pyrophosphate and bromohydrin-pyrophosphate

Vgamma9Vdelta2 (gammadelta) T lymphocytes, a critical peripheral blood lymphocyte subset, are directly cytotoxic against many solid and hematologic tumor types. Vgamma9Vdelta2 T lymphocytes can be selectively expanded in vivo with BrHPP (IPH1101) and IL-2. The present phase I trial was conducted with the aim of determining the maximum-tolerated dose (MTD) and safety of IPH1101 combined with a low dose of IL-2 in patients with solid tumors.. A 1-h intravenous infusion of IPH11 was administered alone at cycle 1, combined with a low dose of SC IL-2 (1 MIU/M(2) d1 to d7) in the subsequent cycles (day 1 every 3 weeks). The dose of IPH1101 was escalated from 200 to 1,800 mg/m(2).. As much as 28 patients with solid tumors underwent a total of 109 treatment cycles. Pharmacodynamics data demonstrate that gammadelta T lymphocyte amplification in humans requires the co-administration of IL-2 and is dependent on IPH 1101 dose. Dose-limiting toxicity occurred in two patients at a dose of 1,800 mg/m(2): one grade 3 fever (1 patient) and one grade 3 hypotension (1 patient) suggesting cytokine release syndrome immediately following the first infusion. At lower doses the treatment was well tolerated; the most frequent adverse events were mild fever, chills and abdominal pain, without exacerbation in the IL-2 combined cycles.. IPH1101 in combination with SC low-dose IL-2 is safe, well tolerated and induces a potent gammadelta T lymphocyte expansion in patients. Its clinical activity will be evaluated in phase II clinical trials.

Topics: Adult; Aged; Antineoplastic Agents; Diphosphates; Dose-Response Relationship, Drug; Female; Humans; Interleukin-2; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; T-Lymphocyte Subsets; T-Lymphocytes

Human Vγ9Vδ2 γδ T cells can kill a variety of cancer cells and have attracted substantial interest for cancer immunotherapy. Toll-like receptor (TLR) ligands are promising adjuvants for cancer immunotherapy, but TLR7/8 ligand Resiquimod has been shown to inhibit CD4 T-cell activation in a monocyte-dependent manner. Therefore, we studied the modulation of human γδ T-cell activation by TLR7/8 ligands.. Peripheral blood mononuclear cells (PBMC) or purified γδ T cells together with purified monocytes were stimulated with zoledronic acid or phosphoantigens in the absence or presence of various imidazoquinoline TLR7 or TLR8 agonists. Read-out systems included interferon-γ induction and cellular expansion of γδ T cells, as well as viability, cell surface antigen modulation, and IL-1β and TNF-α production of monocytes.. TLR8 ligand TL8-506 and TLR7/8 ligand Resiquimod (but not TLR7 ligands) rapidly induced IFN-γ expression in γδ T cells within PBMC, and co-stimulated phosphoantigen-induced IFN-γ expression in γδ T cells. On the other hand, TLR8 ligands potently suppressed γδ T-cell expansion in response to zoledronic acid and phosphoantigen. Purified monocytes secreted large amounts of IL-1β and TNF-α when stimulated with TLR8 ligands but simultaneously underwent substantial cell death after 24 h.. TLR8 ligand-activated monocytes potently co-stimulate early γδ T-cell activation but failed to provide accessory cell function for in vitro expansion of γδ T cells.

Topics: Cell Death; Cell Proliferation; Diphosphates; Humans; Imidazoles; Interferon-gamma; Interleukin-1beta; Intraepithelial Lymphocytes; Ligands; Lymphocyte Activation; Monocytes; Organophosphates; Toll-Like Receptor 7; Toll-Like Receptor 8; Tumor Necrosis Factor-alpha; Zoledronic Acid

γδ T cells are of interest as effector cells for cellular immunotherapy due to their HLA-non-restricted lysis of many different tumor cell types. Potential applications include the adoptive transfer of in vitro-expanded γδ T cells. Therefore, it is important to optimize the culture conditions to enable maximal proliferative and functional activity. Vitamin C (L-ascorbic acid) is an essential vitamin with multiple effects on immune cells. It is a cofactor for several enzymes, has antioxidant activity, and is an epigenetic modifier. Here, we investigated the effects of vitamin C (VC) and its more stable derivative, L-ascorbic acid 2-phosphate (pVC), on the proliferation and effector function of human γδ T cells stimulated with zoledronate (ZOL) or synthetic phosphoantigens (pAgs). VC and pVC did not increase γδ T-cell expansion within ZOL- or pAg-stimulated PBMCs, but increased the proliferation of purified γδ T cells and 14-day-expanded γδ T-cell lines in response to γδ T-cell-specific pAgs. VC reduced the apoptosis of γδ T cells during primary stimulation. While pVC did not prevent activation-induced death of pAg-restimulated γδ T cells, it enhanced the cell cycle progression and cellular expansion. Furthermore, VC and pVC enhanced cytokine production during primary activation, as well as upon pAg restimulation of 14-day-expanded γδ T cells. VC and pVC also increased the oxidative respiration and glycolysis of γδ T cells, but stimulus-dependent differences were observed. The modulatory activity of VC and pVC might help to increase the efficacy of γδ T-cell expansion for adoptive immunotherapy.

Topics: Adult; Antigens; Ascorbic Acid; Biomarkers; Cell Cycle; Cell Death; Cell Line; Cell Proliferation; Diphosphates; Humans; Ki-67 Antigen; Leukocytes, Mononuclear; Phosphorylation; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocytes; Zoledronic Acid

Human γδ T cells are innate-like T cells which are able to kill a broad range of tumour cells and thus may have potential for cancer immunotherapy. The activating receptor natural killer group 2 member D (NKG2D) plays a key role in regulating immune responses driven by γδ T cells. Here, we explored whether recombinant immunoligands consisting of a CD20 single-chain fragment variable (scFv) linked to a NKG2D ligand, either MHC class I chain-related protein A (MICA) or UL16 binding protein 2 (ULBP2), could be employed to engage γδ T cells for tumour cell killing. The two immunoligands, designated MICA:7D8 and ULBP2:7D8, respectively, enhanced cytotoxicity of ex vivo-expanded γδ T cells against CD20-positive lymphoma cells. Both Vδ1 and Vδ2 γδ T cells were triggered by MICA:7D8 or ULBP2:7D8. Killing of CD20-negative tumour cells was not induced by the immunoligands, indicating their antigen specificity. MICA:7D8 and ULBP2:7D8 acted in a dose-dependent manner and induced cytotoxicity at nanomolar concentrations. Importantly, chronic lymphocytic leukaemia (CLL) cells isolated from patients were sensitized by the two immunoligands for γδ T cell cytotoxicity. In a combination approach, the immunoligands were combined with bromohydrin pyrophosphate (BrHPP), an agonist for Vδ2 γδ T cells, which further enhanced the efficacy in target cell killing. Thus, employing tumour-directed recombinant immunoligands which engage NKG2D may represent an attractive strategy to enhance antitumour cytotoxicity of γδ T cells.

