Interestingly, CA46 is a EBV-negative Burkitt lymphoma line and like BL41-, Pom did not increase B7-2 expression in these cells (Supplemental file 9B) suggesting PU.1 alone is not sufficient for Pom to upregulate B7-2 but appears to require EBV infection as well. This evidence concerns the gene SPI1 and Epstein-Barr virus infection.