Requirements for immunoglobulin synthesis in leukocyte cultures exposed to human cytomegalovirus

T cell-depleted leukocytes from normal healthy donors lacking antibody to cytomegalovirus (CMV) were induced to secrete immunoglobulin (Ig) by exposure to inactivated CMV. The responses to two virus strains were compared. One strain had been reported to require specific T cell help to induce Ig synthesis, and the other had been reported to induce Ig synthesis in the presence of only very few cells. Both viruses induced T cell-depleted leukocytes from one group of seronegative donors to secrete Ig. However, both viruses failed to induce leukocytes from a second group of donors to secrete Ig unless B cell growth factor was added as a source of T cell help. These findings suggest that certain individuals are hyperresponsive to CMV and raise the possibility that this group may be most likely to develop mononucleosis after primary infection with CMV.