RESUMEN
Antibody-based immunotherapy represents a promising strategy to target and eliminate chemoresistant leukemic cells. Here, we evaluated the CD33/CD3-bispecific T cell engaging (BiTE) antibody (AMG 330) for its suitability as a therapeutic agent in acute myeloid leukemia (AML). We first assessed CD33 expression levels by flow cytometry and found expression in >99% of patient samples (n = 621). CD33 was highest expressed in AMLs with NPM1 mutations (P < .001) and lower in AMLs with complex karyotypes and t(8;21) translocations (P < .001). Furthermore, leukemic stem cells within the CD34(+)/CD38(-) compartment displayed CD33 at higher levels than healthy donor stem cells (P = .047). In MS-5 feeder cell-based long-term cultures that supported the growth of primary AML blasts for up to 36 days, AMG 330 efficiently recruited and expanded residual CD3(+)/CD45RA(-)/CCR7(+) memory T cells within the patient sample. Even at low effector to target ratios, the recruited T cells lysed autologous blasts completely in the majority of samples and substantially in the remaining samples in a time-dependent manner. This study provides the first correlation of CD33 expression levels with AML genotype in a comprehensive analysis of adult patients. Targeting CD33 ex vivo using AMG 330 in primary AML samples led to T cell recruitment and expansion and remarkable antibody-mediated cytotoxicity, suggesting efficient therapeutic potential in vivo.
Asunto(s)
Anticuerpos Biespecíficos/inmunología , Inmunoterapia/métodos , Leucemia Mieloide Aguda/inmunología , Lectina 3 Similar a Ig de Unión al Ácido Siálico/metabolismo , Linfocitos T/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Biespecíficos/uso terapéutico , Técnicas de Cultivo de Célula , Técnicas de Cocultivo , Femenino , Citometría de Flujo , Genotipo , Humanos , Cariotipificación , Leucemia Mieloide Aguda/terapia , Masculino , Persona de Mediana Edad , Nucleofosmina , Factores de TiempoRESUMEN
It is widely accepted that metastasis is a late event in cancer progression. Here, however, we show that tumor cells can disseminate systemically from earliest epithelial alterations in HER-2 and PyMT transgenic mice and from ductal carcinoma in situ in women. Wild-type mice transplanted with single premalignant HER-2 transgenic glands displayed disseminated tumor cells and micrometastasis in bone marrow and lungs. The number of disseminated cancer cells and their karyotypic abnormalities were similar for small and large tumors in patients and mouse models. When activated by bone marrow transplantation into wild-type recipients, 80 early-disseminated cancer cells sufficed to induce lethal carcinosis. Therefore, release from dormancy of early-disseminated cancer cells may frequently account for metachronous metastasis.
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Neoplasias de la Mama/patología , Neoplasias Mamarias Experimentales/patología , Lesiones Precancerosas/patología , Animales , Células de la Médula Ósea/patología , Neoplasias de la Mama/genética , Proliferación Celular , Transformación Celular Neoplásica , Células Epiteliales/patología , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Cariotipificación , Neoplasias Pulmonares/secundario , Glándulas Mamarias Animales/trasplante , Glándulas Mamarias Animales/ultraestructura , Neoplasias Mamarias Experimentales/genética , Ratones , Ratones Endogámicos BALB C , Ratones Transgénicos , Invasividad Neoplásica , Metástasis de la Neoplasia , Células Neoplásicas Circulantes/patología , Lesiones Precancerosas/genética , HermanosRESUMEN
Immunoglobulin E (IgE) production is tightly regulated at the cellular and genetic levels and is believed to be central to allergy development. At least two cellular pathways exist that lead to systemic anaphylaxis reactions in vivo: IgE-sensitized mast cells and IgG1-sensitized basophils. Passive anaphylaxis, by application of allergen and allergen-specific antibodies in mice, indicates a differential contribution of immunoglobulin isotypes to anaphylaxis. However, analysis of a dynamic immunization-mediated antibody response in anaphylaxis is difficult. Here, we generated IgE knock-in mice (IgE(ki) ), which express the IgE heavy chain instead of IgG1, in order to analyze the contribution of IgG1 and IgE to active anaphylaxis in vivo. IgE(ki) mice display increased IgE production both in vitro and in vivo. The sensitization of IgE(ki) mice by immunization followed by antigen challenge leads to increased anaphylaxis. Homozygous IgE(ki) mice, which lack IgG1 due to the knock-in strategy, are most susceptible to active systemic anaphylaxis. The depletion of basophils demonstrates their importance in IgE-mediated anaphylaxis. Therefore, we propose that an enhanced, antigen-specific, polyclonal IgE response, as is the case in allergic patients, is probably the most efficient way to sensitize basophils to contribute to systemic anaphylaxis in vivo.
