Development of a skin- and neuro-attenuated live vaccine for varicella

Varicella caused by the primary infection of varicella-zoster virus (VZV) exerts a considerable disease burden globally. Current varicella vaccines consisting of the live-attenuated vOka strain of VZV are generally safe and effective. However, vOka retains full neurovirulence and can establish latency and reactivate to cause herpes zoster in vaccine recipients, raising safety concerns. Here, we rationally design a live-attenuated varicella vaccine candidate, v7D. This virus replicates like wild-type virus in MRC-5 fibroblasts and human PBMCs, the carrier for VZV dissemination, but is severely impaired for infection of human skin and neuronal cells. Meanwhile, v7D shows immunogenicity comparable to vOka both in vitro and in multiple small animal species. Finally, v7D is proven well-tolerated and immunogenic in nonhuman primates. Our preclinical data suggest that v7D is a promising candidate as a safer live varicella vaccine with reduced risk of vaccine-related complications, and could inform the design of other herpes virus vaccines.


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Policy information about availability of data All manuscripts must include a data availability statement. This statement should provide the following information, where applicable: -Accession codes, unique identifiers, or web links for publicly available datasets -A list of figures that have associated raw data -A description of any restrictions on data availability Field-specific reporting Please select the one below that is the best fit for your research. If you are not sure, read the appropriate sections before making your selection. Statistical analysis was performed with the GraphPad Prism software (version 7). Flow cytometry data were analyzed with the FACSDiva software (version 6.1.3) and FlowJo (version 10).
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October 2018

Life sciences study design
All studies must disclose on these points even when the disclosure is negative.  , 1993, J. Virol., PMID: 8380293). Sample sizes for evaluation of toxicity and/or immunogenicity in different animal models were selected based on lab experience to ensure the reproducibility and to perform statistical analysis. For in vitro experiments, at least 3 biological replicates per condition was used to perform statistical analysis.
No data points were excluded from data sets.
Experiments were carried out at least two times independently and were successfully reproducible.
The allocation into experimental groups was random in all animal experiments.
For vaccination experiments in small animals, the investigators were blinded to the type of the vaccine used. For toxicity evaluation in nonhuman primates, histopathological analysis was performed by veterinary pathologists who were blinded to treatment groups. All experimental procedures and data collection or analysis were done by two independent investigators.

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Ethics oversight Note that full information on the approval of the study protocol must also be provided in the manuscript.
All antibodies were validated by the manufacturers and by our own and colleagues' labs.
(2) For antibodies that are commercially available, validation data can be found in each of the company's website. We followed the manufactures' instruction to use these commercial antibodies, and all antibodies worked well in this study.
MRC-5 cells and SH-SY5Y cells were authenticated by STR testing, conducted by ATCC. Human dermal fibroblasts and epidermal keratinocytes were authenticated by morphology and immunophenotyping, conducted by ScienCell Research Laboratories.
All cell lines were tested to be negative for mycoplasma contamination.
No commonly misidentified cell lines were used in this study.
For the SCID-hu mouse model, 4-to 6-week-old male CB-17 SCID mice were used.
The study did not involve wild type animals.
The study did not involve samples collected from the field.
For vaccine safety evaluation in SCID-hu mice, the use of the human tissues was approved by the Research Ethics Committee of Xiamen University (Approval NO. SPH-XMU2016006). Animal experiments were carried out under specific-pathogen-free (SPF) conditions and in strict accordance with the approved animal use protocols of Xiamen University Laboratory Animal Center (Approval NO. XMULAC20160050).
For vaccination experiments, all animals were maintained and handled in accordance with standard use protocols and animal welfare regulations of Xiamen University Laboratory Animal Center (Approval NO. XMULAC20160050). For preclinical safety evaluations, all animals were maintained at the animal facility of Joinn Laboratories (China) Co. Ltd (Beijing, China). The non-human primate study protocol and all the experimental procedures were reviewed and approved by the local Institutional Animal Care and Use Committee (NO. ACU16-040 and ACU15-999).
The study used PBMCs from 6 healthy donors of age 20-50 years.
PBMCs were obtained commercially from Hemacare (Van Nuys, CA, USA, PB009C). The healthy donors providing PBMCs were screened for infectious diseases and found negative for hepatitis B virus (HBV) surface antigen, HBV core antibody, hepatitis C virus (HCV) antibody, human immunodeficiency virus -1/2 (HIV-1/2) antibody, HIV-1/HCV/HBV nucleic acid testing, and syphilis. Informed consent was obtained by the source company from all adult subjects providing PBMCs, and samples were de-identified by the company prior to our receipt.
The use of human PBMCs in this study was approved by the Research Ethics Committee of Xiamen University (Approval NO. SPH-XMU2016006).