RESUMO
A method to obtain polyvalent anti-Bitis and polyvalent-anti-Naja antibodies was developed by immunizing horses with B. arietans, B. nasicornis, B. rhinoceros, N. melanoleuca and N. mossambicacrude venoms. Antibody production was followed by the ELISA method during the immunization procedure. Once the desired anti-venom antibody titers were attained, horses were bled and theimmunoglobulins were separated from the sera by (NH4)2SO4 precipitation, cleaved with pepsin and filtered through a 30 kDa ultrafiltration membrane. F(ab´)2 fragments were further purified by Q-Fast Flow chromatography, concentrated by molecular ultrafiltration and sterilized by filtration through 0.22 m membranes. The resulting F(ab´)2 preparations were rich in intact L and in pieces of H IgG(T) chains, as demonstrated by electrophoresis and Western blot and exhibited high antibody titers, as assayed bythe ELISA method. In addition, the preparations possess a significant capacity to neutralize the lethalityof venoms, as estimated by ED50 determination in mouse assay and are free of toxic substances, pyrogen and bacterial or fungal contaminations.
Assuntos
Animais , Camundongos , Antivenenos/imunologia , Mordeduras de Serpentes , Venenos de Serpentes/classificação , ImunoterapiaRESUMO
Localized adherence (LA) of enteropathogenic Escherichia coli (EPEC) to epithelial cells results in attaching and effacing of the surface of these cells. LA depends on the gene bfpA, which codes for the BfpA protein. We found that EPEC-E. coli adherence factor (EAF)((+)), expressing BfpA, significantly reduced HeLa cell viability in comparison with EPEC-EAF((-)), as evaluated by the mitochondrial-dependent succinate dehydrogenase conversion of 3'-[4,5,-dimethylthiazol-2yl]2,5-diphenyltetrazolium bromide (MTT) to its formazan. Apoptosis accounts for a substantial loss of the cell viability, because the cells incubated with EPEC-EAF((+)) or with cloned BfpA (data not shown), but not with EPEC-EAF((-)), were positive for annexin-V binding, demonstrated chromatin condensation and nuclei fragmentation and exhibited a high level of caspase-3 activity. Because the blockade of bacterial cell-surface-associated BfpA by anti-BfpA immunoglobulin (Ig)Y antibody suppressed apoptotic death induced by EPEC-EAF((+)), BfpA may be the trigger for apoptosis. Both EPEC-EAF((+)) and EPEC-EAF((-)), as well as recombinant BfpA (data not shown), activated nuclear factor (NF)-kappaB in a similar manner as analysed by the electrophoretic mobility shift assay (EMSA). EMSA supershift analysis demonstrated the presence of p65/RelA in a DNA-binding complex. In contrast to DNA binding, NF-kappaB-dependent reporter gene transactivation was stimulated more strongly by EPEC B171/EAF((+)), suggesting a role for this virulence factor in the regulation of transcriptional activity of NF-kappaB. Because suppression of NF-kappaB activation by BAY11-7085, a NF-kappaB inhibitor, neither induced apoptosis by itself nor blocked apoptosis induction by EPEC-EAF((+)), it may be suggested that apoptosis is not regulated by the NF-kappaB pathway in HeLa cells.
Assuntos
Apoptose , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Proteínas de Fímbrias/metabolismo , Fímbrias Bacterianas/metabolismo , NF-kappa B/metabolismo , Escherichia coli/patogenicidade , Células HeLa , Humanos , Fatores de Virulência/metabolismoRESUMO
The morphology of the skin of the mutant hairless USP mouse was studied by histological, histochemical and immunohistochemical methods and compared to the skin of BALB/c mice. Representative sections of the dorsal skin from mice of both strains aged 18 days, and 1, 3, 6, and 8 months were studied. Sections stained with hematoxylin and eosin showed cystic formations called utricles and dermal cysts in the dermis that increased in size and number during growth. Skin thickness increased significantly at 8 months. Sections stained with picrosirius and examined with polarized light, displayed different colors, suggesting different thicknesses of dermal collagen fibers (probably types I and III). Weigert, Verhoeff and resorcin-fuchsin stains revealed fibers of the elastic system. The PAS and Alcian blue methods revealed neutral and acid glycosaminoglycans in the skin ground substance of both mouse strains. Immunohistochemical staining for fibronectin and laminin did not show differences between the mutant and BALB/c mice. Mast cells stained by the Gomori method and macrophages positive for HAM 56 antibodies were observed in both mouse strains. Except for the presence of enlarged cysts in the hairless strain, no qualitative differences were found during development of the skin of BALB/c and the mutant hairless mice.
