Unmasking the Influence of Viral Micro-RNAs on Host Immunity

Micro-RNAs (miRNAs) are key regulators of human immunity, controlling critical cellular programmes including proliferation, differentiation, apoptosis, and immune activation to shape the host response to infection. Multiple human-infecting viruses encode their own miRNA (v-miRNA), enabling them to co-opt host gene regulatory machinery to subvert immunity, establish persistence and evade immune-mediated killing. This review synthesizes the current evidence on viral miRNAs and their roles in host-virus interactions, with an explicit focus on immune regulation. We examine how different viruses use v-miRNAs to modulate core immune functions, including antigen presentation, cytokine signaling, NK and CD8 T-cell activation, and apoptosis. We also examine how v-miRNAs manipulate viral gene expression to aid immune evasion and promote persistence. Particular emphasis is placed on experimentally validated immune targets and their clinical consequences. Collectively, these examples illustrate the convergent evolution of v-miRNA-mediated immune evasion across diverse viral families. Understanding this class of molecules will provide insight into critical immune evasion strategies employed by clinically important viruses and may identify novel targets for diagnostic and antiviral therapeutics, including antagomir-based and RNA silencing approaches.