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1.
Science ; 385(6704): 91-99, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38963839

RESUMO

Sickle cell disease (SCD) is a prevalent, life-threatening condition attributable to a heritable mutation in ß-hemoglobin. Therapeutic induction of fetal hemoglobin (HbF) can ameliorate disease complications and has been intently pursued. However, safe and effective small-molecule inducers of HbF remain elusive. We report the discovery of dWIZ-1 and dWIZ-2, molecular glue degraders of the WIZ transcription factor that robustly induce HbF in erythroblasts. Phenotypic screening of a cereblon (CRBN)-biased chemical library revealed WIZ as a previously unknown repressor of HbF. WIZ degradation is mediated by recruitment of WIZ(ZF7) to CRBN by dWIZ-1, as resolved by crystallography of the ternary complex. Pharmacological degradation of WIZ was well tolerated and induced HbF in humanized mice and cynomolgus monkeys. These findings establish WIZ degradation as a globally accessible therapeutic strategy for SCD.


Assuntos
Anemia Falciforme , Antidrepanocíticos , Hemoglobina Fetal , Fatores de Transcrição Kruppel-Like , Proteínas do Tecido Nervoso , Animais , Humanos , Camundongos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/metabolismo , Antidrepanocíticos/química , Antidrepanocíticos/farmacologia , Antidrepanocíticos/uso terapêutico , Cristalografia por Raios X , Descoberta de Drogas , Hemoglobina Fetal/genética , Hemoglobina Fetal/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Macaca fascicularis , Proteínas do Tecido Nervoso/metabolismo , Proteólise/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/uso terapêutico , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética
2.
Nature ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39020178

RESUMO

Plastic production reached 400 million tons in 2022 (ref. 1), with packaging and single-use plastics accounting for a substantial amount of this2. The resulting waste ends up in landfills, incineration or the environment, contributing to environmental pollution3. Shifting to biodegradable and compostable plastics is increasingly being considered as an efficient waste-management alternative4. Although polylactide (PLA) is the most widely used biosourced polymer5, its biodegradation rate under home-compost and soil conditions remains low6-8. Here we present a PLA-based plastic in which an optimized enzyme is embedded to ensure rapid biodegradation and compostability at room temperature, using a scalable industrial process. First, an 80-fold activity enhancement was achieved through structure-based rational engineering of a new hyperthermostable PLA hydrolase. Second, the enzyme was uniformly dispersed within the PLA matrix by means of a masterbatch-based melt extrusion process. The liquid enzyme formulation was incorporated in polycaprolactone, a low-melting-temperature polymer, through melt extrusion at 70 °C, forming an 'enzymated' polycaprolactone masterbatch. Masterbatch pellets were integrated into PLA by melt extrusion at 160 °C, producing an enzymated PLA film (0.02% w/w enzyme) that fully disintegrated under home-compost conditions within 20-24 weeks, meeting home-composting standards. The mechanical and degradation properties of the enzymated film were compatible with industrial packaging applications, and they remained intact during long-term storage. This innovative material not only opens new avenues for composters and biomethane production but also provides a feasible industrial solution for PLA degradation.

3.
Materials (Basel) ; 17(11)2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38893888

RESUMO

This study investigates the effect of extrusion screw speed and carbon nanotube (CNT) concentration on the thermal, mechanical, and electromagnetic interference shielding effectiveness (EMI SE) properties of Polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) and its polymer nanocomposites (PNCs) by means of design of experiments (DoE) approach. A masterbatch method was employed to obtain the best dispersion of the CNTs throughout the polymer matrix. This study evaluates the thermo-mechanical characterisation of the polymers and PNCs at varying screw speeds to assess filler matrix bonding. The results highlight that CNT concentration has a significant effect on all mechanical properties, while screw speed only affects the Charpy impact strength and flexural properties of the samples. Compounding at 200 rpm has the best flexural and tensile strength, which is attributed to the best filler matrix bonding (highest storage modulus) of the PNCs. The best EMI SE results were obtained at 10 wt.% CNTs. This research contributes valuable insights into the effect of CNT concentration and extrusion screw speed on the mechanical, thermal and EMI SE properties of PC/ABS and its PNCs.

