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1.
Nat Commun ; 10(1): 2641, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201325

RESUMO

Epsilon toxin (Etx), a potent pore forming toxin (PFT) produced by Clostridium perfringens, is responsible for the pathogenesis of enterotoxaemia of ruminants and has been suggested to play a role in multiple sclerosis in humans. Etx is a member of the aerolysin family of ß-PFTs (aß-PFTs). While the Etx soluble monomer structure was solved in 2004, Etx pore structure has remained elusive due to the difficulty of isolating the pore complex. Here we show the cryo-electron microscopy structure of Etx pore assembled on the membrane of susceptible cells. The pore structure explains important mutant phenotypes and suggests that the double ß-barrel, a common feature of the aß-PFTs, may be an important structural element in driving efficient pore formation. These insights provide the framework for the development of novel therapeutics to prevent human and animal infections, and are relevant for nano-biotechnology applications.


Assuntos
Toxinas Bacterianas/química , Clostridium perfringens/ultraestrutura , Animais , Toxinas Bacterianas/genética , Toxinas Bacterianas/isolamento & purificação , Toxinas Bacterianas/metabolismo , Biotecnologia/métodos , Linhagem Celular , Infecções por Clostridium/microbiologia , Infecções por Clostridium/prevenção & controle , Clostridium perfringens/genética , Clostridium perfringens/metabolismo , Clostridium perfringens/patogenicidade , Microscopia Crioeletrônica , Cães , Enterotoxemia/microbiologia , Enterotoxemia/prevenção & controle , Modelos Moleculares , Mutagênese Sítio-Dirigida , Nanotecnologia/métodos , Conformação Proteica em Folha beta/genética , Multimerização Proteica/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo
2.
Onderstepoort J Vet Res ; 84(1): e1-e7, 2017 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-28470084

RESUMO

Enterotoxaemia (pulpy kidney) is a common bacterial disease of sheep caused by Clostridium perfringens type D epsilon toxin. It has mortality rates of up to 30% in non-vaccinated animals. Current vaccines from whole cell cultures are expensive to manufacture and can induce local inflammatory responses in sheep. They usually have reduced immunogenicity because of the difficulty of standardising the inactivation step in vaccine manufacturing. In the current study, we evaluated the safety and potency of a recombinant plant-made epsilon toxoid protein (r-Etox) as an affordable and safer alternative vaccine for developing countries. Results of injection site reactions, rectal temperature and toxin neutralisation test in single and prime- boost inoculations of mice, guinea pigs and sheep suggest that the product is not toxic to animals and could protect sheep against enterotoxaemia.


Assuntos
Toxinas Bacterianas/imunologia , Clostridium perfringens/imunologia , Enterotoxemia/prevenção & controle , Doenças dos Ovinos/prevenção & controle , Vacinação/veterinária , Animais , Vacinas Bacterianas , Cobaias , Camundongos , Ovinos , Toxoides
3.
Sci Rep ; 6: 24162, 2016 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-27048879

RESUMO

Epsilon toxin (ETX) is produced by toxinotypes B and D of Clostridium perfringens. It can induce lethal enterotoxemia in domestic animals, mainly in sheep, goats and cattle, causing serious economic losses to global animal husbandry. In this study, a novel and stable epsilon toxin mutant rETX(Y196E)-C, obtained by substituting the 196th tyrosine (Y196) with glutamic acid (E) and introducing of 23 amino acids long C-terminal peptide, was determined as a promising recombinant vaccine candidate against enterotoxemia. After the third vaccination, the antibody titers against recombinant wild type (rETX) could reach 1:10(5) in each immunized group, and the mice were completely protected from 100 × LD50 (50% lethal dose) of rETX challenge. The mice in 15 µg subcutaneously immunized group fully survived at the dose of 500 × LD50 of rETX challenge and 80% of mice survived at 180 µg (1000 × LD50) of rETX administration. In vitro, immune sera from 15 µg subcutaneously immunized group could completely protect MDCK cells from 16 × CT50 (50% lethal dose of cells) of rETX challenge and protect against 10 × LD50 dose (1.8 µg) of rETX challenge in mice. These data suggest that recombinant protein rETX(Y196E)-C is a potential vaccine candidate for future applied researches.


Assuntos
Toxinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Clostridium perfringens , Enterotoxemia/prevenção & controle , Animais , Encéfalo/metabolismo , Linhagem Celular Tumoral , Cães , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunização , Rim/metabolismo , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Mutantes/imunologia , Testes de Neutralização , Peptídeos/imunologia , Domínios Proteicos , Proteínas Recombinantes/imunologia , Temperatura Ambiente , Vacinas Sintéticas/imunologia
4.
Microbiol Immunol ; 58(11): 621-7, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25197030

RESUMO

Cattle enterotoxemia caused by Clostridium perfringens toxins is a noncontagious, sporadic, and fatal disease characterized by sudden death. Strategies for controlling and preventing cattle enterotoxemia are based on systematic vaccination of herds with toxoids. Because the process of producing conventional clostridial vaccines is dangerous, expensive, and time-consuming, the prospect of recombinant toxoid vaccines against diseases caused by C. perfringens toxins is promising. In this study, nontoxic recombinant toxoids derived from α-, ß- and ε-toxins of C. perfringens, namely, rCPA247-370 , rCPB and rEtxHP, respectively, were expressed in Escherichia coli. High levels of specific IgG antibodies and neutralizing antibodies against the toxins were detected in sera from calves vaccinated with either a single recombinant toxoid or a mixed cocktail of all three recombinant toxoids, indicating the potential of these recombinant toxoids to provide calves with protective immunity against enterotoxemia caused by C. perfringens.


