RESUMO
The aim of this study was to develop an assay to analyze the serum profile of Mannose-binding lectin (MBL) through a simple and "in-house" method (called "dot-N-man"). Furthermore, the study attempted to associate molecular masses of MBL to the profile of MBL gene polymorphisms in patients with hepatitis C. Heterogeneity in molecular masses of MBL is due to the impairment of oligomers formation, which is linked to genetic polymorphisms in the MBL gene. Individuals with AA genotype (wild-type) produce high-molecular-mass proteins, whereas AO and OO individuals produce intermediate and low-molecular-mass proteins, respectively. Sera of thirty patients carrying the hepatitis C virus (HCV) were investigated using MBL binding assay with mannan-coated nitrocellulose (dot-N-man). Purified MBL was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Dot-N-Man assay yielded MBL with molecular masses ranging between 55 and 320â¯kDa, comparable to low and high molecular mass forms of MBL. Nonreducing SDS-PAGE showed high molecular mass bands in all AA individuals while bands of 270 and 205â¯kDa were observed in sera for a number of patients with AO and OO genotypes, respectively. Immunoblotting confirmed the MBL samples obtained from the dot-N-man. These results provide new insights to understand the MBL molecular forms profile in patients infected with HCV- which could be useful in future investigations on the influence of the MBL structure/genotype on both the progression of infection and the response to hepatitis C therapy.
Assuntos
Hepacivirus/imunologia , Hepatite C , Immunoblotting/métodos , Lectina de Ligação a Manose , Polimorfismo Genético , Colódio/química , Feminino , Hepatite C/genética , Hepatite C/imunologia , Humanos , Masculino , Mananas/química , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologiaRESUMO
Chagas disease (CD) is a global problem. Currently, it affects approximately 15 million individuals in Latin America. It is well know that the human immune response is related to different clinical manifestations. Mannose binding lectin (MBL) plays an important role in innate immunity, and it mediates the phagocytosis and complement-mediated destruction of pathogens. The binding capacity is enhanced by the oligomerization of MBL. In this study, we evaluated the serum concentration and the binding capacity of MBL in patients with chronic chagasic cardiomyopathy. A total of 77 patients with chronic CD were included with indeterminate (nâ¯=â¯19), mild cardiac (nâ¯=â¯29) and severe cardiac (nâ¯=â¯29) forms. The serum concentration and the binding capacity were measured using enzyme-linked immunosorbent assays (ELISA). There was no significant difference in the serum MBL levels between the groups of patients. However, we found a relationship between the binding capacity and the groups studied. Our results suggest that binding capacity of MBL could be an indicator of clinical manifestation in Chronic Chagas cardiomyopathy. Furthermore, combined with the Mannose Binding Index results in a useful clinical tool for management of Chronic Chagas Patients.
Assuntos
Cardiomiopatia Chagásica/imunologia , Cardiomiopatia Chagásica/patologia , Lectina de Ligação a Manose/imunologia , Doença Crônica , Ensaio de Imunoadsorção Enzimática , Humanos , Imunidade Inata , Lectina de Ligação a Manose/sangue , Ligação ProteicaRESUMO
Leprosy is a chronic infectious disease caused by Mycobacterium leprae. Genetic factors associated with immune response contribute to infection development and disease. M. leprae has the capacity to invade Schwann cells in the peripheral nervous system and cause neuropathy. However, while the responsible molecular mechanisms remain to be fully unveiled, they have begun being elucidated. We studied genetic variants Myelin Protein Zero (MPZ), a major structural component of the myelin sheath, and Mannose Binding Lectin 2 (MBL2), a protein involved in immune response, in 112 family groups of 114 leprosy patients using PCR-RFLP, aiming to calculate the association and allelic transmission of variants associated in first, second and third-degree relatives. Polymorphisms found in MPZ and MBL2 showed association with leprosy. Different probabilities for allelic transmission were found for first and second-degree relatives, a fact that is important to take into account when evaluating risk in contacts of leprosy patients. Structural analysis allows the study of putative amino acids and their possible effect on protein structure and function, as well as on the assembly of a protein homotetramer. Our results suggest that the identified MPZ and MBL2 gene mutations are associated with leprosy in a Colombian population, which correlates with MPZ and MBL2 protein function, and increase the risk of M. leprae infection in leprosy-patients' family members. Additionally, structural analyses were carried out specifically for MPZ protein using information available in databases, and analyzing the substitutions in wildtype and mutant protein. The results show significant structural changes, which may be associated to infection and pathogenicity.