4.
Res Dev Disabil ; 151: 104783, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38924954

RESUMO

Over 50 % of children and youth with cerebral palsy (CP) experience mental health challenges, with anxiety and depression most common. Youth with CP also experience several physiological symptoms such as fatigue, pain, sedentary lifestyle, and sleep disturbances that impact their daily living; however, little is known about the impact of these symptoms on mental health outcomes in these youth. This study addressed this gap and examined the individual and cumulative impacts of physiological symptoms on anxiety and depression symptoms in youth with CP. Forty youth with CP aged 8 to 18 years, and their caregiver, participated in this cross-sectional observational study. Pain, fatigue, anxiety, and depressive symptoms were measured using caregiver- and self-reported questionnaires and participants wore accelerometers for seven consecutive days, providing non-invasive physical activity and sleep pattern data. Youth with CP experienced substantial physiological symptoms and elevated anxiety and depression symptoms. Linear regression models determined that all physiological factors were predictive of caregiver-reported youth anxiety (R2 = 0.23) and youth depressive symptoms (R2 = 0.48). Fatigue, pain severity, sleep efficiency, and physical activity outcomes individually and cumulatively contributed to caregiver-reported youth anxiety and depression symptoms. These findings highlight the important role of physiological symptoms as potential risk factors and potential targets for intervention for mental health issues for in youth with CP.

5.
J Cheminform ; 16(1): 64, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38816825

RESUMO

Generative models are undergoing rapid research and application to de novo drug design. To facilitate their application and evaluation, we present MolScore. MolScore already contains many drug-design-relevant scoring functions commonly used in benchmarks such as, molecular similarity, molecular docking, predictive models, synthesizability, and more. In addition, providing performance metrics to evaluate generative model performance based on the chemistry generated. With this unification of functionality, MolScore re-implements commonly used benchmarks in the field (such as GuacaMol, MOSES, and MolOpt). Moreover, new benchmarks can be created trivially. We demonstrate this by testing a chemical language model with reinforcement learning on three new tasks of increasing complexity related to the design of 5-HT2a ligands that utilise either molecular descriptors, 266 pre-trained QSAR models, or dual molecular docking. Lastly, MolScore can be integrated into an existing Python script with just three lines of code. This framework is a step towards unifying generative model application and evaluation as applied to drug design for both practitioners and researchers. The framework can be found on GitHub and downloaded directly from the Python Package Index.Scientific ContributionMolScore is an open-source platform to facilitate generative molecular design and evaluation thereof for application in drug design. This platform takes important steps towards unifying existing benchmarks, providing a platform to share new benchmarks, and improves customisation, flexibility and usability for practitioners over existing solutions.

7.
Nat Protoc ; 19(7): 2052-2084, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38504137

RESUMO

Modeling immuno-oncology by using patient-derived material and immune cell co-cultures can advance our understanding of immune cell tumor targeting in a patient-specific manner, offering leads to improve cellular immunotherapy. However, fully exploiting these living cultures requires analysis of the dynamic cellular features modeled, for which protocols are currently limited. Here, we describe the application of BEHAV3D, a platform that implements multi-color live 3D imaging and computational tools for: (i) analyzing tumor death dynamics at both single-organoid or cell and population levels, (ii) classifying T cell behavior and (iii) producing data-informed 3D images and videos for visual inspection and further insight into obtained results. Together, this enables a refined assessment of how solid and liquid tumors respond to cellular immunotherapy, critically capturing both inter- and intratumoral heterogeneity in treatment response. In addition, BEHAV3D uncovers T cell behavior involved in tumor targeting, offering insight into their mode of action. Our pipeline thereby has strong implications for comparing, prioritizing and improving immunotherapy products by highlighting the behavioral differences between individual tumor donors, distinct T cell therapy concepts or subpopulations. The protocol describes critical wet lab steps, including co-culture preparations and fast 3D imaging with live cell dyes, a segmentation-based image processing tool to track individual organoids, tumor and immune cells and an analytical pipeline for behavioral profiling. This 1-week protocol, accessible to users with basic cell culture, imaging and programming expertise, can easily be adapted to any type of co-culture to visualize and exploit cell behavior, having far-reaching implications for the immuno-oncology field and beyond.


