In a histological analysis of the tumour specimens, we observed significantly more infiltration of CD8+ and CD4+ T cells in the tumour tissues of mice immunized with miPSDCs-CEA than those of mice immunized with miPSDCs-LacZ or PBS, based on the average of 10 high-power fields (n = 6 for each group, P < 0.01; Fig. 5e). Here, CD4 is linked to neoplasm.