Conditions for Cytomegalovirus Stimulation of Lymphocytes

Abstract

Lymphocytes from healthy donors or from patients with chronic lymphocytic leukemia were subjected to live or inactivated cytomegalovirus (CMV) or the mitogen phytohemagglutinin. No early or late CMV antigens could be demonstrated in the lymphocytes, indicating that neither abortive nor replicative CMV infection takes place. Only cells from CMV antibody-positive leukemic and non-leukemic donors were stimulated by CMV to DNA synthesis with a maximum on day 5. Cells from all individuals responded to phytohemagglutinin stimulation, the peak of activity occurring on day 3. Stimulation with CMV occurred in T cells and was independent of early CMV antigen production, viral DNA synthesis or viral replication. CMV is thus not an in vitro lymphocyte mitogen like Epstein-Barr virus but is a very potent antigen for memory T cells.