1. Inactivated and Immunogenic SARS-CoV-2 for Safe Use in Immunoassays and as an Immunization Control for Non-Clinical Trials.
- Author
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Gomes MPB, Linhares JHR, Dos Santos TP, Pereira RC, Santos RT, da Silva SA, Souza MCO, da Silva JFA, Trindade GF, Gomes VS, Barreto-Vieira DF, Carvalho MMVF, Ano Bom APD, Gardinali NR, Müller R, Alves NDS, Moura LDC, Neves PCDC, Esteves GS, Schwarcz WD, Missailidis S, Mendes YDS, and de Lima SMB
- Subjects
- Mice, Animals, Antibody Formation, Antibodies, Viral, Immunization, Enzyme-Linked Immunosorbent Assay, Antibodies, Neutralizing, SARS-CoV-2, COVID-19 prevention & control
- Abstract
Successful SARS-CoV-2 inactivation allows its safe use in Biosafety Level 2 facilities, and the use of the whole viral particle helps in the development of analytical methods and a more reliable immune response, contributing to the development and improvement of in vitro and in vivo assays. In order to obtain a functional product, we evaluated several inactivation protocols and observed that 0.03% beta-propiolactone for 24 h was the best condition tested, as it promoted SARS-CoV-2 inactivation above 99.99% and no cytopathic effect was visualized after five serial passages. Moreover, RT-qPCR and transmission electron microscopy revealed that RNA quantification and viral structure integrity were preserved. The antigenicity of inactivated SARS-CoV-2 was confirmed by ELISA using different Spike-neutralizing monoclonal antibodies. K18-hACE2 mice immunized with inactivated SARS-CoV-2, formulated in AddaS0
3 TM , presented high neutralizing antibody titers, no significant weight loss, and longer survival than controls from a lethal challenge, despite RNA detection in the oropharyngeal swab, lung, and brain. This work emphasizes the importance of using different techniques to confirm viral inactivation and avoid potentially disastrous contamination. We believe that an efficiently inactivated product can be used in several applications, including the development and improvement of molecular diagnostic kits, as an antigen for antibody production as well as a control for non-clinical trials.- Published
- 2023
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