Tumor regression by CD4 T-cells primed with dendritic/tumor fusion cell vaccines.

BACKGROUND/AIM Vaccination with fusions of dendritic cells (DCs) and mucin-1 (MUC1)-positive tumor cells (FC/MUC1) induces MUC1-specific antitumor immunity. However, little is known about the function of Cluster of Differentiation (CD)4 T-cells primed with FC/MUC1 in MUC1 transgenic (MUC1.Tg) mice. MATERIALS AND METHODS CD4 T-cells primed with FC/MUC1 were analyzed by flow cytometry. Antitumor immunity by adoptive transfer of primed CD4 T-cells in Rag2(-/-) mice was assessed. RESULTS The effector and memory T-cells generated with FC/MUC1 were crucial to maintenance of long-term antitumor immunity. MUC1-8-mer peptide SAPDTRPA presented by FC/MUC1 was recognized by CD4 and CD8 T-cells. A subset of primed CD4 T-cells possessed cytotoxicity to lyse major histocompatibility complex (MHC) class I and MUC1 positive tumor cells. Interestingly, adoptive transfer of primed CD4 T-cells prevented lung metastasis in Rag2(-/-) mice. CONCLUSION CD4 T-cells primed by FC/MUC1 play direct role in antitumor immunity.