RESUMEN
BACKGROUND: Achondroplasia is a genetic disorder that inhibits endochondral ossification, resulting in disproportionate short stature and clinically significant medical complications. Vosoritide is a biologic analogue of C-type natriuretic peptide, a potent stimulator of endochondral ossification. METHODS: In a multinational, phase 2, dose-finding study and extension study, we evaluated the safety and side-effect profile of vosoritide in children (5 to 14 years of age) with achondroplasia. A total of 35 children were enrolled in four sequential cohorts to receive vosoritide at a once-daily subcutaneous dose of 2.5 µg per kilogram of body weight (8 patients in cohort 1), 7.5 µg per kilogram (8 patients in cohort 2), 15.0 µg per kilogram (10 patients in cohort 3), or 30.0 µg per kilogram (9 patients in cohort 4). After 6 months, the dose in cohort 1 was increased to 7.5 µg per kilogram and then to 15.0 µg per kilogram, and in cohort 2, the dose was increased to 15.0 µg per kilogram; the patients in cohorts 3 and 4 continued to receive their initial doses. At the time of data cutoff, the 24-month dose-finding study had been completed, and 30 patients had been enrolled in an ongoing long-term extension study; the median duration of follow-up across both studies was 42 months. RESULTS: During the treatment periods in the dose-finding and extension studies, adverse events occurred in 35 of 35 patients (100%), and serious adverse events occurred in 4 of 35 patients (11%). Therapy was discontinued in 6 patients (in 1 because of an adverse event). During the first 6 months of treatment, a dose-dependent increase in the annualized growth velocity was observed with vosoritide up to a dose of 15.0 µg per kilogram, and a sustained increase in the annualized growth velocity was observed at doses of 15.0 and 30.0 µg per kilogram for up to 42 months. CONCLUSIONS: In children with achondroplasia, once-daily subcutaneous administration of vosoritide was associated with a side-effect profile that appeared generally mild. Treatment resulted in a sustained increase in the annualized growth velocity for up to 42 months. (Funded by BioMarin Pharmaceutical; ClinicalTrials.gov numbers, NCT01603095, NCT02055157, and NCT02724228.).
Asunto(s)
Acondroplasia/tratamiento farmacológico , Crecimiento/efectos de los fármacos , Péptido Natriurético Tipo-C/análogos & derivados , Osteogénesis/efectos de los fármacos , Acondroplasia/fisiopatología , Adolescente , Biomarcadores/análisis , Estatura/efectos de los fármacos , Niño , Preescolar , Colágeno/sangre , GMP Cíclico/orina , Relación Dosis-Respuesta a Droga , Femenino , Gráficos de Crecimiento , Humanos , Inyecciones Subcutáneas , Masculino , Péptido Natriurético Tipo-C/administración & dosificación , Péptido Natriurético Tipo-C/efectos adversos , Péptido Natriurético Tipo-C/uso terapéuticoRESUMEN
Mucopolysaccharidosis type IIIB (MPS IIIB; Sanfilippo syndrome B; OMIM #252920) is a lethal, pediatric, neuropathic, autosomal recessive, and lysosomal storage disease with no approved therapy. Patients are deficient in the activity of N-acetyl-alpha-glucosaminidase (NAGLU; EC 3.2.150), necessary for normal lysosomal degradation of the glycosaminoglycan heparan sulfate (HS). Tralesinidase alfa (TA), a fusion protein comprised of recombinant human NAGLU and a modified human insulin-like growth factor 2, is in development as an enzyme replacement therapy that is administered via intracerebroventricular (ICV) infusion, thus circumventing the blood brain barrier. Previous studies have confirmed ICV infusion results in widespread distribution of TA throughout the brains of mice and nonhuman primates. We assessed the long-term tolerability, pharmacology, and clinical efficacy of TA in a canine model of MPS IIIB over a 20-month study. Long-term administration of TA was well tolerated as compared with administration of vehicle. TA was widely distributed across brain regions, which was confirmed in a follow-up 8-week pharmacokinetic/pharmacodynamic study. MPS IIIB dogs treated for up to 20 months had near-normal levels of HS and nonreducing ends of HS in cerebrospinal fluid and central nervous system (CNS) tissues. TA-treated MPS IIIB dogs performed better on cognitive tests and had improved CNS pathology and decreased cerebellar volume loss relative to vehicle-treated MPS IIIB dogs. These findings demonstrate the ability of TA to prevent or limit the biochemical, pathologic, and cognitive manifestations of canine MPS IIIB disease, thus providing support of its potential long-term tolerability and efficacy in MPS IIIB subjects. SIGNIFICANCE STATEMENT: This work illustrates the efficacy and tolerability of tralesinidase alfa as a potential therapeutic for patients with mucopolysaccharidosis type IIIB (MPS IIIB) by documenting that administration to the central nervous system of MPS IIIB dogs prevents the accumulation of disease-associated glycosaminoglycans in lysosomes, hepatomegaly, cerebellar atrophy, and cognitive decline.
