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1.
Artigo em Inglês | MEDLINE | ID: mdl-36483382

RESUMO

Objectives: Antimicrobial resistance (AMR) is a global priority with significant clinical and economic consequences. Multidrug-resistant (MDR) Pseudomonas aeruginosa is one of the major pathogens associated with significant morbidity and mortality. In healthcare settings, the evaluation of prevalence, microbiological characteristics, as well as mechanisms of resistance is of paramount importance to overcome associated challenges. Methods: Consecutive clinical specimens of P. aeruginosa were collected prospectively from 5 acute-care and specialized hospitals between October 2014 and September 2017, including microbiological, clinical characteristics and outcomes. Identification and antimicrobial susceptibility test were performed using the BD Phoenix identification and susceptibility testing system, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), and minimum inhibitory concentration (MIC) test strips. Overall, 78 selected MDR P. aeruginosa isolates were processed for whole-genome sequencing (WGS). Results: The overall prevalence of MDR P. aeruginosa isolates was 5.9% (525 of 8,892) and showed a decreasing trend; 95% of cases were hospital acquired and 44.8% were from respiratory samples. MDR P. aeruginosa demonstrated >86% resistance to cefepime, ciprofloxacin, meropenem, and piperacillin-tazobactam but 97.5% susceptibility to colistin. WGS revealed 29 different sequence types: 20.5% ST235, 10.3% ST357, 7.7% ST389, and 7.7% ST1284. ST233 was associated with bloodstream infections and increased 30-day mortality. All ST389 isolates were obtained from patients with cystic fibrosis. Encoded exotoxin genes were detected in 96.2% of isolates. Conclusions: MDR P. aeruginosa isolated from clinical specimens from Qatar has significant resistance to most agents, with a decreasing trend that should be explored further. Genomic analysis revealed the dominance of 5 main clonal clusters associated with mortality and bloodstream infections. Microbiological and genomic monitoring of MDR P. aeruginosa has enhanced our understanding of AMR in Qatar.

2.
Intervirology ; 65(4): 188-194, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35640537

RESUMO

INTRODUCTION: Human papillomaviruses (HPVs), Epstein-Barr virus (EBV), and mouse mammary tumor virus-like virus (MMTV-like virus) can be present and contribute to breast cancer development and progression. However, the role of these oncoviruses and their crosstalk in breast cancer is still unclear. METHODS: We explored the co-presence of high-risk HPVs, EBV, and MMTV-like virus in 74 breast cancer samples from Qatar using PCR. RESULTS: We found the presence of HPV and EBV in 65% and 49% of our cancer sample cohorts; 47% of the samples are positive for both oncoviruses. The MMTV-like virus alone was detected in 15% of the samples with no significant association with clinicopathological features. The three oncoviruses were co-present in 14% of the cases; no significant association was noted between the co-presence of these viruses and the clinicopathological features. CONCLUSION: Despite the presence of the oncoviruses, additional studies are necessary to understand their interactions in human breast carcinogenesis.


Assuntos
Alphapapillomavirus , Neoplasias da Mama , Infecções por Vírus Epstein-Barr , Camundongos , Animais , Humanos , Feminino , Herpesvirus Humano 4/genética , Vírus do Tumor Mamário do Camundongo/genética , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/epidemiologia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/etiologia , Neoplasias da Mama/patologia , Incidência , Catar/epidemiologia , Papillomaviridae/genética
4.
Front Immunol ; 12: 631139, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33717166

RESUMO

COVID-19 emerged from China in December 2019 and during 2020 spread to every continent including Antarctica. The coronavirus, SARS-CoV-2, has been identified as the causative pathogen, and its spread has stretched the capacities of healthcare systems and negatively affected the global economy. This review provides an update on the virus, including the genome, the risks associated with the emergence of variants, mode of transmission, immune response, COVID-19 in children and the elderly, and advances made to contain, prevent and manage the disease. Although our knowledge of the mechanics of virus transmission and the immune response has been substantially demystified, concerns over reinfection, susceptibility of the elderly and whether asymptomatic children promote transmission remain unanswered. There are also uncertainties about the pathophysiology of COVID-19 and why there are variations in clinical presentations and why some patients suffer from long lasting symptoms-"the long haulers." To date, there are no significantly effective curative drugs for COVID-19, especially after failure of hydroxychloroquine trials to produce positive results. The RNA polymerase inhibitor, remdesivir, facilitates recovery of severely infected cases but, unlike the anti-inflammatory drug, dexamethasone, does not reduce mortality. However, vaccine development witnessed substantial progress with several being approved in countries around the globe.


Assuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Anti-Inflamatórios/uso terapêutico , Antivirais/uso terapêutico , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , Dexametasona/uso terapêutico , SARS-CoV-2/fisiologia , Monofosfato de Adenosina/uso terapêutico , Idoso , Alanina/uso terapêutico , Variação Antigênica , Doenças Assintomáticas , COVID-19/terapia , COVID-19/transmissão , Criança , Humanos , Imunidade , Pandemias/prevenção & controle , SARS-CoV-2/patogenicidade
5.
Hum Vaccin Immunother ; 17(4): 982-989, 2021 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-33006291

RESUMO

High-risk human papillomaviruses (HPV) can be present and cooperate with Epstein-Barr virus (EBV) to promote the onset and/or progression of various cancers including cervical, breast, head and neck as well as colorectal. In this investigation, we explored the co-prevalence of high-risk HPV and EBV in 74 breast cancer tissues from Qatari women using polymerase chain reaction. We found that high-risk HPV and EBV are present in 48/74 (65%) and 36/74 (49%) of the cases, respectively. While we noted that the presence of HPV presence is associated with triple-negative breast cancer (TNBC) (p = .008), however, the presence of EBV did not correlate with any breast cancer subgroup. Moreover, our data revealed that high-risk HPV and EBV are co-present in 35/74 (47%) of the samples and their co-presence is significantly associated with tumor grade (p = .04) and tumor stage (p = .04). These data indicate that HPV and EBV are commonly co-present in breast cancer and their association could be linked with a more aggressive tumor phenotype. Thus, further investigations are essential to understand the underlying mechanisms of HPV and EBV cooperation in breast carcinogenesis.


Assuntos
Alphapapillomavirus , Neoplasias da Mama , Infecções por Vírus Epstein-Barr , Infecções por Papillomavirus , DNA Viral , Feminino , Herpesvirus Humano 4/genética , Humanos , Papillomaviridae/genética
6.
J Transl Med ; 18(1): 288, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32727491

RESUMO

BACKGROUND: In the past decade, cervical cancer has gone from being the second to the fourth most common cancer in women worldwide, but remains the second most common in developing countries. This cancer is most commonly caused by high-risk types of human papillomavirus (HPV), mainly type 16 (HPV16), which are sexually transmitted. This study aimed to investigate the usefulness of a cyclic synthetic peptide designed from the major L1 capsid protein of HPV16 for detecting anti-HPV16 antibodies. METHODS: We designed and synthetized a peptide that corresponds to the full sequence of the surface-exposed FG loop. We tested the antigenicity of the linear and the cyclic peptides against HPV16 L1 monoclonal antibodies. We used ELISA to detect anti-peptide antibodies in sera and cervical secretions of 179 Tunisian women, and we applied polymerase chain reaction and direct sequencing methods to detect and genotype HPV DNA. RESULTS: Both the linear and the cyclic peptides were recognized by the same neutralizing monoclonal antibodies, but the cyclic peptide was more reactive with human sera. The prevalence of the anti-peptide antibodies in sera was higher in women with low-grade squamous intraepithelial lesions (LGSIL) than in women with high-grade squamous intraepithelial lesions (HGSIL) (44% and 15%, respectively). This contrasts with HPV16 DNA prevalence. Compared to women from the general population, systemic IgG prevalence was significantly higher among sex workers (25%; P = 0.002) and women with LGSIL (44%; P = 0.001). In addition, systemic IgA and cervical IgG prevalence was higher among sex workers only (P = 0.002 and P = 0.001, respectively). We did not observe anti-peptide IgG antibodies in women with a current HPV16 infection. CONCLUSION: Anti-peptide IgG in sera or in cervical secretions could be markers of an effective natural immunization against HPV16. This may open novel perspectives for monitoring vaccinated women and for the design of synthetic peptide-based vaccines.


