RESUMEN
BACKGROUND: About half of AML patients achieving complete remission (CR) display measurable residual disease (MRD) and eventually relapse. FLYSYN is an Fc-optimized antibody for eradication of MRD directed to FLT3/CD135, which is abundantly expressed on AML cells. METHODS: This first-in-human, open-label, single-arm, multicenter trial included AML patients in CR with persisting or increasing MRD and evaluated safety/tolerability, pharmacokinetics and preliminary efficacy of FLYSYN at different dose levels administered intravenously (cohort 1-5: single dose of 0.5 mg/m2, 1.5 mg/m2, 5 mg/m2, 15 mg/m2, 45 mg/m2; cohort 6: 15 mg/m2 on day 1, 15 and 29). Three patients were treated per cohort except for cohorts 4 and 6, which were expanded to nine and ten patients, respectively. Primary objective was safety, and secondary efficacy objective was ≥ 1 log MRD reduction or negativity in bone marrow. RESULTS: Overall, 31 patients were treated, of whom seven patients (22.6%) experienced a transient decrease in neutrophil count (two grade 3, others ≤ grade 2). No infusion-related reaction or dose-limiting toxicity was observed. Adverse events (AEs) were mostly mild to moderate, with the most frequent AEs being hematologic events and laboratory abnormalities. Response per predefined criteria was documented in 35% of patients, and two patients maintained MRD negativity until end of study. Application of 45 mg/m2 FLYSYN as single or cumulative dose achieved objective responses in 46% of patients, whereas 28% responded at lower doses. CONCLUSIONS: FLYSYN monotherapy is safe and well-tolerated in AML patients with MRD. Early efficacy data are promising and warrant further evaluation in an up-coming phase II trial. Trial registration This clinical is registered on clinicaltrials.gov (NCT02789254).
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Antineoplásicos , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Leucemia Mieloide Aguda , Humanos , Anticuerpos Monoclonales , Fragmentos Fc de Inmunoglobulinas , Neoplasia Residual , Leucemia Mieloide Aguda/tratamiento farmacológico , Tirosina Quinasa 3 Similar a fmsRESUMEN
The introduction of monoclonal antibodies (mAbs) has largely improved treatment options for cancer patients. The ability of antitumor mAbs to elicit antibody-dependent cellular cytotoxicity (ADCC) contributes to a large extent to their therapeutic efficacy. Many efforts accordingly aim to improve this important function by engineering mAbs with Fc parts that display enhanced affinity to the Fc receptor CD16 expressed, e.g., on natural killer (NK) cells. Here we characterized the CD133 mAb 293C3-SDIE that contains an engineered Fc part modified by the amino acid exchanges S239D/I332E-that reportedly increase the affinity to CD16-with regard to its ability to induce NK reactivity against colorectal cancer (CRC). 293C3-SDIE was found to be a stable protein with favorable binding characteristics achieving saturating binding to CRC cells at concentrations of approximately 1 µg/mL. While not directly affecting CRC cell growth and viability, 293C3-SDIE potently induced NK cell activation, degranulation, secretion of Interferon-γ, as well as ADCC resulting in potent lysis of CRC cell lines. Based on the preclinical characterization presented in this study and the available data indicating that CD133 is broadly expressed in CRC and represents a negative prognostic marker, we conclude that 293C3-SDIE constitutes a promising therapeutic agent for the treatment of CRC and thus warrants clinical evaluation.
RESUMEN
BACKGROUND: Monoclonal antibodies (mAbs) mediate their effects in great part by inducing ADCC of NK cells, and multiple efforts aim to increase this function by engineering mAbs optimized Fc-parts. Even more potent antitumor immunity can be induced by strategies to stimulate T cells with their profoundly higher effector potential. However, upon increased immunostimulatory potential, the necessity to target highly tumor-specific antigens becomes critically important to reduce side effects. METHODS: We here report on bispecific fusion proteins (BFP) that target ligands of the immunoreceptor NKG2D (NKG2DL), which are widely expressed on malignant cells but generally absent on healthy tissue. They consist of the extracellular domain of NKG2D as targeting moiety fused to Fab-fragments of CD3 (NKG2D-CD3) or CD16 (NKG2D-CD16) antibodies. RESULTS: NKG2D-CD16 displayed increased affinity to the FcγRIII on NK cells compared to engineered Fc-parts, which are contained in optimized mAbs that presently undergo clinical evaluation. In line, NKG2D-CD16 induced superior activation, degranulation, IFN-γ production and lysis of acute myeloid leukemia (AML) cell lines and patient AML cells. NKG2D-CD3 in turn potently stimulated T cells, and comparison of efficacy over time revealed that NKG2D-CD16 was superior upon short term application, while NKG2D-CD3 mediated overall more potent effects which manifested after longer times. This can be attributed to treatment-induced proliferation of T cells but not NK cells. CONCLUSIONS: Taken together, we here introduce novel "antibody-like" BFP that take advantage of the highly tumor-restricted expression of NKG2DL and potently activate the reactivity of NK cells or T cells for immunotherapy of AML.
