RESUMEN
The emergence of multidrug-resistant organisms and the failure to eradicate infection by a number of important pathogens has led to increased efforts to develop vaccines to prevent infectious diseases. However, the nature of the immune response to vaccination with a given antigen can be complex and unpredictable. An example is the galactose- and N-acetylgalactosamine-inhibitable lectin, a surface antigen of Entamoeba histolytica that has been identified as a major candidate in a vaccine to prevent amebiasis. Vaccination with the lectin can induce protective immunity to amebic liver abscess in some animals, but others of the same species exhibit exacerbations of disease after vaccination. To better understand this phenomenon, we used recombinant proteins corresponding to four distinct domains of the molecule, and synthetic peptides to localize both protective and exacerbative epitopes of the heavy chain subunit of the lectin. We show that protective immunity after vaccination can be correlated with the development of an antibody response to a region of 25 amino acid residues of the lectin, and have confirmed the importance of the antibody response to this region by passive immunization studies. In addition, we show that exacerbation of disease can be linked to the development of antibodies that bind to an NH2-terminal domain of the lectin. These findings are clinically relevant, as individuals who are colonized with E. histolytica but are resistant to invasive disease have a high prevalence of antibodies to the protective epitope(s), compared to individuals with a history of invasive amebiasis. These studies should enable us to develop an improved vaccine for amebiasis, and provide a model for the identification of protective and exacerbative epitopes of complex antigens.
Asunto(s)
Anticuerpos Antiprotozoarios/biosíntesis , Antígenos de Protozoos/inmunología , Entamoeba histolytica/inmunología , Entamebiasis/inmunología , Epítopos/inmunología , Lectinas/inmunología , Absceso Hepático Amebiano/inmunología , Vacunas Antiprotozoos , Vacunas Sintéticas , Secuencia de Aminoácidos , Animales , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/biosíntesis , Entamebiasis/prevención & control , Femenino , Gerbillinae , Humanos , Lectinas/biosíntesis , Lectinas/química , Absceso Hepático Amebiano/prevención & control , Glicoproteínas de Membrana/biosíntesis , Glicoproteínas de Membrana/química , Ratones , Ratones SCID , Datos de Secuencia Molecular , Proteínas Protozoarias/biosíntesis , Proteínas Protozoarias/química , Conejos , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/inmunologíaRESUMEN
A fragment F-CB3 which originates from the alpha-chain constituent of bovine fibrinogen could be liberated by CNBr cleavage and was purified by molecular sieve and ion-exchange chromatography. This fragment had a molecular weight of 36 000 and consisted of a single polypeptide chain which is folded into a loop by a single disulfide bridge. Further cleavage of F-CB3 by cyanide or by 2-nitro-5-thiocyanobenzoic acid gave rise to three fragments, CN1, CN2 and CN3, with molecular weights of 23 000, 8000 and 7000, respectively. With both reagents the yield of cleavage did not exceed 50%. Radioactive labeling and amino acid analysis of the purified fragments indicated the order CN1-CN2-CN3 in intact F-CB3. A shorter and apparently degraded form of F-CB3 was observed in some fibrinogen preparations. The shortening involved a region of about 3000 daltons at the N-terminal site of F-CB3, i.e. in fragment CN1.