Assuntos
Papillomavirus Humano 16 , Infecções por Papillomavirus , Neoplasias do Colo do Útero , Anticorpos Antivirais , Capsídeo , Proteínas do Capsídeo , Feminino , Humanos , Infecções por Papillomavirus/diagnóstico , Infecções por Papillomavirus/epidemiologia , Peptídeos Cíclicos , Prevalência , Neoplasias do Colo do Útero/diagnóstico
7.
Cancer Cell Int ; 20: 107, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32265596

RESUMO

BACKGROUND: Infections by both human oncoviruses, human Papillomaviruses (HPV) and Epstein-Barr virus (EBV) are very common in the adult human population and are associated with various malignancies. While HPV is generally transmitted sexually or via skin-to-skin contact, EBV is frequently transmitted by oral secretions, blood transfusions and organ transplants. This study aims to determine the prevalence and circulating genotypes of HPV and EBV in healthy blood donors in Qatar. METHODS: We explored the co-prevalence of high-risk HPVs and EBV in 378 males and only 7 females blood donors of different nationalities (mainly from Qatar, Egypt, Syria, Jordan, Pakistan, and India) residing in Qatar, using polymerase chain reaction (PCR). DNA was extracted from the buffy coat and genotyping was performed using PCR and nested-PCR targeting E6 and E7 as well as LMP-1 of HPV and EBV, respectively. RESULTS: We found that from the total number of 385 cases of healthy blood donors studied, 54.8% and 61% of the samples are HPVs and EBV positive, respectively. Additionally, our data revealed that the co-presence of both high-risk HPVs and EBV is 40.4% of the total samples. More significantly, this study pointed out for the first time that the most frequent high-risk HPV types in Qatar are 59 (54.8%), 31 (53.7%), 52 (49.1%), 51 (48.6%), 58 (47%) and 35 (45.5%), while the most commonly expressed low-risk HPV types are 53 (50.6%), 11 (45.5), 73 (41.7%) and 6 (41.3%), with all the cases showing multiple HPVs infection. CONCLUSION: In this study, we demonstrated for the first time that HPV and EBV are commonly co-present in healthy blood donors in Qatar. On the other hand, it is important to highlight that these oncoviruses can also be co-present in several types of human cancers where they can cooperate in the initiation and/or progression of these cancers. Therefore, more studies regarding the co-presence of these oncoviruses and their interaction are necessary to understand their cooperative role in human diseases.

8.
Hum Vaccin Immunother ; 15(3): 603-610, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30380978

RESUMO

Epstein-Barr virus (EBV) is a well-characterized oncovirus, associated with several malignancies. The complex and heterogeneous nature of colorectal cancer (CRC) has led to many epidemiological causal associations with CRC. However, a direct causal link between microbial infections and CRC has not been established yet. Our review indicates that the current evidence for the presence and role in EBV in CRC is insufficient and contradictory. The design of the analyzed studies, sample size as well as methodology used for EBV detection varied markedly and consequently may not lead to meaningful conclusions. The presence of EBV in other colorectal tumors (lymphomas, smooth muscle tumors) is in line with their status at other anatomic locations and may have therapeutic implications with EBV-specific vaccines. On the other hand, studies exploring EBV in colorectal adenoma-carcinoma sequence and its molecular genetic characteristics are largely missing and may significantly contribute to a better understanding of the role of EBV in CRC.