Assuntos
Tecido Conjuntivo/patologia , Camundongos Pelados/genética , Pele/patologia , Fatores Etários , Animais , Tecido Conjuntivo/química , Feminino , Histocitoquímica/métodos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Mutantes , Pele/química , Coloração e Rotulagem/métodos , Fatores de Transcrição/genéticaRESUMO
The morphology of the skin of the mutant hairless USP mouse was studied by histological, histochemical and immunohistochemical methods and compared to the skin of BALB/c mice. Representative sections of the dorsal skin from mice of both strains aged 18 days, and 1, 3, 6, and 8 months were studied. Sections stained with hematoxylin and eosin showed cystic formations called utricles and dermal cysts in the dermis that increased in size and number during growth. Skin thickness increased significantly at 8 months. Sections stained with picrosirius and examined with polarized light, displayed different colors, suggesting different thicknesses of dermal collagen fibers (probably types I and III). Weigert, Verhoeff and resorcin-fuchsin stains revealed fibers of the elastic system. The PAS and Alcian blue methods revealed neutral and acid glycosaminoglycans in the skin ground substance of both mouse strains. Immunohistochemical staining for fibronectin and laminin did not show differences between the mutant and BALB/c mice. Mast cells stained by the Gomori method and macrophages positive for HAM 56 antibodies were observed in both mouse strains. Except for the presence of enlarged cysts in the hairless strain, no qualitative differences were found during development of the skin of BALB/c and the mutant hairless mice.
Assuntos
Animais , Masculino , Feminino , Camundongos , Tecido Conjuntivo/química , Camundongos Pelados/genética , Pele/patologia , Histocitoquímica/métodos , Imuno-Histoquímica , Camundongos Endogâmicos BALB C , Camundongos Mutantes , Pele/química , Coloração e Rotulagem/métodosRESUMO
This article describes the presence of two new forms of a thrombin-like enzyme, both with apparent molecular masses of 38 kDa, in Bothrops atrox venom. Both share the ability to cleave fibrinogen into fibrin and to digest casein. Both present identical Km on the substrate BApNA. Their N-terminal amino acid sequences are identical for 26 residues, sharing 80 percent homology with batroxobin and flavoxobin. Two groups of monoclonal antibodies (mAbs) raised against the purified enzyme forms recognized different epitopes of the putative corresponding enzymes present in B. atrox crude venom. On Western blotting analysis of B. atrox crude venom, mAbs 5DB2C8, 5AA10 and 5CF11, but not mAbs 6CC5 and 6AD2-G5, revealed two or more protein bands ranging from 25 to 38 kDa. By immunoprecipitation assays, the 6AD2-G5 mAb was able to precipitate protein bands of 36-38 kDa from B. atrox, B. leucurus, B. pradoi, B. moojeni, B. jararaca and B. neuwiedii crude venoms. Fibrinogen-clotting activity was inhibited when the same venom specimens were pre-incubated with mAb 6AD2-G5, except for B. jararaca and B. neuwiedii
Assuntos
Animais , Coagulação Sanguínea/efeitos dos fármacos , Bothrops , Venenos de Crotalídeos/enzimologia , Fibrinogênio/química , Trombina/isolamento & purificação , Sequência de Aminoácidos , Western Blotting , Venenos de Crotalídeos/farmacologia , Eletroforese em Gel de Poliacrilamida , Testes de Precipitina , Trombina/químicaRESUMO
This article describes the presence of two new forms of a thrombin-like enzyme, both with apparent molecular masses of 38 kDa, in Bothrops atrox venom. Both share the ability to cleave fibrinogen into fibrin and to digest casein. Both present identical K(m) on the substrate BApNA. Their N-terminal amino acid sequences are identical for 26 residues, sharing 80% homology with batroxobin and flavoxobin. Two groups of monoclonal antibodies (mAbs) raised against the purified enzyme forms recognized different epitopes of the putative corresponding enzymes present in B. atrox crude venom. On Western blotting analysis of B. atrox crude venom, mAbs 5DB2C8, 5AA10 and 5CF11, but not mAbs 6CC5 and 6AD2-G5, revealed two or more protein bands ranging from 25 to 38 kDa. By immunoprecipitation assays, the 6AD2-G5 mAb was able to precipitate protein bands of 36-38 kDa from B. atrox, B. leucurus, B. pradoi, B. moojeni, B. jararaca and B. neuwiedii crude venoms. Fibrinogen-clotting activity was inhibited when the same venom specimens were pre-incubated with mAb 6AD2-G5, except for B. jararaca and B. neuwiedii.
Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Bothrops , Venenos de Crotalídeos/enzimologia , Fibrinogênio/química , Trombina/isolamento & purificação , Animais , Western Blotting , Venenos de Crotalídeos/farmacologia , Eletroforese em Gel de Poliacrilamida , Isoenzimas/isolamento & purificação , Isoenzimas/farmacologia , Testes de Precipitina , Trombina/químicaRESUMO
Two BCG vaccine formulations of the Moreau strain, commercially manufactured for anti-tuberculosis vaccination, ID-BCG, or anti-cancer adjuvant therapy, Onco-BCG, were compared for immunogenic activity in vitro. The growth rates of both vaccines in murine macrophages were the same, however, Onco-BCG induced stronger and longer-lasting secretion of TNF-alpha, IL-6 and nitric oxide. Onco-vaccine was also more potent in inducing NF-kappaB p65/p50 DNA-binding activity whilst in ID-BCG-infected cells the activity was transient and then gradually replaced by the transcriptionally inactive homodimer p50/p50. Comparative analysis of mycobacterial antigens of the two vaccines demonstrated a difference in expression of the 19 kDa and 38 kDa lipoproteins detected only in Onco-BCG extracts. These results suggest that these molecules may be responsible for the vigorous activation of macrophages induced by the Onco-vaccine. The data obtained show that vaccines from the same BCG strain, when manufactured differently, can vary significantly in their antigen expression and, consequently, in their capacity for macrophage activation which could contribute to the difference in their immunopotentiating effects.