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Mucopolisacaridosis III , Animales , Encéfalo/metabolismo , Niño , Modelos Animales de Enfermedad , Perros , Terapia de Reemplazo Enzimático , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/líquido cefalorraquídeo , Heparitina Sulfato/uso terapéutico , Humanos , Mucopolisacaridosis III/tratamiento farmacológico , Mucopolisacaridosis III/patologíaRESUMEN
Treatment with intracerebroventricular (ICV)-delivered cerliponase alfa enzyme replacement therapy (ERT) in a Phase 1/2 study of 24 subjects with CLN2 disease resulted in a meaningful preservation of motor and language (ML) function and was well tolerated. Treatment was associated with anti-drug antibody (ADA) production in the cerebrospinal fluid (CSF) of 6/24 (25%) and in the serum of 19/24 (79%) of clinical trial subjects, respectively, over a mean exposure of 96.4â¯weeks (range 0.1-129â¯weeks). Neutralizing antibodies (NAb) were not detected in the CSF of any of the subjects. No events of anaphylaxis were reported. Neither the presence of serum ADA nor drug-specific immunoglobulin E was associated with the incidence or severity of hypersensitivity adverse events. Serum and CSF ADA titers did not correlate with change in ML score. Therefore, the development of an ADA response to cerliponase alfa is not predictive of an adverse safety profile or poor treatment outcome.
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Anticuerpos/inmunología , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/inmunología , Terapia de Reemplazo Enzimático , Lipofuscinosis Ceroideas Neuronales/tratamiento farmacológico , Proteínas Recombinantes/inmunología , Adolescente , Anticuerpos Neutralizantes/inmunología , Niño , Preescolar , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/uso terapéutico , Progresión de la Enfermedad , Hipersensibilidad a las Drogas/epidemiología , Hipersensibilidad a las Drogas/inmunología , Femenino , Humanos , Inmunoglobulina E/inmunología , Infusiones Intraventriculares , Masculino , Proteínas Recombinantes/uso terapéutico , Tripeptidil Peptidasa 1RESUMEN
BACKGROUND AND OBJECTIVE: Vosoritide is a recently approved therapy for achondroplasia, the most common form of disproportionate short stature, that has been shown to be well tolerated and effective in increasing linear growth. This study aimed to develop a population pharmacokinetic (PPK) model to characterize pharmacokinetics (PK) of vosoritide and establish a weight-band dosing regimen. METHODS: A PPK model was developed using data from five clinical trials in children with achondroplasia (aged 0.95-15 years) who received daily per-kg doses of vosoritide. The model was used to simulate expected exposures in children with a refined weight-band dosing regimen. Simulated exposure was compared with the observed exposure from the pivotal clinical trial to evaluate appropriateness of the weight-band dosing regimen. RESULTS: A one-compartment model with a change-point first-order absorption and first-order elimination accurately described PK of vosoritide in children with achondroplasia. Body weight was found to be a predictor of vosoritide's clearance and volume of distribution. Additionally, it was observed that dosing solution concentration and duration of treatment influenced bioavailability. The weight-band dosing regimen resulted in simulated exposures that were within the range demonstrated to be well tolerated and effective in the pivotal clinical trial and showed improved consistency in drug exposure across the achondroplasia population. CONCLUSIONS: The weight-band dosing regimen reduced the number of recommended dose levels by body weight and is expected to simplify dosing for children with achondroplasia and their caregivers. CLINICAL TRIAL REGISTRATION: NCT02055157, NCT02724228, NCT03197766, NCT03424018, and NCT03583697.
