CD8A and cytomegalovirus infection: To determine the impact of CMV infection on CD8+ T cells, we compared frequency and differentiation of CMV (pp65495–503, NLVPMVATV)- and IAV (M155-64, GILGFVFTL)-specific CD8+ T cells from CMV-IgG positive and negative healthy young and middle-aged adults (<65-year-old) by flow cytometry (Fig. 1A).