Assuntos
Neoplasias do Colo/virologia , Infecções por Vírus Epstein-Barr/complicações , Herpesvirus Humano 4/patogenicidade , Adenocarcinoma/genética , Adenocarcinoma/virologia , Neoplasias do Colo/genética , Infecções por Vírus Epstein-Barr/virologia , Genoma Viral , Herpesvirus Humano 4/genética , Humanos
10.
J Transl Med ; 16(1): 272, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30286756

RESUMO

BACKGROUND: In the recent years Plasmodium vivax has been reported to cause severe infections associated with mortality. Clinical evaluation has limited accuracy for the early identification of the patients progressing towards the fatal condition. Researchers have tried to identify the serum and the plasma-based indicators of the severe malaria. Discovery of MicroRNA (miRNA) has opened up an era of identification of early biomarkers for various infectious and non-infectious diseases. MicroRNAs (miRNA) are the small non-coding RNA molecules of length 19-24 nts and are responsible for the regulation of the majority of human gene expressions at post transcriptional level. METHODS: We identified the differentially expressed miRNAs by microarray and validated the selected miRNAs by qRT-PCR. We assessed the diagnostic potential of these up-regulated miRNAs for complicated P. vivax malaria. Futher, the bioinformtic analysis was performed to construct protein-protein and mRNA-miRNA networks to identify highly regulated miRNA. RESULTS: In the present study, utility of miRNA as potential biomarker of complicated P. vivax malaria was explored. A total of 276 miRNAs were found to be differentially expressed by miRNA microarray and out of which 5 miRNAs (hsa-miR-7977, hsa-miR-28-3p, hsa-miR-378-5p, hsa-miR-194-5p and hsa-miR-3667-5p) were found to be significantly up-regulated in complicated P. vivax malaria patients using qRT-PCR. The diagnostic potential of these 5 miRNAs were found to be significant with sensitivity and specificity of 60-71% and 69-81% respectively and area under curve (AUC) of 0.7 (p < 0.05). Moreover, in silico analysis of the common targets of up-regulated miRNAs revealed UBA52 and hsa-miR-7977 as majorly regulated hubs in the PPI and mRNA-miRNA networks, suggesting their putative role in complicated P. vivax malaria. CONCLUSION: miR-7977 might act as a potential biomarker for differentiating complicated P. vivax malaria from uncomplicated type. The elevated levels of miR-7977 may have a role to play in the disease pathology through UBA52 or TGF-beta signalling pathway.


Assuntos
Biomarcadores/sangue , Malária Vivax/sangue , Malária Vivax/diagnóstico , Programas de Rastreamento , Plasmodium vivax/fisiologia , Adolescente , Adulto , Algoritmos , Criança , Feminino , Ontologia Genética , Genes Essenciais , Humanos , Malária Vivax/genética , Masculino , MicroRNAs/sangue , MicroRNAs/genética , MicroRNAs/metabolismo , Mapas de Interação de Proteínas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Curva ROC , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Regulação para Cima/genética , Adulto Jovem
11.
Infect Agent Cancer ; 12: 50, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29021820

RESUMO

BACKGROUND: Cervical cancer is the fourth most common cancer in women worldwide with highest incidence reported in Eastern Africa in 2012. The primary goal of this study was to study the expression of p16INK4a in squamous cell carcinoma (SCC) of the cervix by immunohistochemistry (IHC) and determine relation with clinico-pathological parameters. This study further explored the correlation of p16INK4a immunostaining with another proliferation marker, Ki-67 and to study if human papillomavirus (HPV) IHC can be used as a marker for detection of virus in high-grade dysplasia. METHODS: A total of 90 samples, diagnosed for cervical cancer, were included in the study. Fixed Paraffin Embedded (FFPE) tissue sections were stained with anti-p16INK4a, anti-Ki-67 and anti-HPV antibodies using automated immunohistochemistry platform (ASLink 48-DAKO). RESULTS: Immunohistochemical protein expression of p16INK4a positivity was found to be highest in SCC (92.2%, n = 71) than other HPV tumors (76.9%, n = 10). The majority of cases (97.4%) were p16INK4a positive in the age group 41-60 years. In addition, a statistically significant difference between p16INK4a and HPV was observed among total cervical tumor cases and SCC cases. CONCLUSIONS: As expected staining of invasive cervical cancer with anti-HPV showed rare positivity because HPV heralds active infection in dysplastic lesions and not of frank cervical carcinoma. In contrast, anti-p16INK4a IHC results showed positive correlation in SCC and other cervical tumors.

