Vaccine-induced CD4⁺ T cells mediate antitumor immunity. (A) T-cell subsets were isolated by flow cytometric cell sorting from CpG/H11-vaccinated C57BL/6 donors and transferred into lympho-depleted recipients. Cohorts of C57BL/6 recipient mice (n = 10) were followed for tumor growth (left panel) and survival (right panel). (B) T-cell subsets were isolated by flow cytometric cell sorting from CpG/A20-vaccinated BALB/c donors and transferred into lympho-depleted recipients. Cohorts of BALB/c recipient mice (n = 10) were followed for tumor growth (left panel) and survival (right panel). Results are representative of 2 independent experiments.