Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
1.
Parasitology ; 138(1): 89-99, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20663253

RESUMO

Immunohistochemistry and immunogold labelling techniques were used to localize the EG95 vaccine antigen in Echinococcus granulosus oncospheres. In non-activated oncospheres, the cytoplasm of 2 pairs of bilateral cells exhibited specific positive labelling for the presence of EG95. No surface localization was seen in non-activated or recently activated oncospheres. Besides the staining of 2 pairs of bilateral cells, there was also a generalized distribution of specific staining for EG95 throughout the parenchyma of activated oncospheres. Immunogold labelling of non-activated oncosphere revealed specific reactivity for EG95 involving 2 pairs of bilateral cells and the ultrastructural characteristics of these cells were consistent with them being penetration gland cells. No other oncospheral structures stained specifically for the presence of EG95. The absence of surface location of EG95 in oncospheres suggests that the parasite may not be susceptible to vaccine-induced antibody and complement mediated attack until some post-oncospheral development has occurred. Further studies would be required to determine when the EG95 antigen associates with the parasite's surface, thus making them susceptible to immune attack.


Assuntos
Antígenos de Helmintos/imunologia , Equinococose/prevenção & controle , Echinococcus granulosus/citologia , Echinococcus granulosus/imunologia , Proteínas de Helminto/imunologia , Vacinas/imunologia , Animais , Antígenos de Helmintos/genética , Austrália , Equinococose/imunologia , Proteínas de Helminto/genética , Interações Hospedeiro-Parasita , Imuno-Histoquímica , Ovinos
2.
Parasite Immunol ; 32(9-10): 684-95, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20691020

RESUMO

Immunohistochemistry and immunofluorescence with confocal microscopy were used to localize the host-protective antigens of Taenia saginata (TSA9 and TSA18) and Taenia solium (TSOL16, TSOL18 and TSOL45). In nonactivated oncospheres, TSA9 and TSOL45 antigens were found primarily in the cytoplasm of the penetration gland type one (PG1) cell. A similar pattern of staining was seen for TSOL45 in oncospheres of T. solium that remained within the oncospheral membrane. In addition, there was less intense staining of TSA9 and TSOL45 in the quadri-nucleate penetration gland type 2 (PG2) cell. TSA18, TSOL16 and TSOL18 were predominantly found in the PG2 cell. In activated oncospheres that had escaped the oncospheral membrane, the antigens (other than TSA9) were seen both in the penetration gland cell locations and throughout the oncospheral parenchyma. Co-localization analyses revealed that only TSOL16 and TSOL18 antigens were co-localized in the PG2 cell of oncospheres that had not escaped the oncospheral membrane. However, in activated oncospheres that escaped the oncospheral membrane, all three antigens of T. solium were co-localized as they were present throughout the parenchyma. No positive staining was observed on the surface of nonactivated or recently activated oncospheres of T. saginata or T. solium.


Assuntos
Antígenos de Helmintos/imunologia , Taenia saginata/imunologia , Taenia solium/imunologia , Animais , Antígenos de Helmintos/análise , Citoplasma/imunologia , Imunofluorescência , Imuno-Histoquímica , Microscopia Confocal
3.
Gut ; 57(8): 1065-72, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18417532

RESUMO

BACKGROUND: Helicobacter pylori remains a global health hazard, and vaccination would be ideal for its control. Natural infection appears not to induce protective immunity. Thus, the feasibility of a vaccine for humans is doubtful. METHODS: In two prospective, randomised, double-blind, controlled studies (Paul Ehrlich Institute application nos 0802/02 and 1097/01), live vaccines against H pylori were tested in human volunteers seronegative for, and without evidence of, active H pylori infection. Volunteers (n = 58) were immunised orally with Salmonella enterica serovar Typhi Ty21a expressing H pylori urease or HP0231, or solely with Ty21a, and then challenged with 2x10(5) cagPAI(-) H pylori. Adverse events, infection, humoral, cellular and mucosal immune response were monitored. Gastric biopsies were taken before and after vaccination, and postchallenge. Infection was terminated with antibiotics. RESULTS: Vaccines were well tolerated. Challenge infection induced transient, mild to moderate dyspeptic symptoms, and histological and transcriptional changes in the mucosa known from chronic infection. Vaccines did not show satisfactory protection. However, 13 of 58 volunteers, 8 vaccinees and 5 controls, became breath test negative and either cleared H pylori (5/13) completely or reduced the H pylori burden (8/13). H pylori-specific T helper cells were detected in 9 of these 13 (69%), but only in 6 of 45 (13%) breath test-positive volunteers (p = 0.0002; Fisher exact test). T cells were either vaccine induced or pre-existing, depending on the volunteer. CONCLUSION: Challenge infection offers a controlled model for vaccine testing. Importantly, it revealed evidence for T cell-mediated immunity against H pylori infection in humans.