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Acondroplasia , Peso Corporal , Modelos Biológicos , Humanos , Acondroplasia/tratamiento farmacológico , Niño , Adolescente , Femenino , Preescolar , Masculino , Lactante , Péptido Natriurético Tipo-C/farmacocinética , Péptido Natriurético Tipo-C/administración & dosificación , Péptido Natriurético Tipo-C/análogos & derivados , Relación Dosis-Respuesta a DrogaRESUMEN
BACKGROUND: Cerliponase alfa is a recombinant human tripeptidyl peptidase 1 (TPP1) enzyme replacement therapy for the treatment of neuronal ceroid lipofuscinosis type 2 (CLN2 disease), which is caused by mutations in the TPP1 gene. We aimed to determine the long-term safety and efficacy of intracerebroventricular cerliponase alfa in children with CLN2 disease. METHODS: This analysis includes cumulative data from a primary 48-week, single-arm, open-label, multicentre, dose-escalation study (NCT01907087) and the 240-week open-label extension with 6-month safety follow-up, conducted at five hospitals in Germany, Italy, the UK, and the USA. Children aged 3-16 years with CLN2 disease confirmed by genetic analysis and enzyme testing were eligible for inclusion. Treatment was intracerebroventricular infusion of 300 mg cerliponase alfa every 2 weeks. Historical controls with untreated CLN2 disease in the DEM-CHILD database were used as a comparator group. The primary efficacy outcome was time to an unreversed 2-point decline or score of 0 in the combined motor and language domains of the CLN2 Clinical Rating Scale. This extension study is registered with ClinicalTrials.gov, NCT02485899, and is complete. FINDINGS: Between Sept 13, 2013, and Dec 22, 2014, 24 participants were enrolled in the primary study (15 female and 9 male). Of those, 23 participants were enrolled in the extension study, conducted between Feb 2, 2015, and Dec 10, 2020, and received 300 mg cerliponase alfa for a mean of 272·1 (range 162·1-300·1) weeks. 17 participants completed the extension and six discontinued prematurely. Treated patients were significantly less likely than historical untreated controls to have an unreversed 2-point decline or score of 0 in the combined motor and language domains (hazard ratio 0·14, 95% CI 0·06 to 0·33; p<0·0001). All participants experienced at least one adverse event and 21 (88%) experienced a serious adverse event; nine participants experienced intracerebroventricular device-related infections, with nine events in six participants resulting in device replacement. There were no study discontinuations because of an adverse event and no deaths. INTERPRETATION: Cerliponase alfa over a mean treatment period of more than 5 years was seen to confer a clinically meaningful slowing of decline of motor and language function in children with CLN2 disease. Although our study does not have a contemporaneous control group, the results provide crucial insights into the effects of long-term treatment. FUNDING: BioMarin Pharmaceutical.
Asunto(s)
Lipofuscinosis Ceroideas Neuronales , Humanos , Masculino , Femenino , Lipofuscinosis Ceroideas Neuronales/tratamiento farmacológico , Lipofuscinosis Ceroideas Neuronales/genética , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/uso terapéutico , Tripeptidil Peptidasa 1 , Proteínas Recombinantes/efectos adversosRESUMEN
Mucopolysaccharidosis Type IIIB (MPS IIIB) is an ultrarare, fatal pediatric disease with no approved therapy. It is caused by mutations in the gene encoding for lysosomal enzyme alpha-N-acetylglucosaminidase (NAGLU). Tralesinidase alfa (TA) is a fusion protein comprised of recombinant NAGLU and a modified human insulin-like growth factor 2 that is being developed as an enzyme replacement therapy for MPS IIIB. Since MPS IIIB is a pediatric disease the safety/toxicity, pharmacokinetics and biodistribution of TA were evaluated in juvenile non-human primates that were administered up to 5 weekly intracerebroventricular (ICV) or single intravenous (IV) infusions of TA. TA administered by ICV slow-, ICV isovolumetric bolus- or IV-infusion was well-tolerated, and no effects were observed on clinical observations, electrocardiographic or ophthalmologic parameters, or respiratory rates. The drug-related changes observed were limited to increased cell infiltrates in the CSF and along the ICV catheter track after ICV administration. These findings were not associated with functional changes and are associated with the use of ICV catheters. The CSF PK profiles were consistent across all conditions tested and TA distributed widely in the CNS after ICV administration. Anti-drug antibodies were observed but did not appear to significantly affect the exposure to TA. Correlations between TA concentrations in plasma and brain regions in direct contact with the cisterna magna suggest glymphatic drainage may be responsible for clearance of TA from the CNS. The data support the administration of TA by isovolumetric bolus ICV infusion to pediatric patients with MPS IIIB.
