Epstein-Barr virus-infected marmoset cells transfected with c-myc do not form lymphomas in mice with severe combined immunodeficiency

Epstein-Barr virus (EBV) has been associated with several malignant processes in man, most notably Burkitt lymphoma in previously healthy individuals and lesions resembling large cell non-Hodgkin lymphomas in organ transplant recipients. Mice with the severe combined immunodeficiency phenotype (SCID mice) are exquisitely susceptible to the development of EBV- associated lymphoproliferative lesions following the intraperitoneal (ip) inoculation of EBV-infected human lymphocytes. Recently, we reported that EBV-infected marmoset lymphocytes do not form lymphomas in SCID mice following ip injection, while human lymphocytes infected with the same EBV strains do. On the assumption that the EBV-infected marmoset cells were lacking a factor necessary for tumor formation, we transfected a plasmid containing c-myc into EBV-infected marmoset cells (B95-8, FF41, and W91 cells). Despite expression of the c-myc protein as determined by immunoblot and flow cytometry when probed with a monoclonal antibody, no increase over baseline lesion development was seen in SCID mice inoculated with 5 x 10⁶ c- myc-expressing marmoset lymphoblastoid cells. Thus, cells that express c-myc and harbor EBV are not sufficient to form lymphomas in certain immunocompromised hosts.