Assuntos
Hanseníase , Lectina de Ligação a Manose , Proteína P0 da Mielina , Adulto , Colômbia , Feminino , Humanos , Hanseníase/genética , Hanseníase/imunologia , Masculino , Lectina de Ligação a Manose/química , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Pessoa de Meia-Idade , Modelos Moleculares , Proteína P0 da Mielina/química , Proteína P0 da Mielina/genética , Proteína P0 da Mielina/imunologia , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
The complement system plays an important role in the innate and acquired immune response against pathogens. A sophisticated network of activating and regulating proteins allows the distinction between intact and damaged host and non-host surfaces such as bacteria and other parasites. Non-host structures trigger the alternative pathway which may lead to their elimination by phagocytosis or cell lysis. In addition, complement proteins such as C1q, mannose binding lectin (MBL), and ficolins act as pathogen pattern-recognition molecules. Biological functions such as opsonization, activation of B lymphocytes and production of antibodies, degranulation of mast cells and basophils, and cell lysis that are important for elimination of microorganisms are dependent on complement activation. However, several pathogens including spirochetes have developed several specialized mechanisms to evade the complement system, thereby contributing to survival in the host. In this review, we give a brief overview of complement activation and regulation, and discuss in detail the strategies used by spirochetes from the genera Borrelia, Leptospira, and Treponema to overcome complement activation.
Assuntos
Proteínas do Sistema Complemento/imunologia , Evasão da Resposta Imune , Spirochaetales/imunologia , Borrelia/imunologia , Ativação do Complemento , Humanos , Leptospira/imunologia , Lectina de Ligação a Manose/imunologia , Receptores de Reconhecimento de Padrão/imunologia , Treponema/imunologiaRESUMO
The lectin pathway of the complement system has a pivotal role in the defense against infectious organisms. After binding of mannan-binding lectin (MBL), ficolins or collectin 11 to carbohydrates or acetylated residues on pathogen surfaces, dimers of MBL-associated serine proteases 1 and 2 (MASP-1 and MASP-2) activate a proteolytic cascade, which culminates in the formation of the membrane attack complex and pathogen lysis. Alternative splicing of the pre-mRNA encoding MASP-1 results in two other products, MASP-3 and MAp44, which regulate activation of the cascade. A similar mechanism allows the gene encoding MASP-2 to produce the truncated MAp19 protein. Polymorphisms in MASP1 and MASP2 genes are associated with protein serum levels and functional activity. Since the first report of a MASP deficiency in 2003, deficiencies in lectin pathway proteins have been associated with recurrent infections and several polymorphisms were associated with the susceptibility or protection to infectious diseases. In this review, we summarize the findings on the role of MASP polymorphisms and serum levels in bacterial, viral and protozoan infectious diseases.
Assuntos
Infecções Bacterianas/imunologia , Serina Proteases Associadas a Proteína de Ligação a Manose/imunologia , Infecções por Protozoários/imunologia , Viroses/imunologia , Infecções Bacterianas/genética , Infecções Bacterianas/microbiologia , Infecções Bacterianas/patologia , Lectina de Ligação a Manose da Via do Complemento/genética , Proteínas do Sistema Complemento/genética , Proteínas do Sistema Complemento/imunologia , Regulação da Expressão Gênica/imunologia , Humanos , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Serina Proteases Associadas a Proteína de Ligação a Manose/genética , Polimorfismo Genético , Infecções por Protozoários/genética , Infecções por Protozoários/parasitologia , Infecções por Protozoários/patologia , Transdução de Sinais , Viroses/genética , Viroses/patologia , Viroses/virologiaRESUMO
INTRODUCTION: Mannose binding lectin (MBL) has been linked to predisposition to systemic lupus erythematosus (SLE) and to disease activity. Some studies found deposits of MBL in glomerular tissue of patients with lupus nephritis. There is no research about the deposition of MBL in skin. MATERIALS AND METHODS: Skin biopsies from lesional and non lesional skin of 4 discoid lupus erythematosus (DLE) and 10 SLE patients were submitted to immunofluorescence staining for IgG, IgA, IgM, C3, C4, C1q, C5b-9 and MBL. Charts were reviewed for demographic, clinical and serological data. Patients with SLE had disease activity measured by SLEDAI. RESULTS: MBL was found only in SLE lesional skin and its presence showed an association trend towards higher disease activity. Deposition of C5b-9 occurred in vessels only in patients with SLE (70%) and in the two patients with kidney involvement. CONCLUSIONS: MBL deposition was found in the lesional skin of SLE patients but not in SLE non lesional skin nor in DLE patients, and it seems to be less frequent and less strong than observed in the kidneys biopsies, suggesting that the complement participation in the pathophysiology of SLE process may not be the same in these two clinical manifestations.