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Inmunoterapia/métodos , Células Asesinas Naturales/inmunología , Leucemia Mieloide Aguda/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/metabolismo , Linfocitos T/inmunología , Humanos , Leucemia Mieloide Aguda/patología , Proteínas de la Fusión de la MembranaRESUMEN
Chimeric antigen receptor (CAR)-engineered natural killer (NK) cells represent a promising effector cell type for adoptive cancer immunotherapy. Both, genetically modified donor-derived NK cells as well as continuously expanding NK-92 cells are currently under clinical development. To enhance their therapeutic utility for the treatment of pre-B-cell acute lymphoblastic leukemia (B-ALL), we engineered NK-92 cells by lentiviral gene transfer to express a FMS-like tyrosine kinase 3 (FLT3)-specific CAR that contains a composite CD28-CD3ζ signaling domain. FLT3 has primarily been described as a therapeutic target for acute myeloid leukemia, but overexpression of FLT3 has also been reported in B-ALL. Exposure of FLT3-positive targets to CAR NK-92 cells resulted in conjugate formation between NK and leukemia cells, NK-cell degranulation and selective cytotoxicity toward established B-ALL cell lines and primary blasts that were resistant to parental NK-92. In a SEM B-ALL xenograft model in NOD-SCID IL2R γnull mice, treatment with CAR NK-92 but not parental NK-92 cells markedly inhibited disease progression, demonstrating high antileukemic activity in vivo. As FLT3 is known to be also expressed on precursor cells, we assessed the feasibility of incorporating an inducible caspase-9 (iCasp9) suicide switch to enhance safety of our approach. Upon addition of the chemical dimerizer AP20187 to NK-92 cells coexpressing the FLT3-specific CAR and iCasp9, rapid iCasp9 activation was observed, precluding further CAR-mediated cytotoxicity. Our data demonstrate that B-ALL can be effectively targeted by FLT3-specific CAR NK cells which may complement CD19-directed immunotherapies, particularly in cases of inherent or acquired resistance to the latter.
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Inmunoterapia Adoptiva/métodos , Células Asesinas Naturales/trasplante , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Receptores Quiméricos de Antígenos/metabolismo , Tirosina Quinasa 3 Similar a fms/inmunología , Animales , Línea Celular Tumoral , Ingeniería Genética , Células HL-60 , Humanos , Subunidad gamma Común de Receptores de Interleucina/genética , Células Asesinas Naturales/inmunología , Ratones Endogámicos NOD , Ratones SCID , Leucemia-Linfoma Linfoblástico de Células Precursoras B/inmunología , Resultado del Tratamiento , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Hydrophobic interaction chromatography (HIC) is a robust standard analytical method to purify proteins while preserving their biological activity. It is widely used to study post-translational modifications of proteins and drug-protein interactions. In the current manuscript we employed HIC to separate proteins, followed by bottom-up LC-MS/MS experiments. We used this approach to fractionate antibody species followed by comprehensive peptide mapping as well as to study protein complexes in human cells. HIC-reversed-phase chromatography (RPC)-mass spectrometry (MS) is a powerful alternative to fractionate proteins for bottom-up proteomics experiments making use of their distinct hydrophobic properties.
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Cromatografía de Fase Inversa/métodos , Complejos Multiproteicos/análisis , Proteínas/análisis , Proteómica/métodos , Línea Celular , Cromatografía Liquida , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Espectrometría de Masas en TándemRESUMEN
Radioimmunotherapy is considered as treatment option in recurrent and/or refractory B-cell non-Hodgkin lymphoma (B-NHL). To overcome the dose limiting bone marrow toxicity of IgG-based radioimmunoconjugates (RICs), we modified a humanized diabody with 5-, 10-, or 20-kDa polyethylene glycol (PEG) for CD22-targeted radioimmunotherapy using the low-energy ß-emitter lutetium-177 ((177)Lu). A favorable pharmacokinetic profile was observed for the 10-kDa-PEG-diabody in nude mice being xenografted with subcutaneous human Burkitt lymphoma. Even at high doses of 16 MBq this diabody RIC was well tolerated by NOD Rag1(null) IL2rγ(null) (NRG) mice and did not reveal signs of organ long-term toxicity 80 days post injection. Combination therapy of the diabody RIC with unconjugated anti-CD20 Rituximab demonstrated therapeutic efficacy in established disseminated mantle cell lymphoma xenograft models. When compared with the combination of the IgG formatted (177)Lu anti-CD22 antibody and Rituximab, dual targeted therapy with the diabody RIC achieved an improved reduction of disease burden in the first nine days following treatment. The data indicate that the PEGylated anti-CD22 diabody may have potential for extending the repertoire of radiopharmaceuticals for the treatment of patients with B-NHL.