Topics: Antigens, CD20; Cytotoxicity, Immunologic; Diphosphates; Drug Therapy, Combination; GPI-Linked Proteins; Histocompatibility Antigens Class I; Humans; Immunization; Immunotherapy; Intercellular Signaling Peptides and Proteins; Lymphoma; NK Cell Lectin-Like Receptor Subfamily K; Receptors, Antigen, T-Cell, gamma-delta; Single-Chain Antibodies; T-Lymphocytes; Tumor Cells, Cultured

The availability of specific stimuli to induce the anticancer cytotoxicity of human TCRVγ9-expressing T lymphocytes has allowed the development of γδ T cell-based cancer immunotherapies. However, the stringent dependence of such strategies on the inherently toxic IL-2 has raised safety concerns for patients, justifying a search for alternative methods for inducing γδ T cell stimulation. IL-33 is a γ-chain receptor-independent cytokine of the IL-1 superfamily that is expressed by endothelial cells from a tumor microenvironment and can sustain Th1 and Th2 immune responses. Therefore, we investigated its ability to support the stimulation of human TCRVγ9(+) γδ T cells. In this study, we report that IL-33 efficiently sustained the in vitro activation of Vγ9 T lymphocytes by synthetic phosphoantigens, zoledronate, and a BTN3A1 Ab in the absence of an exogenous supply of IL-2. IL-33 was as potent as IL-2 in allowing the proliferative amplification of Vγ9 T cells isolated from PBMC following activation by the synthetic phosphoantigen bromohydrin pyrophosphate. IL-33 also induced an identical maturation into TNF-α- and IFN-γ-producing Th1 effector memory cells, and IL-33-stimulated cells showed an equivalent cytotoxicity for various tumor cells in vitro. Finally, we found that the bioactivity of IL-33 on the Vγ9 T cell was indirectly mediated through contact with CD4 T cells and IL-2 production by CD4 T cells and Vγ9 T cells themselves. These data posit IL-33 as an alternative to IL-2 for Vγ9 T cell-based cancer immunotherapies.

Topics: Antigens, CD; Butyrophilins; Cell Proliferation; Cells, Cultured; Diphosphates; Diphosphonates; Endothelial Cells; Humans; Imidazoles; Immunotherapy; Interferon-gamma; Interleukin-2; Interleukin-33; Leukocytes, Mononuclear; Lymphocyte Activation; Neoplasms; Receptors, Antigen, T-Cell, gamma-delta; Th1 Cells; Tumor Necrosis Factor-alpha; Zoledronic Acid

Vγ9Vδ2 cells are cytotoxic T cells that are able to recognize epithelial ovarian carcinoma (EOC) cells. Therefore, Vγ9Vδ2 cell-based adoptive transfer is an attractive therapy for EOC. However, the inefficient ex vivo expansion after specific stimulation of Vγ9Vδ2 cells from some patients and the relationships between Vγ9Vδ2 cells and clinical course of EOC are issues that remain to be clarified. Herein, peripheral blood mononuclear cells (PBMCs) from 60 EOC patients were stimulated with bromohydrin pyrophosphate (BrHPP) or zoledronate, which are specific agonists of Vγ9Vδ2 cells. The compounds differed in their efficacies to induce ex vivo Vγ9Vδ2 PBMC expansion, but 16/60 samples remained inefficiently expanded with both stimuli. Interestingly, the Vγ9Vδ2 cells in these low-responding PBMCs displayed before expansion (ex vivo PBMCs) an altered production of the pro-inflammatory cytokines IFN-γ and TNF-α, a decreased naive fraction and a reduced frequency. No evidence of an involvement of CD4(+)CD25(+)Foxp3(+) regulatory cells was observed. Importantly, our data also demonstrate that a Vγ9Vδ2 cell frequency of 0.35% or less in EOC PBMCs could be used to predict low responses to both BrHPP and zoledronate. Moreover, our data highlight that such a deficiency is not correlated with advanced EOC stages but is associated with more refractory states to platinum-based chemotherapy and is an independent predictor of shorter disease-free survival after treatment. These results are the first to suggest a potential contribution of Vγ9Vδ2 cells to the anti-tumor effects of chemotherapeutic agents and they strengthen interest in strategies that might increase Vγ9Vδ2 cells in cancer patients.

Topics: Aged; Biomarkers, Tumor; Carcinoma, Ovarian Epithelial; CD3 Complex; Cell Proliferation; Cells, Cultured; Combined Modality Therapy; Diphosphates; Diphosphonates; Disease-Free Survival; Drug Resistance, Neoplasm; Humans; Imidazoles; Interferon-gamma; Middle Aged; Neoplasms, Glandular and Epithelial; Ovarian Neoplasms; Prognosis; Survival Analysis; T-Lymphocytes, Cytotoxic; T-Lymphocytes, Regulatory; Treatment Outcome; Tumor Necrosis Factor-alpha; Zoledronic Acid

Phosphoantigens enable the access to a new anti-tumoral and anti-infectious therapeutic pathway, based on innate immunity through the selective activation of Tγ9δ2 lymphocytes. The first proof of concept of this new immunotherapy approach was demonstrated with the synthetic phosphoantigen named bromohydrin pyrophosphate (BrHPP, IPH 1101) which was administrated in racemic form to about 200 patients in six clinical trials with good safety and promising early signals of efficacy in type C viral hepatitis and follicular non-Hodgkin's lymphoma. Enantiopure samples of BrHPP in gram scale are required for further studies on structure-bioactivity relationship. Thus we developed two complementary synthetic pathways, the first using transformation of a chiral compound and the second involving asymmetric synthesis starting from a prochiral building-block. The synthesis of a second-generation phosphoantigen, N-HDMAPP, which bears a phosphoramidate moiety, was also investigated.

Topics: Diphosphates; Humans; Immunotherapy; Molecular Structure; Neoplasms; Organophosphorus Compounds; Stereoisomerism

Anti-CD20 monoclonal antibodies are major therapeutic agents for patients with follicular lymphoma and work through complement-mediated cytotoxicity and antibody-dependent cellular cytotoxicity. Optimization of antibody-dependent cellular cytotoxicity, in particular by amplifying its effectors, could further increase the efficacy of anti-CD20 monoclonal antibodies.. We investigated the cytotoxic activity of Vγ9Vδ2 T cells against follicular lymphoma cells and whether this killing could be increased by promoting antibody-dependent cellular cytotoxicity with anti-CD20 monoclonal antibodies, in particular a type-II glycoengineered anti-CD20. Vγ9Vδ2 T cells were expanded in vitro in the presence of bromohydrin pyrophosphate (Phosphostim) and interleukin-2 and their ability to kill follicular lymphoma primary cells or cell lines was evaluated by flow cytometry cytotoxic T-lymphocyte assays in the presence or absence of three anti-CD20 monoclonal antibodies: the afucosylated GA101, the chimeric rituximab or the humanized ofatumumab. The ability of these cells to release perforin/granzyme and secrete interferon-γ when co-cultured with follicular lymphoma primary cells or cell lines in the presence or not of the three anti-CD20 monoclonal antibodies was also evaluated by CD107a staining and Elispot assays.. Phosphostim and interleukin-2 expanded Vγ9Vδ2 T cells were cytotoxic to primary follicular lymphoma cells and their cytotoxic potential was dramatically increased by GA101, a type II glycoengineered anti-CD20 monoclonal antibody, and to a lesser extent, by rituximab and ofatumumab. The increased cytotoxicity was associated with increased secretion of perforin/granzyme and interferon-γ.. In-vitro expanded Vγ9Vδ2 T cells efficiently kill primary follicular lymphoma cells and express CD16; anti-CD20 monoclonal antibodies, in particular GA101, dramatically increase the cytotoxic activity of expanded Vγ9Vδ2 T cells. These preclinical results prompt the development of clinical trials using this antibody dependent cellular cytotoxicity property of Vγ9Vδ2 T cells and anti-CD20 monoclonal antibodies.

Topics: Antibodies, Blocking; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal, Murine-Derived; Antibody-Dependent Cell Cytotoxicity; Antigens, CD20; B-Lymphocytes; Cell Culture Techniques; Cell Line, Tumor; Coculture Techniques; Diphosphates; Female; Flow Cytometry; Glycoproteins; Granzymes; Humans; Interferon-gamma; Interleukin-2; Lymphocyte Activation; Lymphoma, Follicular; Male; Middle Aged; Perforin; Rituximab; T-Lymphocytes, Cytotoxic

Human gammadelta cells expressing TCRVgamma9 are HLA-unrestricted CTLs with high relevance for cancer immunotherapy. Many tumor cell types produce TGF-beta, however, a cytokine strongly immunosuppressive for conventional T CD4, CD8, and NK cells. Whether TGF-beta also inhibits TCRVgamma9+ lymphocytes was unknown. Because phosphoantigens (PAgs), such as bromohydrin pyrophosphate, selectively activate the antitumor functions of TCRVgamma9+ T cells, in this study, we investigated whether TGF-beta modulates these functions. We report that TGF-beta does not block activation of TCRVgamma9+ T cells but inhibits their PAg/IL-2-induced proliferation and maturation into effector cells and finally reduces the cytotoxic activity of these gammadelta T cells when exposed to lymphoma target cells. TGF-beta did not bias their differentiation pattern toward gammadelta Th17 or gammadelta regulatory T cells. Nevertheless, increasing doses of PAg stimulus countered TGF-beta inhibition. So, although TGF-beta impairs TCRVgamma9+ gammadelta cells like other cytolytic lymphocytes, PAg alone or combined to therapeutic mAb has the ability to bypass its immunosuppressive activity.

Topics: Antigens; Cell Differentiation; Cell Proliferation; Cell Separation; Diphosphates; Flow Cytometry; Humans; Immune Tolerance; Immunotherapy; Lymphocyte Activation; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocyte Subsets; T-Lymphocytes, Cytotoxic; Transforming Growth Factor beta

Hepatocellular carcinoma (HCC) and colorectal carcinoma with hepatic metastases (mCRC) are cancers with poor prognosis and limited therapeutic options. New approaches are needed and adoptive immunotherapy with Vgamma9Vdelta2 T lymphocytes represents an attractive strategy. Indeed, Vgamma9Vdelta2 T cells were shown to exhibit efficient lytic activity against various human tumor cell lines, and in vitro Vgamma9Vdelta2 T expansion protocol based on single phosphoantigen stimulation could be easily performed for healthy donors. However, a low proliferative response of Vgamma9Vdelta2 T cells was observed in about half of the cancer patients, leading to an important limitation in the development of Vgamma9Vdelta2 T cell-based immunotherapy. Here, for the first time in the context of cancer patients, Vgamma9Vdelta2 T cell expansions were performed by co-culturing peripheral blood mononuclear cell (PBMCs) with autologous dendritic cells (DCs) pretreated with aminobisphosphonate zoledronate. For patients not responding to the conventional culture protocol, co-culture of PBMC with zoledronate-pretreated DCs induced strong cell expansion and allowed reaching a minimal rate of purity of 70% of Vgamma9Vdelta2 T cells. The potent immunostimulatory activity of zoledronate-treated DCs was associated with higher amount of isopentenyl pyrophosphate (IPP) in the culture and was correlated with better ability to activate Vgamma9Vdelta2 T cells as measured by IFN-gamma production. Moreover, we demonstrated that the cytotoxic level of Vgamma9Vdelta2 T cells against freshly autologous tumor cells isolated from patients could be significantly increased by pretreating the tumor cells with zoledronate. Thus, this method of generating Vgamma9Vdelta2 T cells leads eligible for Vgamma9Vdelta2 T cell adoptive immunotherapy the HCC and mCRC patients.

