To investigate the role of CD4 + helper T (Th) cells in the memory CTL2mediated anti2tumor immunity , the
RAG21 gene knock out mice were adoptively transferred with OT21 cells to generate the memory CTL , the C57BLP6 mice im2
munized with the epitope peptide of OVA specific Th cells and with different adjuvants were adoptively transferred with these
memory2CTLs , and then the animals were challenged with tumor cells EG7. It was found that although the simple immuniza2
tion of mice with the epitope peptide of the OVA specific Th cells could generate more effect CTL , but this effect was not so
strong enough to resist completely the challenges with tumor cells. Nevertheless , the memory CTL2mediated anti2tumor im2
mune effect required the helps of Th1 and Th2 cells. The cross2regulation between Th1 and Th2 cells seemed to be beneficial
for the host to generate more effector CTL for mounting an efficient anti2tumor response. It concluded that the interaction be2
tween Th1 and Th2 cells might be more important than the single subset of Th cells in the memory CTL2mediated anti2tumor
immune response. More attention should be paid in this regard for the future studies