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Anafilaxia/inmunología , Anafilaxia/patología , Basófilos/inmunología , Basófilos/patología , Inmunoglobulina E/inmunología , Inmunoglobulina G/inmunología , Alérgenos/administración & dosificación , Alérgenos/inmunología , Anafilaxia/genética , Animales , Anticuerpos Monoclonales/biosíntesis , Anticuerpos Monoclonales/inmunología , Técnicas de Sustitución del Gen , Homocigoto , Humanos , Inmunización , Inmunoglobulina E/genética , Inmunoglobulina G/genética , Mastocitos/inmunología , Mastocitos/patología , Ratones , Ovalbúmina/administración & dosificación , Ovalbúmina/inmunología , Índice de Severidad de la EnfermedadRESUMEN
Persistence or recurrence of minimal residual disease (MRD) after chemotherapy results in clinical relapse in patients with acute lymphoblastic leukemia (ALL). In a phase 2 trial of B-lineage ALL patients with persistent or relapsed MRD, a T cell-engaging bispecific Ab construct induced an 80% MRD response rate. In the present study, we show that after a median follow-up of 33 months, the hematologic relapse-free survival of the entire evaluable study cohort of 20 patients was 61% (Kaplan-Meier estimate). The hema-tologic relapse-free survival rate of a subgroup of 9 patients who received allogeneic hematopoietic stem cell transplantation after blinatumomab treatment was 65% (Kaplan-Meier estimate). Of the subgroup of 6 Philadelphia chromosome-negative MRD responders with no further therapy after blinatumomab, 4 are in ongoing hematologic and molecular remission. We conclude that blinatumomab can induce long-lasting complete remission in B-lineage ALL patients with persistent or recurrent MRD. The original study and this follow-up study are registered at www.clinicaltrials.gov as NCT00198991 and NCT00198978, respectively.
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Anticuerpos Biespecíficos/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patología , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Adulto , Antineoplásicos/uso terapéutico , Terapia Combinada , Supervivencia sin Enfermedad , Estudios de Seguimiento , Trasplante de Células Madre Hematopoyéticas , Humanos , Estimación de Kaplan-Meier , Neoplasia Residual , Leucemia-Linfoma Linfoblástico de Células Precursoras B/sangre , Leucemia-Linfoma Linfoblástico de Células Precursoras B/mortalidad , Recurrencia , Análisis de Supervivencia , Trasplante HomólogoAsunto(s)
Anticuerpos Biespecíficos/farmacología , Linfocitos B/efectos de los fármacos , Complejo CD3/genética , Inmunoglobulina E/genética , Depleción Linfocítica/métodos , Linfocitos B/inmunología , Linfocitos B/patología , Complejo CD3/inmunología , Técnicas de Cocultivo , Expresión Génica , Humanos , Inmunoglobulina E/inmunología , Activación de Linfocitos/efectos de los fármacos , Unión Proteica , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/efectos de los fármacos , Linfocitos T Citotóxicos/inmunologíaRESUMEN
BACKGROUND: Epithelial cell adhesion molecule (EpCAM) is frequently and highly expressed on human carcinomas. The emerging role of EpCAM as a signalling receptor and activator of the wnt pathway, and its expression on tumor-initiating cells, further add to its attractiveness as target for immunotherapy of cancer. Thus far, five conventional monoclonal IgG antibodies have been tested in cancer patients. These are murine IgG2a edrecolomab and its murine/human chimeric IgG1 antibody version, and humanized, human-engineered and fully human IgG1 antibodies 3622W94, ING-1, and adecatumumab (MT201), respectively. Here we compared all anti-EpCAM antibodies in an attempt to explain differences in clinical activity and safety. METHODS: We recombinantly produced all antibodies but murine edrecolomab and investigated them for binding affinity, EpCAM epitope recognition, ADCC and CDC, and inhibition of breast cancer cell proliferation. RESULTS: ING-1 and 3622W94 bound to EpCAM with much higher affinity than adecatumumab and edrecolomab. Edrecolomab, ING-1, and 3622W94 all recognized epitopes in the exon 2-encoded N-terminal domain of EpCAM, while adecatumumab recognized a more membrane proximal epitope encoded by exon 5. All antibodies induced lysis of EpCAM-expressing cancer cell lines by both ADCC and CDC with potencies that correlated with their binding affinities. The chimeric version of edrecolomab with a human Fcγ1 domain was much more potent in ADCC than the murine IgG2a version. Only adecatumumab showed a significant inhibition of MCF-7 breast cancer cell proliferation in the absence of complement and immune cells. CONCLUSION: A moderate binding affinity and recognition of a distinct domain of EpCAM may best explain why adecatumumab showed a larger therapeutic window in cancer patients than the two high-affinity IgG1 antibodies ING-1 and 3622W94, both of which caused acute pancreatitis.
