A novel model system for the study of anti-tumour T-cell memory

Mahnke, Yolanda Dagmar (2001). A novel model system for the study of anti-tumour T-cell memory. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000cc3c

Abstract

An adoptive immunotherapy (ADI) protocol was developed where the fate and requirements of longterm persisting memory T-cells can be monitored. Anti-tumour immune peritoneal exudate cells (iPEC) were produced by injecting a subtumorigenic dose of the highly metastatic, ß-gal⁺ T-Iymphoma into the ear pinna of syngeneic DBN2 mice, followed by an intraperitoneal challenge with irradiation-inactivated tumour cells. 33.9 % of CD8⁺ iPEC were shown to be recognising the immunodominant peptide of ß-gal (aa 876-884), and, consistently, the iPEC exerted specific lysis of ß-gal⁺ cells. Upon adoptive transfer into sublethally irradiated, ESbL-Gal tumour-bearing, athymic Balb/c nu/nu mice, they conferred protective and long-lasting anti-tumour immunity. ADI-treated animals were able to reject subsequent high dose tumour challenges, and memory T-cells appeared to be only partially affected by y-irradiation. ß-gaI^876-884 peptide/MHC class I tetramer stainings identified the bone marrow as the major compartment for the long-term persistence of memory T-cells, as ß-gaI^876-884 specific T -cells occurred at elevated frequencies in this microenvironment as compared to the spleen and lymph nodes. In a "parking experiment", Agremoval led to a decrease of tetramer-binding cells below background levels. Tumour-reactive memory T-cells could be reisolated from AD I-treated animals by recruitment to the peritoneal cavity via Ag-specific challenge at this anatomical site. Reisolated memory PEC (mPEC) retained their reactivity and conferred tumour protection even after multiple transfers to subsequent tumour bearing nude mice.

The present model proved to be a valuable tool for the evaluation of the factors and mechanisms involved in the long-term maintenance of T-cell memory, and promises to yield further invaluable data in this field of research.