Assuntos
Imageamento Tridimensional , Neoplasias , Linfócitos T , Humanos , Linfócitos T/imunologia , Imageamento Tridimensional/métodos , Neoplasias/imunologia , Neoplasias/patologia , Neoplasias/terapia , Imunoterapia/métodos , Técnicas de Cocultura/métodos
8.
Cureus ; 16(2): e54027, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38481907

RESUMO

BACKGROUND: Non-melanoma skin cancer (NMSC) is highly prevalent in the United States, with darker-skinned patients (DSP) exhibiting lower incidence but increased morbidity and mortality. The purpose of this study is to elucidate NMSC disparities between DSP (Fitzpatrick skin phototype IV or more) and lighter-skinned patients (LSP, Fitzpatrick skin phototype III or less), focusing on surgical features of non-Mohs micrographic surgery-treated NMSC. METHODS: This retrospective cohort study included LSP and DSP diagnosed with either basal cell carcinoma (BCC) or squamous cell carcinoma (SCC) in an academic dermatology setting. Variables collected included age, gender, type of NMSC, location, staging, time-to-diagnosis (TTD), pre-operative lesion size, and post-operative defect size. Categorical variables were reported as counts and percentages, while the association between categorical variables was assessed using a two-tailed Fisher's test. A paired t-test was used to determine the association between continuous variables. P-values <0.05 were considered statistically significant. RESULTS: A total of 27 patients with NMSC were identified, of which 9 (33.3%) were DSP. Patients of darker skin were predominantly female (n=7; 77.8%), while no gender predilection was found in LSP (n=9; 50.0% female; p=0.23). Time-to-diagnosis was significantly longer in DSP than in LSP (61.3 weeks vs 25.1 weeks, respectively; p = 0.02). Despite this, there was no statistical difference in terms of staging, pre-operative lesion size (11.89 mm in DSP vs 10.76 mm in LSP, p=0.75), and post-operative defect size (45.56 ± 29.21 mm in DSP vs 31.22 ± 19.60 mm in LSP; p=0.33). CONCLUSIONS: Darker-skinned patients had a longer TTD without staging differences. Our study confirms the need for reducing TTDs for NMSC in DSP. Action initiatives include continued educational efforts to increase awareness of NMSC risk in DSP and more rigorous routine skin cancer screening.

9.
J Immunother Cancer ; 12(3)2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38519054

RESUMO

Human leukocyte antigen (HLA) restriction of conventional T-cell targeting introduces complexity in generating T-cell therapy strategies for patients with cancer with diverse HLA-backgrounds. A subpopulation of atypical, major histocompatibility complex-I related protein 1 (MR1)-restricted T-cells, distinctive from mucosal-associated invariant T-cells (MAITs), was recently identified recognizing currently unidentified MR1-presented cancer-specific metabolites. It is hypothesized that the MC.7.G5 MR1T-clone has potential as a pan-cancer, pan-population T-cell immunotherapy approach. These cells are irresponsive to healthy tissue while conferring T-cell receptor(TCR) dependent, HLA-independent cytotoxicity to a wide range of adult cancers. Studies so far are limited to adult malignancies. Here, we investigated the potential of MR1-targeting cellular therapy strategies in pediatric cancer. Bulk RNA sequencing data of primary pediatric tumors were analyzed to assess MR1 expression. In vitro pediatric tumor models were subsequently screened to evaluate their susceptibility to engineered MC.7.G5 TCR-expressing T-cells. Targeting capacity was correlated with qPCR-based MR1 mRNA and protein overexpression. RNA expression of MR1 in primary pediatric tumors varied widely within and between tumor entities. Notably, embryonal tumors exhibited significantly lower MR1 expression than other pediatric tumors. In line with this, most screened embryonal tumors displayed resistance to MR1T-targeting in vitro MR1T susceptibility was observed particularly in pediatric leukemia and diffuse midline glioma models. This study demonstrates potential of MC.7.G5 MR1T-cell immunotherapy in pediatric leukemias and diffuse midline glioma, while activity against embryonal tumors was limited. The dismal prognosis associated with relapsed/refractory leukemias and high-grade brain tumors highlights the promise to improve survival rates of children with these cancers.