RESUMEN
T cell-engaging immunotherapies are changing the landscape of current cancer care. However, suitable target antigens are scarce, restricting these strategies to very few tumor types. Here, we report on a T cell-engaging antibody derivative that comes in two complementary halves and addresses antigen combinations instead of single molecules. Each half, now coined hemibody, contains an antigen-specific single-chain variable fragment (scFv) fused to either the variable light (VL) or variable heavy (VH) chain domain of an anti-CD3 antibody. When the two hemibodies simultaneously bind their respective antigens on a single cell, they align and reconstitute the original CD3-binding site to engage T cells. Employing preclinical models for aggressive leukemia and breast cancer, we show that by the combinatorial nature of this approach, T lymphocytes exclusively eliminate dual antigen-positive cells while sparing single positive bystanders. This allows for precision targeting of cancers not amenable to current immunotherapies.
Asunto(s)
Anticuerpos/farmacología , Antineoplásicos Inmunológicos/farmacología , Complejo CD3/metabolismo , Inmunoterapia/métodos , Linfocitos T/inmunología , Animales , Anticuerpos/genética , Antineoplásicos Inmunológicos/inmunología , Sitios de Unión , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/patología , Efecto Espectador , Línea Celular Tumoral , Femenino , Antígeno HLA-A2/genética , Antígeno HLA-A2/inmunología , Humanos , Activación de Linfocitos , Ratones Endogámicos BALB C , Ratones Endogámicos NOD , Medicina de Precisión/métodos , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/farmacología , Anticuerpos de Dominio Único/genética , Anticuerpos de Dominio Único/inmunología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
INTRODUCTION: Distant metastases of solid tumors are usually associated with fatal outcome. Disseminated cancer cells are considered early indicators of metastasis. Their sensitive detection and quantification would be a valuable tool for staging of disease and as guidance for therapeutic decisions. EXPERIMENTAL DESIGN: We established a highly sensitive and quantitative multimarker real-time RT-PCR assay for amplification of cancer-related genes MAGE-A1, -A2, -A3/6, -A4, -A10 and -A12 using SYBR green I to detect one single tumor cell in 2 mL of blood or bone marrow. The feasibility of the assay was tested in a large cohort of 177 patients with locally confined prostate carcinoma. RESULTS: Analysis revealed frequent MAGE expression in venous blood and bilateral bone marrow samples (25.5% of all cases) and yielded the first quantitative profile of MAGE expression with a broad range of transcript concentrations for individual markers in the minimal systemic tumor load of patients with localized cancer. CONCLUSIONS: Rare transcripts of different MAGE-A genes can be quantified in clinical samples of cancer patients by a sensitive multimarker real-time RT-PCR. Because of frequent expression of MAGE genes in various types of cancer the multimarker MAGE real-time RT-PCR may be generally useful for detection, quantification and characterization of the individual disseminated tumor load in cancer patients.