RESUMEN
BACKGROUND: Respiratory Syncytial Virus (RSV) causes significant disease in the elderly, in part, because immunosenescence impairs protective immune responses to infection in this population. Despite previous and current efforts, there is no RSV vaccine currently licensed in infants or elderly adults. Adjuvanted RSV subunit vaccines have the potential to boost waning immune responses and reduce the burden of RSV disease in the elderly population. RESULTS: We used an aged BALB/c mouse model to evaluate immune responses to RSV Fusion (F) protein in the absence and presence of an alum adjuvant. We demonstrate that aged BALB/c mice immunized with alum-adjuvanted RSV F protein had significantly reduced lung viral titers at day 4 following challenge with wild-type (wt) RSV. Serum neutralizing antibody titers measured on day 27 correlated with protection in both young and aged vaccinated mice, although the magnitude of antibody titers was lower in aged mice. Unlike young mice, in aged mice, alum-adjuvanted RSV F did not induce lung TH2-type cytokines or eosinophil infiltration compared to non-adjuvanted F protein following wt RSV challenge. CONCLUSION: Our studies demonstrate that neutralizing anti-RSV antibody titers correlate with protection in both young and aged BALB/c mice vaccinated with RSV F protein vaccines. The F + alum formulation mediated greater protection compared to the non-adjuvanted F protein in both young and aged mice. However, while alum can boost F-specific antibody responses in aged mice, it does not completely overcome the reduced ability of a senescent immune system to respond to the RSV F antigen. Thus, our data suggest that a stronger adjuvant may be required for the prevention of RSV disease in immunosenescent populations, to achieve the appropriate balance of protective neutralizing antibodies and effective TH1-type cytokine response along with minimal lung immunopathology.
RESUMEN
BACKGROUND AND OBJECTIVE: Vosoritide, an analog of C-type natriuretic peptide, has been developed for the treatment of children with achondroplasia. The pharmacokinetics of vosoritide and relationships between plasma exposure and efficacy, biomarkers, and safety endpoints were evaluated in a phase II, open-label, dose-escalation study (N = 35 patients aged 5-14 years who received daily subcutaneous injections for 24 months) and a phase III, double-blind, placebo-controlled study (N = 60 patients aged 5-18 years randomized to receive daily subcutaneous injections for 52 weeks). METHODS: Pharmacokinetic parameters for both studies were obtained from non-compartmental analysis. Potential correlations between vosoritide exposure and changes in annualized growth velocity, collagen type X marker (CXM; a biomarker of endochondral ossification), cyclic guanosine monophosphate (cGMP; a biomarker of pharmacological activity), heart rate, and systolic and diastolic blood pressures were then evaluated. RESULTS: The exposure-response relationships for changes in both annualized growth velocity and the CXM biomarker saturated at 15 µg/kg, while systemic pharmacological activity, as measured by urinary cGMP, was near maximal or saturated at exposures obtained at the highest dose studied (i.e. 30 µg/kg). This suggested that the additional bioactivity was likely in tissues not related to endochondral bone formation. In the phase III study, following subcutaneous administration at the recommended dose of 15 µg/kg to patients with achondroplasia aged 5-18 years, vosoritide was rapidly absorbed with a median time to maximal plasma concentration (Cmax) of 15 minutes, and cleared with a mean half-life of 27.9 minutes after 52 weeks of treatment. Vosoritide exposure (Cmax and area under the concentration-time curve [AUC]) was consistent across visits. No evidence of accumulation with once-daily dosing was observed. Total anti-vosoritide antibody (TAb) responses were detected in the serum of 25 of 60 (42%) treated patients in the phase III study, with no apparent impact of TAb development noted on annualized growth velocity or vosoritide exposure. Across the exposure range obtained with 15 µg/kg in the phase III study, no meaningful correlations between vosoritide plasma exposure and changes in annualized growth velocity or CXM, or changes from predose heart rate, and systolic or diastolic blood pressures were observed. CONCLUSIONS: The results support the recommended dose of vosoritide 15 µg/kg for once-daily subcutaneous administration in patients with achondroplasia aged ≥ 5 years whose epiphyses are not closed. CLINICAL TRIALS REGISTRATION: NCT02055157, NCT03197766, and NCT01603095.