Assuntos
Glioma , Leucemia , Neoplasias Embrionárias de Células Germinativas , Humanos , Criança , Antígenos de Histocompatibilidade Classe I , Receptores de Antígenos de Linfócitos T , Antígenos de Histocompatibilidade Classe II , Antígenos de Histocompatibilidade Menor
11.
J Cyst Fibros ; 23(1): 50-57, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37666709

RESUMO

BACKGROUND: Nontuberculous mycobacteria (NTM) are an important cause of airway infections in people with cystic fibrosis (pwCF). Isolation of NTM from respiratory specimens of pwCF do not mandate treatment in the absence of clinical and radiologic features of NTM pulmonary disease (NTM-PD), as some pwCF clear the infection without treatment and others do not appear to progress to NTM-PD despite persistent infection. An evidence-based protocol to standardize diagnosis of NTM-PD is needed to systematically identify pwCF who may benefit from treatment. METHODS: In this multicenter observational study, eligible pwCF who are 6 years of age and older and who have had a recent positive NTM culture are systematically evaluated for NTM-PD. Participants are identified based on positive NTM culture results obtained during routine clinical care and following enrollment are evaluated for NTM-PD and CF-related comorbidities. Participants are followed in PREDICT until they meet NTM-PD diagnostic criteria and are ready to initiate NTM treatment, or until study termination. Active participants who have not met these criteria are re-consented every 5 years to enable long-term participation. RESULTS: The primary endpoint will summarize the proportion of participants who meet the NTM-PD diagnosis definition. The time from enrollment to NTM-PD diagnosis will be derived from Kaplan-Meier estimates. CONCLUSION: A prospective protocol to identify NTM-PD in pwCF will test if this standardized approach defines a cohort with signs and symptoms associated with NTM-PD, to assist with clinical decision making and to build a framework for future therapeutic trials. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02073409.


Assuntos
Fibrose Cística , Infecções por Mycobacterium não Tuberculosas , Humanos , Fibrose Cística/complicações , Fibrose Cística/diagnóstico , Fibrose Cística/microbiologia , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Micobactérias não Tuberculosas
12.
J Psychosoc Oncol ; 42(1): 148-158, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37114974

RESUMO

This study examines feedback from two interventions, hypnosis and progressive muscle relaxation (PMR), to improve body image in a randomized phase II trial. Eighty-seven women were randomized either to hypnosis or PMR. Sixty-three women (72%) were motivated to write comments about their study experience. These comments were explored in an unplanned qualitative analysis. Thematic analysis generated five themes, suggesting both hypnosis and PMR may improve body image through the ability to relax and manage stress, sleep better, improve mood and create a mind-body connection. Sexual health emerged as a theme for participants in only the hypnosis group which suggests hypnotic suggestions for body image may improve overall sexual health. Additional research is needed to assess this further.


Assuntos
Treinamento Autógeno , Hipnose , Feminino , Humanos , Imagem Corporal , Hipnose/métodos
13.
Cell Rep Med ; 4(10): 101210, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37852181

RESUMO

Nearly one-half of patients with cystic fibrosis (CF) carry the homozygous F508del mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene but exhibit variable lung function phenotypes. How adaptive immunity influences their lung function remains unclear, particularly the serological antibody responses to antigens from mucoid Pseudomonas in sera from patients with CF with varying lung function. Sera from patients with CF with reduced lung function show higher anti-outer membrane protein I (OprI) immunoglobulin G1 (IgG1) titers and greater antibody-mediated complement deposition. Induction of anti-OprI antibody isotypes with complement activity enhances lung inflammation in preclinical mouse models. This enhanced inflammation is absent in immunized Rag2-/- mice and is transferrable to unimmunized mice through sera. In a CF cohort undergoing treatment with elexacaftor-tezacaftor-ivacaftor, the declination in anti-OprI IgG1 titers is associated with lung function improvement and reduced hospitalizations. These findings suggest that antibody responses to specific Pseudomonas aeruginosa (PA) antigens worsen lung function in patients with CF.


