Transformation in the presence of dimethyl sulfoxide facilitates recovery of Epstein-Barr virus.

Human umbilical cord blood lymphocytes were immortalized by infection with Epstein-Barr virus (EBV) in the presence of various concentrations of dimethyl sulfoxide (DMSO). 13 continuous lymphoblastoid cell lines were established. DMSO did not affect the efficiency of transformation and establishment of these lines. After a period of 2 months in culture, the lines were tested for EBV production by lethal irradiation (6,000 rad) from a 60Co source and subsequent cocultivation with primary umbilical cord lymphocytes. Cell lines transformed in the presence of 2% DMSO yielded transforming activity in 46.6% of test cultures, compared with 9.5% for lines established without DMSO in the medium. These findings imply that a permanent change in the host/virus relationship resulted from a brief exposure (48 h) to DMSO at the time of transformation.