A NEW COMBI TEST FOR SIMULTANEOUS DETECTION OF ANTIBODIES TO VIRAL CAPSID, EARLY AND EBNA ANTIGENS OF EPSTEIN-BARR-VIRUS

In order to facilitate the differentiation between a recent (acute) an d a past Epstein-Barr virus (EBV) infection, the Combi test was develo ped. This test is an anticomplement immunofluorescence test (ACIF) req uiring only a single serum dilution to be tested on a single cellular spot. The cell line used expresses viral capsid antigen (VCA) and earl y antigen (EA) in about 5 to 10 percent of the cells as well as EBV nu clear antigens (EBNA) in more than 90 percent of cells. A satisfactory agreement between the Combi test and other tests for antibodies to EB V was obtained (IgG and IgM antibodies to VCA by IFA and EIA and antib odies to EBNA by ACIF including tests for heterophile and complement-f ixing antibodies). When the standard serological tests gave negative r esults, the Combi test was also negative (abscence of any fluorescence in the cells). Serologically confirmed recent (acute) infections lead to specific fluorescence in only 5 to 10 percent of the cells, while past infections result in fluorescence in 90 percent or more of the ce lls. For the diagnosis of a reactivated EBV infection or of EBV-associ ated malignancies, other tests should be employed. The test is based o n the measurement of the activation and specific distribution of the C 3 component of complement; the antibody class differentiation is there fore not necessary. The presence of rheumatoid factor (RF) and the IgG competition phenomenon do not influence the results of the Combi test . An introduction of the Combi test will enable a simplified, less exp ensive and more reliable serodiagnosis of EBV infections.