Interaction of strain AD169 and a clinical isolate of cytomegalovirus with peripheral monocytes: the effect of lipopolysaccharide stimulation.

The effect of human cytomegalovirus (CMV) infection on lipopolysaccharide (LPS)-stimulated and unstimulated monocytes from seronegative donors was studied by using the laboratory-adapted strain AD169 and a recent clinical isolate. LPS-stimulated and unstimulated monocytes infected with the isolate showed expression of immediate-early CMV antigens and were significantly more suppressive for lymphocyte proliferation than were strain AD169-infected monocytes, which rarely expressed detectable viral protein. Human CMV infection of LPS-stimulated and unstimulated monocytes resulted in abrogation of interleukin-1 activity, with the effect being marked in LPS-stimulated monocytes infected with the clinical isolate of CMV. Addition of interleukin-1 to infected, stimulated monocytes completely restored lymphoproliferative responses to phytohemagglutinin, whereas addition of this leukokine to infected, unstimulated cells could not restore this response.