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Biomarcadores de Tumor/genética , Proteínas de Neoplasias/genética , Neoplasias de la Próstata/patología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Carga Tumoral , Anciano , Antígenos de Neoplasias/genética , Expresión Génica , Humanos , Masculino , Antígenos Específicos del Melanoma , Persona de Mediana Edad , Pronóstico , ARN Mensajero/análisis , ARN Neoplásico/análisis , Sensibilidad y Especificidad , Transcripción GenéticaAsunto(s)
Anticuerpos Biespecíficos/historia , Anticuerpos Biespecíficos/inmunología , Animales , Anticuerpos Biespecíficos/uso terapéutico , Linfocitos T CD8-positivos/inmunología , Congresos como Asunto , Citotoxicidad Inmunológica , Historia del Siglo XX , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/inmunologíaRESUMEN
In human cancer, early systemic spread of tumor cells is recognized as a leading cause of death. Adjuvant therapies are administered to patients after complete resectioning of their primary tumors to eradicate the few residual and latent metastatic cells. These therapeutic regimens, however, are currently designed without direct information about the presence or nature of the latent cells. To address this problem, we developed a PCR-based technique to analyze the transcriptome of individual tumor cells isolated from the bone marrow of cancer patients. From the same cells, genomic aberrations were identified by comparative genomic hybridization. The utility of this approach for understanding the biology of occult disseminated cells and for the identification of new therapeutic targets is demonstrated here by the detection of frequent extracellular matrix metalloproteinase inducer (EMMPRIN; CD147) expression which was verified by immunostaining.
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Perfilación de la Expresión Génica/métodos , Genoma Humano , Genómica/métodos , Metástasis de la Neoplasia/genética , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Transcripción Genética/genética , Ciclo Celular/genética , Humanos , Metástasis de la Neoplasia/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Neoplásico/genética , ARN Neoplásico/metabolismo , Células Tumorales CultivadasRESUMEN
Experimental research on the immune response to transplanted tumors has led to pioneering discoveries that laid many of the foundations for the current field of immunology. Experimental research in oncology has proven that murine and human tumors have antigens that are truly cancer specific. This article discusses research investigating how can antigens on cancer cells be used to help eradicate cancer.
Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Inmunoterapia/métodos , Neoplasias/terapia , Experimentación Animal , Animales , Humanos , Experimentación Humana TerapéuticaRESUMEN
Systemically disseminated tumor cells have become the subject of intensive research as the presumed seminal precursors of later distant metastasis. We describe here a novel sensitive multimarker nested reverse transcription (RT)-PCR capable of detecting the individual expression of human MAGE-A genes MAGE-1, -2, -3/6, -4, and -12 by rare, disseminated tumor cells in bone marrow and blood of patients with many different types of cancer. We analyzed bone marrow aspirates from 106 patients with breast, lung, colorectal, and prostate cancer and with different sarcomas. Heterogeneous expression of the different MAGE genes was found frequently in all those kinds of malignancies, in sharp contrast to 30 bone marrow and 20 blood samples from healthy donors, which were completely MAGE negative. Expression of at least one MAGE gene in bone marrow was more frequent than cytokeratin-positive tumor cells detected by immunocytochemistry, although the results of both tests overlapped considerably. In 30 patients with clinically localized prostate cancer, analysis by the multimarker MAGE RT-PCR of bilateral bone marrow aspirates from the right and left iliac crest revealed a positivity rate of 60%, which was twice as high as that obtained with either an established prostate-specific antigen RT-PCR or by cytokeratin-based immunocytochemistry. Analysis of primary prostate cancer revealed MAGE expression patterns considerably concordant with those found in the corresponding bone marrow aspirates. Prostate cancer patients carrying an exceptionally high risk of metastatic relapse, as defined by clinical prognostic factors, were significantly more often MAGE positive than patients with a distinctly lower risk (P = 0.02, Fisher's exact test). More frequent MAGE expression in the peripheral blood of patients with metastatic prostate cancer compared with those with clinically localized disease added further evidence for the prognostic impact of the multimarker MAGE RT-PCR. Moreover, MAGE-positive bone marrow samples from a small group of seven sarcoma patients demonstrated the relevance of our multimarker RT-PCR in nonepithelial tumors. Because MAGE antigens can induce autologous cytolytic T lymphocytes in vivo, the determination of individual MAGE expression patterns in cancer patients may furthermore identify candidate vaccine targets for adjuvant immunotherapy.