Assuntos
Vacinas Bacterianas/imunologia , Infecções por Helicobacter/prevenção & controle , Helicobacter pylori/imunologia , Salmonella typhi/imunologia , Subpopulações de Linfócitos T/imunologia , Adulto , Antígenos de Bactérias/imunologia , Testes Respiratórios , Linfócitos T CD4-Positivos/imunologia , Método Duplo-Cego , Gastrite/imunologia , Gastrite/microbiologia , Gastrite/patologia , Infecções por Helicobacter/complicações , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/patologia , Helicobacter pylori/enzimologia , Helicobacter pylori/isolamento & purificação , Humanos , Imunidade Celular , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Vacinas contra Salmonella/imunologia , Urease/imunologia , Vacinação/efeitos adversos , Vacinas Sintéticas/imunologia
4.
J Control Release ; 51(2-3): 269-80, 1998 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-9685925

RESUMO

Biodegradable implants made from cholesterol and lecithin (C:L) were used to deliver a recombinant antigen (recombinant Dichelobacter nodosus pili) and adjuvant (Quil A) to sheep. Implants (5.5- x 1.8-mm) were placed subcutaneously and compared to a conventional vaccination regime (2 injections, 4 weeks apart) for antibody responses and tissue compatibility. Release profiles of antigen and adjuvant were also studied in vitro and in vivo. The presence of Quil A in vaccine implants had a marked effect on the rate at which antigen was released with 29 and 44% being released in the first 24 h from implants containing pili alone and pili with Quil A, respectively. Sheep produced significant levels of antibody when immunized with implants, however the response was short-lived and of significantly lower intensity than the response stimulated by two injections of antigen with Quil A (P < 0.01). A second implant system was developed where implants coated with C:L to delay antigen release, were used in combination with uncoated implants to deliver a priming dose and boosting dose of antigen. Antibody titres stimulated by the 4 double implant system were equivalent to those stimulated by a conventional regime of two injections (four weeks apart) for the first six weeks of the experiment. After this time, antibody levels in the groups which received implants dropped significantly. In vitro studies revealed that some of the implant coatings had caused a delay in the release of antigen (the rate of release peaked at 72 h), however this was not long enough to provide a significant boosting effect. In all cases, implants were well tolerated by sheep and caused less local reaction than injected vaccines.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Vacinas Bacterianas/administração & dosagem , Infecções por Pseudomonas/veterinária , Doenças dos Ovinos/prevenção & controle , Ovinos/imunologia , Adjuvantes Imunológicos/metabolismo , Administração Cutânea , Animais , Anticorpos Antibacterianos/análise , Anticorpos Antibacterianos/imunologia , Vacinas Bacterianas/imunologia , Colesterol , Preparações de Ação Retardada , Implantes de Medicamento , Masculino , Fosfatidilcolinas , Pseudomonas aeruginosa/imunologia , Saponinas de Quilaia , Saponinas/administração & dosagem , Saponinas/metabolismo , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia
5.
Aust Vet J ; 74(6): 451-5, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9006863

RESUMO

OBJECTIVE: To compare the effects of two oil emulsion adjuvants (incomplete Freunds adjuvant and a proprietary oil adjuvant), DEAE-dextran, L-tyrosine particles and Quil A on the humoral immune responses of sheep immunised with recombinant pili of Dichelobacter Nodosus (strain A). PROCEDURE: Antibody titres were studied for up to 32 weeks and were measured by bacterial agglutination and ELISA. The relative avidity of antibodies for pili was determined and the incidence and severity of adverse reactions at the site of injection of vaccines were recorded. RESULTS: The oil emulsion adjuvants and Quil A were more effective than either DEAE-dextran or L-tyrosine at stimulating antibodies in sheep. The incidence and severity of adverse reactions was lower in sheep which received vaccines containing either Quil A or DEAE-dextran than in sheep which received vaccines containing oil emulsion adjuvants. L-tyrosine had no adverse effects. CONCLUSION: Quil A was as effective as oil adjuvants at stimulating high levels of antibodies against recombinant pili in sheep and had the significant advantage of being less irritant after subcutaneous injection.


Assuntos
Adjuvantes Imunológicos/farmacologia , Anticorpos Antibacterianos/biossíntese , Infecções por Bacteroides/veterinária , Bacteroides/imunologia , Fímbrias Bacterianas/imunologia , Doenças dos Ovinos/prevenção & controle , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/efeitos adversos , Animais , Aderência Bacteriana/fisiologia , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Infecções por Bacteroides/imunologia , Infecções por Bacteroides/prevenção & controle , DEAE-Dextrano/administração & dosagem , DEAE-Dextrano/efeitos adversos , DEAE-Dextrano/farmacologia , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Fímbrias Bacterianas/metabolismo , Fímbrias Bacterianas/fisiologia , Imunização/métodos , Imunização/veterinária , Incidência , Injeções Subcutâneas/veterinária , Queensland/epidemiologia , Saponinas de Quilaia , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Saponinas/administração & dosagem , Saponinas/efeitos adversos , Saponinas/farmacologia , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/imunologia , Tirosina/administração & dosagem , Tirosina/efeitos adversos , Tirosina/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA