Long-Lived Antitumor CD8+ Lymphocytes for Adoptive Therapy Generated Using an Artificial Antigen-Presenting Cell

Abstract

Purpose: Antitumor lymphocytes can be generated ex vivo unencumbered by immunoregulation found in vivo. Adoptive transfer of these cells is a promising therapeutic modality that could establish long-term antitumor immunity. However, the widespread use of adoptive therapy has been hampered by the difficulty of consistently generating potent antitumor lymphocytes in a timely manner for every patient. To overcome this, we sought to establish a clinical grade culture system that can reproducibly generate antigen-specific cytotoxic T lymphocytes (CTL). Experimental Design: We created an off-the-shelf, standardized, and renewable artificial antigen-presenting cell (aAPC) line that coexpresses HLA class I, CD54, CD58, CD80, and the dendritic cell maturation marker CD83. We tested the ability of aAPC to generate tumor antigenspecific CTL under optimal culture conditions. The number, phenotype, effector function, and in vitro longevity of generated CTL were determined. Results: Stimulation of CD8+ Tcells with peptide-pulsed aAPC generated large numbers of functional CTL that recognized a variety of tumor antigens. These CTLs, which possess a phenotype consistent with in vivo persistence, survived ex vivo for prolonged periods of time. Clinical grade aAPC 33 , produced under current Good Manufacturing Practices guidelines, generated sufficient numbers of CTL within a short period of time. These CTL specifically lysed a variety of melanoma tumor lines naturally expressing a target melanoma antigen. Furthermore, antitumor CTL were easily generated in all melanoma patients examined. Conclusions: With clinical grade aAPC 33 in hand, we are now poised for clinical translation of ex vivo generated antitumor CTL for adoptive cell transfer.

Establishment and Characterization of a Cell Based Artificial Antigen-Presenting Cell for Expansion and Activation of CD8+ T Cells Ex Vivo

“…Artificial antigen-presenting systems encompass both cell-based and acellular technologies. Several diverse scaffoldding systems such as genetically engineered insect cells, mouse fibroblasts, human tumor cell lines (3,4,(11)(12)(13), microbeads, artificial liposomes, and biomembrane derivatives (exosomes, immunosomes) (14, 15) have been developed. However, the self-limitation of insect cells at 37 o C (the viable temperature for D. melanogaster cells is 27 o C) could lead to massive release of D. melanogaster antigens and limit the duration of the contact between the T cell and the aAPC (16,17).…”

“…The K562 cell-based aAPCs have several advantages over other aAPCs based on beads, insect cells, or biomembrane derivatives, such as negative MHC expression, mycoplasma free, better formation of the immunological synapse as a result of the fluidity of its membrane, well growth in serum-free medium (3,4,11,13). Due to the preferential binding of B7-2 to CD28 and B7-1 to CTLA-4, and both CD28 and B7-2 constitutively expressed on T cells and APCs, respectively, relatively week interaction between CD28 and B7-2 may suffice as an early co-stimulatory interaction to initiate T cell activation (6,7).…”

“…When the K32 cells were transfected with 4-1BBL which can preferentially activate CD8 + T cells, CD8 + T cells showed long-term expansion and survival (3). In addition, K32 cells also show constitutive expression of B7-H3, ICAM-1, and LFA-3 (3,4), all of which are ligands for costimulatory receptors other than CD28.…”

Adoptive cellular immunotherapy for childhood malignancies

“…For example, bead-derived or cell-based aAPC with enforced expression of desired HLA molecules have been used to expand tumor-specific T cells. [28][29][30][31][32][33] As an alternative source of APC, investigators have also used T cells, which can be nonspecifically propagated ex vivo to vast numbers by cross-linking CD3 with OKT3, as a source of antigen present cells (T-APC). [34][35][36][37] (iv) The safe and efficacious infusions of EBV-specific T cells for LPD has facilitated the targeting of other EBV-derived antigens associated with Hodgkin's disease (HD), and nasopharyngeal carcinoma (type II EBV malignancies) with investigators developing technologies to generate T cells with specificity for latency membrane protein (LMP) 1, LMP2 and EBNA-1.…”

Eliciting protective immune responses against murine myeloma challenge in lymphopenia mice through adoptive transfer of tumor antigen-specific lymphocytes and immunization of tumor vaccine secreting mIL-21

“…This immune strategy may deliver abundant tumor-specific immunocytes that are rapidly activated and proliferated in vitro. [1][2][3] The transferred immunocytes complement endogenetic immunocytes and release cytokines to regulate immune responses and to enhance the effect of immunotherapy. In particular, the lymphocytes emerging from the lymphopenia-induced homeostatic proliferation acquire the characteristics of effector/memory cells.…”