Proliferative, phenotypic and functional and molecular characteristics of tumour-infiltrating lymphocytes obtained from unselected patients with malignant melanomas and expanded in vitro in the presence of recombinant interleukin-2

Abstract

Tumour-infiltrating lymphocytes (TIL) derived from several histotypes, including melanoma, can be expanded in vitro in the presence of recombinant interleukin-2 (rIL-2) and infused as part of experimental adoptive immunotherapy protocols. Several authors have described the isolation and the expansion of TIL, but little is known about the actual proportion of unselected melanoma biopsies that give rise to 'positive' TIL cultures. We evaluated the proliferative, phenotypic, functional and molecular characteristics of cultured TIL obtained from 26 patients with metastatic melanomas, eligible for inclusion in a protocol of adoptive immunotherapy. Sixteen proliferating cultures were obtained. All TIL belonged to the T cell lineage and were characterized by a wide range of cytolytic activity against autologous and, to a lesser extent, allogeneic melanoma cells. Molecular analysis of the constant region of T cell receptor-beta (TCR-beta) showed an oligoclonal population of TIL in the majority of expanded samples, indicating that a selected subset of lymphocytes present in the tumour site could be expanded in vitro. These features, together with the high number of proliferating samples, make these populations of TIL suitable for infusion into patients with advanced disease.