Alteration of immunoregulatory mechanisms during cytomegalovirus mononucleosis: effect of in vitro culture on lymphocyte blastogenesis to viral antigens.

Immunoregulation of lymphocyte blastogenesis was studied in 13 patients with acute-phase cytomegalovirus (CMV) mononucleosis and 9 of these patients during the convalescent phase of the illness. Peripheral blood mononuclear leukocytes from acute-phase patients displayed depressed uptake of [3H-]thymidine in response to the lectin-mitogen concanavalin A (Con A) and immune-specific viral antigens (CMV, herpes simplex virus (HSV), mumps virus) compared with convalescent patients or normal donors. Removal of plastic-adherent cells from the patients' samples resulted in further depression of lymphocyte blastogenesis to Con A and CMV and HSV antigens, suggesting a helper function for the predominantly monocytic, adherent cell population in this response. Preliminary culture of mononuclear leukocytes from acute-phase patients for 18 hr at 37 degrees C resulted in significantly enhanced blastogenesis to Con A. In sharp contrast, lymphocyte blastogenesis to viral antigens was not significantly enhanced after preculture. These results suggest that different mechanisms are operative in immunoregulation of lymphocyte recognition responses to the polyclonal activator Con A and immune-specific viral antigens during human CMV infection.