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Anticuerpos Biespecíficos/farmacología , Anticuerpos Monoclonales Humanizados/farmacología , Linfoma de Burkitt/radioterapia , Inmunoconjugados/farmacología , Lutecio/farmacología , Linfoma de Células del Manto/radioterapia , Radioinmunoterapia/métodos , Radioisótopos/farmacología , Lectina 2 Similar a Ig de Unión al Ácido Siálico/inmunología , Animales , Anticuerpos Biespecíficos/inmunología , Anticuerpos Biespecíficos/farmacocinética , Anticuerpos Biespecíficos/toxicidad , Anticuerpos Monoclonales Humanizados/inmunología , Anticuerpos Monoclonales Humanizados/farmacocinética , Anticuerpos Monoclonales Humanizados/toxicidad , Linfoma de Burkitt/inmunología , Linfoma de Burkitt/metabolismo , Linfoma de Burkitt/patología , Línea Celular Tumoral , Femenino , Factores de Transcripción Forkhead/deficiencia , Factores de Transcripción Forkhead/genética , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Inmunoconjugados/farmacocinética , Inmunoconjugados/toxicidad , Inmunoglobulinas Intravenosas/farmacología , Subunidad gamma Común de Receptores de Interleucina/deficiencia , Subunidad gamma Común de Receptores de Interleucina/genética , Lutecio/farmacocinética , Lutecio/toxicidad , Linfoma de Células del Manto/inmunología , Linfoma de Células del Manto/metabolismo , Linfoma de Células del Manto/patología , Ratones Endogámicos NOD , Ratones Noqueados , Ratones Desnudos , Radioinmunoterapia/efectos adversos , Radioisótopos/farmacocinética , Radioisótopos/toxicidad , Rituximab/farmacología , Lectina 2 Similar a Ig de Unión al Ácido Siálico/metabolismo , Distribución Tisular , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Prognosis of primary refractory and relapsed pediatric B-lineage acute lymphoblastic leukemia (ALL) is very poor. Relapse rates significantly correlate with persistent minimal residual disease (MRD). In MRD, favorable effector-target ratios prevail and thus this situation might be optimally suited for immunotherapy with antibodies recruiting immunological effector cells. We here report on the generation, preclinical characterization and first clinical application in B-lineage ALL of an Fc-optimized CD19 antibody. This third-generation antibody (4G7SDIE) mediated enhanced antibody-dependent cellular cytotoxicity (ADCC) against leukemic blasts with effector cells from healthy volunteers and B-lineage ALL patients. The antibody was produced in a university-owned production unit and was applied on a compassionate use basis to 14 pediatric patients with refractory and relapsed B-lineage ALL at the stage of MRD. In 10/14 patients, MRD was reduced by ≥ 1 log or below the patient-individual detection limit, and 5/14 patients have achieved ongoing complete molecular remission with a median leukemia-free survival of 428 days. Two additional patients died in complete molecular remission due to complications not related to antibody therapy. Besides profound in vivo B-cell depletion, side effects were negligible. A clinical phase 1/2 study to further assess the therapeutic activity of 4G7SDIE is in preparation.
