Ganoderma lucidum spore powder enhances IFN-α-mediated antiviral capacity of COVID-19 vaccine boosters revealed by single-cell multi-omics sequencing

Reduced vaccine efficacy may hinder stable herd immunity. Traditional natural medicinal ingredients, such as Ganoderma lucidum products, have shown potential as safe and effective adjuvants to improve vaccine efficacy. However, their roles in assisting human epidemiological vaccines remain uninvestigated.

This study aimed to evaluate Ganoderma lucidum spore powder (GLSP) as an adjuvant for coronavirus disease 2019 (COVID-19) vaccine boosters and to elucidate its underlying immunomodulatory mechanisms.

The microneutralization assay was utilized to measure the percentage of neutralizing antibodies (NAbs) inhibition. The single-cell multi-omics sequencing was performed to investigate the mechanism of GLSP. The ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and ultra-performance liquid chromatography multiple reaction monitoring mass spectrometry (UPLC-MRM-MS) were used to characterize the chemical composition of GLSP. The molecular docking and in vitro validated experiments were performed to identify triterpenoids that are active in inducing interferon (IFN)-α production and signaling.

In comparison with vaccination alone, GLSP significantly enhanced the NAbs percent inhibition in participants with moderate baseline immunity at 90 days post-vaccination. At the cellular level, GLSP substantially expanded the myeloid cell proportions, particularly classical monocytes (CMs), and augmented their interactions with T and B cells. It also promoted a stronger IFN-α response in innate and adaptive immune cells. In innate immunity, GLSP enhanced the transcription factor activity and chromatin accessibility related to IFN-α stimulation. In adaptive immunity, GLSP induced distinct biases for gene usage and clonal expansion of BCRs and TCRs, contributing to stronger antiviral immunity. Crucially, a combination of chemical profiling and functional validation identified the triterpenoid ganoderic acid H (GH) as the key active component responsible for inducing the IFN-α response.

GLSP demonstrates significant potential as a safe, orally administered adjuvant to counteract waning vaccine efficacy by promoting a robust, IFN-α-mediated antiviral state at the multi-omics level.