Topics: Adenocarcinoma; Aged; Blotting, Western; Bone Density Conservation Agents; Carcinoma, Hepatocellular; Cell Differentiation; Cell Proliferation; Coculture Techniques; Colorectal Neoplasms; Cytotoxicity, Immunologic; Dendritic Cells; Diphosphates; Diphosphonates; Female; Flow Cytometry; Hemiterpenes; Humans; Imidazoles; Immunotherapy, Adoptive; Liver Neoplasms; Male; Middle Aged; Organophosphorus Compounds; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocyte Subsets; Zoledronic Acid

Tumour growth promotes the expansion of CD4(+) CD25(+) FoxP3(+) regulatory T cells (Tregs) which suppress various arms of immune responses and might therefore contribute to tumour immunosurveillance. In this study, we found an inverse correlation between circulating Treg frequencies and phosphoantigen-induced gammadelta T-cell proliferation in cancer patients, which prompted us to address the role of Tregs in controlling the gammadelta T-cell arm of innate immune responses. In vitro, human Treg-peripheral blood mononuclear cell (PBMC) co-cultures strongly inhibited phosphoantigen-induced proliferation of gammadelta T cells and depletion of Tregs restored the impaired phosphoantigen-induced gammadelta T-cell proliferation of cancer patients. Tregs did not suppress other effector functions of gammadelta T cells such as cytokine production or cytotoxicity. Our experiments indicate that Tregs do not mediate their suppressive activity via a cell-cell contact-dependent mechanism, but rather secrete a soluble non-proteinaceous factor, which is independent of known soluble factors interacting with amino acid depletion (e.g. arginase-diminished arginine and indolamine 2,3-dioxygenase-diminished tryptophan) or nitric oxide (NO) production. However, the proliferative activity of alphabeta T cells was not affected by this cell-cell contact-independent suppressive activity induced by Tregs. In conclusion, these findings indicate a potential new mechanism by which Tregs can specifically suppress gammadelta T cells and highlight the strategy of combining Treg inhibition with subsequent gammadelta T-cell activation to enhance gammadelta T cell-mediated immunotherapy.

Topics: Antigens; Cell Communication; Cell Proliferation; Cells, Cultured; Cytotoxicity, Immunologic; Diphosphates; Forkhead Transcription Factors; Humans; Immune Tolerance; Immunity, Innate; Interleukin-2 Receptor alpha Subunit; Lymphocyte Culture Test, Mixed; Neoplasms; Phosphoproteins; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocyte Subsets; T-Lymphocytes, Regulatory; Tumor Cells, Cultured

In human blood, 1% to 5% of lymphocytes are gammadelta T cells; they mostly express the gammadelta T-cell receptor (TCR)Vgamma9, recognize nonpeptide phosphoantigens (PAgs) produced by microbes and tumor cells, and mediate different modes of lytic activities directed against tumor target cells. Antibody-dependent cell-mediated cytotoxicity (ADCC) mediated by cytolytic lymphoid cells is essential for the clinical activity of anticancer monoclonal antibodies (mAbs), but whether PAgs affect ADCC by gammadelta T cells is unknown. Here we report that, in association with the CD20(+)-specific mAb rituximab (RTX), the synthetic PAg bromohydrin pyrophosphate (BrHPP) increased TCRVgamma9(+) cell binding to CD20(+) lymphoma cells in vitro. This combination activated phospho-ZAP70 and phospho-ERK1/2 signaling in TCRVgamma9(+) cells and strongly enhanced their ADCC activity. We obtained similar results with BrHPP in the context of the mAbs alemtuzumab and trastuzumab. Furthermore, BrHPP enhanced RTX-mediated depletion of CD20(+) cells in vitro from peripheral blood mononuclear cells of healthy subjects and enhanced ADCC by gammadelta T cells from patients with chronic lymphocytic leukemia. In cynomolgus macaques, a regimen combining RTX, BrHPP, and IL2 activated TCRVgamma9(+) lymphocytes and enhanced B-cell depletion from blood and lymph nodes. Thus, the combination with BrHPP PAg is able to improve the efficacy of cancer immunotherapy by therapeutic mAbs.

Topics: Adult; Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antibody-Dependent Cell Cytotoxicity; Antineoplastic Combined Chemotherapy Protocols; B-Lymphocytes; Cells, Cultured; Diphosphates; Drug Screening Assays, Antitumor; Female; Humans; Interleukin-2; Leukemia, Lymphocytic, Chronic, B-Cell; Macaca fascicularis; Male; Phosphates; Receptors, Antigen, T-Cell, gamma-delta; Rituximab; T-Lymphocytes; Up-Regulation

We previously reported that the function and proliferation of natural killer cells in myelodysplastic syndromes are defective. T-cell receptor gammadelta T cells are other important components of innate immunity that have been recently implicated in the immune response against hematologic malignancies.. We evaluated the phenotype, function, and in vitro expansion of myelodysplastic syndrome patient-derived gammadelta T cells in response to interleukin-2 and bromohalohydrin pyrophosphate, a synthetic phosphoantigen with a potent T-cell receptor gammadelta agonist effect that specifically activates and amplifies this T-cell population.. Vgamma9Vdelta2 T cells, the major circulating gammadelta T-cell subset, were reduced in myelodysplastic syndromes, but mainly in myelodysplastic syndromes' patients with associated autoimmune diseases, suggesting that this anomaly was largely due to the autoimmune component. On the other hand, bromohalohydrin pyrophosphate-induced expansion of the Vgamma9Vdelta2 T-cell population in all 15 control samples, but in only 26 of 43 (60%) myelodysplastic syndromes patients. The response to bromohalohydrin pyrophosphate was independent of World Health Organization subtype, cytogenetic findings and International Prognostic Scoring System score. In responding myelodysplastic syndromes patients, expanded Vgamma 9Vdelta2 T cells exhibited normal cytolytic and secretory activity against leukemic and myelodysplastic syndromes cell lines; fluorescence in situ hybridization analysis indicated that these Vgamma 9Vdelta2 T cells were not derived from the myelodysplastic syndromes clone. However, these Vgamma 9Vdelta2 T cells from the MDS patients had limited proliferative capacity in response to interleukin-2 despite having normal expression of interleukin-2 receptor chains (alpha beta gamma ).. These results, combined with our previous findings concerning natural killer cells, suggest that there are immune surveillance defects in myelodysplastic syndromes, which may contribute to the pathogenesis of these syndromes.

