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1.
Int Arch Allergy Immunol ; 182(11): 1026-1035, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34082425

RESUMO

Allergic rhinitis (AR) is prevalent, and many patients present with moderate-to-severe symptomatic disease. The majority of patients are not satisfied with their AR treatment, despite the use of concurrent medications. These gaps underscore the need for treatment with more effective options for moderate-to-severe AR. The authors' objective was to review systematically the efficacy and safety of MP-AzeFlu for the treatment of AR. The primary outcomes studied were nasal, ocular, and total symptoms. Other outcomes included time to onset and of AR control, quality of life, and safety. Searches of PubMed and Cochrane databases were conducted on May 14, 2020, with no date restrictions, to identify publications reporting data on MP-AzeFlu. Clinical studies of any phase were included. Studies were excluded if they were not in English, were review articles, did not discuss the safety and efficacy of MP-AzeFlu for AR symptoms. Treatment of AR with MP-AzeFlu results in effective, sustained relief of nasal and ocular symptoms, and faster onset and time to control compared with intranasal azelastine or fluticasone propionate. Long-term use of MP-AzeFlu was safe, with benefits in children, adults, and adults aged ≥65 years. Other treatment options, including fluticasone propionate and azelastine alone or the combination of intranasal corticosteroids and oral antihistamine, do not provide the same level of efficacy as MP-AzeFlu in terms of rapid and sustained relief of the entire AR symptom complex. Furthermore, MP-AzeFlu significantly improves patient quality of life. MP-AzeFlu is a currently available combination that may satisfy all these patient needs and expectations.


Assuntos
Corticosteroides/administração & dosagem , Antialérgicos/administração & dosagem , Fluticasona/administração & dosagem , Antagonistas dos Receptores Histamínicos H1/administração & dosagem , Ftalazinas/administração & dosagem , Rinite Alérgica/tratamento farmacológico , Corticosteroides/efeitos adversos , Antialérgicos/efeitos adversos , Combinação de Medicamentos , Fluticasona/efeitos adversos , Antagonistas dos Receptores Histamínicos H1/efeitos adversos , Humanos , Ftalazinas/efeitos adversos , Ensaios Clínicos Controlados Aleatórios como Assunto , Índice de Gravidade de Doença
2.
Int Arch Allergy Immunol ; 181(10): 754-764, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32829329

RESUMO

INTRODUCTION: Phenotyping allergic rhinitis (AR) by immunoglobulin E (IgE) sensitivity and comorbidities may help characterize AR and provide a framework for treatment decisions. METHODS: This prospective, noninterventional study evaluated the effectiveness of MP-AzeFlu (azelastine hydrochloride plus fluticasone propionate intranasal spray formulation) across AR phenotypes. Patients with moderate-to--severe seasonal or perennial AR for whom MP-AzeFlu was prescribed were enrolled. AR subpopulations (ARPs) were assigned based on the classification of IgE response and comorbidities. AR symptoms over the previous 24 h were documented using an AR visual analog scale (AR-VAS), with ratings from "not at all bothersome" (0 mm) to "extremely bothersome" (100 mm), at the inclusion visit and on days 1, 3, 7, and the last day of the study (approximately day 14). AR quality-of-life measures were recorded using a VAS. RESULTS: A total of 1,103 patients with AR were included. Mean baseline AR-VAS scores ranged from 70.3 to 75.1 mm (severe) across ARPs. In the overall population, 86.6% of patients responded to treatment (AR-VAS score <50 mm on ≥1 days). In the ARPs, response rates ranged from 79.3 to 89.6%. Mean reduction in AR-VAS scores ranged from 47.9 to 40.9 mm, a decrease from severe to mild across all ARPs. Quality-of-life VAS scores were similarly reduced in the total population and ARPs. DISCUSSION/CONCLUSION: MP-AzeFlu treatment reduced VAS severity and quality-of-life scores from baseline in the total population and ARPs, supporting MP-AzeFlu as an effective treatment for all patients with moderate-to-severe AR, regardless of AR phenotype or comorbidities.


