Generation of tumour-specific cytotoxic T-cell clones from histocompatibility leucocyte antigen-identical siblings of patients with melanoma

Linking antigen specific T-cell dynamics in a microfluidic chip to single cell transcription patterns

A new non-invasive screening profile has been realized that can aid in determining T-cell activation state at single-cell level. Production of activated T-cells with good specificity and stable proliferation is greatly beneficial for advancing adoptive immunotherapy as innate immunological cells are not effective in recognizing and eliminating cancer as expected. The screening method is realized by relating intracellular Ca²⁺ intensity and motility of T-cells interacting with APC (Antigen Presenting Cells) in a microfluidic chip. The system is tested using APC pulsed with OVA_257-264 peptide and its modified affinities (N4, Q4, T4 and V4), and the T-cells from OT-1 mice. In addition, single cell RNA sequencing reveals the activation states of the cells and the clusters from the derived profiles can be indicative of the T-cell activation state. The presented system here can be versatile for a comprehensive application to proceed with T-cell-based immunotherapy and screen the antigen-specific T-cells with excellent efficiency and high proliferation.

Ex vivo enrichment of PRAME antigen-specific T cells for adoptive immunotherapy using CD137 activation marker selection

Objective

Adoptive immunotherapy with ex vivo expanded tumor‐specific T cells has potential as anticancer therapy. Preferentially expressed antigen in melanoma (PRAME) is an attractive target overexpressed in several cancers including melanoma and acute myeloid leukaemia (AML), with low expression in normal tissue outside the gonads. We developed a GMP‐compliant manufacturing method for PRAME‐specific T cells from healthy donors for adoptive immunotherapy.

Methods

Mononuclear cells were pulsed with PRAME 15‐mer overlapping peptide mix. After 16 h, activated cells expressing CD137 were isolated with immunomagnetic beads and cocultured with irradiated CD137^neg fraction in medium supplemented with interleukin (IL)‐2, IL‐7 and IL‐15. Cultured T cells were restimulated with antigen‐pulsed autologous cells after 10 days. Cellular phenotype and cytokine response following antigen re‐exposure were assessed with flow cytometry, enzyme‐linked immunospot (ELISPOT) and supernatant cytokine detection. Detailed phenotypic and functional analysis with mass cytometry and T‐cell receptor (TCR) beta clonality studies were performed on selected cultures.

Results

PRAME‐stimulated cultures (n = 10) had mean expansion of 2500‐fold at day 18. Mean CD3⁺ percentage was 96% with CD4:CD8 ratio of 4:1. Re‐exposure to PRAME peptide mixture showed enrichment of CD4 cells expressing interferon (IFN)‐γ (mean: 12.2%) and TNF‐α (mean: 19.7%). Central and effector memory cells were 23% and 72%, respectively, with 24% T cells expressing PD1. Mass cytometry showed predominance of Th1 phenotype (CXCR3⁺/CCR4^neg/CCR6^neg/Tbet⁺, mean: 73%) and cytokine production including IL‐2, IL‐4, IL‐8, IL‐13 and GM‐CSF (2%, 6%, 8%, 4% and 11%, respectively).

Conclusion

PRAME‐specific T cells for adoptive immunotherapy were enriched from healthy donor mononuclear cells. The products were oligoclonal, exhibited Th1 phenotype and produced multiple cytokines.

Adoptive immunotherapy against sarcomas

INTRODUCTION

Conventional treatments reached an unsatisfactory therapeutic plateau in the treatment of advanced unresectable bone and soft tissue sarcomas that remain an unsolved medical need. Several evidences support the concept that adoptive immunotherapy may effectively integrate within the complex and multidisciplinary treatment of sarcomas.

AREAS COVERED

In this work we reviewed adoptive immunotherapy strategies that have been explored in sarcoma settings, with specific focus on issues related to their clinic transferability. We schematically divided approaches based on T lymphocytes specific for MHC-restricted tumor-associated antigens or relying on MHC-independent immune effectors such as natural killer (NK), cytokine-induced killer (CIK) or γδ T cells.

EXPERT OPINION

Preclinical findings and initial clinical reports showed the potentialities and drawbacks of different adoptive immunotherapy strategies. The expansion of tumor infiltrating lymphocytes is difficult to be reproduced outside melanoma. Genetically redirected T cells appear to be a promising option and initial reports are encouraging against patients with sarcomas. Adoptive immunotherapy with MHC-unrestricted effectors such as NK, CIK or γδ T cells has recently shown great preclinical potential in sarcoma setting and biologic features that may favor clinical transferability. Combination of different immunotherapy approaches and integration with conventional treatments appear to be key issues for successful designing of next clinical trials.

Aberrant expression of BCL2A1-restricted minor histocompatibility antigens in melanoma cells: application for allogeneic transplantation

It has been shown that allogeneic hematopoietic stem cell transplantation (HSCT) can be one of the therapeutic options for patients with metastatic solid tumors, such as renal cancer. However, the development of relatively severe GVHD seems to be necessary to achieve tumor regression in the current setting. Thus, it is crucial to identify minor histocompatibility antigens (mHags) only expressed in tumor cells but not GVHD target organs. In this study, we examined whether three mHags: ACC-1 and ACC-2 encoded by BCL2A1, and HA-1 encoded by HMHA1, could serve as such targets for melanoma. Real-time PCR and immunohistochemical analysis revealed that the expression of both BCL2A1and HMHA1 in melanoma cell lines and primary melanoma cells was comparable to that of hematopoietic cells. Indeed, melanoma cell lines were efficiently lysed by cytotoxic T lymphocytes specific for ACC-1, ACC-2, and HA-1. Our data suggest that targeting mHags encoded not only by HMHA1, whose aberrant expression in solid tumors has been reported, but also BCL2A1 may bring about beneficial selective graft-versus-tumor effects in a population of melanoma patients for whom these mHags are applicable.

Rapid expansion of tumor-reactive cells from HLA-matched siblings for adoptive immunotherapy of melanoma

BACKGROUND

Administration of expanded tumor-infiltrating lymphocytes in association with lymphodepleting chemotherapy is effective in some patients with advanced malignant melanoma. However, obtaining lymphocytes and subsequent expansion is labor intensive, making it impractical for broad clinical application. Allogeneic transplantation may have anti-melanoma efficacy because of a graft vs. tumor effect. The disappointing tumor control observed post-transplant suggests that adoptive immunotherapy using melanoma-reactive cells will be essential for sustained responses.

METHODS

Melanoma cell lines were grown from two patients with advanced disease. High-level CD80 and CD86 expression was obtained in the tumor lines using a retroviral vector for gene transfer. Transduced melanoma and controls were cultured with mononuclear cells from HLA-identical sibling donors.

RESULTS

Expression of CD80 and CD86, particularly the former, promoted marked expansion of lymphocytes from HLA-matched sibling donors. Proliferation of up to 300-fold after 4 weeks of culture was observed. Lymphocytes from cultures stimulated with CD80 demonstrated cytotoxicity against recipient-untransfected melanoma (45-75% specific lysis at an E:T ratio of 50:1). Although expanded lymphocytes were predominantly CD4(+), cytotoxicity was greatest in the numerically smaller CD8(+) subpopulation. Both CD4(+) and CD8(+) cells secreted IFN-gamma (but not IL-4) on exposure to untransduced stimulator melanoma cells.

DISCUSSION

Our strategy generates a large number of melanoma-reactive lymphocytes from HLA-identical siblings using a 4-week culture strategy. Lymphocytes expanded in this way offer an alternative to tumor-infiltrating lymphocytes for allogeneic cellular immunotherapy after stem cell transplantation in young patients.