Asunto(s)
Fibrinógeno , Aminoácidos/análisis , Animales , Sitios de Unión , Bovinos , Cianuros , Bromuro de Cianógeno , Disulfuros/análisis , Sustancias Macromoleculares , Peso Molecular , Fragmentos de Péptidos/análisis , Unión Proteica , Conformación ProteicaRESUMEN
Antibody raised against the N,N'-dicyclohexylcarbodiimide (DCCD)-binding polypeptide of Escherichia coli bound to the cytoplasmic surface of the cell membrane. A weak reaction was seen with everted vesicles of the thermophile PS3. Rat-liver mitochondrial membranes did not react with the antibody. Reaction of the isolated DCCD-binding polypeptide with the antibody was prevented by oxidation of methionine residues or cleavage of the polypeptide with cyanogen bromide. Modification of the arginine residues of the DCCD-binding polypeptide did not affect interaction with the antibody. Purified F1-ATPase of E. coli bound to the isolated DCCD-binding polypeptide as shown by solid-phase radioimmune assay. Binding involved the alpha and/or beta subunits of F1 and the arginine residues of the polar central region of the DCCD-binding polypeptide. Our results are consistent with a looped arrangement of the DCCD-binding polypeptide in the membrane in which the carboxyl- and amino-terminal regions of the molecule are at the periplasmic surface and the polar central region, interacting with F1, is at the cytoplasmic surface of the cell membrane.
Asunto(s)
Carbodiimidas/metabolismo , Proteínas Portadoras/metabolismo , Diciclohexilcarbodiimida/metabolismo , Escherichia coli/enzimología , ATPasas de Translocación de Protón/metabolismo , Secuencia de Aminoácidos , Complejo Antígeno-Anticuerpo , Membrana Celular/enzimología , Sueros Inmunes , CinéticaRESUMEN
The rapid determination of cysteinyl residues by Creighton's method [(1980) Nature 284, 487-489] led to the discovery of a discrepancy between protein and DNA sequence data in the alpha-subunit of the F1 ATPase from Escherichia coli [(1984) Arch. Biochem. Biophys. 229, 320-328]. We have isolated a cysteinyl-containing decapeptide from the alpha-subunit with a protein sequence (AGCAMGEYFR) which is only partially recognizable from DNA data. Re-sequencing of DNA in the region coding for the peptide has resulted in two corrections: insertion of a cytosine before position 715 and deletion of a thymine at position 731 of the uncA gene.
Asunto(s)
Cisteína/análisis , ADN Bacteriano , Escherichia coli/enzimología , ATPasas de Translocación de Protón/genética , Secuencia de Aminoácidos , Secuencia de Bases , ADN Recombinante/metabolismo , Focalización Isoeléctrica , Fragmentos de Péptidos/análisis , ATPasas de Translocación de Protón/análisis , ATPasas de Translocación de Protón/biosíntesis , TripsinaRESUMEN
To determine whether the presence of ungulates may inhibit transmission of the agent of Lyme disease (Borrelia burgdorferi) while promoting the abundance of its European vector tick (Ixodes ricinus), we compared the feeding density of subadult ticks on roe deer (Capreolus capreolus), red deer (Cervus elaphus), fallow deer (Dama dama), and wild sheep (Ovis ammon) near Berlin and in Brandenburg State, Germany. The prevalence of spirochetal infection in these ticks was compared with that in ticks swept from nearby vegetation. Spirochetes are present in nearly one-fifth of nonfed, questing nymphal and adult wood ticks in the region. Many ungulates in this intensely enzootic region fail to mount a detectable humoral response against the agent of Lyme disease, even when exposed to numerous infected ticks. During the height of the summer, each ungulate may support the feeding of hundreds of subadult ticks. Larvae feed lower on the bodies of hoofed game than do nymphs. Few ticks retain infection by the Lyme disease spirochete after feeding on hoofed game animals. We conclude that numerous I. ricinus ticks feed on ungulates, but that such host-contact fails to infect these ticks while eliminating pre-existing spirochetal infection.