Assuntos
Fluticasona/uso terapêutico , Imunoglobulina E/metabolismo , Ftalazinas/uso terapêutico , Rinite Alérgica/tratamento farmacológico , Administração Intranasal , Adulto , Comorbidade , Combinação de Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sprays Nasais , Fenótipo , Estudos Prospectivos , Qualidade de Vida , Rinite Alérgica/diagnóstico , Índice de Gravidade de Doença , Resultado do Tratamento , Escala Visual Analógica , Adulto Jovem
3.
Clin Mol Allergy ; 18: 15, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32782442

RESUMO

BACKGROUND: Asthma affects up to nearly 40% of patients with allergic rhinitis (AR). Poor control of AR symptoms is associated with poor asthma control. The goal of this study was to evaluate the effect of AR treatment with MP-AzeFlu on symptoms of AR as well as symptoms of asthma. METHODS: This prospective study used a visual analog scale (VAS) to assess symptoms of AR and asthma before and after treatment with MP-AzeFlu (Dymista®; azelastine hydrochloride plus fluticasone propionate; 1 spray in each nostril twice daily for 2 weeks). Participants suffered from moderate-to-severe AR according to Allergic Rhinitis and its Impact on Asthma criteria, with acute AR symptoms (AR-VAS scores ≥ 50 mm) on inclusion day. In addition to symptom assessment, patients recorded the impact of AR symptoms on quality-of-life measures before, during, and at the conclusion of the treatment period (approximately 14 days). Patients self-reported change in frequency of their usage of asthma reliever medication on the last day of treatment. RESULTS: Of 1103 study participants, 267 (24.2%) had comorbid asthma. These participants reported using a mean of 5.1 puffs of asthma reliever medication in the week before treatment with MP-AzeFlu. A total of 81.8% of patients with comorbid asthma responded to AR therapy (AR-VAS < 50 mm on at least 1 study day). Among patients with AR and comorbid asthma, MP-AzeFlu was associated with improved VAS scores across all study parameters, including AR symptom severity, asthma symptom severity, sleep quality, daily work or school activities, daily social activities, and daily outdoor activities. Asthma symptom severity decreased from a mean of 48.9 mm to 24.1 mm on the VAS. Self-reported frequency of asthma reliever medication use was reduced for 57.6% of participants (n = 139/241). CONCLUSION: MP-AzeFlu used to relieve AR symptoms was associated with reduced asthma symptom VAS scores and frequency of asthma reliever medication usage. Changes in overall symptoms of AR and asthma were correlated.

4.
Allergy Asthma Proc ; 41(4): 265-270, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32393418

RESUMO

Background: Intranasal antihistamines and steroids should be delivered in a volume and with a technique that allow for optimal drug retention within the entire nasal cavity, maximize local absorption by the nasal mucosa, and, subsequently, increase the potential for the most desirable local availability and therapeutic effect. Objective: This in vitro evaluation simulated nasal medication deposition and evaluated the extent of runoff. MP-AzeFlu, a novel intranasal formulation of azelastine hydrochloride (AZE) plus fluticasone propionate (FP), was compared with sequential sprays of available commercial products with the individual medication components. Methods: A model of a normal adult human nasal cavity was used to visualize deposition of nasal spray products. A single spray of MP-AzeFlu (0.137 mL [137 µg of AZE/50 µg of FP]) or single sequential sprays of AZE nasal spray (0.137 mL [137 µg]) followed by brand name or generic FP nasal spray (0.100 mL [50 µg]) were manually actuated into the model. The interior was coated with a water-sensitive dye that changes to magenta when exposed to aqueous-based formulations. A slight vacuum was applied during spray delivery to simulate sniffing. The results were photographed by using anterior and lateral views. Results: Three replicates of MP-AzeFlu showed no dripping from the front of the nostril or backflow from the nasal cavity. However, three replicates of AZE nasal spray, followed by a brand name or generic FP nasal spray, showed significant dripping from the front of the nostril and backflow from the nasal cavity. Conclusion: A single spray of MP-AzeFlu resulted in no runoff compared with sequential dosing of the two other therapeutic products. Product runoff is likely due to the volume exceeding the capacity of the nasal cavity model. Furthermore, the common clinical dosing regimen of two sprays per nostril of each of the individual components would promote even greater increased undesirable flooding and leakage.


