In vivo manipulation of Vgamma9Vdelta2 T cells with zoledronate and low-dose interleukin-2 for immunotherapy of advanced breast cancer patients.

The potent anti-tumour activities of gammadelta T cells have prompted the development of protocols in which gammadelta-agonists are administered to cancer patients. Encouraging results from small Phase I trials have fuelled efforts to characterize more clearly the application of this approach to unmet clinical needs such as metastatic carcinoma. To examine this approach in breast cancer, a Phase I trial was conducted in which zoledronate, a Vgamma9Vdelta2 T cell agonist, plus low-dose interleukin (IL)-2 were administered to 10 therapeutically terminal, advanced metastatic breast cancer patients. Treatment was well tolerated and promoted the effector maturation of Vgamma9Vdelta2 T cells in all patients. However, a statistically significant correlation of clinical outcome with peripheral Vgamma9Vdelta2 T cell numbers emerged, as seven patients who failed to sustain Vgamma9Vdelta2 T cells showed progressive clinical deterioration, while three patients who sustained robust peripheral Vgamma9Vdelta2 cell populations showed declining CA15-3 levels and displayed one instance of partial remission and two of stable disease, respectively. In the context of an earlier trial in prostate cancer, these data emphasize the strong linkage of Vgamma9Vdelta2 T cell status to reduced carcinoma progression, and suggest that zoledronate plus low-dose IL-2 offers a novel, safe and feasible approach to enhance this in a subset of treatment-refractory patients with advanced breast cancer.

Nivolumab in metastatic melanoma: good efficacy and tolerability in elderly patients.

Background: Nivolumab is an anti-PD-1 antibody that restores the antitumour immune function of T cells, blocking the binding of PD-1 with its ligand PD-L1. PD-1 is expressed on T cells and interacts with PD-L1 on tumour cells. The PD-1-PD-L1 link inhibits T cell activation. In metastatic melanoma, PD-1-PD-L1 binding plays a critical role, and the advent of the immune checkpoint inhibitor nivolumab has delivered new and effective treatment options with proven clinical benefit. In the present study, we evaluated the efficacy of nivolumab in elderly patients with metastatic melanoma. Methods: The study enrolled 55 elderly patients (75 years of age and older) with a diagnosis of metastatic melanoma. Primary endpoints of the study were progression-free survival (pfs) and the objective response rate; secondary endpoints were overall survival, reduction in serum lactate dehydrogenase (ldh) from before to after treatment, and tolerability. Results: Nivolumab was well tolerated and resulted in good disease control, with a manageable toxicity profile and significant clinical benefit. The duration of pfs was 5.1 months (95% confidence interval: 3.5 months to 6.8 months). A significant correlation was observed between reduction in serum ldh and pfs: 0.60 (95% confidence interval: 0.28 to 0.86; p = 0.002). Conclusions: Nivolumab is an immunotherapy treatment that has proved to be an effective and well-tolerated therapeutic option in elderly patients with metastatic melanoma.

Γδ T Cell-Based Immunotherapy in Melanoma: State of the Art.

Metastatic melanoma is still associated with a poor prognosis, and there is increasing interest in immunotherapy alone or in combination with other adjuvant therapies. Γδ T lymphocytes play a pivot role in the immune response against cancer, but while γδ-based immunotherapy is already a clinical reality for several solid tumors, data on melanoma are still limited and fragmented. This systematic review presents preclinical and clinical evidence for a role of γδ T lymphocytes in immunotherapeutic strategies for advanced melanoma and discusses research state of the art and future perspectives. Current strategies focus on in vivo stimulation, and ex vivo adoptive therapy and vaccination; results are promising, but further studies are needed to better investigate the interactions in tumoral microenvironment and to improve clinical efficacy of immunotherapeutic protocols.

Distinctive features of tumor-infiltrating γδ T lymphocytes in human colorectal cancer.

γδ T cells usually infiltrate many different types of cancer, but it is unclear whether they inhibit or promote tumor progression. Moreover, properties of tumor-infiltrating γδ T cells and those in the corresponding normal tissue remain largely unknown. Here we have studied features of γδ T cells in colorectal cancer, normal colon tissue and peripheral blood, and correlated their levels with clinicopathologic hallmarks. Flow cytometry and transcriptome analyses showed that the tumor comprised a highly variable rate of TILs (5-90%) and 4% γδ T cells on average, with the majority expressing Vδ1. Most Vδ1 and Vδ2 T cells showed a predominant effector memory phenotype and had reduced production of IFN- Î³ which was likely due to yet unidentified inhibitory molecules present in cancer stem cell secretome. Transcriptome analyses revealed that patients containing abundant γδ T cells had significantly longer 5-year disease free survival rate, suggesting their efficacy in controlling tumor at very early stage.

In vitro effects of aminobisphosphonates on Vgamma9Vdelta2 T cell activation and differentiation.

