Altered production of GM-CSF and IL-8 in cytomegalovirus-infected, IL-1-primed umbilical cord endothelial cells.

The human cytomegaloviruses (HCMVs) appear to have the potential to disrupt production of hematopoietic cytokines. We examined the production of granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-8 by cultured and CMV-infected human umbilical vein endothelial cells (HUVECs) and compared this production with that of uninfected cells. Endothelial cells are, among other things, an integral component of human bone marrow stroma, and are responsible for production of factors that modulate the proliferation and differentiation of human hematopoietic progenitors. HCMV infection increased the production of GM-CSF in IL-1-primed HUVECs without altering GM-CSF levels in infected but unprimed HUVECs. However, this same virus was capable of causing increased production of the inhibitory cytokine IL-8. Both the viral pellet and the cleared viral supernatant appeared to contribute equally to the increased IL-8 and GM-CSF production, because each of these preparations alone was capable of exerting only half the effect seen with whole virus preparations. That both live virus and soluble protein factors within the viral stock contributed to the enhancement in GM-CSF and IL-8 production was further confirmed by inactivation with either ultraviolet or heat treatment of the viral stocks. Although the identity of the factor within the HCMV stock that contributes to this effect remains unknown, studies conducted in the presence of neutralizing antibodies or polymyxin B ruled out a role for tumor necrosis factor-alpha, IL-6, or endotoxin, all known inducers of GM-CSF. These studies indicate that HCMVs can exert both direct and indirect effects on the production of the hematopoietic factor GM-CSF and the inflammatory/inhibitory cytokine IL-8.