Low Susceptibility of Rubella Virus in First-Trimester Trophoblast Cell Lines

Viruses. 2022 May 27;14(6):1169. doi: 10.3390/v14061169.

Abstract

We recently published an article about myelin oligodendrocyte glycoprotein-independent rubella infection of keratinocytes in vitro, in which first-trimester trophoblast cells were shown as rubella virus (RuV)-resistant. Given an incident rate as high as 90% of congenital rubella syndrome in the first eight weeks of pregnancy, the RuV infection of first-trimester trophoblasts is considered key to opening the gate to transplacental transmission mechanisms. Therefore, with this study, we aimed to verify the susceptibility/resistance of first-trimester trophoblast cell lines, HTR-8/SVneo and Swan.71, against RuV. Cells cultured on multi-well plates were challenged with a RuV clinical strain at a multiplicity of infection from 5 to 10 for 3 h. The infectivity was investigated by immunofluorescence (IF) assay and flow cytometry (FCM) analysis. Supernatants collected during the post-infection period were used to determine virus-progeny production. The scattered signaling of RuV infection of these cells was noted by IF assay, and the FCM analysis showed an average of 4-5% of gated cells infected with RuV. In addition, a small but significant production of virus progeny was also observed. In conclusion, by employing appropriate approaches, we determined the low infectivity of RuV in first-trimester trophoblast cell lines but not resistance as in our previous report.

Keywords: HTR-8/SVneo; Swan.71; correction; first trimester; flow cytometry; resistance; rubella; susceptibility; trophoblast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Female
  • Humans
  • Pregnancy
  • Pregnancy Trimester, First
  • Rubella virus*
  • Rubella* / metabolism
  • Trophoblasts / metabolism

Grants and funding

This study was supported by Grants-in-Aid for Scientific Research under the Japan Society for the Promotion of Science (JSPS KAKENHI), grant numbers 17H04341 and 22H03229 (to S.H.) and 20K08829 (to Q.D.T.). The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.