With the exception of M09133-147 specific CD4 T cells that show delayed expansion at later time points post infection (p.i.)[37], expansion of CD4 T cells against all other previously identified MCMV epitopes peaks around day 7 p.i. [37] and can be identified polyclonally through co-expression of CD11a and CD49d [38]. This evidence concerns the gene CD4 and infection.