Asunto(s)
Acondroplasia , Péptido Natriurético Tipo-C , Acondroplasia/inducido químicamente , Acondroplasia/tratamiento farmacológico , Adolescente , Área Bajo la Curva , Biomarcadores , Niño , Preescolar , Método Doble Ciego , Humanos , Inyecciones Subcutáneas , Péptido Natriurético Tipo-C/análogos & derivados , Péptido Natriurético Tipo-C/farmacocinética , Péptido Natriurético Tipo-C/uso terapéuticoRESUMEN
Cerliponase alfa is recombinant human tripeptidyl peptidase 1 (TPP1) delivered by i.c.v. infusion for CLN2, a pediatric neurodegenerative disease caused by deficiency in lysosomal enzyme TPP1. We report the pharmacokinetics (PK) and pharmacodynamics of cerliponase alfa, the first i.c.v. enzyme replacement therapy, characterized in a phase I/II study. Escalating doses (30-300 mg Q2W) followed by 300 mg Q2W for ≥ 48 weeks were administered in 24 patients aged ≥ 3 years. Concentrations peaked in cerebrospinal fluid (CSF) at the end of ~ 4-hour i.c.v. infusion and 8 hours thereafter in plasma. Plasma exposure was 300-1,000-fold lower than in CSF, with no correlation in the magnitude of peak concentration (Cmax ) or area under the concentration-time curve (AUC) among body sites. There was no apparent accumulation in CSF or plasma exposure with Q2W dosing. Interpatient and intrapatient variability of AUC, respectively, were 31-49% and 24% in CSF vs. 59-103% and 80% in plasma. PK variability was not explained by baseline demographics, as sex, age, weight, and CLN2 disease severity score did not appear to impact CSF or plasma PK. No apparent correlation was noted between CSF or plasma PK and incidence of adverse events (pyrexia, hypersensitivity, seizure, and epilepsy) or presence of antidrug antibodies in CSF and serum. There was no relationship between magnitude of CSF exposure and efficacy (change in CLN2 score from baseline), indicating maximum benefit was obtained across the range of exposures with 300 mg Q2W. Data from this small trial of ultra-rare disease were leveraged to adequately profile cerliponase alfa and support 300 mg i.c.v. Q2W for CLN2 treatment.
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Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/administración & dosificación , Terapia de Reemplazo Enzimático/métodos , Lipofuscinosis Ceroideas Neuronales/tratamiento farmacológico , Proteínas Recombinantes/administración & dosificación , Niño , Preescolar , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/efectos adversos , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/farmacocinética , Progresión de la Enfermedad , Esquema de Medicación , Femenino , Humanos , Inyecciones Intraventriculares , Masculino , Lipofuscinosis Ceroideas Neuronales/líquido cefalorraquídeo , Lipofuscinosis Ceroideas Neuronales/genética , Proteínas Recombinantes/efectos adversos , Proteínas Recombinantes/farmacocinética , Tripeptidil Peptidasa 1/deficienciaRESUMEN
B-cell chronic lymphocytic leukemia (B-CLL) is a lymphoproliferative disorder characterized by the surface expression of CD20, CD5 antigens, as well as the receptor CD40. Activation of CD40 by its ligand (CD40L) induces proliferation and rescues the cells from spontaneous and chemotherapy-induced apoptosis. CD40 activation also induces secretion of cytokines, such as IL-6, IL-10, TNF-alpha, IL-8, and GM-CSF, which are involved in tumor cell survival, migration, and interaction with cells in the tumor microenvironment. Here we demonstrate that in primary B-CLL tumor cells, the novel antagonist anti-CD40 monoclonal antibody, HCD122, inhibits CD40L-induced activation of signaling pathways, proliferation and survival, and secretion of cytokines. Furthermore, HCD122 is also a potent mediator of antibody-dependent cellular cytotoxicity (ADCC), lysing B-CLL cells more efficiently than rituximab in vitro, despite a significantly higher number of cell surface CD20 binding sites compared with CD40. Unlike rituximab, however, HCD122 (formerly CHIR-12.12) does not internalize upon binding to the cells. Our data suggest that HCD122 may inhibit B-CLL growth by blocking CD40 signaling and by ADCC-mediated cell lysis.
Asunto(s)
Anticuerpos Monoclonales/farmacología , Antineoplásicos/farmacología , Antígenos CD40/inmunología , Leucemia de Células B/inmunología , Adulto , Anciano , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales de Origen Murino , Citotoxicidad Celular Dependiente de Anticuerpos/efectos de los fármacos , Sitios de Unión , Femenino , Humanos , Masculino , Persona de Mediana Edad , Rituximab , Transducción de Señal/efectos de los fármacosRESUMEN
Recent advances in cell biology have provided evidence that the plasma membrane is not a homogeneous lipid bilayer but rather contains within it sphingolipid- and cholesterol-rich membrane microdomains, termed lipid rafts, which serve as platforms for both receptor signaling and trafficking. In B lymphocytes lipid rafts appear to play a key role in the initiation of B-cell antigen receptor (BCR) signaling. Current methods to isolate lipid rafts rely on the relative detergent insolubility of lipid rafts as compared to the nonraft, glycerophospholipid bilayer. Here a method to isolate and characterize lipid rafts from B lymphocytes is described. Particular emphasis is given to the potential artifacts inherent in current procedures that rely on detergents to isolate lipid rafts and alternative technologies that may circumvent these.
