Dynamic alterations in bacterial and fungal microbiome and inflammatory cytokines following SRV-8 infection in cynomolgus monkeys.

While viral infections can disturb the host gut microbiome, the dynamic alterations in microbial composition following infection remain poorly characterized. This study identified SRV-8-infected monkeys and classified them into five groups based on infection progression. 16S rRNA amplicon sequencing revealed significant alterations in the relative and inferred absolute abundance of bacterial genera UCG-002, Agathobacter, Coprococcus, and Holdemanella during the early stage of SRV-8 infection, coinciding with provirus formation. These microbial shifts were accompanied by functional modifications in bacterial communities at the same stage. In contrast, ITS amplicon sequencing indicated no significant differences in fungal composition between healthy wild-type and SRV-8-infected monkeys. Spearman correlation analyses demonstrated close interactions between intestinal bacteria and fungi following SRV-8 infection. Additionally, SRV-8 seropositive groups exhibited significantly elevated mRNA expression levels of pro-inflammatory ( TNF-α, IFN-γ, IL-1β, and IL-6) and anti-inflammatory ( IL-10) cytokine genes, highlighting close associations between inflammatory cytokines and immune responses. Overall, these findings provide a comprehensive characterization of bacterial and fungal microbiota dynamics and inflammatory cytokine responses associated with SRV-8 infection, clarifying the pathobiological mechanisms underlying SRV-8 infection from the perspective of the gut microbiome.