After primary infection, B cells are activated by antigens with the help of HCMV-specific CD4+ T cells, mainly Th2 cells, leading to the production of antibodies specific for a number of HCMV proteins (Wang and Shenk, 2005; Gerna et al., 2008; Macagno et al., 2010; Genini et al., 2011). This evidence concerns the gene CD4 and infection.