Neuroblastoma (NB) is a pediatric extracranial tumor characterized by downregulation of human leukocyte antigen class I and defects of the antigen processing machinery, two features that make it an appropriate target for natural killer (NK)-mediated lysis. NKG2D is an activating immunoreceptor expressed by cytotoxic T lymphocytes and NK cells. The ligands for NKG2D are the major histocompatibility complex class I-related chain (MIC)A and MICB glycoproteins, and the UL-16-binding proteins (ULBPs). Here, the expression of NKG2D ligands was investigated in human primary NB tumors and cell lines because scanty information is available on this issue. MICA, MICB, and ULBP transcripts were found in most tumors and cell lines. MICA protein was detected in some NB cell lines but not in primary tumors. A soluble form of MICA (sMICA) was identified in most patient sera and in some cell line supernatants. sMICA downregulated surface NKG2D in normal peripheral blood CD8(+) cells and decreased NK-mediated killing of MICA(+) NB cells. MICB was detected exclusively in the cytosol of primary tumors and cell lines. Approximately 50% of primary tumors expressed ULBP-2, but not ULBP-1 or -3. ULBP-3 was expressed in 5 of 9 cell lines, ULBP-2 in 2 of 9, whereas ULBP-1 was never detected. These studies delineate novel potential pathways of tumor escape and immunodeficiency in NB.

Key Points: Vδ1 and Vδ2 T cells promptly reconstitute in children given haploidentical stem cell transplantation depleted of αβ+ T and CD19+ B cells. Vδ1 cells are expanded in patients experiencing cytomegalovirus reactivation; ZOL potentiates Vδ2 killing against leukemia blasts.

γδ T cells have recently gained considerable attention as an attractive tool for cancer adoptive immunotherapy due to their potent anti-tumor activity and unique role in immunosurveillance. The remarkable success of engineered T cells for the treatment of hematological malignancies has revolutionized the field of adoptive cell immunotherapy. Accordingly, major efforts are underway to translate this exciting technology to the treatment of solid tumors and the development of allogeneic therapies. The unique features of γδ T cells, including their major histocompatibility complex (MHC)-independent anti-cancer activity, tissue tropism, and multivalent response against a broad spectrum of the tumors, render them ideal for designing universal ‘third-party’ cell products, with the potential to overcome the challenges of allogeneic cell therapy. In this review, we describe the crucial role of γδ T cells in anti-tumor immunosurveillance and we summarize the different approaches used for the ex vivo and in vivo expansion of γδ T cells suitable for the development of novel strategies for cancer therapy. We further discuss the different transduction strategies aiming at redirecting or improving the function of γδ T cells, as well as, the considerations for the clinical applications.

IL-27 induces the expression of IDO and PD-L1 in human cancer cells

The interleukin-12 receptor β2 (Il12rb2) gene is silenced in tumor cells from different human B-cell malignancies as opposed to their normal counterparts. It was hypothesized that this silencing allows neoplastic B cells to escape the control exerted by IL-12 on their growth. The aim of this study was to investigate whether targeted inactivation of the Il12rb2 gene in mice resulted into increased susceptibility to spontaneous tumor formation and immunopathology. Il12rb2 gene–deficient animals developed in the first year of life immune-complex mesangial glomerulonephritis with serum antinuclear antibodies. In older animals, multiorgan lymphoid infiltrates with features of vasculitis and Sjögren syndrome were detected in association with systemic B- and T-cell activation. In half of aged animals, lymph node plasmacytoma or lung carcinoma was observed. A mechanism for spontaneous development of autoimmune pathology and B-cell tumors is suggested by a strong IL-6 up-regulation detected in splenocytes and lymphoid infiltrates associated with oligoclonal B-cell expansion. The emergence of lung tumors may likely be attributed to an interferon-γ (IFN-γ) deficiency secondary to lack of IL-12 signaling. The development of autoimmunity, lymphoproliferation, and B-cell tumors in Il12rb2 knockout (KO) mice suggests that IL-12 functions physiologically to restrain aberrant B-cell activation.