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Anticuerpos Monoclonales/uso terapéutico , Antígenos CD19 , Fragmentos Fc de Inmunoglobulinas , Neoplasia Residual/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Adolescente , Anticuerpos Monoclonales/farmacología , Citotoxicidad Celular Dependiente de Anticuerpos , Antígenos CD19/inmunología , Antígenos CD19/metabolismo , Línea Celular Tumoral , Niño , Preescolar , Terapia Combinada , Monitoreo de Drogas , Resistencia a Antineoplásicos , Femenino , Expresión Génica , Humanos , Fragmentos Fc de Inmunoglobulinas/inmunología , Estimación de Kaplan-Meier , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Retratamiento , Resultado del Tratamiento , Adulto JovenRESUMEN
PURPOSE: Dual-targeted therapy has been shown to be a promising treatment option in recurrent and/or refractory B-cell non-Hodgkin's lymphoma (B-NHL). We generated radioimmunoconjugates (RICs) comprising either a novel humanized anti-CD22 monoclonal antibody, huRFB4, or rituximab, and the low-energy ß-emitter (177)Lu. Both RICs were evaluated as single agents in a human Burkitt's lymphoma xenograft mouse model. To increase the therapeutic efficacy of the anti-CD22 RIC, combination therapy with unlabelled anti-CD20 rituximab was explored. METHODS: The binding activity of CHX-Aâ³-DTPA-conjugated antibodies to target cells was analysed by flow cytometry. To assess tumour targeting of (177)Lu-labelled antibodies, in vivo biodistribution experiments were performed. For radioimmunotherapy (RIT) studies, non-obese diabetic recombination activating gene-1 (NOD-Rag1 (null) ) interleukin-2 receptor common gamma chain (IL2rγ (null) ) null mice (NRG mice) were xenografted subcutaneously with Raji Burkitt's lymphoma cells. (177)Lu-conjugated antibodies were administered at a single dose of 9.5 MBq per mouse. For dual-targeted therapy, rituximab was injected at weekly intervals (0.5 - 1.0 mg). Tumour accumulation of RICs was monitored by planar scintigraphy. RESULTS: Conjugation of CHX-A"-DTPA resulted in highly stable RICs with excellent antigen-binding properties. Biodistribution experiments revealed higher tumour uptake of the (177)Lu-labelled anti-CD22 IgG than of (177)Lu-labelled rituximab. Treatment with (177)Lu-conjugated huRFB4 resulted in increased tumour growth inhibition and significantly longer survival than treatment with (177)Lu-conjugated rituximab. The therapeutic efficacy of the anti-CD22 RIC could be markedly enhanced by combination with unlabelled rituximab. CONCLUSION: These findings suggest that dual targeting with (177)Lu-based CD22-specific RIT in combination with rituximab is a promising new treatment option for refractory B-NHL.
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Linfoma de Burkitt/terapia , Inmunoconjugados/uso terapéutico , Lutecio/química , Radioinmunoterapia/métodos , Rituximab/uso terapéutico , Lectina 2 Similar a Ig de Unión al Ácido Siálico/química , Animales , Linfoma de Burkitt/radioterapia , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Inmunoglobulina G/uso terapéutico , Dosis Máxima Tolerada , Ratones , Ratones Endogámicos NOD , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Monoclonal antibodies directed to the B-cell-specific CD20-antigen are successfully used for the treatment of lymphomas and autoimmune diseases. Here, we compare the anti-B-cell activity of three different antibodies directed to CD20: (i) a chimeric, monospecific antibody, (ii) an Fc-optimized variant thereof, and (iii) a bispecific CD20×CD95-antibody in a newly developed recombinant format, termed Fabsc. The bispecific antibody specifically triggers the CD95 death receptor on malignant, as well as activated, normal B-cells. We found that the capability of this antibody to suppress the growth of malignant B-cells in vitro and in vivo and to specifically deplete normal, activated B-cells from peripheral blood mononuclear cell (PBMC) cultures was superior to that of the Fc-optimized monospecific antibody. This antibody in turn was more effective than its nonoptimized variant. Moreover, the bispecific antibody was the only reagent capable of significantly suppressing antibody production in vitro. Our findings imply that the bispecific CD20×CD95-antibody might become a new, prototypical reagent for the treatment of B-cell-mediated autoimmune disease.
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Anticuerpos Biespecíficos/administración & dosificación , Anticuerpos Monoclonales/administración & dosificación , Antígenos CD20/inmunología , Linfocitos B/efectos de los fármacos , Linfoma de Células B/tratamiento farmacológico , Receptor fas/inmunología , Animales , Anticuerpos Biespecíficos/farmacología , Anticuerpos Monoclonales/farmacología , Linfocitos B/inmunología , Linfocitos B/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Humanos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Linfoma de Células B/inmunología , RatonesRESUMEN
Antibody-drug conjugates (ADCs) have evolved as a new class of potent cancer therapeutics. We here report on the development of ADCs with specificity for the B-cell lineage specific (surface) antigen CD22 being expressed in the majority of hematological malignancies. As targeting moiety a previously generated humanized anti-CD22 single-chain variable fragment (scFv) derivative from the monoclonal antibody RFB4 was reengineered into a humanized IgG1 antibody format (huRFB4). Onconase (ranpirnase), a clinically active pancreatic-type ribonuclease, was employed as cytotoxic payload moiety. Chemical conjugation via thiol-cleavable disulfide linkage retained full enzymatic activity and full binding affinity of the ADC. Development of sophisticated purification procedures using size exclusion and ion exchange chromatography allowed the separation of immunoconjugate species with stoichiometrically defined number of Onconase cargos. A minimum of two Onconase molecules per IgG was required for achieving significant in vitro cytotoxicity towards lymphoma and leukemia cell lines. Antibody-drug conjugates with an Onconase to antibody ratio of 3 : 1 exhibited an IC50 of 0.08 nM, corresponding to more than 18,400-fold increased cytotoxicity of the ADC when compared with unconjugated Onconase. These results justify further development of this ADC as a promising first-in-class compound for the treatment of CD22-positive malignancies.
