Infectious mononucleosis: complement-fixing antibodies to herpes-like virus associated with Burkitt lymphoma

Complement-fixing antibodies to a herpes-like virus derived from a Burkitt tumor-cell line developed in each of 21 patients with infectious mononu-cleosis. These antibodies were absent in all serums before the patients became ill, appeared during the early phases of illness, and persisted for long periods of time. These antibodies are distinct from heterophile antibodies. None of the patients developed immune responses to herpes simplex, cytomegalo-, or reoviruses in the course of their illness. The data suggest that the development of complement-fixing antibodies to this herpes-like virus in these patients may be linked to infectious mononucleosis.