A novel tumour model system for the study of long-term protective immunity and immune T cell memory.

We present a novel non-transgenic system to be used for studies on anti-tumour adoptive immunotherapy (ADI) and long-term T cell memory. Tumour-reactive donor immune cells against lacZ-transfected syngeneic tumour cells (ESbL-Gal) were generated from a naíve T cell repertoire in DBA/2 mice by a well-established priming/restimulation protocol, and transferred to tumour-inoculated athymic nu/nu mice. The donor immune cells efficiently mediated protective anti-tumour immunity involving both CD4(+) and CD8(+) T cells, and anti-metastatic effects were stronger in 4.5 Gy pre-irradiated than in non-irradiated tumour-inoculated hosts. Long-term persistence of beta-galactosidase (Gal)-specific T cells was shown ex vivo by tetramer staining of CD8(+) T cells specific for an immunodominant Gal epitope. Resistance of treated nu/nu mice against tumour rechallenge revealed the existence of long-term protective immune memory.