Regulation of EBI2 expression by the EBV BRRF1 gene in B lymphocytes (VIR1P.1152)

Abstract Background: Epstein Barr Virus Induced gene 2 (EBI2), also known as GPR183, plays a role in migration of B cells. Expression of EBI2 is activated by Epstein Barr Virus (EBV). We investigated the mechanism of EBV activation of EBI2. By regulating EBI2 expression EBV may be able to manipulate B cell migration and interactions between B and T cells. Materials and Methods: EBI2 and EBV gene expression was measured using quantitative-PCR. The effects of the EBV gene BRRF1 were investigated using an EBV strain deficient for the Na protein and lentiviral transfection of the Na gene (BRRF1). Results: B cell lines and ex vivo B cells up-regulate EBI2 after EBV infection (p < .005). Treatment with inactivated virus did not affect EBI2 expression. EBI2 expression is higher in primary B cells than cell lines containing EBV (LCL and Ramos cells; LCL p =0.012, Ramos p=0.027, N=3). EBV BRRF1 expression correlated with EBI2, and BRRF1 deficient EBV did not affect EBI2 expression. Overexpression of BRRF1 using a lentiviral vector resulted in elevated expression of EBI2. Conclusions: EBI2 expression is directly influenced by EBV infection, rather than general cellular activation. BRRF1 is the viral gene responsible for EBI2 upregulation during infection of B cells with EBV. Since BRRF1 is expressed early in infection and during lytic infection, there may be an advantage to EBV in disrupting B cell migration at these times.