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Anticuerpos Monoclonales Humanizados/farmacología , Antineoplásicos/farmacología , Inmunoconjugados/farmacología , Ribonucleasas/farmacología , Lectina 2 Similar a Ig de Unión al Ácido Siálico/inmunología , Anticuerpos Monoclonales Humanizados/química , Anticuerpos Monoclonales Humanizados/inmunología , Antineoplásicos/química , Línea Celular Tumoral , Pruebas Inmunológicas de Citotoxicidad , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Inmunoconjugados/química , Inmunoconjugados/inmunología , Inmunoglobulina G/inmunología , Ribonucleasas/químicaRESUMEN
BACKGROUND: 30 years ago, the potential of bispecific antibodies to engage cytotoxic T cells for the lysis of cancer cells was discovered. Today a variety of bispecific antibodies against diverse cell surface structures have been developed, the majority of them produced in mammalian cell culture systems. Beside the r28M, described here, no such bispecific antibody is known to be expressed by transgenic livestock, although various biologicals for medical needs are already harvested-mostly from the milk-of these transgenics. In this study we investigated the large-scale purification and biological activity of the bispecific antibody r28M, expressed in the blood of transgenic cattle. This tandem single-chain variable fragment antibody is designed to target human CD28 and the melanoma/glioblastoma-associated cell surface chondroitin sulfate proteoglycan 4 (CSPG4). RESULTS: With the described optimized purification protocol an average yield of 30 mg enriched r28M fraction out of 2 liters bovine plasma could be obtained. Separation of this enriched fraction by size exclusion chromatography into monomers, dimers and aggregates and further testing regarding the biological activity revealed the monomer fraction as being the most appropriate one to continue working with. The detailed characterization of the antibody's activity confirmed its high specificity to induce the killing of CSPG4 positive cells. In addition, first insights into tumor cell death pathways mediated by r28M-activated peripheral blood mononuclear cells were gained. In consideration of possible applications in vivo we also tested the effect of the addition of different excipients to r28M. CONCLUSION: Summing up, we managed to purify monomeric r28M from bovine plasma in a large-scale preparation and could prove that its biological activity is unaffected and still highly specific and thus, might be applicable for the treatment of melanoma.
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Anticuerpos Biespecíficos/inmunología , Bovinos/inmunología , Proteoglicanos Tipo Condroitín Sulfato/inmunología , Melanoma/inmunología , Proteínas de la Membrana/inmunología , Anticuerpos de Cadena Única/inmunología , Adulto , Animales , Animales Modificados Genéticamente , Antígenos CD28/inmunología , Bovinos/genética , Línea Celular Tumoral , Humanos , MasculinoRESUMEN
FLT3 is a receptor-tyrosine-kinase that is expressed on leukemic cells of the myeloid and lymphoid lineage rather specifically. We here report on the construction and selection of bispecific FLT3 X CD3 antibodies in a new recombinant format, termed Fabsc, that resembles the normal antibody structure more closely than the well-established bispecific single chain (bssc)-format. Our preferred antibody, which emerged from an initial selection procedure utilizing different FLT3- and CD3-antibodies, contains the FLT3-antibody 4G8 and the CD3-antibody UCHT1. The 4G8 X UCHT1 Fabsc-antibody was found to be superior to a bssc-antibody with identical specificities with respect to (i) affinity to the target antigen FLT3, (ii) production yield by transfected cells, and (iii) the diminished formation of aggregates. T-cell activation in the presence and absence of cultured leukemic cells and killing of these cells was comparable for both molecules. In addition, the 4G8 X UCHT1 Fabsc-antibody was found to induce T-cell activation and efficient killing of leukemic blasts in primary peripheral blood mononuclear cell (PBMC) cultures of acute myeloid leukemia (AML) patients. In these experiments, the bispecific molecule was clearly superior to an Fc-optimized monospecific FLT3-antibody described previously, indicating that within PBMC of AML patients the recruitment of T cells is more effective than that of natural killer cells.
