Inducibility of the Epstein-Barr virus (EBV) cycle and surface marker properties of EBV-negative lymphoma lines and their in vitro EBV-converted sublines

Abstract

Two EBV-negative lymphoma lines of human B-cell origin, BJAB and Ramos, were compared with altogether six of their in vitro EBV-converted, EBNA- and EBV-DNA-carrying sublines (four of Ramos and two of BJAB derivation). All converted lines closely resembled the parental line with regard to karyotype and HL-A and B antigen typing. Induction of EBV antigens (EA and VCA) by P3HR-1 virus superinfection was either similar in the converted and the negative lines, or somewhat increased in certain converted lines. These findings argue against a simple, virally determined repressor model and emphasize the role or cellular controls in restricting the EBV cycle in virus-carrying B-lymphocyte lines of human origin. IUdR inducibility varied in the different converted lines. There was a possible relationship between average number of EBV-genome equivalents per cell and inducibility. Converted sublines did not differ from the original negative lines with regard to surface immunoglobulin and Fc receptors. There was a dramatic increase in complement-consuming ability, however, following EBV conversion. Among the EBV-positive lines, there was a linear relationship between complement-consuming and EBV-receptor activity, the latter measured by a quantitative absorption test.