Asunto(s)
Antígenos de Neoplasias/genética , Biomarcadores de Tumor/genética , Metástasis de la Neoplasia/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Antígenos de Neoplasias/biosíntesis , Biomarcadores de Tumor/biosíntesis , Neoplasias de la Mama/genética , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/patología , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Femenino , Humanos , Inmunohistoquímica , Queratinas/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Metástasis de la Neoplasia/inmunología , Antígeno Prostático Específico/biosíntesis , Antígeno Prostático Específico/genética , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/inmunología , Neoplasias de la Próstata/patología , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Factores de RiesgoRESUMEN
PURPOSE: The finding of melanoma cells in the peripheral blood, thus far mainly inferred from the PCR-based demonstration of tyrosinase mRNA, has been associated with metastatic melanoma. Neither the malignant nature nor the prognostic significance of circulating cells could be established. To address this question, we analyzed immunomagnetically isolated circulating melanoma cells for chromosomal aberrations and performed a clinical follow-up study of the enrolled patients. EXPERIMENTAL DESIGN: In a prospective study, blood samples were taken from 164 melanoma patients and 50 donors without malignant disease. Circulating melanoma cells were enriched by immunomagnetic cell sorting using a murine monoclonal antibody against the melanoma-associated chondroitin sulfate proteoglycan. To prove the malignant origin of the positive cells and to define their chromosomal aberrations, we analyzed the genomes of 15 individually isolated cells from seven patients by single-cell comparative genomic hybridization (SCOMP). RESULTS: Absolute and relative frequencies of circulating melanoma cells were associated with stage and with the presence or absence of detectable tumor. The detection of two or more cells correlated significantly with a reduced survival of patients with metastatic melanoma. All of the cells that were analyzed by SCOMP displayed multiple chromosomal changes and carried aberrations typical for melanoma. CONCLUSIONS: Immunomagnetic enrichment enables isolation and genomic characterization of circulating melanoma cells. The prognostic impact on survival of metastatic patients apparently reflects the aggressiveness of an ongoing tumor spread. Direct genomic analysis of the enriched and isolated cells will help to clarify the molecular-genetic basis of the establishment of generalized melanoma.
Asunto(s)
Separación Inmunomagnética/métodos , Melanoma/genética , Melanoma/metabolismo , Células Neoplásicas Circulantes/metabolismo , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo , Anticuerpos Monoclonales/química , Separación Celular , Proteoglicanos Tipo Condroitín Sulfato/metabolismo , Aberraciones Cromosómicas , Análisis por Conglomerados , Humanos , Metástasis de la Neoplasia , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Prospectivos , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de TiempoRESUMEN
PURPOSE: Blinatumomab, a bispecific single-chain antibody targeting the CD19 antigen, is a member of a novel class of antibodies that redirect T cells for selective lysis of tumor cells. In acute lymphoblastic leukemia (ALL), persistence or relapse of minimal residual disease (MRD) after chemotherapy indicates resistance to chemotherapy and results in hematologic relapse. A phase II clinical study was conducted to determine the efficacy of blinatumomab in MRD-positive B-lineage ALL. PATIENTS AND METHODS: Patients with MRD persistence or relapse after induction and consolidation therapy were included. MRD was assessed by quantitative reverse transcriptase polymerase chain reaction for either rearrangements of immunoglobulin or T-cell receptor genes, or specific genetic aberrations. Blinatumomab was administered as a 4-week continuous intravenous infusion at a dose of 15 µg/m2/24 hours. RESULTS: Twenty-one patients were treated, of whom 16 patients became MRD negative. One patient was not evaluable due to a grade 3 adverse event leading to treatment discontinuation. Among the 16 responders, 12 patients had been molecularly refractory to previous chemotherapy. Probability for relapse-free survival is 78% at a median follow-up of 405 days. The most frequent grade 3 and 4 adverse event was lymphopenia, which was completely reversible like most other adverse events. CONCLUSION: Blinatumomab is an efficacious and well-tolerated treatment in patients with MRD-positive B-lineage ALL after intensive chemotherapy. T cells engaged by blinatumomab seem capable of eradicating chemotherapy-resistant tumor cells that otherwise cause clinical relapse.
