Fig. 5.

Tumor infiltration of CD4⁺ and CD8⁺ T cells. Tumors were excised from mice treated with either the HER-2/neu DNA vaccine, AC, or both. The infiltration of CD4⁺ (a) and CD8⁺ (b) T cells was determined in cryosections following staining with primary antibodies specific for CD4 or CD8. A peroxidase-conjugated antibody was used as the secondary antibody. The dark spots indicate positive cells (×400)