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Anticuerpos Biespecíficos/uso terapéutico , Complejo CD3/inmunología , Leucemia Experimental/terapia , Tirosina Quinasa 3 Similar a fms/inmunología , Animales , Ratones , Ratones Endogámicos C57BLRESUMEN
Recruitment of Fc-receptor-bearing effector cells, such as natural killer (NK) cells, is a feature critical for the therapeutic success of antitumor antibodies and can be improved by the modifications of an antibody's Fc part. The various ligands of the activating immunoreceptor NKG2D, NKG2DL) are selectively expressed on malignant cells including leukemia. We here took advantage of the tumor-associated expression of NKG2DL for targeting leukemic cells by NKG2D-immunoglobulin G (IgG)1 fusion proteins containing modified Fc parts. Compared to NKG2D-Fc containing a wild-type Fc part (NKG2D-Fc-WT), our mutants (S239D/I332E and E233P/L234V/L235A/ΔG236/A327G/A330S) displayed highly enhanced (NKG2D-Fc-ADCC) and abrogated (NKG2D-Fc-KO) affinity to the NK cell Fc receptor, respectively. Functional analyses with allogenic as well as autologous NK cells and primary malignant cells of leukemia patients revealed that NKG2D-Fc-KO significantly reduced NK reactivity by blocking immunostimulatory NKG2D-NKG2DL interaction. NKG2D-Fc-WT already enhanced antileukemia reactivity by inducing antibody-dependent cellular cytotoxicity (ADCC) with NKG2D-Fc-ADCC mediating significantly stronger effects. Parallel application of NKG2D-Fc-ADCC with Rituximab caused additive effects in lymphoid leukemia. In line with the tumor-associated expression of NKG2DL, no NK cell ADCC against resting healthy blood cells was induced. Thus, NKG2D-Fc-ADCC potently enhances NK antileukemia reactivity despite the inevitable reduction of activating signals upon binding to NKG2DL and may constitute an attractive means for immunotherapy of leukemia.
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Fragmentos Fc de Inmunoglobulinas/inmunología , Inmunoglobulina G/inmunología , Células Asesinas Naturales/inmunología , Leucemia/inmunología , Leucemia/patología , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología , Proteínas Recombinantes de Fusión/inmunología , Citotoxicidad Celular Dependiente de Anticuerpos , Citotoxicidad Inmunológica/inmunología , Humanos , Fragmentos Fc de Inmunoglobulinas/genética , Inmunoglobulina G/genética , Inmunoterapia , Células Asesinas Naturales/patología , Leucemia/genética , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Proteínas Recombinantes de Fusión/genéticaRESUMEN
γδ T cells are not MHC restricted, elicit cytotoxicity against various malignancies, are present in early post-transplant phases in novel stem cell transplantation strategies and have been shown to mediate antibody-dependent cellular cytotoxicity (ADCC) with monoclonal antibodies (mAbs). These features make γδ T cells promising effector cells for antibody-based immunotherapy in pediatric patients with B-lineage acute lymphoblastic leukemia (ALL). To evaluate combination of human γδ T cells with CD19 antibodies for immunotherapy of B-lineage ALL, γδ T cells were expanded after a GMP-compliant protocol and ADCC of both primary and expanded γδ T cells with an Fc-optimized CD19 antibody (4G7SDIE) and a bi-specific antibody with the specificities CD19 and CD16 (N19-C16) was evaluated in CD107a-degranulation assays and intracellular cytokine staining. CD107a, TNFα, and IFNγ expression of primary γδ T cells were significantly increased and correlated with CD16-expression of γδ T cells. γδ T cells highly expressed CD107a after expansion and no further increased expression by 4G7SDIE and N19-C16 was measured. Cytotoxicity of purified expanded γδ T cells targeting CD19-expressing cells was assessed in both europium-TDA release and in an impedance-based label-free method (using the xCELLigence system) measuring γδ T cell lysis in real-time. Albeit in the 2 h end-point europium-TDA release assay no increased lysis was observed, in real-time xCELLigence assays both significant antibody-independent cytotoxicity and ADCC of γδ T cells were observed. The xCELLigence system outperformed the end-point europium-TDA release assay in sensitivity and allows drawing of conclusions to lysis kinetics of γδ T cells over prolonged periods of time periods. Combination of CD19 antibodies with primary as well as expanded γδ T cells exhibits a promising approach, which may enhance clinical outcome of patients with pediatric B-lineage ALL and requires clinical evaluation.
