Epstein-Barr virus (EBV) induces expression of B-cell activation markers on in vitro infection of EBV-negative B-lymphoma cells.

A set of B-cell activation markers, including the EBV/C3d receptor [complement receptor type 2 (CR2) (CD21)], the 45-kDa lymphoblastoid cell-associated (Blast-2) antigen (CD23), and the B-cell restricted activation (Bac-1) antigen (which was recently identified as a potential B-cell growth factor receptor) can be turned on by infecting lymphoma cells that are genome negative for Epstein-Barr virus (EBV) with the B95-8 immortalizing strain of the virus. The nonimmortalizing EBV variant, strain P3HR-1, which possesses a deletion within the BamHI WYH region of the genome containing the coding sequence for the EBV-determined nuclear antigen 2, does not induce expression of these markers. Other lymphoblastoid cell-associated antigen markers can be activated by infection with either immortalizing or nonimmortalizing viruses. These results suggest that the immortalizing potential of EBV is correlated with its ability to induce expression of B-cell activation markers, which are suspected to play a major role in the physiological pathway leading to lymphoid cell proliferation. The viral genomic region deleted in the nonimmortalizing strain of EBV seems to be required for activation of some of these markers. Human lymphoma cell lines, such as those used in this study, can thus help identify the specific EBV genes involved in lymphoid B-cell proliferation and the mechanism of action of these genes.