.Expression and purification of Mycobacterium tuberculosis MPT83 protein and its application in tuberculosis immunological diagnosis / 中国热带医学

@#Abstract: Objective To express and purify MPT83 protein of Mycobacterium tuberculosis and evaluate its application value in immunological diagnosis of tuberculosis (TB) using clinical samples. Methods Using Mycobacterium tuberculosis (Mtb) H37Rv genome as the template, Mtb mpt83 gene was amplified by PCR and connected to PET-21a (+) to construct prokaryotic expression vector, and then transferred into E.coli DH5α. The positive colonies were picked out and retained. The recombinant plasmid pET-mpt83 of the strain with positive colony PCR was extracted, identified by double digestion, and the samples of the positive colonies were sent for sequencing. The correctly sequenced plasmids then were transferred into BL21 competent cells for induction, expression and purification with nickel column affinity chromatography. The purified products were identified by 12 alkyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Mouse polyclonal antiserum was prepared by immunizing mice with purified protein. 8 patients clinically diagnosed as tuberculosis pleural effusion (TB group) and 8 adenocarcinomas patients (CA group) were enrolled and their pleural effusion and plasma were collected. 8 healthy people (HC group) were enrolled as the control group and their plasma were collected. An indirect ELISA was used to detect the level of specific antibodies recognizing MPT83 protein in the samples. Results Mtb MPT83 protein was successfully expressed and purified. The serum titer of MPT83 mouse polyclonal antibody was as high as 1∶1 280 000. The plasma levels of MPT83 antigen specific antibodies in TB group were significantly higher than those in HC group (P<0.05), while the plasma levels of MPT83 antigen specific antibodies in CA group were not significantly different from those in HC group (P>0.05). Compared with the HC group, there was no significant difference in pleural fluid in both the TB and CA groups (P>0.05). The ROC curve was used to analyze the OD values of plasma in TB group and HC group, and the area under the curve was greater than 0.7, showing high diagnostic efficacy. Conclusion　MPT83 protein has high antigen specificity and immunogenicity, which has great application value in the immunological diagnosis of tuberculosis.

Cloning expression and serological evaluation on Mycobacterium tuberculosis four new antigens / 中华流行病学杂志

Objective To evaluate the serological diagnostic value of Mycobacterium (M.)tuberculosis four new antigens Rv0432,Rv0674,Rv1566c and Rv1547.Methods Rv0432,Rv0674,Rv1566c and Rv1547 were amplified from M.tuberculosis strain H37Rv genomic DNA by using PCR,among which Rv1547 was divided into two segments for amplification (Rv1547-1 and Rv1547-2).The segments were cloned into expression vector PET-32a while the recombinant proteins were purified by affinity chromatography.Serums were incubated with BL21 (DE3) proteins.Antibodies IgG against M.tuberculosis were tested with 151 serum samples (41 healthy people and 110 TB patients) by using ELISA.The diagnostic efficiency of antigens was analyzed by means of receiver operating characteristic curve.Difference of the objective proteins in TB patients and healthy controls was compared by t-test.Results Recombinant antigens Rv0432,Rv0674,Rv1566c,Rv1547-1 and Rv1547-2 were successfully expressed and purified.Results from ELISA showed that the sensitivity,specificity,positive predictive value,negative predictive value,Youden index and area under the curve of Rv0432,Rv0674,Rv1566c,Rv1547-1 and Rv1547-2,as 43.64％-92.73％,80.49％-92.68％,0.92-0.94,0.38-0.80,0.363-0.732 and 0.649-0.915.All the objective proteins showed significantly higher antibody levels in TB patients,when compared to the healthy controls (P＜0.000 1).Condnsion The newly identified antigens Rv0432,Rv0674,Rv1566c,Rv1547-1 and Rv1547-2 all performed well when being used for TB serological diagnosis,thus were expected to be new candidate antigens used for TB diagnosis.

