Long-term survival and complete cures of B16 melanoma–carrying animals after therapy with tumor-targeted IL-2 and SEA
✍ Scribed by Alexander Rosendahl; Karin Kristensson; Mats Carlsson; Niels Jørgen Skartved; Kristian Riesbeck; Morten Søgaard; Mikael Dohlsten
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- French
- Weight
- 260 KB
- Volume
- 81
- Category
- Article
- ISSN
- 0020-7136
No coin nor oath required. For personal study only.
✦ Synopsis
The bacterial superantigen (SAg) staphylococcal enterotoxin A (SEA) is a potent inducer of CTL activity and cytokine production in vivo. To engineer SAg for cancer immunotherapy, we genetically fused SEA to a Fab fragment of the C215 tumor-reactive antibody. Strong reduction of lung metastasis was seen in mice carrying established lung metastases of the poorly immunogenic B16-C215 melanoma after Fab-SEA therapy. However, important anti-tumor effector functions, such as IFN-␥ secretion and CTL activity, gradually declined during therapy. In this study, we show that Fab-SEA immunotherapy is strongly potentiated by Fab-IL-2 coadministration. Combined Fab-IL-2 and Fab-SEA therapy prolongs the immune response in vivo, limits the development of immunological unresponsiveness and promotes maximal anti-tumor effects. Significantly prolonged survival was noted in tumor-carrying animals treated with Fab-SEA/ Fab-IL-2 as compared with Fab-SEA or Fab-IL-2 alone. Combination therapy resulted in complete cure in 90% of tumor-bearing animals, whereas only 10% long-term survival was seen in Fab-SEA or Fab-IL-2-treated animals. Single Fab-SEA therapy induced a hyporesponsive state after 2 cycles of treatment. In contrast, the immune response after combination therapy was characterized by substantially augmented IFN-␥ and TNF-␣ production and strong CTL activity. Our data demonstrate that combined Fab-SEA and Fab-IL-2 therapy prolongs the immune response in vivo and induced long-term survival of more than 90% of the animals carrying the highly aggressive B16 melanoma.