Gene sharing between Epstein-Barr virus and human immune response genes.

Epstein-Barr virus (also termed HHV-4, EBV), a component of the human virome or metagenome, is associated as a co-factor in many common human autoimmune diseases through epidemiologic evidence. Numerous EBV genes are functional as well as structural homologues of important immune response genes. For example, EBV-encoded BCRF1 is a functional homologue of IL-10, a critical cytokine regulator of immune tolerance. BZLF-1, an EBV-encoded transcription factor, contains regions with functional homology to both AP-1 and NF-κB DNA binding immune response regulatory factors. The author proposes a paradigm of "gene sharing" between viral- and host-encoded proteins as extension of molecular mimicry that has been largely overlooked in animal models that consider only host genomic factors rather than viral pathogens and the metagenome. Gene sharing may trigger chaotic behavior in human autoimmune disease through unstable feedback loops and perturbations of immune tolerance.