Assuntos
Fibrose Cística , Humanos , Animais , Camundongos , Fibrose Cística/genética , Pseudomonas , Pseudomonas aeruginosa , Pulmão , Imunoglobulina G
15.
Polymers (Basel) ; 15(18)2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37765679

RESUMO

In recent years, the creative use of polymers has been expanded as the range of achievable material properties and options for manufacturing and post-processing continually grows. The main goal of this research was to design and develop a fully-functioning material extrusion additive manufacturing device with the capability to produce functionally graded high-temperature thermoplastic PEEK (polyether ether ketone) materials through the manipulation of microstructure during manufacturing. Five different strategies to control the chamber temperature and crystallinity were investigated, and concepts of thermal control were introduced to govern the crystallisation and cooling mechanics during the extrusion process. The interaction of individually deposited beads of material during the printing process was investigated using scanning electron microscopy to observe and quantify the porosity levels and interlayer bonding strength, which affect the quality of the final part. Functional testing of the printed parts was carried out to identify crystallinity, boundary layer adhesion, and mechanical behaviour. Furnace cooling and annealing were found to be the most effective methods, resulting in the highest crystallinity of the part. Finally, a functionally graded material cylindrical part was printed successfully, incorporating both low and high crystalline regions.

16.
3D Print Addit Manuf ; 10(4): 749-761, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37609592

RESUMO

Laser beam powder bed fusion (PBF-LB) is a leading technique among metal additive manufacturing (AM), and it has a wide range of applications in aerospace and medical devices. Most of the existing PBF-LB process modeling is mainly based on the fabrication of a single part on a large build plate, which is not reflective of the practical multipart PBF-LB manufacturing. The effects of batch size on the thermal and mechanical behavior of additively manufactured parts have not been investigated. In this work, the multipart PBF-LB thermomechanical modeling framework was proposed for the first time. The effects of sample numbers (1, 2, and 4) on temperature and residual stress (RS) of part-scale components were computationally investigated. It is found that RS within the parts decreased with increasing number of components per build. Parts located at the central areas of the build plate had larger RS than at the border. These findings can be beneficial for informing AM designers and operators of the optimum printing setup to minimize RS of metal parts in PBF-LB.

17.
Polymers (Basel) ; 15(14)2023 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-37514382

RESUMO

Functionally Graded Materials represent the next generation of engineering design for metal and plastic components. In this research, a specifically modified and optimised 3D printer was used to manufacture functionally graded polyether ether ketone components. This paper details the design and manufacturing methodologies used in the development of a polyether ether ketone printer capable of producing functionally graded materials through the manipulation of microstructure. The interaction of individually deposited beads of material during the printing process was investigated using scanning electron microscopy, to observe and quantify the porosity levels and interlayer bonding strength, which affects the quality of the final parts. Specimens were produced under varying process conditions and tested to characterise the influence of the process conditions on the resulting material properties. The specimens printed at high enclosure temperatures exhibited greater strength than parts printed without the active addition of heat, due to improved bond formation between individual layers of the print and a large degree of crystallinity through maintenance at these elevated temperatures.

