[Show abstract][Hide abstract] ABSTRACT: Adoptive cell therapy (ACT) with tumor-reactive lymphocytes in patients with refractory melanoma can result in tumor regression and prolonged survival. Generating tumor-reactive lymphocyte cultures is technically difficult and resource intensive; these limitations have restricted the widespread application of ACT. Tumor-infiltrating lymphocytes (TIL) from melanoma contain tumor antigen-reactive cells. The "standard" method for producing TIL cultures for clinical administration requires extended in vitro expansion in interleukin-2, then identification of tumor-reactive cells by immunologic assays. We show here that limitations in reagents and methods during screening underrepresent the actual reactivity of TIL cultures. Furthermore, the extended culture times necessitated by the screening assays resulted in telomere shortening and reduced expression of CD27 and CD28 in the TIL cultures, properties that our prior studies showed are correlated with in vivo persistence and clinical response. We have thus developed an alternative "young" TIL method that demonstrated superior in vitro attributes compared with standard TIL. This approach uses the entire resected tumor to rapidly expand TIL for administration without in vitro testing for tumor recognition. Our observations suggest that younger TIL can have an undetermined but high level of antigen reactivity, and other advantageous attributes such as long telomeres and high levels of CD27 and CD28. We suggest that minimally cultured, unselected lymphocytes represent an alternative strategy for generating TIL cultures suitable for use in ACT that, if effective in vivo, may facilitate the widespread application of this approach to a broader population of patients with melanoma.
[Show abstract][Hide abstract] ABSTRACT: Adoptive cell transfer of tumor-infiltrating lymphocytes (TILs) after lymphodepletion mediates regression in 50% of patients with metastatic melanoma. In vivo persistence and telomere length of the transferred cells correlate with antitumor response. In an attempt to prolong the in vivo survival of the transferred cells, TILs were genetically engineered to produce interleukin (IL)-2. In vitro, these transduced TILs secreted IL-2 while retaining tumor specificity and exhibited prolonged survival after IL-2 withdrawal. In a phase I/II clinical trial, seven evaluable patients received transduced TILs and one patient experienced a partial response associated with in vivo persistence of IL-2-transduced TILs in circulating lymphocytes. An additional five patients received transduced TILs in conjunction with IL-2 administration. Persistence of IL-2-transduced TILs was observed in three patients, including one partial responder. The transgene DNA as well as vector-derived IL2 mRNA could be detected for 4 months in responding patients. The low response rate in this trial was possibly due to a reduction in telomere length in cells as a result of prolonged in vitro culture. In this study, insertion of the IL-2 gene into antitumor TILs increased their ability to survive after IL-2 withdrawal in vitro but did not increase their in vivo persistence or clinical effectiveness.
Human gene therapy 06/2008; 19(5):496-510. · 4.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The generation of T lymphocytes with specific reactivity against tumor antigens is a prerequisite for effective adoptive transfer therapies. Melanoma-specific lymphocyte cultures can be established from tumor infiltrating lymphocytes (TILs) by in vitro culture in high levels of IL-2. We have optimized methods for generating melanoma-reactive TIL cultures from small resected tumor specimens. We report a retrospective analysis of 860 attempted TIL cultures from 90 sequential melanoma biopsy specimens from 62 HLA-A2+ patients. Multiple independent TIL derived from a single tumor often exhibited substantial functional and phenotypic variation. Tumor specific activity was detected in TIL from 29 (81%) of 36 patients screened. TIL cultures selected for high activity were generally capable of large numerical expansion using a single round of a rapid expansion protocol. Limited clonal T-cell populations in an oligoclonal TIL culture could confer specific tumor recognition in these highly selected, highly expanded TIL cultures. These methods were efficient at generating TILs suitable for adoptive transfer therapy.
Journla of Immunotherapy 01/2003; 26(4):332-42. · 3.46 Impact Factor