Anti-complement immunofluorescence ( A CZF) was used to study the complemcntfixing antigens of human lymphoblastoid cell lines. These cell lines carry the Epstein-Barr virus (EBV) genome although only producer cultures synthetize EB V-specific antigens (virus capsid antigen, VCA and early antigen, E A ) detectable by direct and indirect immunofluorescence, usually in less than 5 % of the cells. The ACIF test revealed an antigen localized in the nucleus of the lymphoblastoid cells. In contrast to EA and VCA, this antigen was present in over 90% of the cells of both producer and Ronproducer cultures. The antigen was shown to be specific for EBV by comparing the reactions of 52 sera in the ACIF test. Sera giving the nuclear reaction contained antibodies to VCA, EA or antigens detectable by complement fixation tests on cell extracts, but sera without EBVantibodies failed to give the reaction. Weak, equivocal or discordant reactions occurred with six sera with low titres in VCA, E A or complement fixation tests. Cell lines derived by transformation of human and primate lymphocyt?s by EBV gave the nuclear reaction. Control cells with no known association wit}, EBV were non-reactive. These included foetal lymphocytes transformed by phytohaetnagglutinin, cell lines derived from breast cancer, glioma, normal glia, pleuritis maligna arid myeloma, and two marmoset lymphoid lines carrying Herpesvirus saimiri ( H V S ) . In preliminary

Twenty-six of 27 African Burkitt lymphomas with histologically confirmed diagnosis contained relatively large amounts of EBV D N A (10-101 viral genomes per cell), as determined by nucleic acid hybridization. Twenty-Jive of the 26 EB V D NA-positive lymphomas contained the E B V-determined nuclear antigen, EBNA, in the majority of the nuclei. Technical reasons may have accounted for the apparent EBNA-negativity of one EB V D NA-positive biopsy. Four African lymphoma biopsies, one with a definite diagnosis of' Burkitt's lymphoma and three with a questionable diagnosis of the same disease, were all EBV DNA-and EBNA-negative. The same was true for a collection of Swedish cases of Hodgkin's disease, lymphocytic lymphoma, chronic lymphatic leukemia and some other lymphoproliferative malignancies. Thus, there is excellent agreement between the presence of EBV D N A and of EBNA in tumor biopsies. The EBNA antigen test therefore appears a relatively simple way of testing for the presence of the virus genome, provided it is carried out with appropriate controls. Several of the EBV-genome and EBNA-negative cases came from patients with high seruni titers of EB V antibodies. It is concluded that the virus does not readily travel along with malignant lytnphoinas as a passenger in the seropositive patients. In comparison with other lymphomas, African Burkitt's lyniphorna of the high endemic areas is unique in that the tumors (with rare exceptions) represent the proliferation of an EB V-genome carrying clone. These findings stress the necessity to distinguish between EB V-seropositive status and e ) iderice for EB V-genome-carrying neoplastic cells. Received: February 19, 1974. B. M. Reedman is a visiting scientist from Queensland lnstitute

Cells from Burkitt lymphoma ( B L ) biopsies were examined for Epstein-Barr virus ( E B V)-associated antigens by complement fixation (CF) tests