Lymphocyte reactivity in infectious mononucleosis.

Reactivity of lymphocytes to a purified preparation of Epstein-Barr virus (EBV) was studied in 17 healthy individuals and 15 patients with primary EVB infection and clinical signs of infectious mononucleosis. Lymphocyte reactivity to EBV was negative in individuals who were seronegative for antibody to EBV and in seven of 15 patients examined less than or equal to 21 days after onset of clinical signs of illness. Positive lymphocyte reactivity was observed in all patients by day 36; once it was established, it remained in individual patients for up to 480 days. During the acute phase of infectious mononucleosis, negative lymphocyte reactivity was always associated with a strong antibody response to EBV capsid antigens. This disparity was paralleled by the inability of lymphocytes to respond to recall antigens and mitogens, especially concanavalin A. Positive lymphocyte reactivity to EBV indicates a specific cellular memory function, probably of thymus-cell origin, which is acquired following primary EBV infection, and may be retained into later life.