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Membrana Celular/metabolismo , Colesterol/análisis , Microdominios de Membrana/química , Receptores de Antígenos de Linfocitos B/inmunología , Esfingolípidos/análisis , Animales , Centrifugación por Gradiente de Densidad , Detergentes/química , Inmunoglobulina G/farmacología , Inmunoglobulina M/farmacología , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/inmunología , Linfoma/inmunología , Linfoma/metabolismo , Microdominios de Membrana/inmunología , Ratones , Receptores de Antígenos de Linfocitos B/análisis , Transducción de Señal , Células Tumorales CultivadasRESUMEN
Respiratory syncytial virus (RSV) causes significant disease in elderly adults, and we have previously reported that individuals 65 years of age and older have reduced RSV F protein-specific gamma interferon (IFN-γ)-producing T cells compared to healthy younger adults. To measure RSV F-specific memory T cell responses in the elderly following infection or vaccination, we optimized and qualified an IFN-γ enzyme-linked immunospot (ELISPOT) assay. Since peripheral blood mononuclear cells (PBMC) from the elderly could be more fragile, we established optimal cryopreservation techniques and minimal viability acceptance criteria. The number of cells per well, types and concentrations of stimulation antigens, and incubation times were evaluated to maximize assay sensitivity and precision. The optimized assay uses 300,000 cells/well, 2 µg/ml of an RSV F peptide pool (RSV Fpp), and incubation for 22 ± 2 h in serum-free CTL-Test medium. The assay was qualified by 3 analysts using 3 RSV F-responding donor PBMC samples (high, medium, and low responders) tested on 5 different assay days. The assay sensitivity or limit of detection (LOD) was determined to be 21 spot-forming cells (SFC) per 10(6) PBMC, and the lower limit of quantitation (LLOQ) was estimated to be 63 SFC/10(6) PBMC. The intra- and interassay percent coefficients of variation (CV) were <10.5% and <31%, respectively. The results of the qualification study demonstrate that a robust, precise, and sensitive IFN-γ ELISPOT assay has been developed that is fit for measuring RSV F-specific IFN-γ T cell responses in subjects enrolled in a vaccine clinical trial or in epidemiology studies.
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Interferón gamma/metabolismo , Virus Sincitial Respiratorio Humano/inmunología , Linfocitos T/inmunología , Proteínas Virales de Fusión/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Células Cultivadas , Ensayo de Immunospot Ligado a Enzimas/métodos , Femenino , Humanos , Memoria Inmunológica , Leucocitos Mononucleares/inmunología , Masculino , Preservación Biológica , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto JovenRESUMEN
Respiratory syncytial virus (RSV) infects elderly (≥65 years) adults, causing medically attended illness and hospitalizations. While RSV neutralizing antibody levels correlate inversely with RSV-associated hospitalization in the elderly, the role of RSV-specific T cells in preventing disease in the elderly remains unclear. We examined RSV-specific humoral, mucosal, and cellular immune profiles in healthy elderly (65 to 85 years) and young (20 to 30 years) adults. RSV neutralization antibody titers in the elderly (10.5 ± 2.2 log(2)) and young (10.5 ± 2.1 log(2)) were similar. In contrast, levels of RSV F protein-specific gamma interferon (IFN-γ)-producing T cells were lower in elderly (180 ± 80 spot-forming cells [SFC]/10(6) peripheral blood mononuclear cells [PBMC]) than in young adults (1,250 ± 420 SFC/10(6) PBMC). Higher levels of interleukin-13 (IL-13; 3,000 ± 1,000 pg/ml) in cultured PBMC supernatants and lower frequency of RSV F-specific CD107a(+) CD8(+) T cells (3.0% ± 1.6% versus 5.0% ± 1.6%) were measured in PBMC from elderly than young adults. These results suggest that deficient RSV F-specific T cell responses contribute to susceptibility to severe RSV disease in elderly adults.
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Envejecimiento/inmunología , Anticuerpos Antivirales/sangre , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Virus Sincitiales Respiratorios/inmunología , Proteínas Virales de Fusión/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Neutralizantes/sangre , Humanos , Memoria Inmunológica/inmunología , Interferón gamma/biosíntesis , Interleucina-13/análisis , Leucocitos Mononucleares/inmunología , Recuento de Linfocitos , Proteína 1 de la Membrana Asociada a los Lisosomas/biosíntesis , Infecciones por Virus Sincitial Respiratorio/inmunología , Infecciones por Virus Sincitial Respiratorio/prevención & control , Infecciones por Virus Sincitial Respiratorio/virología , Adulto JovenRESUMEN
Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in infants and the elderly. Despite its relatively low degree of antigenic variation, it causes frequent reinfection throughout life. Clinical manifestations of RSV disease and the immune response to infection differ in infants and the elderly, suggesting that vaccines designed to protect these two populations may require different attributes. Here, the authors describe the translational approach of utilizing data from epidemiology studies performed in these populations, the use of RSV diagnostics in clinical practice, lessons learned from previous vaccine clinical trials and the success of palivizumab in prevention of RSV disease in premature and high-risk infants to aid the development of safe and effective RSV vaccines.
