Appearance of DN TCRαβ T cells in peritoneal cavity, liver and spleen after MCMV infection. C57BL/6 and BALB/c mice were infected intraperitoneally with 1 × 105 and 4 × 103 PFU, respectively. The non-adherent PEC, liver and spleen lymphocytes were harvested on days 0, 3, 5, 7, 10 and 15 after infection and the DN TCRαβ+ T cells were determined by FACS analysis as described in the Materials and Methods. ▪ and □ represent the DN TCRαβ+ T cells of C57BL/6 and BALB/c mice, respectively, and ▴ and ▵ are for the combined populations of CD4+ and CD8+ TCRαβ+ T cells of C57BL/6 and BALB/c mice, respectively. The figure represents one of the three independent experiments with similar results.