Safety and immunogenicity of inactivated Zika virus vaccine by gamma irradiation
Issued Date
2025-10-01
Resource Type
eISSN
25901362
Scopus ID
2-s2.0-105013477164
Journal Title
Vaccine X
Volume
26
Rights Holder(s)
SCOPUS
Bibliographic Citation
Vaccine X Vol.26 (2025)
Suggested Citation
Sintara P., Suphaprueksapong P., Jetawattana S., Wiriyarat W., Akkhawattanangkul Y., Charngkaew K., Chomanee N., Saelee J., Wongsa A., Priengprom T., Tassaneetrithep B. Safety and immunogenicity of inactivated Zika virus vaccine by gamma irradiation. Vaccine X Vol.26 (2025). doi:10.1016/j.jvacx.2025.100706 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/111816
Title
Safety and immunogenicity of inactivated Zika virus vaccine by gamma irradiation
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Corresponding Author(s)
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Abstract
Developing the Zika virus (ZIKV) vaccine remains a critical global public health need. This study assessed the safety and immunogenicity of gamma-irradiated Thai ZIKV isolate. Inactivation was confirmed by serial passaging and detection of viral replication using RT-PCR, which demonstrated complete loss of infectivity in ZIKV irradiated with 25 and 50 kGy. Western blotting confirmed that irradiation preserved viral envelope protein antigenicity. BALB/c mice were subcutaneously immunized twice with 25 kGy-irradiated ZIKV, either alone or with alum adjuvant, at two-week intervals. No mortality or local reactions were observed in any group of mice. Antigen-specific IgG and neutralizing antibody titers were measured by ELISA and focus reduction neutralization test, respectively. T cell responses were assessed via intracellular IFN-γ and TNF-α staining by flow cytometry. The irradiated vaccine induced ZIKV-specific antibody and cytokine-producing T cell responses; however, neutralizing antibody titers were low. Mice immunized with irradiated ZIKV combined with alum adjuvant had higher ZIKV-specific antibody titers and T cells producing IFN-γ or TNF-α than those without adjuvant, though differences were not statistically significant. Although the viral integrity and antigenicity remained unchanged, these findings demonstrate that gamma-irradiated ZIKV is non-infectious and immunogenic in mice, supporting its safety profile and the potential for further optimization in future dose-ranging and efficacy studies.