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Anticuerpos Monoclonales Humanizados/administración & dosificación , Antivirales/administración & dosificación , Infecciones por Virus Sincitial Respiratorio/tratamiento farmacológico , Infecciones por Virus Sincitial Respiratorio/epidemiología , Vacunas contra Virus Sincitial Respiratorio/inmunología , Vacunas contra Virus Sincitial Respiratorio/aislamiento & purificación , Virus Sincitiales Respiratorios/inmunología , Descubrimiento de Drogas/tendencias , Humanos , Palivizumab , Infecciones por Virus Sincitial Respiratorio/prevención & controlRESUMEN
Currently, a robust set of immune correlates for live attenuated influenza vaccine (LAIV) efficacy in humans has not been fully elucidated. The serum hemagglutination inhibition (HAI) assay has been historically used to measure humoral immune responses to injectable inactivated influenza vaccination. However, serum antibody titers do not reliably reflect the complete mechanism of action of LAIV, which is an intranasally delivered vaccine and is expected to induce local mucosal and cellular immune responses in addition to humoral immune responses. Therefore, we designed a study to evaluate potential immune correlates of LAIV vaccination in the ferret animal model of influenza infection. Ferrets were vaccinated with increasing doses of LAIV and four weeks later challenged with a homologous wild-type (wt) H1N1 strain. Humoral immune responses measured following LAIV vaccination included HAI, serum antibodies and antibody secreting cells (ASC); and the responses were found to correlate with the dose level of LAIV administered in this model. Protection from wt virus challenge was determined by measuring inhibition of wt viral replication in nasal washes and in lung tissue. Results demonstrated that LAIV doses ≥ 5.0 log(10) Plaque Forming Units (PFU) elicited vaccine-specific IgG and IgA ASC frequencies and induced complete protection in the lungs. Further, we developed a novel model utilizing seropositive older ferrets to demonstrate that in the background of previous wt influenza infection LAIV induces a robust vaccine-specific B-cell response even in the absence of serum antibody response, a result that suggests that effector B-cell responses generated by LAIV are not inhibited by prior viral exposure. Finally, we demonstrated that LAIV elicits strain-specific memory B-cell responses that are measurable in a background of wt influenza infections. Taken together, results from these studies identified the antigen-specific ASC frequency as a useful early biomarker of LAIV-induced B-cell immune response.
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Células Productoras de Anticuerpos/inmunología , Linfocitos B/inmunología , Subtipo H1N1 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Animales , Anticuerpos Antivirales/sangre , Biomarcadores , Modelos Animales de Enfermedad , Femenino , Hurones , Pruebas de Inhibición de Hemaglutinación , Inmunoglobulina A/inmunología , Inmunoglobulina G/inmunología , Memoria Inmunológica , Vacunas contra la Influenza/administración & dosificación , Pulmón/virología , Masculino , Mucosa Nasal/virología , Infecciones por Orthomyxoviridae/prevención & control , Vacunas Atenuadas/administración & dosificación , Vacunas Atenuadas/inmunologíaRESUMEN
The adaptive immune response is tightly regulated to limit responding cells in an Ag-specific manner. On B cells, coreceptors CD21/CD19 modulate the strength of BCR signals, potentially influencing cell fate. The importance of the CD95 pathway was examined in response of B cells to moderate affinity Ag using an adoptive transfer model of lysozyme-specific Ig transgenic (HEL immunoglobulin transgene (MD4) strain) B cells. Although adoptively transferred Cr2+/+ MD4 B cells are activated and persist within splenic follicles of duck egg lysozyme-immunized mice, Cr2-/- MD4 B cells do not. In contrast, Cr2-/- MD4 lpr B cells persist after transfer, suggesting that lack of CD21/CD35 signaling results in CD95-mediated elimination. Cr2 deficiency did not affect CD95 levels, but cellular FLIP (c-FLIP) protein and mRNA levels were reduced 2-fold compared with levels in Cr2+/+ MD4 B cells. In vitro culture with Cr2+/+ MD4 B cells demonstrated that equimolar amounts of rHEL-C3d3 were more effective than hen egg lysozyme alone in up-regulating c-FLIP levels and for protection against CD95-mediated apoptosis. Collectively, this study implies a mechanism for regulating B cell survival in vivo whereby the strength of BCR signaling (including coreceptor) determines c-FLIP levels and protection from CD95-induced death.