Asunto(s)
Vectores Arácnidos/microbiología , Grupo Borrelia Burgdorferi/aislamiento & purificación , Ciervos , Enfermedad de Lyme/transmisión , Garrapatas/microbiología , Animales , Animales Salvajes , Anticuerpos Antibacterianos/sangre , Vectores Arácnidos/crecimiento & desarrollo , Berlin , Grupo Borrelia Burgdorferi/inmunología , Ciervos/parasitología , Reservorios de Enfermedades , Femenino , Alemania , Humanos , Larva/crecimiento & desarrollo , Enfermedad de Lyme/epidemiología , Enfermedad de Lyme/veterinaria , Masculino , Ninfa/crecimiento & desarrollo , Ninfa/microbiología , Ovinos , Enfermedades de las Ovejas/epidemiología , Infestaciones por Garrapatas/epidemiología , Infestaciones por Garrapatas/parasitología , Infestaciones por Garrapatas/veterinaria , Garrapatas/crecimiento & desarrolloRESUMEN
DNA of Borrelia burgdorferi was cleaved by the endonuclease EcoRI and ligated with the bacteriophage expression vector lambda gt11. After infection of the Escherichia coli strain Y1089, the plaques of recombinant phages were screened with a B. burgdorferi antiserum (human) for fusion proteins containing borrelia antigen.s A positive clone produced a hybrid protein (p200) of c. 200 Kda. The corresponding native borrelia protein (p97) was identified as having an Mr of 97 Kda. To localise protein p97 in the B. burgdorferi cell, immunoelectronmicroscopy and a Western blot of isolated flagella were used. Antibodies directed against proteins p200 and p97 recognised epitopes associated with the flagella.
Asunto(s)
Proteínas Bacterianas/aislamiento & purificación , Grupo Borrelia Burgdorferi/química , Flagelos/química , Animales , Anticuerpos Antibacterianos/inmunología , Antígenos Bacterianos/química , Antígenos Bacterianos/genética , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Western Blotting , Grupo Borrelia Burgdorferi/genética , Grupo Borrelia Burgdorferi/ultraestructura , Clonación Molecular , ADN Bacteriano/análisis , ADN Bacteriano/aislamiento & purificación , ADN Bacteriano/metabolismo , ADN Recombinante/análisis , ADN Recombinante/aislamiento & purificación , ADN Recombinante/metabolismo , Desoxirribonucleasa EcoRI , Electroforesis , Epítopos/análisis , Vectores Genéticos , Microscopía Inmunoelectrónica , Peso Molecular , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/aislamiento & purificación , Garrapatas/microbiologíaRESUMEN
The discovery of a V-type ATPase in the gram-negative bacterium Thermus thermophilus HB8 (YOKOYAMA et al., J. Biol. Chem. 265, 21946, 1990) was unexpected, since only eukaryotic endomembranes and archaea were thought to contain this enzyme complex, and horizontal gene transfer was suggested to explain the finding. We examined membrane-associated ATPases from representatives of several groups of the genus Thermus. The enzymes were extracted with chloroform and purified by ion exchange chromatography or native gel electrophoresis. One novel Islandic isolate, T. scotoductus SE-1, as well as strain T. filiformis from New Zealand, possessed F-ATPases, as judged by the typical five subunit composition of the F1-moiety, sensitivity to azide, insensitivity to nitrate and a strong crossreaction with antibodies against the F1-ATPase from E. coli. In addition, N-terminal amino acid sequencing of the beta subunit from T. scotoductus SE-1 confirmed its homology with beta subunits from known F-ATPases. In contrast, the same extraction procedure released a V-ATPase from the membranes of T. thermophilus HB27 and T. aquaticus YT-1. The related species Meiothermus (formerly Thermus) chliarophilus ALT-8 also possessed a V-ATPase. All V-ATPases examined in this study contained larger major subunits than F-ATPases, crossreacted with antiserum against subunit A of the V-ATPase from the archaeon Halobacterium saccharovorum, and the N-terminal sequences of their major subunits were homologous to those of other V-ATPases. Sequences of the 16S rRNA gene clearly placed T. scotoductus SE-1, along with other non-pigmented Thermus strains, as a distinct species close to T. aquaticus. Our results suggested that at least two members of the genus, T. scotoductus SE-1 and T. filiformis, contain an F-ATPase, whereas several others possess a V-ATPase. These data could indicate a greater diversity of the genus Thermus than was previously thought. Alternatively, the genus may consist of species where horizontal gene transfer has occurred and others, where it has not.