Assuntos
Lúpus Eritematoso Discoide/patologia , Lúpus Eritematoso Sistêmico/patologia , Lectina de Ligação a Manose/genética , Pele/patologia , Adulto , Complemento C1q/genética , Complemento C1q/imunologia , Complemento C3/genética , Complemento C3/imunologia , Complemento C4/genética , Complemento C4/imunologia , Complexo de Ataque à Membrana do Sistema Complemento/genética , Complexo de Ataque à Membrana do Sistema Complemento/imunologia , Feminino , Expressão Gênica , Humanos , Imunoglobulinas/genética , Imunoglobulinas/imunologia , Lúpus Eritematoso Discoide/genética , Lúpus Eritematoso Discoide/imunologia , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Lectina de Ligação a Manose/imunologia , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Pele/imunologiaRESUMO
A doença de Chagas (DC) é uma infecção causada pelo Trypanosoma cruzi, é considerada endêmica na América Latina, afetando cerca de 15 milhões de indivíduos. Estima-se que cerca de 30 por cento das pessoas infectadas desenvolvem cardiomiopatia chagásica crônica, entre 5 à 30 anos após a infecção aguda. Com o objetivo de diferenciar portadores de DC com a evolução potencial para formas clínicas crônicas graves, pesquisadores tentam estabelecer marcadores biológicos de prognóstico da evolução da doença por meio de marcadores imunológicos. Lectina de Ligação a Manose (MBL) é uma molécula de reconhecimento de que a imunidade inata que desempenha um papel fundamental na defesa do hospedeiro, mediando a fagocitose e a destruição dos agentes patogénicos mediada pelo complemento. Existem vários estudos que enfatizam a relevância da MBL em diferentes doenças infecciosas, inflamatórias e auto-imunes. A deficiência de MBL pode implicar na susceptibilidade bacteriana, fúngica, por protozoários e infecções virais. Nosso objetivo foi investigar a associação dos níveis séricos e atividade de ligação da MBL com cardiomiopatia chagásica crônica, através da formação de um índice, que inferiu as moléculas ligantes. Para isso, foi feita uma avaliação, através de ELISA, dos níveis séricos e da capacidade de ligação da MBL, para formação desse índice de relação (Mbi), em pacientes crônicos assintomáticos e cardíacos da doença de Chagas. O estudo incluiu 77 pacientes portadores DC indeterminados (n = 19), cardíaco grave (n = 29) e cardíaco leve (n = 29)...
Assuntos
Humanos , Adulto , Cardiomiopatia Chagásica/imunologia , Doença de Chagas/imunologia , Lectina de Ligação a Manose/imunologia , Doença Crônica , Ensaio de Imunoadsorção Enzimática/métodos , Biomarcadores , Ligação ProteicaRESUMO
The innate immune system is evolutionary and ancient and is the pivotal line of the host defense system to protect against invading pathogens and abnormal self-derived components. Cellular and molecular components are involved in recognition and effector mechanisms for a successful innate immune response. The complement lectin pathway (CLP) was discovered in 1990. These new components at the complement world are very efficient. Mannan-binding lectin (MBL) and ficolin not only recognize many molecular patterns of pathogens rapidly to activate complement but also display several strategies to evade innate immunity. Many studies have shown a relation between the deficit of complement factors and susceptibility to infection. The recently discovered CLP was shown to be important in host defense against protozoan microbes. Although the recognition of pathogen-associated molecular patterns by MBL and Ficolins reveal efficient complement activations, an increase in deficiency of complement factors and diversity of parasite strategies of immune evasion demonstrate the unsuccessful effort to control the infection. In the present paper, we will discuss basic aspects of complement activation, the structure of the lectin pathway components, genetic deficiency of complement factors, and new therapeutic opportunities to target the complement system to control infection.