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Anticuerpos Biespecíficos/uso terapéutico , Sistemas de Liberación de Medicamentos , Inmunoterapia/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Linfocitos T Citotóxicos/efectos de los fármacos , Adulto , Agammaglobulinemia/inducido químicamente , Anciano , Anciano de 80 o más Años , Anticuerpos Biespecíficos/efectos adversos , Anticuerpos Biespecíficos/farmacocinética , Especificidad de Anticuerpos , Antígenos CD19/inmunología , Antígenos de Neoplasias/inmunología , Linfocitos B/inmunología , Linfocitos B/patología , Médula Ósea/patología , Complejo CD3/inmunología , Linaje de la Célula , Terapia Combinada , Supervivencia sin Enfermedad , Resistencia a Antineoplásicos , Femenino , Humanos , Estimación de Kaplan-Meier , Activación de Linfocitos , Linfopenia/inducido químicamente , Masculino , Persona de Mediana Edad , Terapia Molecular Dirigida , Neoplasia Residual , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Inducción de Remisión , Especificidad del Receptor de Antígeno de Linfocitos T/efectos de los fármacos , Especificidad del Receptor de Antígeno de Linfocitos T/inmunología , Linfocitos T Citotóxicos/inmunología , Adulto JovenRESUMEN
Previous attempts have shown the potential of T cells in immunotherapy of cancer. Here, we report on the clinical activity of a bispecific antibody construct called blinatumomab, which has the potential to engage all cytotoxic T cells in patients for lysis of cancer cells. Doses as low as 0.005 milligrams per square meter per day in non-Hodgkin's lymphoma patients led to an elimination of target cells in blood. Partial and complete tumor regressions were first observed at a dose level of 0.015 milligrams, and all seven patients treated at a dose level of 0.06 milligrams experienced a tumor regression. Blinatumomab also led to clearance of tumor cells from bone marrow and liver. T cell-engaging antibodies appear to have therapeutic potential for the treatment of malignant diseases.
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Anticuerpos Biespecíficos/administración & dosificación , Antineoplásicos/administración & dosificación , Linfoma de Células B/tratamiento farmacológico , Linfoma Folicular/tratamiento farmacológico , Linfoma de Células del Manto/tratamiento farmacológico , Linfocitos T Citotóxicos/inmunología , Anticuerpos Biespecíficos/efectos adversos , Anticuerpos Biespecíficos/inmunología , Anticuerpos Biespecíficos/uso terapéutico , Antineoplásicos/efectos adversos , Antineoplásicos/uso terapéutico , Linfocitos B/inmunología , Humanos , Memoria Inmunológica , Inmunofenotipificación , Leucemia Linfocítica Crónica de Células B/tratamiento farmacológico , Leucemia Linfocítica Crónica de Células B/inmunología , Recuento de Linfocitos , Linfoma de Células B/inmunología , Linfoma Folicular/inmunología , Linfoma de Células del Manto/inmunología , Recurrencia , Linfocitos T/inmunologíaRESUMEN
Two receptors, CD4 and one of several chemokine receptors, are required for cellular HIV-1 infection, with CCR5 being the main coreceptor for macrophage-tropic strains. We have designed bifunctional fusion proteins, consisting of RANTES/CCL5 and a single-chain Fv Ab fragment against CD4 to simultaneously block CD4 and CCR5. The fusion proteins bind to both receptors, compete with RANTES/CCL5 binding, and induce down-modulation of CCR5 approximately 10 times more efficiently on CD4+ compared with CD8+ T cells. Moreover, after short incubation and subsequent washout, a significant down-modulation of CCR5 was only seen with the fusion proteins and only on CD4+ cells, but not with unmodified RANTES or on CD4- cells, indicating a preferential targeting of CCR5 on CD4+ T cells. The fusion proteins block M-tropic HIV infection more efficiently than RANTES/CCL5 and CD4 Abs alone or in combination. To our knowledge this is the first report of simultaneous blockade of an HIV-1 receptor and coreceptor with bifunctional inhibitors.