Asunto(s)
ATPasas de Translocación de Protón/metabolismo , Thermus thermophilus/enzimología , Thermus/enzimología , ATPasas de Translocación de Protón Vacuolares , Secuencia de Aminoácidos , Animales , ADN Ribosómico/análisis , Electroforesis en Gel de Poliacrilamida , Transferencia de Gen Horizontal , Filogenia , ATPasas de Translocación de Protón/química , ATPasas de Translocación de Protón/genética , ATPasas de Translocación de Protón/aislamiento & purificación , ARN Ribosómico 16S/genética , Conejos , Alineación de Secuencia , Análisis de Secuencia de ADN , Temperatura , Thermus/genética , Thermus/inmunología , Thermus/aislamiento & purificación , Thermus thermophilus/genética , Thermus thermophilus/aislamiento & purificaciónRESUMEN
Munchiwarin, a chalcone with the first 2,2, 6-tri-isoprenyl-cyclohex-5-ene-1,3-dione skeleton, was isolated from Crotalaria trifoliastrum and structurally identified by various NMR techniques in combination with X-ray crystallography.
RESUMEN
Viable extremely halophilic archaea (haloarchaea) have been isolated from million-year-old salt deposits around the world; however, an explanation of their supposed longevity remains a fundamental challenge. Recently small roundish particles in fluid inclusions of 22 000- to 34 000-year-old halite were identified as haloarchaea capable of proliferation (Schubert BA, Lowenstein TK, Timofeeff MN, Parker MA, 2010, Environmental Microbiology, 12, 440-454). Searching for a method to produce such particles in the laboratory, we exposed rod-shaped cells of Halobacterium species to reduced external water activity (a(w)). Gradual formation of spheres of about 0.4 µm diameter occurred in 4 M NaCl buffer of a(w) ≤ 0.75, but exposure to buffered 4 M LiCl (a(w) ≤ 0.73) split cells into spheres within seconds, with concomitant release of several proteins. From one rod, three or four spheres emerged, which re-grew to normal rods in nutrient media. Biochemical properties of rods and spheres were similar, except for a markedly reduced ATP content (about 50-fold) and an increased lag phase of spheres, as is known from dormant bacteria. The presence of viable particles of similar sizes in ancient fluid inclusions suggested that spheres might represent dormant states of haloarchaea. The easy production of spheres by lowering a(w) should facilitate their investigation and could help to understand the mechanisms for microbial survival over geological times.
Asunto(s)
Sedimentos Geológicos/microbiología , Halobacterium/efectos de los fármacos , Halobacterium/aislamiento & purificación , Halobacterium/citología , Halobacterium/crecimiento & desarrollo , Cloruro de Litio/química , Viabilidad Microbiana/efectos de los fármacos , Salinidad , Cloruro de Sodio/metabolismo , Agua/químicaRESUMEN
The antigenic properties of the cyanogen bromide peptide F-CB3 from bovine fibrinogen alpha-chain were studied in radioimmune assays with rabbit antibodies to fibrinogen or to peptide F-CB3. Both fibrinogen and peptide F-CB3 were indistinguishable in inhibition and dissociation tests. Modification of the single disulfide bridge in peptide F-CB3 either by reduction or by cleavage with cyanide was not accompanied by loss of serologic activity. Inhibition studies with three individual fragments obtained after cyanide cleavage (molecular weight range 7000 to 23000) indicated the presence of at least three distinct antigenic determinants in peptide F-CB3. After trypsin digestion of peptide F-CB3 still 75% of its maximal inhibiting capacity was retained. Lack of change in antigenic activity of peptide F-CB3 after release from the fibrinogen molecule by cyanogen bromide and upon further fragmentation is presumably due to the presence of several sequential antigenic determinants but the presence of conformational determinants could not be entirely excluded. Since no cross-reaction was observed between bovine and human peptides F-B3 one may expect considerable variation in their amino acid sequence.