Assuntos
Lectina de Ligação a Manose da Via do Complemento , Evasão da Resposta Imune , Trypanosomatina/imunologia , Ativação do Complemento , Suscetibilidade a Doenças/imunologia , Predisposição Genética para Doença , Glicoproteínas/sangue , Glicoproteínas/imunologia , Haplótipos , Humanos , Lectinas/sangue , Lectinas/imunologia , Malária/genética , Malária/imunologia , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Serina Proteases Associadas a Proteína de Ligação a Manose/genética , Serina Proteases Associadas a Proteína de Ligação a Manose/imunologiaRESUMO
No commercially live vaccine against cholera caused by Vibrio cholerae O139 serogroup is available and it is currently needed. Virulent O139 strain CRC266 was genetically modified by firstly deleting multiple copies of the filamentous phage CTXφ, further tagging by insertion of the endoglucanase A coding gene from Clostridium thermocellum into the hemagglutinin/protease gene and finally deleting the mshA gene, just to improve the vaccine biosafety. One of the derived strains designated as TLP01 showed full attenuation and good colonizing capacity in the infant mouse cholera model, as well as highly immunogenic properties in the adult rabbit and rat models. Since TLP01 lacks MSHA fimbriae, it is refractory to infection with another filamentous phage VGJφ and therefore protected of acquiring CTXφ from a recombinant hybrid VGJφ/CTXφ. This strategy could reduce the possibilities of stable reversion to virulence out of the human gut. Furthermore, this vaccine strain was impaired to produce biofilms under certain culture conditions, which might have implications for the strain survival in natural settings contributing to vaccine biosafety as well. The above results has encouraged us to consider TLP01 as a live attenuated vaccine strain having an adequate performance in animal models, in terms of attenuation and immunogenicity, so that it fulfills the requirements to be evaluated in human volunteers.
Assuntos
Vacinas contra Cólera/imunologia , Proteínas de Fímbrias/imunologia , Vibrio cholerae O139/imunologia , Administração Oral , Animais , Anticorpos Antibacterianos/imunologia , Derrame de Bactérias , Sequência de Bases , Biofilmes , Cólera/imunologia , Cólera/prevenção & controle , Vacinas contra Cólera/genética , Vacinas contra Cólera/farmacologia , Modelos Animais de Doenças , Fezes/microbiologia , Proteínas de Fímbrias/genética , Mucosa Intestinal/imunologia , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Dados de Sequência Molecular , Coelhos , Ratos , Ratos Sprague-Dawley , Alinhamento de Sequência , Deleção de Sequência/genética , Estatísticas não Paramétricas , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologia , Vacinas Atenuadas/farmacologia , Vibrio cholerae O139/genéticaRESUMO
OBJECTIVE: This study investigates the role of mannose-binding lectin (MBL) in the susceptibility to HIV-1 infection analyzing polymorphisms located at the MBL2 promoter and exon 1 regions. MATERIALS AND METHODS: The prevalence of MBL2 variant alleles was investigated in 410 HIV-1-infected patients from the South Brazilian HIV cohort and in 345 unexposed uninfected healthy individuals. The promoter variants were genotyped using polymerase chain reaction with sequence-specific primers (PCR-SSP) and exon 1 variants were analyzed by real-time PCR using a melting temperature assay and were confirmed by PCR-restriction fragment length polymorphism (RFLP). MBL2 genotypic and allelic frequencies were compared between HIV-1-infected patients and controls using the chi-squared tests. RESULTS: The analyses were performed subdividing the individuals according to their ethnic origin. Among Euro-derived individuals a higher frequency of the LX/LX genotype was observed in patients when compared to controls (P < 0.001). The haplotypic analysis also showed a higher frequency of the haplotypes associated with lower MBL levels among HIV-1-infected patients (P = 0.0001). Among Afro-derived individuals the frequencies of LY/LY and HY/HY genotypes were higher in patients when compared to controls (P = 0.009 and P = 0.02). CONCLUSIONS: An increased frequency of MBL2 genotypes associated with low MBL levels was observed in Euro-derived patients, suggesting a potential role for MBL in the susceptibility to HIV-1 infection in Euro-derived individuals.