Assuntos
Antiasmáticos/administração & dosagem , Fluticasona/administração & dosagem , Modelos Anatômicos , Cavidade Nasal , Sprays Nasais , Ftalazinas/administração & dosagem , Administração Intranasal , Humanos , Técnicas In Vitro
6.
Immun Inflamm Dis ; 11(1): e709, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36705401

RESUMO

MP-AzeFlu (intranasal fluticasone and azelastine) has been widely studied and has demonstrated efficacy in Allergic rhinitis with a superior effect compared to these drugs administered individually; however, the mechanism by which MP-AzeFlu produces this improved clinical effect has not yet been fully explained. In this study, we investigated the effect of MP-AzeFlu and fluticasone propionate (FP) on arachidonic acid metabolism as measured by changes in regulation of cyclooxygenase (COX) isoforms, prostaglandin (PG) D2 , PGE2 , PGE2 receptor (EP) 2, and EP3. Expression of these key inflammation markers was assessed through an in vitro model of upper airway inflammation using fibroblasts derived from both healthy and inflamed upper airway mucosa. Both MP-AzeFlu and FP inhibited interleukin-1ß-induced COX-2 messenger RNA (mRNA) and protein expression and PGE2 secretion in vitro. MP-AzeFlu and FP both upregulated EP2 mRNA expression, though neither upregulated EP2 protein expression. This downregulation of COX-2 and PGE2 coupled with upregulation of EP2 receptor expression reinforces the anti-inflammatory effect of MP-AzeFlu in upper airway inflammation.


Assuntos
Dinoprostona , Mucosa , Humanos , Ciclo-Oxigenase 2/genética , Fluticasona/uso terapêutico , RNA Mensageiro , Inflamação/tratamento farmacológico
7.
J Gen Virol ; 93(Pt 11): 2425-2430, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22894923

RESUMO

The human immunodeficiency virus type 1 accessory protein Vif is important for viral infectivity because it counteracts the antiviral protein APOBEC3G (A3G). ³²P metabolic labelling of stimulated cells revealed in vivo phosphorylation of the control protein, whereas no serine/threonine phosphorylation was detected for Vif or the A3G protein. These data were confirmed by in vitro kinase assays using active recombinant kinase. Mitogen-activated protein kinase/extracellular signal-regulated kinase 2 efficiently phosphorylated its target ELK, but failed to phosphorylate Vif. Putative serine/threonine phosphorylation point mutations in Vif (T96, S144, S165, T188) using single-round infection assays demonstrated that these mutations did not alter Vif activity, with the exception of Vif.T96E. Interestingly, T96E and not T96A was functionally impaired, indicating that this residue is critical for Vif-A3G physical interaction and activity. Our data suggest that Vif and A3G are not serine/threonine phosphorylated in human cells and phosphorylation is not linked to their functional activities.


Assuntos
Citidina Desaminase/metabolismo , HIV-1/classificação , Produtos do Gene vif do Vírus da Imunodeficiência Humana/metabolismo , Desaminase APOBEC-3G , Sequência de Aminoácidos , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico , Citidina Desaminase/genética , Regulação da Expressão Gênica , Células HEK293 , HIV-1/genética , Humanos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno , Fosforilação , Mutação Puntual , Serina/metabolismo , Treonina/metabolismo , Produtos do Gene vif do Vírus da Imunodeficiência Humana/genética
8.
Proc Natl Acad Sci U S A ; 106(29): 12079-84, 2009 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-19581596

RESUMO

Human APOBEC3 (A3) proteins form part of the intrinsic immunity to retroviruses. Carrying 1 or 2 copies of a cytidine deaminase motif, A3s act by deamination of retroviral genomes during reverse transcription. HIV-1 overcomes this inhibition by the Vif protein, which prevents incorporation of A3 into virions. In this study we modeled and probed the structure of APOBEC3C (A3C), a single-domain A3 with strong antilentiviral activity. The 3-dimensional protein model was used to predict the effect of mutations on antiviral activity, which was tested in a Deltavif simian immunodeficiency virus (SIV) reporter virus assay. We found that A3C activity requires protein dimerization for antiviral activity against SIV. Furthermore, by using a structure-based algorithm for automated pocket extraction, we detected a putative substrate binding pocket of A3C distal from the zinc-coordinating deaminase motif. Mutations in this region diminished antiviral activity by excluding A3C from virions. We found evidence that the small 5.8S RNA specifically binds to this locus and mediates incorporation of A3C into virus particles.