12.
PLoS One ; 12(1): e0169197, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28046025

RESUMO

Human Papillomavirus (HPV) infections are known to cause cervical cancer worldwide, however, limited information is currently available on prevalence, types distribution and risk factors for HPV infection in the Arab countries. We conducted a cross-sectional observational study exclusively of women of Arabic origin residing in Qatar (n = 406) who were selected from the Women's Hospital at Hamad Medical Corporation (HMC) and Health Centers of the Primary Health Care Corporation in Doha, Qatar over the period March 2013 to August 2014. Socio-demographic, behavioral and clinical data were collected. Four hundred and six cervical smears and 292 blood samples were included in the study. HPV typing was done using HPV type-specific primers-based real-time PCR, and Sanger sequencing. HPV-IgG and IgM were quantified using ELISA assays. The prevalence of HPV infection amongst Qatari and non-Qatari Arab women were 9.8% and 6.1%, respectively and 7.6% and 16.7% in women with normal and abnormal cytology, respectively. HPV 81 was the most commonly found genotype in women with normal cytology (34.5%), whereas HPV 81, 16 and 59 in women with abnormal cytology (25.0% each). All the HPV DNA positive women were seronegative and HPV-IgG prevalence was higher in Qatari women than in non-Qatari Arab women. None of the studied factors had any significant association with HPV-DNA positivity or HPV-IgG seropositivity. The overall identified HPV DNA prevalence and HPV seroprevalence among Arab women in Qatar were on the low side compared to global levels.


Assuntos
Epidemiologia Molecular , Papillomaviridae/classificação , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Adulto , Anticorpos Antivirais/sangue , Árabes , Estudos Transversais , DNA Viral/genética , Feminino , Genótipo , Humanos , Imunoglobulina G/sangue , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Catar , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Risco , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/virologia , Adulto Jovem
13.
J Transl Med ; 12: 300, 2014 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-25424736

RESUMO

BACKGROUND: Human Papilloma Virus (HPV) infection is the major cause of cervical cancer worldwide. With limited data available on HPV prevalence in the Arab countries, this study aimed to identify the prevalence and genotypic distribution of HPV in the State of Qatar. METHODS: 3008 cervical samples, exclusively of women with Arabic origin residing in Qatar were collected from the Women's Hospital and Primary Health Care Corporation in Doha, State of Qatar. HPV DNA detection was done using GP5+/6+ primers based real time-polymerase chain reaction (RT-PCR) assay followed by the usage of HPV type specific primers based RT- PCR reactions and Sanger sequencing for genotype identification. RESULTS: Similar prevalence rates of HPV infection was identified in both Qatari and non-Qatari women at 6.2% and 5.9% respectively. HPV prevalence rate of 5.8% and 18.4% was identified in women with normal cytology and in women with abnormal cytology respectively. HPV 81, 11 and 16, in decreasing order were the most commonly identified genotypes. HPV 81 was the most frequent low-risk genotype among women with both normal (74.0%) and abnormal (33.3%) cytology. HPV 16 (4.6%) was identified as the predominant high-risk HPV genotype among women with normal cytology and HPV 16, HPV 18, and HPV 56 (22.2% each) were the most common identified high-risk genotypes in women with abnormal cytology. CONCLUSIONS: The overall HPV prevalence in Arab women in Qatar was identified as 6.1% with an increased HPV prevalence seen in women with abnormal cytology results and no significant trends seen with age. In contrast to Western countries, we report a varied genotypic profile of HPV with a high prevalence of low-risk HPV genotype 81 among the Arab women residing in Qatar.