Assuntos
Predisposição Genética para Doença/genética , Infecções por HIV/genética , HIV-1 , Lectina de Ligação a Manose/genética , Regiões Promotoras Genéticas/genética , Adulto , Idoso , Brasil/epidemiologia , Feminino , Infecções por HIV/epidemiologia , Infecções por HIV/imunologia , Humanos , Lectinas Tipo C/genética , Lectinas Tipo C/imunologia , Masculino , Receptor de Manose , Lectina de Ligação a Manose/imunologia , Lectinas de Ligação a Manose/genética , Lectinas de Ligação a Manose/imunologia , Pessoa de Meia-Idade , Polimorfismo Genético , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/imunologia , Adulto JovemRESUMO
Paracoccidioides brasiliensis (Pb) is a dimorphic fungal pathogen that causes paracoccidioidomycosis, the most severe deep mycosis from South America. Although cell mediated immunity is considered the most efficient protective mechanism against Pb infection, mechanisms of innate immunity are poorly defined. Herein, we investigated the interaction of the complement system with high and low virulence isolates of Pb. We demonstrated that Pb18, a high virulence Pb isolate, when incubated with normal human serum (NHS) induces consumption of hemolytic complement and, when immobilized, promotes binding of C4b, C3b and C5b-C9. Both, low virulence (Pb265) and high virulence (Pb18) isolates consumed C4, C3 and mannose-binding lectin (MBL) of MBL-sufficient, but not of MBL-deficient serum as revealed by deposition of residual C4, C3 and MBL on immune complexes and mannan. However, higher complement components consumption was observed with Pb265, as compared with Pb18. The suggested relationship between low virulence and significant complement activation properties of Pb isolates, was confirmed by the demonstration that virulence attenuation of Pb 18 results in acquisition of the ability to activate complement. Conversely, reactivation of attenuated Pb18, results in loss of the ability to activate complement. Our results demonstrate for the first time that Pb yeasts activate the complement system by the lectin pathway, and there is an inverse correlation between complement activating ability and Pb virulence. These differences could exert an influence on innate immunity and severity of the disease developed by infected hosts.
Assuntos
Lectina de Ligação a Manose da Via do Complemento/imunologia , Paracoccidioides/imunologia , Paracoccidioidomicose/imunologia , Transdução de Sinais/imunologia , Animais , Ensaio de Imunoadsorção Enzimática , Humanos , Lectina de Ligação a Manose/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Paracoccidioides/patogenicidade , VirulênciaRESUMO
PROBLEM: Mannose-binding lectin (MBL) is involved in the maintenance of an inflammatory environment in uterus. High MBL levels have been associated with successful pregnancies whereas low levels are involved in pre-eclampsia (PE) development. Here, we evaluated MBL2 gene polymorphisms in the structural and promoter regions addressing their association with PE. METHOD OF STUDY: DNA samples from 162 control pregnant women and 157 pregnant PE women were genotyped and data compared with demographic and clinical characteristics. RESULTS: High frequency of C and D alleles (related to low MBL levels) was observed in PE women when compared to controls (C: 0.08 versus 0.03, P = 0.006; D: 0.10 versus 0.05, P = 0.009). Grouping the MBL genotypes according to phenotype, a higher frequency of OO genotype was observed in PE women when compared to control women (0.15 versus 0.04, P = 0.007). CONCLUSION: Our data suggest that women with genotypes associated with low MBL levels could be potential PE developers.
Assuntos
Lectina de Ligação a Manose/genética , Pré-Eclâmpsia/genética , Adulto , Brasil , Distribuição de Qui-Quadrado , DNA/química , DNA/genética , Feminino , Variação Genética , Haplótipos , Humanos , Desequilíbrio de Ligação , Lectina de Ligação a Manose/imunologia , Mutagênese Sítio-Dirigida , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Polimorfismo de Nucleotídeo Único , Pré-Eclâmpsia/imunologia , Gravidez , Regiões Promotoras GenéticasRESUMO
Giardia intestinalis (syn. G. lamblia, G. duodenalis) is a flagellated unicellular eukaryotic microorganism that commonly causes diarrheal disease throughout the world. In humans, the clinical effects of Giardia infection range from the asymptomatic carrier state to a severe malabsorption syndrome possibly due to different virulence of the Giardia strain, the number of cysts ingested, the age of the host, and the state of the host immune system at the time of infection. The question about how G. intestinalis is controlled by the organism remains unanswered. Here, we investigated the role of the complement system and in particular, the lectin pathway during Giardia infections. We present the first evidence that G. intestinalis activate the complement lectin pathway and in doing so participate in eradication of the parasite. We detected rapid binding of mannan-binding lectin, H-ficolin and L-ficolin to the surface of G. intestinalis trophozoites and normal human serum depleted of these molecules failed to kill the parasites. Our finding provides insight into the role of lectin pathway in the control of G. intestinalis and about the nature of surface components of parasite.