Topics: Aged; Aged, 80 and over; Autoimmune Diseases; Clone Cells; Diphosphates; Female; Humans; Immunologic Surveillance; In Situ Hybridization, Fluorescence; Interferon-gamma; Interleukin-2; Killer Cells, Natural; Lymphocyte Activation; Male; Middle Aged; Myelodysplastic Syndromes; Receptors, Antigen, T-Cell, gamma-delta; Receptors, Interleukin-2; T-Lymphocyte Subsets

We previously showed that Vdelta2 T cells infiltrate renal tumors and can be expanded as potent cytotoxic effectors from peripheral blood mononuclear cells of most renal cell carcinoma (RCC) patients, using a structural analog of nonconventional T-cell receptor gamma9delta2 ligand, bromohydrin pyrophosphate, and interleukin-2 (IL-2). In this study, we have further investigated the differentiation status and the migration potential of circulating and tumor-infiltrating Vgamma9Vdelta2 T lymphocytes from RCC patients. The repertoire of tumor-infiltrating and peripheral Vgamma9Vdelta2 T cells from RCC patients was characterized by a dominant CD27- CD45RA- subset. These effector memory Vgamma9Vdelta2 T cells were efficiently expanded using bromohydrin pyrophosphate combined with IL-15, but not IL-2. In addition, peripheral Vgamma9Vdelta2 T cells from RCC patients present a modified chemotactic pattern compared with donors. After ex vivo activation, peripheral expanded Vgamma9Vdelta2 T cells acquire low-migration capacities toward renal cells. Tumor-infiltrating Vgamma9Vdelta2 T cells migrated with higher efficiency toward primary renal tumor cells. The traffic toward tumor cells required the CXCL12/CXCR4 interaction. Altogether, these results outline that those Vgamma9Vdelta2 effectors exhibit differential migration capacities according to their localization, their differentiation status, and the tumor microenvironment parameters that may influence their use in immunotherapy.

Topics: Carcinoma, Renal Cell; Cell Movement; Cell Proliferation; Cells, Cultured; Chemokine CXCL12; Chemotaxis, Leukocyte; Diphosphates; Gene Expression Profiling; Humans; Immunologic Memory; Interleukin-15; Kidney Neoplasms; Lymphocyte Activation; Lymphocyte Subsets; Lymphocytes, Tumor-Infiltrating; Protein Array Analysis; Receptors, Antigen, T-Cell, gamma-delta; Receptors, Chemokine; Receptors, CXCR4; T-Lymphocytes

Phosphoantigens are mycobacterial non-peptide antigens that might enhance the immunogenicity of current subunit candidate vaccines for tuberculosis. However, their testing requires monkeys, the only animal models suitable for gammadelta T cell responses to mycobacteria. Thus here, the immunogenicity of 6-kDa early secretory antigenic target-mycolyl transferase complex antigen 85B (ESAT-6-Ag85B) (H-1 hybrid) fusion protein associated or not to a synthetic phosphoantigen was compared by a prime-boost regimen of two groups of eight cynomolgus. Although phosphoantigen activated immediately a strong release of systemic Th1 cytokines (IL-2, IL-6, IFN-gamma, TNF-alpha), it further anergized blood gammadelta T lymphocytes selectively. By contrast, the hybrid H-1 induced only memory alphabeta T cell responses, regardless of phosphoantigen. These latter essentially comprised cytotoxic T lymphocytes specific for Ag85B (on average + 430 cells/million PBMC) and few IFN-gamma-secreting cells (+ 40 cells/million PBMC, equally specific for ESAT-6 and for Ag85B). Hence, in macaques, a prime-boost with the H-1/phosphoantigen subunit combination induces two waves of immune responses, successively by gammadelta T and alphabeta T lymphocytes.

Topics: Animals; Antigens, Bacterial; Bacterial Proteins; Cytokines; Diphosphates; Female; Flow Cytometry; Macaca fascicularis; Male; Receptors, Antigen, T-Cell, alpha-beta; Recombinant Fusion Proteins; T-Lymphocyte Subsets; T-Lymphocytes; Tuberculosis Vaccines; Tuberculosis, Pulmonary

T-cell-mediated immunotherapy is a promising therapeutic option for multiple myeloma (MM). Gamma-delta T cells (gammadelta T cells) recognize phosphoantigens and display strong anti-tumour cytotoxicity. The synthetic agonist Phosphostim (bromohydrin pyrophosphate, BrHPP) has been shown to selectively activate Vgamma9Vdelta2 T cells. This study aimed to evaluate the expansion capacity and anti-myeloma cell cytotoxicity of circulating gammadelta T cells from MM patients at different time points throughout the disease, using Phosphostim and interleukin 2 (IL-2). Circulating gammadelta T cell counts in patients with newly diagnosed MM or in relapse did not differ from those in healthy donors. A 14-d culture of peripheral blood mononuclear cells with Phosphostim and IL-2 triggered a 100-fold expansion of gammadelta T cells in 78% of newly diagnosed patients. Gammadelta T cells harvested at the time of haematopoietic progenitor collection or in relapsing patients expanded less efficiently. Expanded gammadelta T cells killed 13/14 myeloma cell lines as well as primary myeloma cells, but not normal CD34 cells. Their killing efficiency was not affected by 2-d IL-2 starvation. This study demonstrated the ability of Phosphostim and IL-2 to expand gammadelta T cells from MM patients, and the efficient and stable killing of human myeloma cells by gd T cells.

Topics: Adoptive Transfer; Antigens, CD34; CD3 Complex; Cell Line, Tumor; Cell Proliferation; Cytotoxicity, Immunologic; Diphosphates; Female; Humans; Interleukin-2; Lymphocyte Count; Male; Middle Aged; Multiple Myeloma; Receptors, Antigen, T-Cell, gamma-delta; Receptors, CXCR4; T-Lymphocytes

Vgamma9Vdelta2 T cells, a major gammadelta PBL subset in human adults, have been previously implicated in dendritic cell (DC) licensing, owing to their high frequency in peripheral tissues and their ability to produce inflammatory cytokines upon recognition of a broad array of conserved Ags. Although these observations implied efficient recognition of Ag-expressing immature DC (iDC) by Vgamma9Vdelta2 T cells, the role played by DC subsets in activation of these lymphocytes has not been carefully studied so far. We show that iDC, and to a lesser extent mature DC, potentiated Th1 and Th2 cytokine, but not cytolytic or proliferative responses, of established Vgamma9Vdelta2 T cell clones and ex vivo memory Vgamma9Vdelta2 PBL stimulated by synthetic agonists. The ability of iDC to potentiate Vgamma9Vdelta2 production of inflammatory cytokines required for their own maturation suggested that Vgamma9Vdelta2 T cells, despite their strong lytic activity, could promote efficient iDC licensing without killing at suboptimal Ag doses. Accordingly Vgamma9Vdelta2 cells induced accelerated maturation of Ag-expressing iDC but not "bystander" DC, even within mixed cell populations comprising both Ag-expressing and nonexpressing iDC. Furthermore Vgamma9Vdelta2 cells induced full differentiation into IL-12-producing cells of iDC infected by Vgamma9Vdelta2-stimulating mycobacteria that were otherwise unable to induce complete DC maturation. In conclusion the ability of iDC to selectively potentiate cytokine response of memory Vgamma9Vdelta2 T cells could underlie the adjuvant effect of these lymphocytes, and possibly other natural memory T cells, on conventional T cell responses.

Topics: Antigens; Antineoplastic Agents; Calcium; Cell Adhesion; Cell Differentiation; Cells, Cultured; Coculture Techniques; Cytokines; Dendritic Cells; Diphosphates; Diphosphonates; Humans; Kinetics; Mycobacterium bovis; Pamidronate; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocytes; Th1 Cells; Th2 Cells; Tumor Necrosis Factor-alpha

We report the crystallographic structures of the potent phosphoantigens Phosphostim (the bromohydrin of isopentenyl pyrophosphate) and E-4-hydroxy-3-methyl-but-2-enyl pyrophosphate bound to the mevalonate pathway enzyme isopentenyl pyrophosphate/dimethylallyl pyrophosphate isomerase (IPPI). Racemic Phosphostim forms covalent complexes with IPPI: a 4-thioether with C67 and a 4-ester with E116. Only the E116 ester forms with the chiral species, S-Phosphostim, with the w.t. enzyme, while the C67 thioether forms with a mutant Y104F IPPI. The potent phosphoantigen HMBPP also binds to IPPI, but is only a weak ( approximately 50 muM) inhibitor. These results strongly support an SN2 reaction for inhibition of IPPI by Phosphostim, in contrast to the SN1 or concerted type of reaction found with epoxide inhibitors, which react at C-3, and are of general interest in the context of the development of novel mevalonate pathway inhibitors. They also provide clues as to the nature of the binding site of synthetic phosphoantigens in gammadelta T cell activation. In particular, both bromohydrin and epoxy phosphoantigens are potent, irreversible inhibitors of IPPI while HMBPP is only a weak inhibitor, ruling out an IPPI or IPPI-like target for HMBPP in gammadelta T cell activation.

Topics: Antigens; Carbon-Carbon Double Bond Isomerases; Crystallography, X-Ray; Diphosphates; Hemiterpenes

Metastatic renal cell carcinoma, inherently resistant to conventional treatments, is considered immunogenic. Indeed, partial responses are obtained after treatment with cytokines such as IL-2 or IFN-alpha, suggesting that the immune system may control the tumor growth. In this study, we have investigated the ability of the main subset of peripheral gammadelta lymphocytes, the Vgamma9Vdelta2-TCR T lymphocytes, to induce an effective cytotoxic response against autologous primary renal cell carcinoma lines. These gammadelta T cells were expanded ex vivo using a Vgamma9Vdelta2 agonist, a synthetic phosphoantigen called Phosphostim. From 11 of 15 patients, the peripheral Vgamma9Vdelta2 T cells were amplified in vitro by stimulating PBMCs with IL-2 and Phosphostim molecule. These expanded Vgamma9Vdelta2 T cells express activation markers and exhibit an effector/memory phenotype. They display a selective lytic potential toward autologous primary renal tumor cells and not against renal NC. The lytic activity involves the perforin-granzyme pathway and is mainly TCR and NKG2D receptor dependent. Furthermore, an increased expression of MHC class I-related molecule A or B proteins, known ligands of NKG2D, are detected on primary renal tumor cells. Interestingly, from 2 of the 11 positive cultures in response to Phosphostim, expanded-Vgamma9Vdelta2 T cells present an expression of killer cell Ig-like receptors, suggesting their prior recruitment in vivo. Unexpectedly, on serial frozen sections from three tumors, we observe a gammadelta lymphocyte infiltrate that was mainly composed of Vgamma9Vdelta2 T cells. These results outline that Vgamma9Vdelta2-TCR effectors may represent a promising approach for the treatment of metastatic renal cell carcinoma.

Topics: Adult; Aged; Aged, 80 and over; Antigens; Carcinoma, Renal Cell; Cell Differentiation; Cell Line, Tumor; Cytotoxicity, Immunologic; Diphosphates; Female; Humans; Immunophenotyping; Kidney Neoplasms; Killer Cells, Natural; Leukocytes, Mononuclear; Lymphocyte Activation; Lymphocytes, Tumor-Infiltrating; Male; Middle Aged; NK Cell Lectin-Like Receptor Subfamily K; Receptors, Antigen, T-Cell, gamma-delta; Receptors, Immunologic; Receptors, KIR; Receptors, Natural Killer Cell; T-Lymphocyte Subsets

Human Vgamma9Vdelta2 T cells recognize nonpeptidic Ags generated by the 1-deoxy-d-xylulose 5-phosphate (many eubacteria, algae, plants, and Apicomplexa) and mevalonate (eukaryotes, archaebacteria, and certain eubacteria) pathways of isoprenoid synthesis. The potent Vgamma9Vdelta2 T cell reactivity 1) against certain cancer cells or 2) induced by infectious agents indicates that therapeutic augmentations of Vgamma9Vdelta2 T cell activities may be clinically beneficial. The functional characteristics of Vgamma9Vdelta2 T cells from Macaca fascicularis (cynomolgus monkey) are very similar to those from Homo sapiens. We have found that the i.v. administration of nitrogen-containing bisphosphonate or pyrophosphomonoester drugs into cynomolgus monkeys combined with s.c. low-dose (6 x 10(5) U/animal) IL-2 induces a large pool of CD27+ and CD27- effector/memory T cells in the peripheral blood of treated animals. The administration of these drugs in the absence of IL-2 is substantially less effective, indicating the importance of additional exogenous costimuli. Shortly after the costimulatory IL-2 treatment, only gammadelta (but not alphabeta) T cells expressed the CD69 activation marker, indicating that Vgamma9Vdelta2 T lymphocytes are more responsive to low-dose IL-2 than alphabeta T cells. Up to 100-fold increases in the numbers of peripheral blood Vgamma9Vdelta2 T cells were observed in animals receiving the gammadelta stimulatory drug plus IL-2. Moreover, the expanded Vgamma9Vdelta2 T cells were potent Th1 effectors capable of releasing large amounts of IFN-gamma. These results may be relevant for designing novel (or modifying current) immunotherapeutic trials with nitrogen-containing bisphosphonate or pyrophosphomonoester drugs.

