Epstein-Barr virus-induced increase in the concanavalin-A receptor density of established EBV-negative lymphoma lines in vitro

Abstract

Infection of two human EBV-genome negative lymphoma lines with the EBV-variants P3HR-I and B95-8 converts the lines to permanent carriers of EBV-DNA and the EBV-determined nuclear antigen. This process is accompanied by a series of biologic changes similar to those in oncogenic transformation by known tumor viruses (e.g. polyoma, SV40, Rous SV). They include altered growth properties and membrane changes, one of which is expressed in an increased agglutinability by Con-A. Although most transformed cell systems are more agglutinable than the non-transformed counterparts it is controversial whether they possess similar or changed numbers of lectin receptors. Since little was known about lectin receptor densities of virus transformed lymphoma cells, we set out to determine the densities of Con-A receptors on the EBV-negative lymphoma lines BJAB and Ramos and their EBV-converted sublines by simultaneous recording of the cell membrane fluorescence of FITC-Con-A and the cell volume using the FLUVO-METRICELL flow cytometer. We found that EBV infection gave rise to cell lines with a significantly elevated Con-A receptor density compared to the EBV-negative parental lines. The similar changes found in a number of independently converted sublines suggest that they are due to the direct or indirect action of the viral genome.