[Humoral antibodies to Epstein-Barr virus in infectious mononucleosis].

A high level of humoral antibody to the capsid antigen of Epstein-Barr virus was found in sera from patients with infectious mononucleosis. For detection of antibody, the method of indirect immunofluorescence in fixed P3HEHR cells of Burkitt's lymphoma was used. Sera from normal subjects were also shown to contain antibody to the capsid antigen of Epstein-Barr virus, but the titers were 5--10 times lower than in the sera from infectious mononucleosis patients. The occurrance of high titers of antibody to EBV in the sera from patients with infectious mononucleosis is diagnostic for IM and may be used for practical purposes.