radiation technology in vaccines development

One of the earliest methods used in the manufacture of stable and safe vaccines is the use of chemical and physical treatments to produce inactivated forms of pathogens. Although these types of vaccines have been successful in eliciting specific humoral immune responses to pathogen-associated immunogens, there is a large demand for the development of fast, safe, and effective vaccine manufacturing strategies. Radiation sterilization has been used to develop a variety of vaccine types, because it can eradicate chemical contaminants and penetrate pathogens to destroy nucleic acids without damaging the pathogen surface antigens. Nevertheless, irradiated vaccines have not widely been used at an industrial level because of difficulties obtaining the necessary equipment. Recent successful clinical trials of irradiated vaccines against pathogens and tumors have led to a reevaluation of radiation technology as an alternative method to produce vaccines. In the present article, we review the challenges associated with creating irradiated vaccines and discuss potential strategies for developing vaccines using radiation technology.

Inactivation of non-enveloped virus by 1,5 iodonaphthyl azide

BACKGROUND

A photoactive hydrophobic agent 1,5-iodonaphthyl-azide (INA), has been previously shown to completely inactivate the enveloped viruses. INA sequesters into the lipid bilayer of the virus envelope and upon UV-irradiation bind to the hydrophobic domains of the envelope glycoproteins. In our earlier study, we have shown that the Venezuelan equine encephalitis virus (VEEV) genomic RNA was also inactivated during the inactivation of the virus with INA.

FINDINGS

In the present study, we evaluated if the RNA inactivation property of INA can be used to inactivate non-enveloped RNA viruses. Encephalomyocarditis virus (EMCV) was used as a model non-enveloped virus. Treatment with INA followed by UV-irradiation resulted in complete inactivation of EMCV. RNA isolated from INA-inactivated EMCV was non-infectious and INA was found to be associated with the viral RNA genome. INA-inactivated EMCV induced robust total antibody response. However binding capacity of INA-inactivated EMCV to neutralizing antibody was inhibited.

CONCLUSION

This is the first study to show that INA can completely inactivate non-enveloped virus. Our results suggest that the amino acid composition of the neutralizing epitope may interfere with the protective antibody response generated by the INA-inactivated non-enveloped virus.