CpG, CD40L/IL-4, and EBV infection induce proliferation in human B cells (Fig. 2A to C), but EBV-infected cells exhibited a roughly 3-fold increase in CD226 expression compared to mitogen-stimulated B cells, suggesting that CD226 upregulation is unique to EBV infection (Fig. 2D). Here, CD226 is linked to Epstein-Barr virus infection.