Assuntos
Capsídeo/metabolismo , Citosina Desaminase/química , Citosina Desaminase/metabolismo , Modelos Moleculares , RNA/metabolismo , Desaminases APOBEC , Sítios de Ligação , Linhagem Celular , Citidina Desaminase , Humanos , Immunoblotting , Proteínas Mutantes/metabolismo , Multimerização Proteica , Processamento de Proteína Pós-Traducional , Estrutura Secundária de Proteína , Produtos do Gene vif do Vírus da Imunodeficiência Humana/metabolismo
9.
J Immunol ; 182(12): 7613-24, 2009 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-19494285

RESUMO

In transgenic animal models, humoral immunity directed against the beta-amyloid peptide (Abeta), which is deposited in the brains of AD patients, can reduce Abeta plaques and restore memory. However, initial clinical trials using active immunization with Abeta1-42 (plus adjuvant) had to be stopped as a subset of patients developed meningoencephalitis, likely due to cytotoxic T cell reactions against Abeta. Previously, we demonstrated that retrovirus-like particles displaying on their surface repetitive arrays of self and foreign Ags can serve as potent immunogens. In this study, we generated retrovirus-like particles that display the 15 N-terminal residues of human Abeta (lacking known T cell epitopes) fused to the transmembrane domain of platelet-derived growth factor receptor (Abeta retroparticles). Western blot analysis, ELISA, and immunogold electron microscopy revealed efficient incorporation of the fusion proteins into the particle membrane. Without the use of adjuvants, single immunization of WT mice with Abeta retroparticles evoked high and long-lived Abeta-specific IgG titers of noninflammatory Th2 isotypes (IgG1 and IgG2b) and led to restimulatable B cell memory. Likewise, immunization of transgenic APP23 model mice induced comparable Ab levels. The CNS of immunized wild-type mice revealed neither infiltrating lymphocytes nor activated microglia, and no peripheral autoreactive T cells were detectable. Importantly, vaccination not only reduced Abeta plaque load to approximately 60% of controls and lowered both insoluble Abeta40 as well as Abeta42 in APP23 brain, but also significantly reduced cerebral soluble Abeta species. In summary, Abeta retroparticle vaccination may thus hold promise as a novel efficient future candidate vaccine for active immunotherapy of Alzheimer's disease.


Assuntos
Peptídeos beta-Amiloides/imunologia , Encéfalo/imunologia , Encéfalo/metabolismo , Peptídeos beta-Amiloides/ultraestrutura , Animais , Anticorpos/imunologia , Especificidade de Anticorpos/imunologia , Encéfalo/ultraestrutura , Linhagem Celular , Sistema Nervoso Central/imunologia , Feminino , Humanos , Ativação Linfocitária/imunologia , Linfócitos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Imunoeletrônica , Solubilidade , Linfócitos T/imunologia , Vacinação , Vírion/ultraestrutura
10.
J Asthma Allergy ; 14: 335-345, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33854340

RESUMO

BACKGROUND: Allergic rhinitis (AR) is characterized by nasal and ocular symptoms, and substantially impacts the quality of life. Therapy selection for patients with AR depends on several factors, including symptom severity, age, patient preference, patient adherence, and cost. METHODS: The purpose of this multicenter, noninterventional, cross-sectional survey was to evaluate current therapy decisions in routine clinical practice for patients with symptomatic AR, and to determine how these decisions are linked to experiences with previous treatments and current symptom severity as assessed by aVAS. The survey included patients aged 18 years or older in Spain and 12 years or older in Hungary who consulted a physician for treatment of AR symptoms. Physicians recorded AR symptom burden in the previous 7 days, previous AR treatments, and the current AR therapy decision made at the visit. RESULTS: Overall, 72.9% of 181 patients (Spain) and 67.1% of 228 patients (Hungary) had received treatment in the previous 7 days. Among patients who had received step 3 treatment, 82.9% (Spain) and 75.8% (Hungary) received a free combination of intranasal corticosteroid (INCS) and antihistamines. Despite the high number of pretreated patients in both countries, 72.9% and 78.9% in Spain and Hungary, respectively, reported uncontrolled symptoms (VAS ≥50 mm). Of pretreated patients, 58.3% (Spain) and 61.4% (Hungary) received a step-up in treatment during the visit. Physicians more often prescribed a fixed combination of INCS and intranasal antihistamine than a free combination. However, of patients with uncontrolled symptoms who received previous therapy, 28.0% (Hungary) and 40.6% (Spain) did not receive a step-up as suggested by the guidelines. CONCLUSION: Many patients suffering from acute AR symptoms consulted with their physician because of insufficient medications. Not all patients with uncontrolled symptoms received a step-up in treatment, underscoring the need for improved physician education to enhance AR management and control in accordance with consensus treatment guidelines.

