A comparative study of the effect of UV and formalin inactivation on the stability and immunogenicity of a Coxsackievirus B1 vaccine

Minna M Hankaniemi,Virginia M Stone,Amir-Babak Sioofy-Khojine,Suvi Heinimäki,Varpu Marjomäki,Heikki Hyöty,Vesna Blazevic,Olli H Laitinen,Malin Flodström-Tullberg,Vesa P Hytönen

doi:10.1016/j.vaccine.2019.08.037

Minna M Hankaniemi, Virginia M Stone + Show 8 more

Open Access

https://doi.org/10.1016/j.vaccine.2019.08.037

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Abstract

Type B Coxsackieviruses (CVBs) belong to the enterovirus genus, and they cause both acute and chronic diseases in humans. CVB infections usually lead to flu-like symptoms but can also result in more serious diseases such as myocarditis, aseptic meningitis and life-threatening multi-organ infections in young infants. Thus, CVBs have long been considered as important targets of future vaccines.We have previously observed CVB1 capsid disintegration and virus concentration decrease with 12-day long formalin inactivation protocol. Here a scalable ion exchange chromatography purification method was developed, and purified CVB1 was inactivated with UV-C or formalin. Virus morphology and concentration remained unchanged, when the UV (2 min) or formalin (5 days) inactivation were performed in the presence of tween80 detergent. The concentration of the native and UV inactivated CVB1 remained constant at 4 °C during a six months stability study, whereas the concentration of the formalin inactivated vaccine decreased 29% during this time. UV treatment decreased, whereas formalin treatment increased the thermal stability of the capsid.The formalin inactivated CVB1 vaccine was more immunogenic than the UV inactivated vaccine; the protective neutralizing antibody levels were higher in mice immunized with formalin inactivated vaccine. High levels of CVB1 neutralizing antibodies as well as IgG1 antibodies were detected in mice that were protected against viremia induced by experimental CVB1 infection.In conclusion, this study describes a scalable ion exchange chromatography purification method and optimized 5-day long formalin inactivation method that preserves CVB1 capsid structure and immunogenicity. Formalin treatment stabilizes the virus particle at elevated temperatures, and the formalin inactivated vaccine induces high levels of serum IgG1 antibodies (Th2 type response) and protective levels of neutralizing antibodies. Formalin inactivated CVB vaccines are promising candidates for human clinical trials.

Highlights

Coxsackievirus B1 (CVB1) is a RNA virus belonging to the picornaviridae family and the enterovirus genus
The virus was further purified with anion exchange chromatography (AEX) in the presence of 0.1% tween80, which was compatible with the chromatography
In our previous study we developed a scalable three-step purification method for the production of a CVB1 vaccine, which relied on 30% sucrose cushion pelleting, gelatin affinity chromatography and 30/50% sucrose cushion pelleting [14]

Summary

Introduction

Coxsackievirus B1 (CVB1) is a RNA virus belonging to the picornaviridae family and the enterovirus genus. Infections caused by the six Coxsackievirus B types are usually asymptomatic or lead to flu-like symptoms. CVBs have constantly been among those 15 enteroviruses most commonly reported to CDC by diagnostic laboratories in US causing significant morbidity especially among young children [5]. CVBs have been linked to chronic diseases such as cardiomyopathies and type 1 diabetes [6,7,8]. CVBs have long been considered as potential targets of future enterovirus vaccines [9,10,11]

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