Cloning expression and serological evaluation on Mycobacterium tuberculosis four new antigens / 中华流行病学杂志

Objective To evaluate the serological diagnostic value of Mycobacterium (M.)tuberculosis four new antigens Rv0432,Rv0674,Rv1566c and Rv1547.Methods Rv0432,Rv0674,Rv1566c and Rv1547 were amplified from M.tuberculosis strain H37Rv genomic DNA by using PCR,among which Rv1547 was divided into two segments for amplification (Rv1547-1 and Rv1547-2).The segments were cloned into expression vector PET-32a while the recombinant proteins were purified by affinity chromatography.Serums were incubated with BL21 (DE3) proteins.Antibodies IgG against M.tuberculosis were tested with 151 serum samples (41 healthy people and 110 TB patients) by using ELISA.The diagnostic efficiency of antigens was analyzed by means of receiver operating characteristic curve.Difference of the objective proteins in TB patients and healthy controls was compared by t-test.Results Recombinant antigens Rv0432,Rv0674,Rv1566c,Rv1547-1 and Rv1547-2 were successfully expressed and purified.Results from ELISA showed that the sensitivity,specificity,positive predictive value,negative predictive value,Youden index and area under the curve of Rv0432,Rv0674,Rv1566c,Rv1547-1 and Rv1547-2,as 43.64％-92.73％,80.49％-92.68％,0.92-0.94,0.38-0.80,0.363-0.732 and 0.649-0.915.All the objective proteins showed significantly higher antibody levels in TB patients,when compared to the healthy controls (P＜0.000 1).Condnsion The newly identified antigens Rv0432,Rv0674,Rv1566c,Rv1547-1 and Rv1547-2 all performed well when being used for TB serological diagnosis,thus were expected to be new candidate antigens used for TB diagnosis.

Espondilodiscitis tuberculosa: uso de los exámenes complementarios con una nueva perspectiva: A propósito de dos casos clínicos y revisión de la literatura / Tuberculous spondylodiscitis: use of complementary tests with a new perspective: A report of two cases and review of literature

Introducción. La tuberculosis constituye actualmente un grave problema sanitario. Es una enfermedad reemergente, su principal factor de riesgo es la infección por el virus de la inmunodeficiencia humana (VIH), siendo las formas extrapulmonares mucho más frecuentes en este grupo respecto a la población general. La espondilodiscitis tuberculosa (ET) representa 3% del total de las infecciones tuberculosas y 35% de las formas extrapulmonares. Su clínica es insidiosa, de diagnóstico complejo, la imagenología y microbiología son imprescindibles para un correcto diagnóstico. Todo esto suele determinar un retraso importante en el manejo, con consecuencias directas en el pronóstico del paciente. Material y método. Se presentan dos casos de ET asistidos en un Hospital público uruguayo (2012-2013), en pacientes con inmunocompromiso severo y noción de contacto epidemiológico en uno de ellos, diagnosticados tras la sospecha clínico-imagenológica y confirmación microbiológica por punción-aspiración bajo tomografía computarizada (TC). Resultados. Se inició el tratamiento con una latencia superior a tres meses. Discusión y Conclusiones. Las técnicas de biología molecular e inmunología constituyen hoy día una herramienta de gran valor para el diagnóstico precoz de esta enfermedad, permitiendo abreviar los tiempos en el inicio del tratamiento y reduciendo la tasa de complicaciones asociadas a ella.

Introduction. Tuberculosis (TB) constitutes a serious health problem nowadays. It is a reemerging disease whose main risk factor is the human immunodeficiency virus (HIV) infection, in which extrapulmonary forms are much more frequent than in general population. Tuberculous spondylodiscitis (TS) represents 3% of all TB infections and 35% of extrapulmonary forms. It has an insidious clinical presentation; the diagnosis is difficult requiring imagenologic and microbiologic technics. These characteristics result in a significant diagnosis delay which impacts on patient prognosis. Materials and methods. We present two cases of TS admitted to a public hospital in Uruguay (2012-2013) in immunocompromised patients and with epidemiological notion of contact in one of them. Results. The diagnosis was done after clinical and radiological suspicion; needle aspiration guided by computed tomography was performed. The treatment was instituted with a latency exceeding three months. Discussion and conclusions. The techniques of molecular biology and immunology are now a valuable tool for early diagnosis of this disease, shortening the initiation of treatment and reducing the rate of complications associated with it.