11.
J Asthma Allergy ; 13: 187-192, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547111

RESUMO

PURPOSE: Most patients with allergic rhinitis (AR) have moderate-to-severe disease, requiring complete and prompt relief when symptoms occur. The time course of fluticasone propionate (FP) penetration into nasal tissues after intranasal administration is not well characterized. The goal of this proof-of-concept study was to evaluate the mucosal penetration of FP from fixed-combination FP-azelastine nasal spray (MP-AzeFlu) compared with an FP-only nasal spray in an in vitro, 3-dimensional human bronchial tissue model. MATERIALS AND METHODS: Absorption of FP from MP-AzeFlu and FP nasal spray was modeled using EpiAirway™606 (MatTek Corporation; Ashland, MA, USA) tissue cultured in vertical diffusion cells. The dosing amount of MP-AzeFlu was optimized in a pilot study. Based on the results of the pilot study, 10 µL of MP-AzeFlu (3.65 µg; n = 8) and 10 µL of FP nasal spray (5.00 µg; n = 8) were evaluated for penetration of tissue. Tissue integrity was monitored with Lucifer yellow. FP in the receiving media was quantified for each sample using liquid chromatography with tandem mass spectrometry. RESULTS: MP-AzeFlu and FP nasal spray were associated with similar FP accumulation profiles in the receiving media, but the permeability of FP was greater for MP-AzeFlu during hours 0 to 6, suggesting faster absorption for MP-AzeFlu. No indications of compromised tissue integrity were found in any of the tested cells. CONCLUSION: The higher and more rapid penetration of FP from MP-AzeFlu supports the use of MP-AzeFlu for patients with AR, particularly when prioritizing fast and pronounced symptom relief.

12.
J Asthma Allergy ; 13: 633-645, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33293835

RESUMO

PURPOSE: Patients with poorly controlled allergic rhinitis (AR) experience nasal symptoms, sleep disturbances, activity impairment, and decreased quality-of-life (QoL). MP-AzeFlu is safe and effective for moderate-to-severe seasonal and perennial AR, but its impact on QoL requires investigation in the real-world, especially among phenotypes of immunoglobulin (Ig)E-mediated AR. This subanalysis of an observational study evaluated response to MP-AzeFlu via assessment of sleep quality and trouble with daily activities. PATIENTS AND METHODS: This multicenter, prospective, non-interventional, real-life study included a convenience sample of patients with a history of moderate-to-severe AR presenting with acute AR symptoms (visual analog scale [VAS] ≥50 mm). Over approximately 14 days of treatment with MP-AzeFlu (137 µg azelastine HCL and 50 µg fluticasone propionate administered via single 0.137-mL spray in each nostril twice daily), changes in sleep quality and trouble with daily work, school, social, and outdoor activities were evaluated using a VAS for the entire study population and for four subgroups based on IgE response phenotype. VAS scores ranged from "not at all troubled" (0 mm) to "extremely troubled" (100 mm). RESULTS: Following MP-AzeFlu treatment, mean VAS scores for sleep quality impairment and work or school impairment decreased from 55.2 mm at baseline to 22.1 mm and 57.6 mm at baseline to 23.0 mm, respectively, after ~14 days. Similar results were observed for mean VAS scores for impairment of social activity (55.1 mm to 22.4 mm) and impairment of outdoor activity (64.4 mm to 25.0 mm). For all VAS scores, results were similar across populations, regardless of phenotype of IgE-mediated disease, comorbidity, age, and sex. CONCLUSION: MP-AzeFlu relieves symptoms and improves patient-reported QoL, illustrated by better sleep quality and less impairment of work, school, social, and outdoor activities after 14 days. The QoL benefits of MP-AzeFlu were consistent regardless of the phenotype of IgE-mediated disease. REGISTRATION: Clinical Trial Registration (CTR) Number: EUPAS23075. Trial Register Date: March 12, 2018. First patient visit; Last patient visit: February 2018; April 2019.

