Human Herpesvirus 6A Partially Suppresses Functional Properties of DC without Viral Replication

Human herpesvirus 6A (HHV-6A) is a common virus with a worldwide distribution that has been associated with multiple sclerosis. Whether HHV-6A can replicate in dendritic cells (DC) and how the infection might modulate the functional properties of the cell are currently not well known and need further investigations. Here, we show that a non-productive infection of HHV-6A in DC leads to the up-regulation of HLA-ABC, via autocrine IFN-α signaling, as well as the up-regulation of HLA-DR and CD86. However, HHV-6A exposure reduces IL-8 secretion by DC and their capacity to stimulate allogenic T cell proliferation. The ability to suppress DC functions important for activation of innate and adaptive immune responses might be one successful strategy by which HHV-6A avoids the induction of appropriate host defense mechanisms, and thus facilitating persistent infection.