Membrane fractions from Strongyloides venezuelensis in the immunodiagnosis of human strongyloidiasis / Frações de membrana de Strongyloides venezuelensis para o imunodiagnóstico da estrongiloidíase humana

Strongyloides venezuelensis is a parasitic nematode of rodents frequently used to obtain heterologous antigens for the immunological diagnosis of human strongyloidiasis. The aim of this study was to evaluate membrane fractions from S. venezuelensis for human strongyloidiasis immunodiagnosis. Soluble and membrane fractions were obtained in phosphate saline (SS and SM) and Tris-HCl (TS and TM) from filariform larvae of S. venezuelensis. Ninety-two serum samples (n = 92) were obtained from 20 strongyloidiasis patients (Group I), 32 from patients with other parasitic diseases (Group II), and 40 from healthy individuals (Group III), and were analyzed by enzyme-linked immunosorbent assay (ELISA). Soluble fractions (SS and TS) showed 90.0% sensitivity and 88.9% specificity, whereas the membrane fractions (SM and TM) showed 95.0% sensitivity and 94.4% specificity. The present results suggest the possible use of membrane fractions of S. venezuelensis as an alternative antigen for human strongyloidiasis immunodiagnosis.

Strongyloides venezuelensis é um nematódeo parasita de roedores, frequentemente usado como antígeno heterólogo para o diagnóstico imunológico da estrongiloidíase humana. O objetivo deste estudo foi avaliar frações de membrana de S. venezuelensis para o imunodiagnóstico da estrongiloidíase humana. Para tanto, frações solúveis e de membrana foram obtidas em solução salina fosfato (SS e MS) e Tris-HCl (ST e MT) de larvas filarioides de S. venezuelensis. Amostras de soro de 92 indivíduos, sendo 20 com estrongiloidíase (Grupo I); 32 com outras parasitoses (Grupo II), e 40 indivíduos saudáveis (Grupo III), foram analisadas pelo teste Imunoenzimático (ELISA). As frações solúveis (SS e ST) apresentaram 90,0% e 88,9%, enquanto que as frações de membrana (MS e MT) demonstraram 95,0% e 94,4%, de sensibilidade e especificidade, respectivamente. Os resultados obtidos permitem indicar as frações de membranas como antígeno alternativo para o diagnóstico da estrongiloidíase humana.

Acute schistosomiasis diagnosis: a new tool for the diagnosis of schistosomiasis in a group of travelers recently infected in a new focus of Schistosoma mansoni

Introduction The diagnosis of schistosomiasis mansoni on early stages of infection is important to prevent late morbidity. A simple, cheap, sensitive and specific assay for routine diagnosis of schistosome infection based on the detection of specific IgG for schistosomula tegument antigens (ELISA-SmTeg) was developed by our group. Methods We describe here an acute outbreak involving a travel group of 80 individuals from a non-endemic area of the State of Minas Gerais, Brazil. These individuals were in contact with a freshwater pool where Biomphalaria glabrata was found. Results obtained from our new methodology were compared to IgG antibody titers against soluble worm antigenic preparation (SWAP) by ELISA and, also to parasitological examination, nuclear magnetic resonance and clinical findings. Results ELISA-SmTeg was capable of detecting 64 positive cases among the 80 individuals participating at the survey with a positivity ratio of 80% and a higher sensitivity than ELISA-SWAP that was only sensitive for 56% of positive cases. Besides, a significant correlation was found for the severity of the infection and the specific IgG titers against SmTeg. Conclusions Our data showed that ELISA-SmTeg might serve as the initial diagnostic tool for acute stages of the infection in community-based helminth control programs or for the surveillance of individuals from non-endemic areas. .