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Antígenos CD4/inmunología , Infecciones por VIH/prevención & control , Receptores CCR5/inmunología , Proteínas Recombinantes de Fusión/inmunología , Linfocitos T/inmunología , Animales , Unión Competitiva , Células CHO , Quimiocina CCL5/inmunología , Quimiocina CCL5/metabolismo , Quimiocinas CC/inmunología , Quimiocinas CC/metabolismo , Cricetinae , Citometría de Flujo , VIH-1/inmunología , Humanos , Fragmentos Fab de Inmunoglobulinas/inmunología , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Linfocitos T/virologíaRESUMEN
We report on a case of a 70-year-old woman with an ocular melanoma, which was diagnosed and treated 14 years ago. The patient was referred to the hospital with a suspected lymphoma. Cytological examination of bone marrow proved a marked infiltration with melanoma cells. Because detection of isolated tumor cells in the bone marrow of patients with various types of tumors was shown to be of prognostic significance and since current tumor-staging techniques are unable to detect single disseminated tumor cells or small aggregates of tumor cells, which might be the seed for subsequent metastatic relapse, we therefore evaluated the feasibility of immunocytochemical screening of bone marrow aspirates of 36 melanoma patients in different clinical stages using three monoclonal antibodies against melanoma-associated antigens in comparison with 43 non-melanoma control patients. Two of these antibodies (HMB45 and NKI-beteb) are directed against the melanoma antigen gp100/pmel17, whereas the third one (TA99) recognizes gp75/Tyrosinase-related protein 1 (TRP-1). None of the patients demonstrated a macroscopic bone marrow infiltration as was present in our patient with metastatic ocular melanoma. Seven (20.6%) of the 34 eligible melanoma patients presented with cells in the bone marrow positive for one or more of the above-mentioned melanosomal markers. Four of the positive patients were clinically free of tumors by the time of puncture, whereas the remaining 3 patients showed overt metastases in the subcutaneous fat (2 patients) and the brain (1 patient). On the other hand, 20 (66%) of the 29 patients with negative bone marrow findings also presented with clinical advanced disease with overt metastasis in the skin, lymph node, spleen, liver, lung, bone and brain. In conclusion, immunocytochemical screening of bone marrow samples is a feasible procedure that allows the detection of micrometastatic tumor cells in a subset of melanoma patients. Massive invasion of bone marrow with melanoma cells is a rare event even in far-advanced metastatic stages and no clear correlation between tumor load and bone marrow infiltration could be established.
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Neoplasias de la Médula Ósea/secundario , Melanoma/secundario , Anciano , Anticuerpos Monoclonales , Anticuerpos Antineoplásicos , Especificidad de Anticuerpos , Antígenos de Neoplasias/metabolismo , Examen de la Médula Ósea , Neoplasias de la Médula Ósea/patología , Neoplasias del Ojo , Femenino , Secciones por Congelación , Humanos , Inmunohistoquímica , Masculino , Melanoma/patologíaRESUMEN
Conserved molecular patterns derived from pathogenic microorganisms prime antigen-presenting dendritic cells (DC) to induce adaptive T cell responses. In contrast, virus-infected or tumor cells that express low levels of major histocompatibility complex (MHC) class I activate natural killer (NK) cells for direct killing. It is unknown whether NK cell recognition of MHC class I(low) targets can also induce adaptive T cell responses. Here, we show that MHC class I(low) targets initiate a cascade of immune responses, starting with the immediate activation of NK cells. The activated NK cells then prime DC to produce IL-12 and to induce highly protective CD8 T cell memory responses. Therefore, sensing of MHC class I(low) targets by NK cells can link innate and adaptive immunity to induce protective T cell responses and may alarm the immune system during early infection with noncytopathic viruses.
Asunto(s)
Linfocitos T CD8-positivos/metabolismo , Células Dendríticas/metabolismo , Antígenos de Histocompatibilidad Clase I/metabolismo , Células Asesinas Naturales/metabolismo , Animales , Linfocitos T CD8-positivos/inmunología , Carcinoma/inmunología , Carcinoma/metabolismo , Linfoma/inmunología , Linfoma/metabolismo , Ratones , Neoplasias/metabolismoRESUMEN
In our study, a novel, fully human, recombinant monoclonal antibody of the IgG1 isotype, called MT201, was characterized for its binding properties, complement-dependent (CDC) and antibody-dependent cellular cytotoxicity (ADCC), as well as for its in vivo antitumor activity in a nude mouse model. MT201 was found to bind its target, the epithelial cell adhesion molecule (Ep-CAM; also called 17-1A antigen, KSA, EGP-2, GA733-2), with low affinity in a range similar to that of the clinically validated, murine monoclonal IgG2a antibody edrecolomab (Panorex(R)). MT201 exhibited Ep-CAM-specific CDC with a potency similar to that of edrecolomab. However, the efficacy of ADCC of MT201, as mediated by human immune effector cells, was by 2 orders of magnitude higher than that of edrecolomab. Addition of human serum reduced the ADCC of MT201 while it essentially abolished ADCC of edrecolomab within the concentration range tested. In a nude mouse xenograft model, growth of tumors derived from the human colon carcinoma line HT-29 was significantly and comparably suppressed by MT201 and edrecolomab. The fully human nature and the improved ADCC of MT201 with human effector cells will make MT201 a promising candidate for the clinical development of a novel pan-carcinoma antibody that is superior to edrecolomab.