Cytotoxic T-lymphocyte (CTL) therapy directed to Epstein-Barr virus (EBV) antigens has produced numerous and strong antitumor responses in patients with EBV-associated Hodgkin disease or non-Hodgkin lymphoma (NHL) without toxicity, but in the vast majority of cases the lymphoma cells do not express EBV antigens, obviating CTL therapy targeted to this virus. Moreover, virtually all standard treatments for Hodgkin disease and NHL impose high rates of morbidity that remain an issue for long-term survivors of these diseases. To extend CTL immunotherapy to all patients with relapsed lymphoma, regardless of the EBV status of their tumors, we have turned our attention to cancer testis antigens (CTAs), which are expressed by as many as 55% of the malignant cells in Hodgkin disease and survivin, which is expressed in the majority, and to strategies that might overcome the mechanisms that protect tumors from the cytotoxic effects of immunotherapy. Thus, in Aim 1, we propose to generate tumor-specific CTLs that recognize particular tumor antigens on EBV-negative Hodgkin tumors, such as survivin, MAGE-A4, SSX2, and SSX4, and then attempt to upregulate their expression on tumors by use of demethylating agents, including decitabine, both in vitro and in murine models. The safety, function and persistence of adoptively transferred CTA-specific CTL lines generated in Aim 1will be assessed in a Aim 2 in a Phase I trial enrolling patients with relapsed Hodgkin disease. The patients will also receive any demethylating agents found to be effective in upregulating CTAs in animal models. Finally, Aim 3 seeks to genetically modify the CTA-specific CTL lines to become resistant to Fas/FasL-mediated apoptosis and to circumvent the lethal anti-CTL consequences of indoleamine2,3- dioxygenase (IDO) expression by dendritic cells. Although restricted to preclinical models initially, these studies will ultimately be translated to clinical trials conducted outside the SPORE mechanism. Lay summary: Effective use of the immune system to combat cancer has been difficult because cancer cells have few features that are easily recognized by immune cells, such as T lymphocytes. In this project, scientists help T lymphocytes to recognize these features and will also attempt to find ways to avoid the tactics used by tumor cells to bypass the killing effects of T lymphocytes.
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