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The ability of NK cells to mediate Ab-dependent cellular cytotoxicity (ADCC) largely contributes to the clinical success of antitumor Abs, including trastuzumab, which is approved for the treatment of breast cancer with HER2/neu overexpression. Notably, only â¼25% of breast cancer patients overexpress HER2/neu. Moreover, HER2/neu is expressed on healthy cells, and trastuzumab application is associated with side effects. In contrast, the ligands of the activating immunoreceptor NKG2D (NKG2DL) are selectively expressed on malignant cells. In this study, we took advantage of the tumor-associated expression of NKG2DL by using them as target Ags for NKG2D-IgG1 fusion proteins optimized by amino acid exchange S239D/I332E in their Fc part. Compared to constructs with wild-type Fc parts, fusion proteins carrying the S239D/I332E modification (NKG2D-Fc-ADCC) mediated highly enhanced degranulation, ADCC, and IFN-γ production of NK cells in response to breast cancer cells. NKG2D-Fc-ADCC substantially enhanced NK reactivity also against HER2/neu-low targets that were unaffected by trastuzumab, as both compounds mediated their immunostimulatory effects in strict dependence of target Ag expression levels. Thus, in line with the hierarchically organized potential of the various activating receptors governing NK reactivity and due to its highly increased affinity to CD16, NKG2D-Fc-ADCC potently enhances NK cell reactivity despite the inevitable reduction of activating signals upon binding to NKG2DL. Due to the tumor-restricted expression of NKG2DL, NKG2D-Fc-ADCC may constitute an attractive means for immunotherapy especially of HER2/neu-low or -negative breast cancer.
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Citotoxicidad Celular Dependiente de Anticuerpos/inmunología , Neoplasias de la Mama/inmunología , Fragmentos Fc de Inmunoglobulinas/inmunología , Células Asesinas Naturales/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología , Anticuerpos Monoclonales Humanizados/farmacología , Citotoxicidad Inmunológica/inmunología , Femenino , Humanos , Fragmentos Fc de Inmunoglobulinas/genética , Inmunoterapia/métodos , Interferón gamma/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Receptor ErbB-2/biosíntesis , Receptores de IgG/genética , Receptores de IgG/inmunología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , TrastuzumabRESUMEN
Receptor activator of NFκB ligand (RANKL) is mainly known for its role in bone metabolism, constituting a target for therapeutic interventions. Increasing evidence suggests that RANKL is also involved in oncogenesis and tumor progression, including a prominent role in host-tumor interaction. Our data suggest that targeting RANKL may reinforce natural killer (NK) cell-mediated antitumor responses in patients affected by hematological malignancies.
RESUMEN
Despite the availability of antiviral chemotherapy, herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections remain a severe global health problem. Of particular concern is the growing incidence of drug resistance in immunocompromised patients, which stresses the urgency to develop new effective treatment alternatives. We have developed a humanized monoclonal antibody (mAb hu2c) that completely abrogates viral cell-to-cell spread, a key mechanism by which HSV-1/2 escapes humoral immune surveillance. Moreover, mAb hu2c neutralized HSV fully independent of complement and/or immune effector cell recruitment in a highly efficient manner. Prophylactic and therapeutic administration of mAb hu2c completely prevented infection-related mortality of severely immunodeficient mice being challenged with a lethal dose of HSV-1. The high neutralization capacity of mAb hu2c was fully maintained toward clinical HSV isolates being multiresistant to standard antiviral drugs, and infection was fully resolved in 7/8 nonobese diabetic/SCID mice being infected with a multidrug resistant HSV-1 patient isolate. Immunohistochemical studies revealed no significant cross-reactivity of the antibody toward human tissues. These features warrant further clinical development of mAb hu2c as an immunotherapeutic compound for the management of severe and particularly drug-resistant HSV infections.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Antivirales/uso terapéutico , Herpes Simple/tratamiento farmacológico , Simplexvirus/inmunología , Aciclovir , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , Chlorocebus aethiops , Farmacorresistencia Viral , Herpes Simple/inmunología , Inmunohistoquímica , Ratones , Ratones SCID , Microscopía Fluorescente , Pruebas de Neutralización , Simplexvirus/genética , Células VeroRESUMEN
Natural killer (NK) cells are cytotoxic lymphocytes that largely contribute to the efficacy of therapeutic strategies like allogenic stem cell transplantation in acute myeloid leukemia (AML) and application of Rituximab in chronic lymphocytic leukemia (CLL). The tumor necrosis factor (TNF) family member GITR ligand (GITRL) is frequently expressed on leukemia cells in AML and CLL and impairs the reactivity of NK cells which express GITR and upregulate its expression following activation. We developed a strategy to reinforce NK anti-leukemia reactivity by combining disruption of GITR-GITRL interaction with targeting leukemia cells for NK antibody-dependent cellular cytotoxicity (ADCC) using GITR-Ig fusion proteins with modified Fc moieties. Neutralization of leukemia-expressed GITRL by the GITR domain enhanced cytotoxicity and cytokine production of NK cells depending on activation state with NK reactivity being further largely dependent on the engineered affinity of the fusion proteins to the Fc receptor. Compared with wild-type GITR-Ig, treatment of primary AML and CLL cells with mutants containing a S239D/I332E modification potently increased cytotoxicity, degranulation, and cytokine production of NK cells in a target-antigen-dependent manner with additive effects being observed with CLL cells upon parallel exposure to Rituximab. Fc-optimized GITR-Ig may thus constitute an attractive means for immunotherapy of leukemia that warrants clinical evaluation.