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Antígenos CD19/fisiología , Linfocitos B/inmunología , Receptores de Complemento 3d/fisiología , Transducción de Señal/fisiología , Animales , Apoptosis , Linfocitos B/fisiología , Proteína Reguladora de Apoptosis Similar a CASP8 y FADD , Supervivencia Celular , Complemento C3d/inmunología , Péptidos y Proteínas de Señalización Intracelular/análisis , Ratones , Ratones Endogámicos C57BL , Muramidasa/inmunología , Receptores de Complemento 3b/fisiología , Receptor fas/fisiologíaRESUMEN
The cells of both the adaptive and innate immune systems express a dizzying array of receptors that transduce and integrate an enormous amount of information about the environment that allows the cells to mount effective immune responses. Over the past several years, significant advances have been made in elucidating the molecular details of signal cascades initiated by the engagement of immune cell receptors by their ligands. Recent evidence indicates that immune receptors and components of their signaling cascades are spatially organized and that this spatial organization plays a central role in the initiation and regulation of signaling. A key organizing element for signaling receptors appears to be cholesterol- and sphingolipid-rich plasma membrane microdomains termed lipid rafts. Research into the molecular basis of the spatial segregation and organization of signaling receptors provided by rafts is adding fundamentally to our understanding of the initiation and prolongation of signals in the immune system.
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Microdominios de Membrana/inmunología , Animales , Linfocitos B/inmunología , Humanos , Infecciones/inmunología , Microdominios de Membrana/química , Modelos Inmunológicos , Receptores Inmunológicos/metabolismo , Transducción de Señal , Linfocitos T/inmunologíaRESUMEN
Signaling through the B cell antigen receptor (BCR) is amplified and prolonged by coligation of the BCR to the CD19/CD21/CD81 coreceptor complex. Coligation is induced during immune responses by the simultaneous binding of complement-tagged antigens to the complement receptor, CD21, and to the BCR. Enhanced signaling is due in part to the ability of the CD19/CD21/CD81 complex to stabilize the BCR in sphingolipid- and cholesterol-rich membrane microdomains termed lipid rafts. The tetraspanin CD81 is essential for the raft-stabilizing function of the coreceptor. Here we show that coligation of the BCR and the CD19/CD21/CD81 complex leads to selective, rapid, and reversible palmitoylation of CD81 and that palmitoylation is necessary for the raft stabilizing function of the CD19/CD21/CD81 complex. Inducible palmitoylation may represent a novel mechanism by which tetraspanins function to facilitate lipid raft-dependent receptor signaling.
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Antígenos CD/química , Antígenos CD/metabolismo , Linfocitos B/inmunología , Ácido Palmítico/metabolismo , Anticuerpos Monoclonales , Antígenos CD19/química , Antígenos CD19/metabolismo , Linfocitos B/metabolismo , Línea Celular , Colesterol/metabolismo , Reactivos de Enlaces Cruzados , Humanos , Sustancias Macromoleculares , Microdominios de Membrana/inmunología , Microdominios de Membrana/metabolismo , Receptores de Antígenos de Linfocitos B/metabolismo , Receptores de Complemento 3d/química , Receptores de Complemento 3d/metabolismo , Transducción de Señal , Tetraspanina 28RESUMEN
Tetraspanins have been hypothesized to facilitate the organization of functional multimolecular membrane complexes. In B cells the tetraspanin CD81 is a component of the CD19/CD21 complex. When coligated to the B cell Ag receptor (BCR), the CD19/CD21 complex significantly enhances BCR signaling in part by prolonging the association of the BCR with signaling-active lipid rafts. In this study CD81 is shown to associate with lipid rafts upon coligation of the BCR and the CD19/CD21 complex. Using B cells from CD81-deficient mice we demonstrate that in the absence of CD81, coligated BCR and CD19/CD21 complexes fail to partition into lipid rafts and enhance BCR signaling from rafts. Furthermore, a chimeric CD19 protein that associates only weakly if at all with CD81 fails to promote the association of coligated BCR with lipid rafts. The requirement for CD81 to promote lipid raft association may define a novel mechanism by which tetraspanins function as molecular facilitators of signaling receptors.