Assuntos
Árabes , Papillomaviridae/genética , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Adolescente , Adulto , Distribuição por Idade , DNA Viral/genética , Demografia , Feminino , Genótipo , Humanos , Pessoa de Meia-Idade , Epidemiologia Molecular , Razão de Chances , Prevalência , Catar/epidemiologia , Adulto Jovem
14.
Infect Immun ; 73(9): 5883-91, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16113307

RESUMO

Malaria infection is initiated when the insect vector injects Plasmodium sporozoites into a susceptible vertebrate host. Sporozoites rapidly leave the circulatory system to invade hepatocytes, where further development generates the parasite form that invades and multiplies within erythrocytes. Previous experiments have shown that the thrombospondin-related adhesive protein (TRAP) plays an important role in sporozoite infectivity for hepatocytes. TRAP, a typical type-1 transmembrane protein, has a long extracellular region, which contains two adhesive domains, an A-domain and a thrombospondin repeat. We have generated recombinant proteins of the TRAP adhesive domains. These TRAP fragments show direct interaction with hepatocytes and inhibit sporozoite invasion in vitro. When the recombinant TRAP A-domain was used for immunoprecipitation against hepatocyte membrane fractions, it bound to alpha2-Heremans-Schmid glycoprotein/fetuin-A, a hepatocyte-specific protein associated with the extracellular matrix. When the soluble sporozoite protein fraction was immunoprecipitated on a fetuin-A-adsorbed protein A column, TRAP bound this ligand. Importantly, anti-fetuin-A antibodies inhibited invasion of hepatocytes by sporozoites. Further, onset of malaria infection was delayed in fetuin-A-deficient mice compared to that in wild-type C57BL/6 mice when they were challenged with Plasmodium berghei sporozoites. These data demonstrate that the extracellular region of TRAP interacts with fetuin-A on hepatocyte membranes and that this interaction enhances the parasite's ability to invade hepatocytes.


Assuntos
Proteínas Sanguíneas/metabolismo , Hepatócitos/metabolismo , Malária/imunologia , Malária/metabolismo , Plasmodium berghei/metabolismo , Proteínas de Protozoários/metabolismo , Animais , Proteínas Sanguíneas/deficiência , Proteínas Sanguíneas/genética , Linhagem Celular Tumoral , Hepatócitos/parasitologia , Humanos , Malária/genética , Malária/parasitologia , Camundongos , Camundongos Knockout , Plasmodium berghei/genética , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium berghei/patogenicidade , Ligação Proteica/genética , Ligação Proteica/imunologia , Proteínas de Protozoários/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Esporozoítos/imunologia , Esporozoítos/metabolismo , Esporozoítos/patogenicidade , alfa-2-Glicoproteína-HS
15.
J Exp Med ; 198(12): 1817-27, 2003 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-14676296

RESUMO

Much of the pathology of malaria is mediated by inflammatory cytokines (such as interleukin 12, interferon gamma, and tumor necrosis factor alpha), which are part of the immune response that kills the parasite. The antiinflammatory cytokine transforming growth factor (TGF)-beta plays a crucial role in preventing the severe pathology of malaria in mice and TGF-beta production is associated with reduced risk of clinical malaria in humans. Here we show that serum-free preparations of Plasmodium falciparum, Plasmodium yoelii 17XL, and Plasmodium berghei schizont-infected erythrocytes, but not equivalent preparations of uninfected erythrocytes, are directly able to activate latent TGF-beta (LatTGF-beta) in vitro. Antibodies to thrombospondin (TSP) and to a P. falciparum TSP-related adhesive protein (PfTRAP), and synthetic peptides from PfTRAP and P. berghei TRAP that represent homologues of TGF-beta binding motifs of TSP, all inhibit malaria-mediated TGF-beta activation. Importantly, TRAP-deficient P. berghei parasites are less able to activate LatTGF-beta than wild-type parasites and their replication is attenuated in vitro. We show that activation of TGF-beta by malaria parasites is a two step process involving TSP-like molecules and metalloproteinase activity. Activation of LatTGF-beta represents a novel mechanism for direct modulation of the host response by malaria parasites.


Assuntos
Metaloproteases/fisiologia , Plasmodium/fisiologia , Proteínas de Protozoários/fisiologia , Trombospondina 1/fisiologia , Fator de Crescimento Transformador beta/metabolismo , Sequência de Aminoácidos , Animais , Eritrócitos/parasitologia , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Plasmodium/enzimologia
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