18.
Polymers (Basel) ; 15(13)2023 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-37447519

RESUMO

Biodegradable polyesters are a popular choice for both packaging and medical device manufacture owing to their ability to break down into harmless components once they have completed their function. However, commonly used polyesters such as poly(hydroxybutyrate) (PHB), poly(lactic acid) (PLA), and polycaprolactone (PCL), while readily available and have a relatively low price compared to other biodegradable polyesters, do not meet the degradation profiles required for many applications. As such, this study aimed to determine if the mechanical and degradation properties of biodegradable polymers could be tailored by blending different polymers. The seawater degradation mechanisms were evaluated, revealing surface erosion and bulk degradation in the blends. The extent of degradation was found to be dependent on the specific chemical composition of the polymer and the blend ratio, with degradation occurring via hydrolytic, enzymatic, oxidative, or physical pathways. PLA presents the highest tensile strength (67 MPa); the addition of PHB and PCL increased the flexibility of the samples; however, the tensile strength reduced to 25.5 and 18 MPa for the blends 30/50/20 and 50/25/25, respectively. Additionally, PCL presented weight loss of up to 10 wt.% and PHB of up to 6 wt.%; the seawater degradation in the blends occurs by bulk and surface erosion. The blending process facilitated the flexibility of the blends, enabling their use in diverse industrial applications such as medical devices and packaging. The proposed methodology produced biodegradable blends with tailored properties within a seawater environment. Additionally, further tests that fully track the biodegradation process should be put in place; incorporating compatibilizers might promote the miscibility of different polymers, improving their mechanical properties and biodegradability.

19.
J Med Chem ; 66(13): 9095-9119, 2023 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-37399505

RESUMO

The allosteric inhibitor of the mechanistic target of rapamycin (mTOR) everolimus reduces seizures in tuberous sclerosis complex (TSC) patients through partial inhibition of mTOR functions. Due to its limited brain permeability, we sought to develop a catalytic mTOR inhibitor optimized for central nervous system (CNS) indications. We recently reported an mTOR inhibitor (1) that is able to block mTOR functions in the mouse brain and extend the survival of mice with neuronal-specific ablation of the Tsc1 gene. However, 1 showed the risk of genotoxicity in vitro. Through structure-activity relationship (SAR) optimization, we identified compounds 9 and 11 without genotoxicity risk. In neuronal cell-based models of mTOR hyperactivity, both corrected aberrant mTOR activity and significantly improved the survival rate of mice in the Tsc1 gene knockout model. Unfortunately, 9 and 11 showed limited oral exposures in higher species and dose-limiting toxicities in cynomolgus macaque, respectively. However, they remain optimal tools to explore mTOR hyperactivity in CNS disease models.


Assuntos
Inibidores de MTOR , Sirolimo , Camundongos , Animais , Síndrome , Sistema Nervoso Central/metabolismo , Encéfalo/metabolismo , Serina-Treonina Quinases TOR , Trifosfato de Adenosina
20.
bioRxiv ; 2023 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-37293112

RESUMO

Mycobacterium abscessus is a nontuberculous mycobacterium emerging as a significant pathogen for individuals with chronic lung disease, including cystic fibrosis and chronic obstructive pulmonary disease. Current therapeutics have poor efficacy. New strategies of bacterial control based on host defenses are appealing, but anti-mycobacterial immune mechanisms are poorly understood and are complicated by the appearance of smooth and rough morphotypes with distinct host responses. We explored the role of the complement system in the clearance of M. abscessus morphotypes by neutrophils, an abundant cell in these infections. M. abscessus opsonized with plasma from healthy individuals promoted greater killing by neutrophils compared to opsonization in heat-inactivated plasma. Rough clinical isolates were more resistant to complement but were still efficiently killed. Complement C3 associated strongly with the smooth morphotype while mannose-binding lectin 2 was associated with the rough morphotype. M. abscessus killing was dependent on C3, but not on C1q or Factor B; furthermore, competition of mannose-binding lectin 2 binding with mannan or N-acetyl-glucosamine during opsonization did not inhibit killing. These data suggest that M. abscessus does not canonically activate complement through the classical, alternative, or lectin pathways. Complement-mediated killing was dependent on IgG and IgM for smooth and on IgG for rough M. abscessus. Both morphotypes were recognized by Complement Receptor 3 (CD11b), but not CR1 (CD35), and in a carbohydrate- and calcium-dependent manner. These data suggest the smooth-to-rough adaptation changes complement recognition of M. abscessus and that complement is an important factor for M. abscessus infection.

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