Assuntos
Lectina de Ligação a Manose da Via do Complemento , Proteínas do Sistema Complemento/imunologia , Giardia lamblia/imunologia , Giardíase/imunologia , Interações Hospedeiro-Parasita/imunologia , Lectina de Ligação a Manose/imunologia , Giardíase/parasitologia , Humanos , Imunidade Inata , Lectinas/imunologia , FicolinasRESUMO
Down syndrome (DS) is the most frequent cause of intellectual disability worldwide. DS individuals present abnormalities in the immune system that include high susceptibility to recurrent infections (RI) as well as to autoimmune diseases. Respiratory tract infections remain one of the major causes of death in DS individuals. Mannan-binding lectin (MBL) functions as an opsonina and initiates the lectin complement pathway. MBL deficiency was shown to increase the susceptibility to different infectious diseases, notably by extracellular pathogens. In the present study, MBL circulating levels were evaluated in 150 children with DS from Brazil, to clarify whether MBL deficiency is associated with the presence of RI in these patients. According to the clinical history 30.7% (46/150) of the DS children experienced RI, and MBL deficiency was seen in 34.8% (16/46) of them compared with 13.5% (14/104) of the DS children without RI (p = 0.005, odds ratio = 3.43, 95% confidence interval = 1.5-7.85). Moreover, MBL deficiency was significantly associated with the occurrence of pneumonia when compared with DS without RI (37.5%, 12/32 vs. 13.5% 14/104, p = 0.005, odds ratio = 3.68, 95% confidence interval = 1.5-6.95). These findings demonstrated that MBL deficiency increases the susceptibility to RI in DS patients and that, in the future, they could potentially benefit from MBL therapy.
Assuntos
Síndrome de Down/imunologia , Lectina de Ligação a Manose/imunologia , Infecções Respiratórias/imunologia , Adolescente , Brasil , Criança , Pré-Escolar , Síndrome de Down/sangue , Síndrome de Down/complicações , Feminino , Humanos , Imunoglobulinas/sangue , Imunoglobulinas/imunologia , Masculino , Lectina de Ligação a Manose/sangue , Lectina de Ligação a Manose/deficiência , Recidiva , Infecções Respiratórias/sangue , Infecções Respiratórias/complicações , Fatores de RiscoRESUMO
The present study compares the genotype frequencies between two population groups composed by 73 hepatitis C virus (HCV)-infected patients and 92 seronegative controls and investigates the role of allele variants as a possible factor in the susceptibility to HCV infection and the influence on disease progression. The identification of MBL*B and MBL*C alleles was performed by restriction fragment length polymorphism analysis of the 349-bp product using BanI and MboII restriction enzymes, respectively, and a polymerase chain reaction-sequence-specific polymorphism for discrimination of MBL*D. The analysis of allele and genotype frequencies between an HCV-infected group and seronegative controls did not indicate significant differences. The comparison of chronically infected subjects with and without liver cirrhosis was also not statistically significant. The odds ratio estimations were not significant, and the values obtained cannot suggest that the presence of allele variant MBL*B could have some influence in the risk of HCV infection progression to liver cirrhosis and that the presence of allele MBL*D could confer some protection against disease progression, but a larger sample size is necessary to confirm the present results.
