# Lactiplantibacillus plantarum GUANKE Enhances Antiviral Defense Against Respiratory Syncytial Virus Through the STING-TBK1-IRF3-IFN Pathway

## TL;DR

This study shows that the probiotic Lactiplantibacillus plantarum GUANKE helps fight respiratory syncytial virus by boosting the body's antiviral defenses.

## Contribution

The novel contribution is identifying the STING-TBK1-IRF3-IFN pathway as the mechanism through which GUANKE exerts anti-RSV effects.

## Key findings

- GUANKE reduces RSV replication and lung inflammation in mice.
- GUANKE activates the STING-TBK1-IRF3-IFN pathway to enhance antiviral responses.
- GUANKE lowers inflammatory cytokine levels like IL-1β, IL-6, MCP-1, and TNF-α.

## Abstract

Background/Objectives: To investigate the antagonistic effect of probiotic Lactiplantibacillus plantarum GUANKE against respiratory syncytial virus (RSV) and its underlying molecular mechanisms. Methods: in vitro cell models (A549 and HEp2 cells) and an in vivo mouse model (BALB/c mice) were employed. RT-qPCR, TCID50 assay, immunofluorescence, ELISA, Western blot, and histopathological analysis were used to investigate the effects of GUANKE on RSV replication, inflammatory responses, and the type I interferon pathway. Results: Oral administration of GUANKE effectively cleared RSV and alleviated RSV-induced pulmonary inflammatory responses. GUANKE inhibited viral replication. The GUANKE intervention group exhibited significantly reduced pathological damage to lung tissue and decreased the expression of inflammatory cytokines (IL-1β, IL-6, MCP-1, TNF-α). GUANKE augmented the early type I interferon response and activated the STING-TBK1-IRF3-IFN signaling pathway. Conclusions: GUANKE exerts anti-RSV effects by enhancing the early type I interferon response and activating the STING-TBK1-IRF3-IFN signaling pathway, thereby inhibiting RSV replication and alleviating pulmonary inflammatory responses. This suggests its potential value as an anti-RSV agent.