In this study we have evaluated the in vitro effects of four different aminobisphosphonates, alendronate, risedronate, neridronate and zoledronate, on Vgamma9Vdelta2 T cell activation and differentiation. All tested aminobisphosphonates induce an IL-2-dependent activation and expansion of Vgamma9Vdelta2 T lymphocytes in primary PBMC cultures of healthy donors. Most notably, they also determine a different distribution of Vgamma9Vdelta2 T cell subsets, with decrease of T(naive) and T(CM) cells and increase of T(EM) and T(EMRA) Vgamma9Vdelta2cells, indicating that in vitro treatment with aminobisphosphonates induces Vgamma9Vdelta2 T lymphocytes to differentiate towards an effector/cytotoxic phenotype. Accordingly, Vgamma9Vdelta2 T lymphocytes cultured with aminobisphosphonates and IL-2 showed a major content of IFN-gamma and acquired the ability to kill tumor target cells.

Optimizing tumor-reactive γδ T cells for antibody-based cancer immunotherapy.

Monoclonal antibodies (mAbs) constitute the most rapidly growing class of human therapeutics and the second largest class of drugs after vaccines. The treatment of B-cell malignancies and HER2/Neu(+) breast cancer has benefited considerably from the use of therapeutic mAbs, either alone or in combination with standard chemotherapy. Frequent relapses, however, demonstrate that the bioactivity of these mAbs is still suboptimal. The concept of improving the anti-tumor activity of mAbs is well established and potentiating the cytotoxicity induced by anticancer mAbs can be achieved by strategies that target the downstream cytolytic effector cells. The recruitment of Fcγ receptor-dependent functions appears well suited in this regard, because several lines of evidence suggest that enhancing antibody-dependent cellular cytotoxicity (ADCC) induced by therapeutic mAbs may directly improve their clinical efficacy. The cytolytic effector cells involved in ADCC are FcγR-expressing natural killer (NK) cells, but also γδ T cells can be amplified and finetuned for stronger ADCC activity. γδ T cells are raising a considerable interest in the immunotherapy community given their intrinsic antitumor activity that can be boosted by stimulation with synthetic phosphoantigens (PAgs), or with drugs that cause their accumulation into target cells, like aminobisphosphonates (N-BPs), and low doses interleukin (IL)-2. The field is interesting, and several papers have already explored this approach in solid and haematological malignancies. Thus, we propose that enhancing the efficacy of mAbs by combination with γδ T cell activation may have considerable therapeutic potential for a variety of malignancies, most especially for patients whose FcγR alleles impair ADCC.

Cytokine profile, HLA restriction and TCR sequence analysis of human CD4+ T clones specific for an immunodominant epitope of Mycobacterium tuberculosis 16-kDa protein.

The identification of immunodominant and universal mycobacterial peptides could be applied to vaccine design and have an employment as diagnostic reagents. In this paper we have investigated the fine specificity, clonal composition and HLA class II restriction of CD4+ T cell clones specific for an immunodominant epitope spanning amino acids 91-110 of the 16-kDa protein of Mycobacterium tuberculosis. Twenty-one of the tested 28 clones had a Th1 profile, while seven clones had a Th0 profile. None of the clones had a Th2 profile. While the TCR AV gene usage of the clones was heterogeneous, a dominant TCR BV2 gene family was used by 18 of the 28 clones. The CDR3 regions of BV2+ T cell clones showed variation in lengths, but a putative common motif R-L/V-G/S-Y/W-E/D was detected in 13 of the 18 clones. Moreover, the last two to three residues of the putative CDR3 loops, encoded by conserved BJ sequences, could also play a role in peptide recognition. Antibody blockade and fine restriction analysis using HLA-DR homozygous antigen-presenting cells established that 16 of 18 BV2+ peptide-specific clones were DR restricted and two clones were DR-DQ and DR-DP restricted. Additionally, five of the 18 TCRBV2+ clones recognized peptide 91-110 in association with both parental and diverse HLA-DR molecules, indicating their promiscuous recognition pattern. The ability of peptide 91-110 to bind a wide range of HLA-DR molecules, and to stimulate a Th1-type interferon (IFN)-gamma response more readily, encourage the use of this peptide as a subunit vaccine component.

A human leucocyte antigen-DR1 transgene confers susceptibility to experimental allergic encephalomyelitis elicited by an epitope of myelin basic protein.

Much evidence now indicates that human leucocyte antigen (HLA) class I and class II transgenic (Tg) mice can be of value in analysing HLA-restricted presentation of T-cell epitopes relevant to experimental models of autoimmune diseases. One area where this has been applied is the characterization of myelin epitopes presented by HLA class II molecules in experimental model of multiple sclerosis (experimental allergic encephalomyelitis (EAE)). As a first step towards humanized disease models in HLA Tg mice, we have analysed immune response of lymph node cells of HLA-DR1 Tg mice immunized with the human myelin basic protein (MBP) peptides 13-33, 87-106 and 139-154 bound by HLA-DR1. We report here that HLA-DR1 Tg mice display a hierarchy of response in vivo and in vitro to MBP epitopes depending on the binding affinity to DRB*0101 molecule. In fact, the 13-33 epitope induced a strong T helper 1 (Th1) response accompanied by high T-cell precursor frequency and caused mild EAE, while the two other epitopes gave poor (139-154) or no disease (87-106), and these data correlate with in vitro Th1 response. These data could prove a useful tool in understanding the role played by different MBP epitopes in EAE.