Interaction between tumorantigen-reactive T-cells of bone marrow and tumor cells in patients with breast cancer

Breast cancer is an immunogenic tumor which expresses a wide range of tumor-associated antigens (TAA). As breast cancer cells are able to metastasize even in the early stages to lymph nodes and via blood to visceral organs and bone, there seems to be an immunological confrontation which takes place in the beginning of the disease. Breast cancer cells can be recognized by parts of the cellular immune system via antigen-presenting cells such as dendritic cells which present TAAs to naive immune cells. Only in bone marrow of primary and metastatic breast cancer patients were we able to find tumorantigen-reactive CD45RO(+) memory T-cells (MTC) by using interferon-gamma-ELISPbT analysis. Furthermore we were able to reactivate those inactive T-cells ex vivo by stimulating them with TAA-pulsed dendritic cells. The reactivated CD8(+) and CD4(+) TAA-specific T-effector cells exhibited anti-tumoral effects like the production of INF-gamma and perforin. In tumor-loaded NOD/SCID mice treated with those reactivated T-cells we found tumor regression in 80%. These hopeful results may play an important role in further active and passive vaccination strategies.