Asunto(s)
Epítopos , Fibrinógeno/análisis , Animales , Reacciones Antígeno-Anticuerpo , Bovinos , Reacciones Cruzadas , Bromuro de Cianógeno , Fibrinógeno/metabolismo , Fragmentos de Péptidos/análisis , Conejos/inmunologíaRESUMEN
Invasive amoebiasis, a spectrum of diseases caused by the enteric protozoan parasite Entamoeba histolytica, constitutes a major health problem mainly in tropical and subtropical countries with poor sanitary conditions. The different forms of the disease are characterized by massive tissue lesions. Amoeba-induced tissue destruction requires an intimate contact between E. histolytica trophozoites and host cells. This contact is predominantly mediated by a galactose-inhibitable lectin located on the surface of the amoebae. Therefore, the lectin is considered a prime candidate for the development of a vaccine to prevent amoebiasis. This communication reports on recent developments in characterizing the structure and function of the E. histolytica surface lectin and its use as a subunit vaccine.
Asunto(s)
Entamoeba histolytica/inmunología , Entamebiasis/prevención & control , Lectinas , Glicoproteínas de Membrana/inmunología , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos , Vacunas Sintéticas , Animales , Entamoeba histolytica/fisiología , Entamebiasis/inmunología , Interacciones Huésped-Parásitos , Humanos , Sustancias Macromoleculares , Glicoproteínas de Membrana/química , Proteínas Protozoarias/química , Clima TropicalRESUMEN
Three different agglutination tests were developed for the detection of serum antibodies against Entamoeba histolytica. These tests are based on carboxylated polystyrene beads loaded either with a purified recombinant E. histolytica protein, designated recEh-P1, or a soluble fraction, or a membrane fraction (M-LA) both prepared from E. histolytica trophozoites. The three agglutination tests were compared with an enzyme-linked immunosorbent assay and a complement fixation test based on crude soluble E. histolytica antigens as well as with an enzyme-linked immunosorbent assay using recEh-P1 as antigen (P1-EIA). Serum samples from patients with invasive amebiasis (n = 30), or infectious diseases unrelated to E. histolytica (n = 57), as well as sera of apparently healthy individuals (n = 25) including some with noninvasive amebiasis (n = 5) were analysed by all six methods. Depending on the assay used, the results obtained, revealed sensitivities ranging from 83% to 100% and specificities ranging from 93% to 100%. P1-EIA and M-LA exhibited best results, both with a sensitivity of 100% and a specificity of 98%.
Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos , Entamoeba histolytica/inmunología , Entamebiasis/diagnóstico , Proteínas Protozoarias , Animales , Antígenos de Protozoos/inmunología , Pruebas de Fijación del Complemento , Entamoeba histolytica/química , Ensayo de Inmunoadsorción Enzimática , Reacciones Falso Positivas , Humanos , Pruebas de Fijación de Látex , Microesferas , Proteínas Protozoarias/inmunología , Proteínas Recombinantes/inmunología , Sensibilidad y EspecificidadRESUMEN
We have developed a modified ELISA for the detection of anti-Borrelia burgdorferi (Bb) antibodies based on a peroxidase enzyme labelled antigen (ELAT). Microtiter plates were coated with antigen of Bb. The immunoglobulins of the serum samples were bound to the antigen and specific antibodies were detected by an enzyme labelled antigen. The test principle facilitates the recognition of specific antibodies in different collectives of human and animal sera. We performed epidemiological studies with the ELAT on 231 sera from mothers in maternity wards (9.5% positive), 219 patient sera sent to the Bb routine diagnostics (15% positive) and 230 sera from forestry workers (21.3% positive). We further investigated sera from red deer from South Lower Saxony which remained 55% Bb-antibody positive; deer were 37% and fallow deer were 29% positive.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos , Grupo Borrelia Burgdorferi/inmunología , Enfermedad de Lyme/epidemiología , Animales , Especificidad de Anticuerpos , Reacciones Cruzadas , Ciervos , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina G/análisis , Enfermedad de Lyme/diagnóstico , Enfermedad de Lyme/veterinaria , Enfermedades Profesionales/diagnóstico , Enfermedades Profesionales/epidemiología , Valor Predictivo de las Pruebas , Embarazo , Prevalencia , ConejosRESUMEN
From the leaves of CHRYSANTHEMUM PARTHENIUM (L.) Bernh. (feverfew) two new chlorine-containing sesquiterpene lactones were isolated and structurally elucidated, mainly by NMR spectroscopy and X-ray analysis.
