biostudies-literatureAnzengruber FNational Institute of Allergy and Infectious DiseasesNIAID NIH HHSFundação de Amparo à Pesquisa do Estado de São Paulo1492-1509https://www.ebi.ac.uk/biostudies/studies/S-EPMC4547550biostudies-literatureUnknown14(8)Photodynamic therapy (PDT) uses the combination of non-toxic photosensitizers and harmless light to generate reactive oxygen species that destroy tumors by a combination of direct tumor cell killing, vascular shutdown, and activation of the immune system. It has been shown in some animal models that mice that have been cured of cancer by PDT, may exhibit resistance to rechallenge. The cured mice can also possess tumor specific T-cells that recognize defined tumor antigens, destroy tumor cells in vitro, and can be adoptively transferred to protect naïve mice from cancer. However, these beneficial outcomes are the exception rather than the rule. The reasons for this lack of consistency lie in the ability of many tumors to suppress the host immune system and to actively evade immune attack. TPhotochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for PhotobiologyT-cell mediated anti-tumor immunity after photodynamic therapy: why does it not always work and how can we improve it?PMC4547550R01 AI050875R01AI0508752013/20599-4Anzengruber FAvci PHamblin MRde Freitas LFfalseT-cell mediated anti-tumor immunity after photodynamic therapy: why does it not always work and how can we improve it?Photodynamic therapy (PDT) uses the combination of non-toxic photosensitizers and harmless light to generate reactive oxygen species that destroy tumors by a combination of direct tumor cell killing, vascular shutdown, and activation of the immune system. It has been shown in some animal models that mice that have been cured of cancer by PDT, may exhibit resistance to rechallenge. The cured mice can also possess tumor specific T-cells that recognize defined tumor antigens, destroy tumor cells in vitro, and can be adoptively transferred to protect naïve mice from cancer. However, these beneficial outcomes are the exception rather than the rule. The reasons for this lack of consistency lie in the ability of many tumors to suppress the host immune system and to actively evade immune attack. T2015-01-01T00:00:00Z2015 Aug2025-04-22T20:47:05.294Z2019-03-27T01:57:14ZS-EPMC45475502606298710.1039/c4pp00455h