Stimulation of human lymphocytes by cytomegalovirions and dense bodies.

Lymphocytes from healthy adult individuals were examined for their ability to incorporate thymidine in the presence of cytomegalovirus (CMV) and dense bodies. It was found that lymphocytes from donors with antibodies to CMV were stimulated to incorporate thymidine-14C both by preparation of CMV and CMV dense bodies. Lymphocytes from CMV seronegative donors did not respond. Dilution experiments and the dose-response curve indicate that the stimulation induced by the dense body preparation was not caused by the small amounts of contaminating CMV particles. These results indicate that in healthy human adults there is a correlation between CMV seropositivity and in vitro lymphocyte transformation, induced by either CMV or by dense bodies.