Topics: 2,3-Diphosphoglycerate; Animals; Antigens; CD4-CD8 Ratio; Cell Differentiation; Cell Proliferation; Cells, Cultured; Diphosphates; Diphosphonates; Epoxy Compounds; Hemiterpenes; Immunologic Memory; Injections, Intravenous; Injections, Subcutaneous; Interferon-gamma; Interleukin-2; Macaca fascicularis; Organophosphorus Compounds; Pamidronate; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocyte Subsets; Th1 Cells

Vgamma9(+)Vdelta2(+) gammadelta T cells (Vdelta 2(+) T cells) are activated by Mycobacterium tuberculosis and secrete interferon (IFN)-gamma. Vdelta 2(+) T cells recognize phosphoantigens, such as bromohydrin pyrophosphate (BrHPP), and link innate and adaptive immunity.. A whole-blood assay was developed that used IFN-gamma secretion in response to BrHPP as a measurement of Vdelta2(+) T cell function.. Peak IFN-gamma levels were detected after stimulating whole blood with BrHPP for 7-9 days. IFN- gamma production in whole blood in response to BrHPP paralleled IFN-gamma production and Vdelta2(+) T cell expansion of peripheral-blood mononuclear cells. The assay was used to evaluate Vdelta2(+) T cell function in subjects in the United States (n = 24) and Uganda (n = 178) who were or were not infected with M. tuberculosis and/or human immunodeficiency virus (HIV) type 1. When 50 micromol/L BrHPP was used, 100% of healthy subjects produced IFN-gamma. The Vdelta2(+) T cell response was independent of the tuberculin skin test response. In Uganda, Vdelta2(+) T cell responses were decreased in patients with tuberculosis (n = 73) compared with responses in household contacts (n = 105). HIV-1-positive household contacts had lower responses than did HIV-1-negative household contacts. HIV-1-positive patients with tuberculosis had the lowest V delta 2(+) T cell responses.. Tuberculosis and HIV-1 infection are associated with decreased Velta2(+) T cell function. Decreased Vdelta2(+) T cell function may contribute to increased risk for tuberculosis in HIV-1-positive patients.

Topics: Adolescent; Adult; Cells, Cultured; Diphosphates; Female; HIV Infections; HIV-1; Humans; Interferon-gamma; Lymphocyte Activation; Male; Middle Aged; Mycobacterium tuberculosis; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocytes; Tuberculosis; Uganda; United States

We have obtained the three-dimensional X-ray crystallographic structure of a C67A mutant Escherichia coli isopentenylpyrophosphate-dimethylallylpyrophosphate isomerase (EC 5.3.3.2) complexed with the bromohydrin of isopentenylpyrophosphate, at 1.93 A resolution. The overall backbone fold is very similar to that obtained previously for the wild-type enzyme in the presence of a divalent metal cation (Mn2+ or Mg2+). However, in the new structure, there are two metal binding sites, not just one. The first metal binding site is occupied by Mn2+, coordinated to three histidine and two glutamate residues, while the second is occupied by Mg2+, coordinated to two bromohydrin-ligand phosphate oxygens, the carbonyl oxygen of A67, a carboxyl oxygen of E87, and two water molecules. The C3 hydroxyl group of the bromohydrin inhibitor is involved in a short hydrogen bond to the carboxyl group of E116, one of the two Mn-bound glutamates. The structure obtained is consistent with a mechanism of action of the enzyme in which the carboxyl group of E116 protonates the double bond in isopentenylpyrophosphate, forming a carbocation, followed by removal of a C2 proton by the thiolate of C67, in the wild-type enzyme. The inhibition of the enzyme by a wide variety of other potent inhibitors is also readily explained on the basis of the bromohydrin inhibitor structure.

Topics: Carbon-Carbon Double Bond Isomerases; Diphosphates; Enzyme Inhibitors; Hemiterpenes; Kinetics; Models, Molecular; Protein Conformation; Structure-Activity Relationship

Human T lymphocytes expressing the Vgamma9Vdelta2 TCR recognize non-peptidic Ags, referred to as phosphoantigens, produced by microbial pathogens and by human tumor cells. Here we show that gammadelta T cells establish a mature immunological synapse (IS) with the myelomonocytic THP-1 tumoral cell line. This synapse is characterized by an enrichment for phosphotyrosine, CD2, and gammadelta TCR together with the exclusion of CD45. The CD94 and NKG2D receptors are also recruited to the signaling area, while the C-lectin-like activation marker CD69 segregates out of the synapse. gammadelta T cell conjugation to THP-1 increases upon stimulation by soluble phosphoantigen, is paralleled by the metabolic activation of gammadelta T cells and leads to cytokine production. Molecular segregation of the above molecules also occurs at the gammadelta T cell/THP-1 interface in the absence of exogenously added phosphoantigen, although it does not result in intracellular signaling and cytokine production under these conditions. Hence the molecular interactions at the gammadelta T cell-THP-1 target cell interface are sufficient to induce the formation of an IS, but cytokine production requires the full engagement of gammadelta TCR by a strong agonist. Thus in gammadelta T cells, formation of the IS is uncoupled from its functional outcome.