Assuntos
Antígenos de Bactérias/análise , Vacina BCG/imunologia , Macrófagos/imunologia , Macrófagos/microbiologia , NF-kappa B/metabolismo , Animais , Linhagem Celular , Interleucina-6/biossíntese , Ativação de Macrófagos , Camundongos , Mycobacterium bovis/imunologia , Óxido Nítrico/biossíntese , Fagocitose , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Viperine and crotaline snake venoms contain one or more hemorrhagic metalloproteases called hemorrhagins. The most potent hemorrhagins belong to the P-III class and have, in addition to the protease domain, disintegrin-like and cysteine-rich domains. Although proteolytic degradation of vascular endothelium basement membrane has been established to be the main factor responsible for hemorrhage, several studies reveal other factors that actually do facilitate this process. Recent evidence has shown that the nonprotease domains of the P-III class hemorrhagins are able to inhibit the platelet aggregation by blocking essential procoagulant integrins on platelets. In this study we report the identification of a hemorrhagin from Bothrops atrox venom. This enzyme, a P-III class metalloprotease, undergoes an apparent spontaneous degradation, releasing a proteic fragment containing the disintegrin-like/cysteine-rich domains. This fragment shows the capability to induce an edematogenic process, suggesting the existence of a still unknown nonenzymatic mechanism of vascular permeability increase.
Assuntos
Venenos de Crotalídeos , Desintegrinas/toxicidade , Edema/induzido quimicamente , Endopeptidases/toxicidade , Inibidores da Agregação Plaquetária/toxicidade , Sequência de Aminoácidos , Animais , Bothrops , Cisteína , Endopeptidases/química , Endopeptidases/genética , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência MolecularRESUMO
Adult white leghorn hens hyperimmunised with Brazilian snake venoms of the genus Bothrops and/or Crotalus produced antibodies capable of recognising, combining with and neutralising the toxic and lethal components of the venoms. The antibodies were first detected by an enzyme-linked immunosorbent assay two weeks after starting the immunisation schedule, reached the highest titres by the third week and remained high for at least 24 weeks. These antibodies are transferred to the egg yolk from which they were isolated as enriched IgY preparations by a combination of methods using positive and negative precipitation with sodium sulphate and/or caprylic acid. The yolk-derived IgY preparations contained antibodies which blocked the phospholipase A2-dependent haemolytic activity of both venoms and the haemorrhagic activity of Bothrops venom, and neutralised the toxic lethal activities of the venoms with good efficacy. The median effective dose (ED50) of the IgY anti-Bothrops venom was 592.5 microliters/2LD50 and, 1.0 ml neutralised 0.0675 mg of venom. The ED50 of the IgY anti-Crotalus venom was 457.5 microliters/3LD50 and 1.0 ml neutralised 0.075 mg of venom.
Assuntos
Antivenenos/imunologia , Bothrops , Venenos de Crotalídeos/imunologia , Venenos de Crotalídeos/toxicidade , Crotalus , Venenos de Serpentes/imunologia , Animais , Formação de Anticorpos , Antivenenos/biossíntese , Galinhas/imunologia , Gema de Ovo , Ensaio de Imunoadsorção Enzimática , Imunoglobulinas/análise , Imunoglobulinas/imunologiaRESUMO
Bothrops atrox snake venoms from two different Amazon regions, i.e., Manaus, AM (3 degrees 0.6'40"S; 60 degrees 0.1'6.0"W) and Tucurui, PA (3 degrees 0.42'30"S; 49 degrees 0.41'45"W), were analyzed with respect to the thrombin-like activity component by elution profile on gel-filtration and reverse phase HPLC chromatography, electrophoretic mobility on SDS-PAGE, and enzymatic activity on fibrinogen. Despite some individual discrepancies among venom specimens, the thrombin-like activity present in the Manaus pool was eluted earlier compared with the Tucurui pool but its enzymatic specific activity on thrombin was lower (s.a. = 6.0) than that observed in the Tucurui pool (s.a. = 134.0). However, the electrophoretic mobilities of the pools were similar, with most protein bands being concentrated around three main regions, i.e., protein bands with an apparent mr of 100 kDa, of 38-37 kDa and 30 kDa. However, no significant differences were observed in amidolytic activity on the synthetic substrate Tos-Gly-Pro-Arg-pNa, and there was no correlation between thrombin-like and amidolytic activities. A 32 kDa protein endowed with thrombin-like activity and specific activity of 2444 recognized and neutralized by horse anti-B. atrox antivenom, was purified by the successive use of gel filtration, electrofocusing and reverse phase HPLC.