RESUMEN
The protozoan parasite Entamoeba histolytica causes extensive morbidity and mortality through intestinal infection and amebic liver abscess. Here we show that immunization of gerbils with a single keyhole limpet hemocyanin-coupled 25-mer peptide derived from the 170-kDa subunit of the E. histolytica galactose-binding adhesin is sufficient to confer substantial protection against experimentally induced amebic liver abscesses. Vaccination provided total protection in 5 of 15 immunized gerbils, and abscesses were significantly smaller (P < 0.01) in the remaining vaccinated animals. The degree of protection correlated with the titer of antibodies to the peptide, and results of passive transfer experiments performed with SCID mice were consistent with a role for antibodies in protection. In addition, parenteral or oral vaccination of gerbils with 13-amino-acid subfragments of the peptide N-terminally fused to the B subunit of cholera toxin also significantly inhibited liver abscess formation (P < 0.05). These data indicate that small peptides derived from the galactose-binding adhesin administered by the parenteral or oral route can provide protection against amebic liver abscess and should be considered as components of a subunit vaccine against invasive amoebiasis.
Asunto(s)
Lectinas/uso terapéutico , Absceso Hepático Amebiano/prevención & control , Glicoproteínas de Membrana/uso terapéutico , Fragmentos de Péptidos/uso terapéutico , Proteínas Protozoarias/uso terapéutico , Vacunas Antiprotozoos/uso terapéutico , Vacunación , Adyuvantes Inmunológicos , Administración Oral , Animales , Toxina del Cólera/genética , Toxina del Cólera/inmunología , Cisteína , Femenino , Gerbillinae , Hemocianinas , Inmunización Pasiva , Lectinas/genética , Lectinas/inmunología , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Ratones , Ratones SCID , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos/genética , Vacunas Antiprotozoos/inmunología , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes de Fusión/uso terapéuticoRESUMEN
A recombinantly expressed protein, recEh-P1, representing part of an immunodominant surface antigen of pathogenic Entamoeba histolytica, was used for serodiagnosis of invasive amebiasis. Expression was performed under the control of a T7-RNA promoter by using a modified procaryotic expression vector, designated pHisT7. This vector allowed high-yield expression of recEh-P1 fused to a stretch of sequence containing eight histidine residues, which facilitated purification by metal chelate affinity chromatography on Ni2+ columns under highly denatured conditions. Purified recEh-P1 was found to be water soluble after prolonged dialysis and was used as the antigen for the detection of antiamebic serum antibodies by immunoblotting and enzyme-linked immunosorbent assay. In both tests all sera of patients with invasive amebiasis reacted to recEh-P1 whereas none of those collected from healthy controls, including individuals with noninvasive amebiasis, or from patients suffering from bacterial or protozoan infections unrelated to E. histolytica did so.
Asunto(s)
Entamoeba histolytica/inmunología , Entamebiasis/diagnóstico , Proteínas Protozoarias/inmunología , Pruebas Serológicas/métodos , Secuencia de Aminoácidos , Animales , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/genética , Secuencia de Bases , ADN Protozoario/genética , Entamoeba histolytica/genética , Ensayo de Inmunoadsorción Enzimática , Humanos , Immunoblotting , Datos de Secuencia Molecular , Proteínas Protozoarias/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Sensibilidad y Especificidad , Pruebas Serológicas/estadística & datos numéricosRESUMEN
From the leaves of Allophyllus edulis var. edulis and Allophyllus edulis var. gracilis nine C-glycosylflavones have been isolated and identified as schaftoside (8), vicenin-2 (9), lucenin-2 (10), isovitexin 2"-O-rhamnoside (11), cerarvensin 2"-O-rhamnoside (12), vitexin 2"-O-rhamnoside (13), isoorientin 2"-O-rhamnoside (15), orientin 2"-O-rhamnoside (16) and saponarin (17). In addition, gallic acid (2), the phenol C-glycosides bergenin (3) and 11-O-galloylbergenin (4), three flavonol 3-O-rhamnosides and a new C-glycosylflavone identified as mollupentin 2"-O-rhamnoside (14) were obtained from the leaves of Allophyllus edulis var. edulis. Their structures were elucidated on the basis of chemical and spectral data. For the first time the C-glycosylflavones were found to have remarkable anti-hepatotoxic activities against CCl4 and galactosamine cytotoxicity in primary cultured rat hepatocytes. Structure-activity relationships are discussed.
Asunto(s)
Flavonoides/farmacología , Hígado/efectos de los fármacos , Plantas Medicinales , Animales , Células Cultivadas , Flavonoides/química , Flavonoides/aislamiento & purificación , Estructura Molecular , Plantas Medicinales/química , RatasRESUMEN
Investigations of immunoblots using Borrelia burgdorferi antigen demonstrated that a band, migrating faster than the bromophenol blue front in sodium dodecyl sulfate-gel electrophoresis, reacted strongly with sera containing anti-Borrelia burgdorferi antibodies preferentially of the IgG class. Extraction of this antigenic component and chemical analyses showed that the substance was composed mainly of fatty acids and carbohydrates. Typical structures of classical lipooolysaccharides such as 3-deoxy-D-manno-2-octulosonic acid, hydroxy fatty acids or lipid A could not be detected.
Asunto(s)
Antígenos Bacterianos/aislamiento & purificación , Grupo Borrelia Burgdorferi/inmunología , Anticuerpos Antibacterianos/inmunología , Antígenos Bacterianos/química , Cromatografía en Capa Delgada , Reacciones Cruzadas/inmunología , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Epítopos/inmunología , Humanos , Immunoblotting , Enfermedad de Lyme/inmunologíaRESUMEN
Two enzyme immuno assays based on a single recombinant Entamoeba histolytica antigen (P1-EIA) or soluble E. histolytica extract (SA-EIA) as well as a latex agglutination test using an E. histolytica membrane fraction (M-LA) were evaluated for its use to detect anti-amebic serum antibodies in patients from Durban, South Africa, an area endemic for amebiasis. In a previous study, all three test systems were found to be reliable in terms of sensitivity and specificity when applied to sera of European individuals. By analysing a total of 167 serum samples of patients from the Durban area, suffering from invasive amebiasis (n = 76) or miscellaneous diseases unrelated to E. histolytica infection (n = 91), the present study revealed sensitivity for the detection of anti-amebic antibodies of 97.4% for SA-EIA, 86.8% for P1-EIA and 96.1% for M-LA, respectively. Specificity was high for P1-EIA (96.7%) and M-LA (92.3%) but substantially lower for SA-EIA (62.6%). In addition, antibody responses to the recombinant P1 antigen were analysed in 16 patients with amebic liver abscess before and after anti-amebic treatment. The results indicated that most of the patients lost their specific antibody response within 7 month of follow up. Therefore, P1-EIA seems to be a valuable test for distinguishing between present and past E. histolytica infections.