Topics: Antigens; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Biomarkers; Cell Aggregation; Cell Communication; Cell Line, Tumor; Cytokines; Diphosphates; Histocompatibility Antigens Class I; Humans; Killer Cells, Natural; Lectins, C-Type; Lymphocyte Activation; NK Cell Lectin-Like Receptor Subfamily D; NK Cell Lectin-Like Receptor Subfamily K; Receptors, Antigen, T-Cell, gamma-delta; Receptors, Immunologic; Receptors, Natural Killer Cell; Signal Transduction; Solubility; T-Lymphocyte Subsets

Vgamma9Vdelta2+ T cells (gammadelta T cells) are activated by Mycobacterium tuberculosis and recognize mycobacterial nonpeptide phosphoantigens. The role of antigen-presenting cells in the processing and presentation of phosphoantigens to Vgamma9Vdelta2+ T cells is not understood. We analyzed the role of macrophages for activation of gammadelta T cells by a new synthetic phosphoantigen bromohydrin pyrophosphate (BrHPP) and M. tuberculosis. Macrophages greatly increased gammadelta T-cell activation by both BrHPP and M. tuberculosis. Fixation of macrophages before infection demonstrated that uptake of M. tuberculosis was required for presentation to gammadelta T cells. Antigens of M. tuberculosis remained stably associated with macrophage surface and were not removed by paraformaldehyde fixation or washing. Macrophages processed M. tuberculosis for gammadelta T cells through a brefeldin A-insensitive pathway, suggesting that transport through the endoplasmic reticulum and Golgi complex of a putative presenting molecule is not important in the early processing of M. tuberculosis antigens for gammadelta T cells. Processing of M. tuberculosis was not eliminated by chloroquine, indicating that processing of gammadelta antigens is not dependent on acidic pH in the lysosomes. Chloroquine treatment of BrHPP-pulsed macrophages increased activation of gammadelta T cells. Ammonium chloride treatment of macrophages did not increase reactivity of gammadelta T cells to BrHPP, indicating that the effect of chloroquine was independent of pH changes in endosomes. Chloroquine, by inhibiting membrane traffic, may increase association and retention of phosphoantigens with cell surface membrane molecules on macrophages.

Topics: Adult; Antigen Presentation; Antigen-Presenting Cells; Antigens, Bacterial; Brefeldin A; Cell Division; Chloroquine; Diphosphates; Humans; Interferon-gamma; Interleukin-2; Macrophages; Middle Aged; Mycobacterium tuberculosis; Phosphoproteins; Protein Synthesis Inhibitors; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocytes

gamma delta T cells are known to be involved in the innate immune defenses against infectious microorganisms. Herein, we considered that gamma delta T cells could also influence adaptative immunity by interacting with dendritic cells (DC) in the early phase of the immune response. To investigate this hypothesis, gamma delta T cells isolated from the peripheral blood of healthy volunteers were cocultured with autologous monocyte-derived dendritic cells, which were subsequently analyzed for their expression of key surface molecules and for their production of IL-12. First, we found that gamma delta T cells induced the upregulation of HLA-DR, CD86, and CD83 on DC. This effect did not require cell to cell contact and could be blocked by a neutralizing anti-TNF antibody. We then observed that gamma delta T cells activated by the synthetic phosphoantigen bromohydrin pyrophosphate (BrHPP) induced the production of IL-12 (p40) and IL-12 (p70) by DC, an effect that involved IFN-gamma production. The relevance of this finding to DC function was demonstrated by the increased production of IFN-gamma by alloreactive T cells when stimulated in a mixed leucocyte reaction with DC preincubated with activated gamma delta T cells. We conclude that gamma delta T cell activation might result in DC maturation and thereby in enhanced alpha beta T cell responses.

Topics: Antigens, CD; B7-2 Antigen; CD83 Antigen; Coculture Techniques; Dendritic Cells; Diphosphates; Flow Cytometry; Gene Expression Regulation; HLA-DR Antigens; Humans; Immunoglobulins; Interferon-gamma; Interleukin-12; Lymphocyte Culture Test, Mixed; Membrane Glycoproteins; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocytes; Tumor Necrosis Factor-alpha; Up-Regulation

B, alpha beta T, and NK lymphocytes establish immunological synapses (IS) with their targets to enable recognition. Transfer of target cell-derived Ags together with proximal molecules onto the effector cell appears also to occur through synapses. Little is known about the molecular basis of this transfer, but it is assumed to result from Ag receptor internalization. Because human gamma delta T cells recognize soluble nonpeptidic phosphoantigens as well as tumor cells such as Daudi, it is unknown whether they establish IS with, and extract molecules from, target cells. Using flow cytometry and confocal microscopy, we show in this work that Ag-stimulated human V gamma 9/V delta 2 T cells conjugate to, and perform molecular transfer from, various tumor cell targets. The molecular transfer appears to be linked to IS establishment, evolves in a dose-dependent manner in the presence of either soluble or cellular Ag, and requires gamma delta TCR ligation, Src family kinase signaling, and participation of the actin cytoskeleton. Although CD45 exclusion characterized the IS performed by gamma delta T cells, no obvious capping of the gamma delta TCR was detected. The synaptic transfer mediated by gamma delta T cells involved target molecules unrelated to the cognate Ag and occurred independently of MHC class I expression by target cells. From these observations, we conclude that despite the particular features of gamma delta T cell activation, both synapse formation and molecular transfer of determinants belonging to target cell characterize gamma delta T cell recognition of Ags.

Topics: Antigens; Burkitt Lymphoma; Cell Communication; Cell Membrane; Diphosphates; Hemiterpenes; Humans; K562 Cells; Levamisole; Lymphocyte Activation; Lymphoma, Non-Hodgkin; Organophosphorus Compounds; Receptors, Antigen, T-Cell, gamma-delta; Solubility; T-Lymphocyte Subsets; Tumor Cells, Cultured

Small phosphorylated metabolites from mycobacteria stimulate human gammadelta T lymphocytes. Although such phosphoantigens could prove useful in the composition of vaccines involving gammadelta T cell-mediated immunity, their very low abundance in natural sources limits such applications. Here, we describe the chemical production, purification, and bioactivity of a phosphorylated bromohydrin (BrHPP) analogue that mimics the biological properties of natural phosphoantigens. This compound can be obtained in gram amounts, is easy to detect, and is of high stability in aqueous solutions. Whereas unspecific binding of BrHPP to a wide panel of cell surface receptors is not detected even at micromolar concentrations, nanomolar concentrations specifically trigger effector responses of human gammadelta T lymphocytes. Thus, BrHPP is a novel molecule enabling potent immunostimulation of human gammadelta T lymphocytes.

Topics: Alcohols; Diphosphates; Humans; Lymphocyte Activation; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocytes