Plasmacytoid dendritic cells stimulated with Lactococcus lactis strain Plasma produce soluble factors to suppress SARS-CoV-2 replication

Biochem Biophys Res Commun. 2023 Jun 25:662:26-30. doi: 10.1016/j.bbrc.2023.04.046. Epub 2023 Apr 17.

Abstract

Innate immune responses are important in the control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. We have previously found a lactic acid bacteria species, Lactococcus lactis strain Plasma (LC-Plasma), which possesses specific feature to activate plasmacytoid dendritic cells (pDCs) and thus may affect innate immune responses. Here, we investigated the impact of pDC activation by LC-Plasma on SARS-CoV-2 replication in vitro. Addition of the culture supernatant of pDCs stimulated with LC-Plasma resulted in suppression of SARS-CoV-2 replication in Vero and Calu-3 cells. We confirmed interferon-α (IFN-α) secretion in the supernatant of pDCs stimulated with LC-Plasma and induction of IFN-stimulated genes in cells treated with the pDC supernatant. Anti-IFN-α antibody impaired the suppression of SARS-CoV-2 replication by the supernatant of LC-Plasma-stimulated pDCs, suggesting that IFN-α plays an important role in the SARS-CoV-2 suppression. Our results indicate the potential of LC-Plasma to induce inhibitory responses against SARS-CoV-2 replication through pDC stimulation with IFN-α secretion.

Keywords: Innate immunity; Interferon; LC-Plasma; SARS-CoV-2; pDC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19*
  • Dendritic Cells
  • Humans
  • Interferon-alpha
  • Lactococcus lactis*
  • SARS-CoV-2

Substances

  • Interferon-alpha