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Células Asesinas Naturales/citología , Leucemia/terapia , Proteínas Recombinantes de Fusión/farmacología , Células Cultivadas , Citometría de Flujo , Proteína Relacionada con TNFR Inducida por Glucocorticoide/genética , Proteína Relacionada con TNFR Inducida por Glucocorticoide/metabolismo , Humanos , Células Asesinas Naturales/efectos de los fármacos , Leucemia/inmunología , Receptores Fc/genética , Receptores Fc/metabolismo , Proteínas Recombinantes de Fusión/genéticaRESUMEN
A mutation in the hydin gene has been recently described as one possible mechanism leading to lethal congenital hydrocephalus in mice, and a similar defect is proposed to be involved in an autosomal recessive form of hydrocephalus in human. Here, we report for the first time on the cancer association and immunogenicity of two HYDIN variants in humans. One is a previously described sequence derived from the chromosome 1 gene copy, that is, KIAA1864. The second is encoded by a novel alternative transcript originating from the chromosome 16, which we identified by immunoscreening of a testis-derived cDNA expression library with sera of patients with colorectal cancer, and called MO-TES391. Both variants are targeted by immunoglobulin G antibodies in a significant subset of cancer patients but only rarely in healthy donors. Moreover, we identify HLA-A*0201-restricted sequences derived from MO-TES391 and KIAA1864, which are specifically recognized by human cytotoxic CD8(+) T cells. Taken together, these results suggest frequent and coordinated adaptive immune responses against HYDIN variants in patients with cancer and propose HYDIN as a novel cancer-associated antigen.
Asunto(s)
Inmunidad Adaptativa/genética , Antígenos de Neoplasias/inmunología , Linfocitos T CD8-positivos/inmunología , Proteínas de Microfilamentos/inmunología , Empalme Alternativo , Animales , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Cromosomas Humanos Par 1 , Cromosomas Humanos Par 16 , Antígeno HLA-A2/metabolismo , Humanos , Ratones , Proteínas de Microfilamentos/genética , Proteínas de Microfilamentos/metabolismo , Mutación , Neoplasias/inmunología , ARN Mensajero/inmunología , ARN Mensajero/metabolismoRESUMEN
Bone destruction is a prominent feature of multiple myeloma, but conflicting data exist on the expression and pathophysiologic involvement of the bone remodeling ligand RANKL in this disease and the potential therapeutic benefits of its targeted inhibition. Here, we show that RANKL is expressed by primary multiple myeloma and chronic lymphocytic leukemia (CLL) cells, whereas release of soluble RANKL was observed exclusively with multiple myeloma cells and was strongly influenced by posttranscriptional/posttranslational regulation. Signaling via RANKL into multiple myeloma and CLL cells induced release of cytokines involved in disease pathophysiology. Both the effects of RANKL on osteoclastogenesis and cytokine production by malignant cells could be blocked by disruption of RANK-RANKL interaction with denosumab. As we aimed to combine neutralization of RANKL with induction of antibody-dependent cellular cytotoxicity of natural killer (NK) cells against RANKL-expressing malignant cells and as denosumab does not stimulate NK reactivity, we generated RANK-Fc fusion proteins with modified Fc moieties. The latter displayed similar capacity compared with denosumab to neutralize the effects of RANKL on osteoclastogenesis in vitro, but also potently stimulated NK cell reactivity against primary RANKL-expressing malignant B cells, which was dependent on their engineered affinity to CD16. Our findings introduce Fc-optimized RANK-Ig fusion proteins as attractive tools to neutralize the detrimental function of RANKL while at the same time potently stimulating NK cell antitumor immunity.