Development of a highly specific serodiagnostic ELISA for West Nile virus infection using subviral particles

Keisuke Maezono,Kentaro Yoshii,Hiroaki Kariwa,Shintaro Kobayashi,Koshiro Tabata

doi:10.1038/s41598-021-88777-5

Keisuke Maezono, Kentaro Yoshii + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-88777-5

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Abstract

West Nile virus (WNV), a member of the Japanese encephalitis virus (JEV) serocomplex group, causes lethal encephalitis in humans and horses. Because serodiagnosis of WNV and JEV is hampered by cross-reactivity, the development of a simple, secure, and WNV-specific serodiagnostic system is required. The coexpression of prM protein and E protein leads to the secretion of subviral particles (SPs). Deletion of the C-terminal region of E protein is reported to affect the production of SPs by some flaviviruses. However, the influence of such a deletion on the properties and antigenicity of WNV E protein is unclear. We analyzed the properties of full-length E protein and E proteins lacking the C-terminal region as novel serodiagnostics for WNV infection. Deletion of the C-terminal region of E protein suppressed the formation of SPs but did not affect the production of E protein. The sensitivity of an enzyme-linked immunosorbent assay (ELISA) using the full-length E protein was higher than that using the truncated E proteins. Furthermore, in the ELISA using full-length E protein, there was little cross-reactivity with anti-JEV antibodies, and the sensitivity was similar to that of the neutralization test.

Highlights

West Nile virus (WNV) belongs to the genus Flavivirus in Family Flaviviridae and is a member of the Japanese encephalitis serocomplex group, which includes Japanese encephalitis virus (JEV), Murray Valley encephalitis virus, and Saint Louis encephalitis v irus[1]
The E proteins expressed upon transfection with the plasmids are labeled “∆C47” for pCAG-prME∆C47-OSF, “∆C71” for pCAG-prME∆C71-OSF, “∆C88” for pCAG-prME∆C88-OSF, “∆C101” for pCAG-prME∆C101-OSF, and “Full” for pCAG-WNV-prM-OSF-E. (B–G) 293 T cells were transfected with plasmids expressing Full, ∆C47, ∆C71, ∆C88, and ∆C101 E proteins. (B) The E proteins in cell lysates and supernatants after precipitation using anti-WNV E antibody or Strep-Tactin were detected via Western blotting using anti-WNV E antibody
We analyzed the properties of OSF-tagged full-length WNV E protein and various truncated WNV E proteins lacking the C-terminal region and used them in a serodiagnostic enzyme-linked immunosorbent assay (ELISA) for WNV infection

Summary

Introduction

West Nile virus (WNV) belongs to the genus Flavivirus in Family Flaviviridae and is a member of the Japanese encephalitis serocomplex group, which includes Japanese encephalitis virus (JEV), Murray Valley encephalitis virus, and Saint Louis encephalitis v irus[1]. The E proteins expressed upon transfection with the plasmids are labeled “∆C47” for pCAG-prME∆C47-OSF, “∆C71” for pCAG-prME∆C71-OSF, “∆C88” for pCAG-prME∆C88-OSF, “∆C101” for pCAG-prME∆C101-OSF, and “Full” for pCAG-WNV-prM-OSF-E. As the epitope cross-reactive among flaviviruses is less exposed on SPs, an ELISA using SPs enabled the specific serodiagnosis of tick-borne encephalitis virus (TBEV) infection[11]. Truncation of the C-terminal region promoted more efficient secretion of the TBEV E protein compared to the full-length E protein[27].

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