TNF-α Signaling is not Required for in vivo Transcriptional Reactivation of Latent Murine Cytomegalovirus

Background. Reactivation of cytomegalovirus (CMV) is frequently observed in recipients of solid organs and bone marrow transplants and is associated with increased risk of acute and chronic allograft rejection, opportunistic infection, graft failure, and patient mortality. The molecular mechanisms by which reactivation occurs are not well understood. Previous studies have suggested that tumor necrosis factor (TNF)-α, which is induced by allogeneic transplantation, may have a role in reactivation of CMV through activation of nuclear factor kappa-light-chain-enhancer of activated B cells and subsequent transcriptional reactivation of immediate early (ie) gene expression. Methods and Results. We have tested the role of TNF-α in the reactivation of CMV directly by testing whether TNF-α is required to initiate transcription of ie gene expression in a murine model of allogeneic transplantation of kidneys latently infected with mouse CMV. Conclusions. Our studies show that although TNF-α seems to be sufficient, it is not required for initiating transcription of ie gene expression in this model, suggesting that both TNF-α-dependent and -independent pathways play an important role in the reactivation of latent CMV infection.