Assuntos
Hepacivirus/imunologia , Hepatite C Crônica/genética , Lectina de Ligação a Manose/genética , Adolescente , Adulto , Idoso , Alelos , Brasil , Análise Mutacional de DNA , Progressão da Doença , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Hepacivirus/patogenicidade , Hepatite C Crônica/imunologia , Hepatite C Crônica/fisiopatologia , Humanos , Masculino , Lectina de Ligação a Manose/imunologia , Lectina de Ligação a Manose/metabolismo , Pessoa de Meia-Idade , Polimorfismo Genético , Fatores de Risco , VirulênciaRESUMO
The clinical heterogeneity observed in leptospirosis may be associated with host factors or bacteria virulence. Human serum mannose-binding lectin (MBL) recognizes many pathogens, and low levels of this lectin are associated with susceptibility to infection. MBL is also implicated in the modulation of the inflammatory process. We determined the levels of serum MBL during leptospirosis infection. A double-antibody sandwich ELISA was used to detect the immunoreactive serum MBL. The ELISA plates were coated with monoclonal antibody to MBL and bound MBL or recombinant human MBL were detected by rabbit anti-human MBL serum. HRPO-conjugated goat anti-rabbit antibody was used for detection of the reaction. Two groups of patients seen at referral hospitals in Recife, PE, Brazil, were divided according to the year of infection, 2001 (N = 61) or 2002 (N = 57) and compared in terms of disease severity and levels of serum MBL. A group of healthy volunteers (N = 97) matched by age, gender, and ethnic background was used as control. Patients infected in 2001 had more severe outcomes than those infected in 2002, including jaundice, hemorrhage, respiratory alteration, and renal complication (P = 0.0009; chi-square test). The frequency of patients producing serum MBL >1000 ng/mL was higher in the 2001 group than in the 2002 and control groups (P < 0.01), suggesting an association of MBL level with disease severity. The involvement of MBL and genetic variation of the MBL2 gene should be further evaluated to establish the role of this lectin in the pathogenesis of leptospirosis.
Assuntos
Adolescente , Animais , Feminino , Humanos , Masculino , Coelhos , Adulto Jovem , Leptospirose/sangue , Lectina de Ligação a Manose/sangue , Anticorpos Monoclonais/sangue , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática/métodos , Leptospirose/complicações , Leptospirose/imunologia , Lectina de Ligação a Manose/imunologia , Índice de Gravidade de Doença , Adulto JovemRESUMO
The clinical heterogeneity observed in leptospirosis may be associated with host factors or bacteria virulence. Human serum mannose-binding lectin (MBL) recognizes many pathogens, and low levels of this lectin are associated with susceptibility to infection. MBL is also implicated in the modulation of the inflammatory process. We determined the levels of serum MBL during leptospirosis infection. A double-antibody sandwich ELISA was used to detect the immunoreactive serum MBL. The ELISA plates were coated with monoclonal antibody to MBL and bound MBL or recombinant human MBL were detected by rabbit anti-human MBL serum. HRPO-conjugated goat anti-rabbit antibody was used for detection of the reaction. Two groups of patients seen at referral hospitals in Recife, PE, Brazil, were divided according to the year of infection, 2001 (N = 61) or 2002 (N = 57) and compared in terms of disease severity and levels of serum MBL. A group of healthy volunteers (N = 97) matched by age, gender, and ethnic background was used as control. Patients infected in 2001 had more severe outcomes than those infected in 2002, including jaundice, hemorrhage, respiratory alteration, and renal complication (P = 0.0009; chi-square test). The frequency of patients producing serum MBL >1000 ng/mL was higher in the 2001 group than in the 2002 and control groups (P < 0.01), suggesting an association of MBL level with disease severity. The involvement of MBL and genetic variation of the MBL2 gene should be further evaluated to establish the role of this lectin in the pathogenesis of leptospirosis.
Assuntos
Leptospirose/sangue , Lectina de Ligação a Manose/sangue , Adolescente , Animais , Anticorpos Monoclonais/sangue , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Leptospirose/complicações , Leptospirose/imunologia , Masculino , Lectina de Ligação a Manose/imunologia , Coelhos , Índice de Gravidade de Doença , Adulto JovemRESUMO
Susceptibility to systemic lupus erythematosus (SLE) is associated with genetic, hormonal, immunological, and environmental factors. Many genes have been related with the appearance of SLE, including several loci that code different complement components and their receptors. Some genetic deficiencies of complement molecules are strongly associated with SLE, probably because these deficiencies could cause decreased clearance of apoptotic cell material. As a consequence of the apoptotic material accumulation, high levels of autoantigens can be presented inappropriately to the immune system in an inflammatory context, resulting in an imbalance on the mechanisms of immunological tolerance, immune system activation, and autoantibody production. Recent studies proposed a role to the mannose-binding lectin (MBL) in the SLE physiopathogenesis. This protein activates the complement system, and the presence of several polymorphisms at the promoter and coding regions of the MBL-2 gene determines alterations at the plasma levels of MBL. Some of these polymorphisms have been associated with SLE susceptibility, as well as with clinical and laboratory typical features of this disease, cardiovascular events, and infections. Besides, it has been described that the presence of anti-MBL autoantibodies in sera of SLE patients can influence MBL plasma levels and its functional activity.
