CD44 and Epstein-Barr virus infection: For further investigation of the immunophenotypic effects of EBV infection on B-cell during early infection, we also analyzed the expression profiles of several B-cell activation and proliferation surface antigen markers (CD5, CD10, CD23, CD39, CD40, and CD44) as well as the intracellular proliferation marker (Ki-67) at different times post-infection in non-infected B-cells i.e. GFP negative cells.