14.
J Allergy Clin Immunol Pract ; 6(5): 1726-1732.e6, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29425904

RESUMO

BACKGROUND: A fixed-dose combination of intranasal azelastine hydrochloride and fluticasone propionate (MP-AzeFlu) is the most effective treatment of allergic rhinitis, but its onset of action requires further investigation. OBJECTIVE: To compare the onset of action of MP-AzeFlu with the free combination of oral loratadine (LORA) and intranasal fluticasone propionate (INFP). METHODS: In this single-center, randomized, placebo-controlled, double-blind, double-dummy, 3-period crossover trial, allergic rhinitis symptoms were induced in asymptomatic patients by ragweed pollen challenge in an allergen environmental exposure chamber. Patients received single-dose MP-AzeFlu, LORA/INFP, or placebo and were monitored for 4 hours. The primary outcome was onset of action measured by total nasal symptom score (TNSS). Secondary measures were total ocular symptom score (TOSS), total score of the 7 nasal and ocular symptoms (T7SS), and the global visual analog scale (VAS). RESULTS: The full analysis set included 82 patients, of which 78 completed all treatments. TNSS was significantly reduced versus placebo from 5 minutes for MP-AzeFlu and 150 minutes for LORA/INFP onward (both P < .05) till the end of assessment (0-4 hours). MP-AzeFlu reduced TNSS to a greater extent at each time point from 5 to 90 minutes (P < .05) and over the entire assessment interval (P ≤ .005) versus LORA/INFP or placebo. No statistically significant difference between LORA/INFP and placebo was observed over the assessment interval (P = .182). The onset of action of MP-AzeFlu assessed by TOSS, T7SS, and VAS was 10 minutes, 2 hours earlier than with LORA/INFP. CONCLUSION: MP-AzeFlu had a more rapid onset of action (5 minutes) and was more effective than LORA/INFP.


Assuntos
Combinação de Medicamentos , Fluticasona/uso terapêutico , Ftalazinas/uso terapêutico , Rinite Alérgica/tratamento farmacológico , Administração Intranasal , Adulto , Alérgenos/imunologia , Ambrosia/imunologia , Antígenos de Plantas/imunologia , Câmaras de Exposição Atmosférica , Estudos Cross-Over , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Loratadina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Obstrução Nasal , Pólen/imunologia
15.
J Biol Chem ; 284(9): 5819-26, 2009 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-19074429

RESUMO

The APOBEC3 cytidine deaminases are part of the intrinsic defense of cells against retroviruses. Lentiviruses and spumaviruses have evolved essential accessory proteins, Vif and Bet, respectively, which counteract the APOBEC3 proteins. We show here that Bet of the Prototype foamy virus inhibits the antiviral APOBEC3C activity by a mechanism distinct to Vif: Bet forms a complex with APOBEC3C without inducing its degradation. Bet abolished APOBEC3C dimerization as shown by coimmunoprecipitation and cross-linking experiments. These findings implicate a physical interaction between Bet and the APOBEC3C. Subsequently, we identified the Bet interaction domain in human APOBEC3C in the predicted APOBEC3C dimerization site. Taken together, these data support the hypothesis that Bet inhibits incorporation of APOBEC3Cs into retroviral particles. Bet likely achieves this by trapping APOBEC3C protein in complexes rendering them unavailable for newly generated viruses due to direct immobilization.


Assuntos
Citidina Desaminase/antagonistas & inibidores , Citidina Desaminase/metabolismo , Provírus/genética , Proteínas dos Retroviridae/fisiologia , Desaminase APOBEC-3G , Animais , Células Cultivadas , Chlorocebus aethiops , Cricetinae , Reagentes de Ligações Cruzadas , Dimerização , Produtos do Gene vif/fisiologia , Humanos , Immunoblotting , Imunoprecipitação , Rim/citologia , Rim/metabolismo , Lentivirus/genética , Lentivirus/metabolismo , Macaca mulatta , Macaca nemestrina , Pan troglodytes , Vírus Espumoso dos Símios , Transfecção , Montagem de Vírus , Replicação Viral/efeitos dos fármacos , Replicação Viral/genética
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