Assuntos
Lúpus Eritematoso Sistêmico/etiologia , Lectina de Ligação a Manose/fisiologia , Autoanticorpos/sangue , Proteínas do Sistema Complemento , Predisposição Genética para Doença/genética , Humanos , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Polimorfismo Genético/genética , Fatores de RiscoRESUMO
In our study we investigated the role of the polymorphisms in the first exon of MBL2 gene in the susceptibility to HCV infection and disease progression in a Northeastern Brazilian population. One hundred and eleven patients seen at the Gastroenterology Service of the Oswaldo Cruz Hospital of the University of Pernambuco were included in this study. A total of 165 unexposed, uninfected individuals matched for place of origin were employed as healthy controls. MBL2 genotyping was performed by using a melting temperature assay. The 0 allele was significantly more frequent in the HCV positive group than the healthy controls (34% vs. 20%, p<0.01, respectively) and was associated to an increased risk of HCV-1 infection (O.R.=2.1; C.I. 1.41-3.19). Also genotypes frequencies were significantly different in HCV positive subjects when compared to healthy controls with the 00 and A0 genotypes being significantly overrepresented in HCV infected subject (15% and 37%, respectively) as compared to healthy subjects (6% and 27%, respectively, p<0.01 ) Allele and genotypes frequencies were also evaluated in HCV infected subjects according to their response to pegylated-INFalpha/riboviron therapy. There was a trend for HCV positive responders vs. non-responders to be 0 allele positive and a similar trend was observed for the MBL2 A0 and 00 genotypes, but neither of these reached statistical significance. Our findings indicate that MBL might represent an important antiviral molecule having a protective role in the first stages of HCV infection, as shown by the increased frequency of wild-type alleles in control population as compared to the infected group.
Assuntos
Genótipo , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/genética , Lectina de Ligação a Manose/genética , Polimorfismo de Nucleotídeo Único/genética , Adulto , Idoso , Antivirais/uso terapêutico , Brasil , Estudos de Casos e Controles , Progressão da Doença , Éxons , Feminino , Frequência do Gene/genética , Predisposição Genética para Doença , Hepatite C Crônica/patologia , Humanos , Interferon alfa-2 , Interferon-alfa/uso terapêutico , Masculino , Lectina de Ligação a Manose/imunologia , Pessoa de Meia-Idade , Polietilenoglicóis , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único/imunologia , Proteínas Recombinantes , Ribavirina/uso terapêutico , Resultado do TratamentoRESUMO
Mannan-binding lectin (MBL) is an innate pattern recognition molecule known to play a key role in pathogen clearance. As MBL2 gene polymorphism is associated to an increased susceptibility to infection, we aimed to determine genetic variations in the MBL2 gene in rheumatic heart disease (RHD). Genetic variations in the promoter and exon 1 region of the MBL2 gene were analyzed in 107 patients with RHD and 105 controls by real-time polymerase chain reaction. The frequency of MBL2* A/A genotype was significantly higher in RHD patients (71/107, 66.36% vs 52/105, 49.52%, pAssuntos
Frequência do Gene
, Predisposição Genética para Doença
, Lectina de Ligação a Manose/genética
, Polimorfismo Genético
, Cardiopatia Reumática/genética
, Adulto
, Idoso
, Estudos de Casos e Controles
, Éxons/imunologia
, Feminino
, Haplótipos
, Humanos
, Masculino
, Lectina de Ligação a Manose/imunologia
, Pessoa de Meia-Idade
, Regiões Promotoras Genéticas/imunologia
, Cardiopatia Reumática/imunologia