CD11c+ dendritic cells and plasmacytoid DCs are activated by human cytomegalovirus and retain efficient T cell-stimulatory capability upon infection

It has been suggested that human cytomegalovirus (HCMV) evades the immune system by infecting and paralyzing antigen-presenting cells. This view is based mainly on studies of dendritic cells (DCs) obtained after culture of monocytes (moDCs). It is contradicted by the asymptomatic course of HCMV infection in healthy persons, indicating that other key antigen-presenting cells induce an efficient immune response. Here we show that HCMV activates CD11c(+) DCs and retained full capacity to stimulate T cells. Renal transplant recipients receiving immunosuppressive treatment had lower frequencies of CD11c(+) DCs and PDCs in blood than did healthy controls. The results show that HCMV activates the immune system by interacting with CD11c+ DCs and PDCs and that recipients of renal transplants have low frequencies of these cell types in blood.