Assuntos
Doenças dos Bovinos/prevenção & controle , Infecções por Clostridium/veterinária , Clostridium perfringens/imunologia , Enterotoxemia/prevenção & controle , Toxoides/administração & dosagem , Toxoides/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Neutralizantes/sangue , Antitoxinas/sangue , Bovinos , Infecções por Clostridium/prevenção & controle , Clostridium perfringens/genética , Escherichia coli/genética , Feminino , Expressão Gênica , Imunoglobulina G/sangue , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Toxoides/genética , Toxoides/isolamento & purificação
5.
J S Afr Vet Assoc ; 85(1): 977, 2014 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-24832497

RESUMO

Enterotoxaemia, an economically important disease of sheep, goats and calves, is caused by systemic effects of the epsilon toxin produced by the anaerobic bacterium Clostridium perfringens type D. The only practical means of controlling the occurrence of enterotoxaemia is to immunise animals by vaccination. The vaccine is prepared by deriving a toxoid from the bacterial culture filtrate and the potency of the vaccine is tested with the in vivo mouse neutralisation test (MNT). Due to ethical, economic and technical reasons, alternative in vitro assays are needed. In this study an indirect cytometric bead immunoassay (I-CBA) was developed for use in vaccine potency testing and the results were compared with those obtained using an indirect enzyme-linked immunosorbent assay (I-ELISA) and the MNT. Sera were collected from guinea pigs immunised with three different production batches of enterotoxaemia vaccine and the levels of anti-epsilon toxin antibodies were determined. Although the intra- and inter-assay variability was satisfactory, epsilon antitoxin levels determined by both the I-ELISA and indirect cytometric bead immunoassay (I-CBA) tests were higher than those of the MNT assay. In contrast to the MNT, all of the serum samples were identified as having antitoxin levels above the required minimum (not less than 5 U/mL). These results indicate that the respective in vitro tests in their current formats are not yet suitable alternatives to the in vivo MNT. The growing demand for a more humane, cost-effective and efficient method for testing the potency of enterotoxaemia vaccines, however, provides a strong impetus for further optimisation and standardisation of the I-CBA assay but further analytical research is required.


Assuntos
Vacinas Bacterianas/imunologia , Clostridium perfringens/imunologia , Enterotoxemia/prevenção & controle , Citometria de Fluxo/veterinária , Imunoensaio/veterinária , Animais , Toxinas Bacterianas/imunologia , Citometria de Fluxo/métodos , Cobaias , Imunoensaio/métodos , Camundongos , Testes de Neutralização , Distribuição Aleatória
6.
Vaccine ; 32(23): 2682-7, 2014 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-24709588

RESUMO

Epsilon toxin (Etx) is a ß-pore-forming toxin produced by Clostridium perfringens toxinotypes B and D and plays a key role in the pathogenesis of enterotoxemia, a severe, often fatal disease of ruminants that causes significant economic losses to the farming industry worldwide. This study aimed to determine the potential of a site-directed mutant of Etx (Y30A-Y196A) to be exploited as a recombinant vaccine against enterotoxemia. Replacement of Y30 and Y196 with alanine generated a stable variant of Etx with significantly reduced cell binding and cytotoxic activities in MDCK.2 cells relative to wild type toxin (>430-fold increase in CT50) and Y30A-Y196A was inactive in mice after intraperitoneal administration of trypsin activated toxin at 1000× the expected LD50 dose of trypsin activated wild type toxin. Moreover, polyclonal antibody raised in rabbits against Y30A-Y196A provided protection against wild type toxin in an in vitro neutralisation assay. These data suggest that Y30A-Y196A mutant could form the basis of an improved recombinant vaccine against enterotoxemia.


Assuntos
Toxinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Enterotoxemia/prevenção & controle , Animais , Cães , Feminino , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Mutagênese Sítio-Dirigida , Testes de Neutralização , Estrutura Terciária de Proteína , Coelhos , Proteínas Recombinantes/imunologia , Vacinas Sintéticas/imunologia
7.
Vet Immunol Immunopathol ; 138(1-2): 129-33, 2010 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-20709411

RESUMO

The aim of the present study was to evaluate and standardize the ToBI test in vitro as a substitute for the serum neutralization test in mice for quality control of clostridial vaccines. The ToBI test in vitro was used to evaluate 40 serum samples of known antibody content, obtained from rabbits immunized against clostridiosis with experimental vaccine. The correlation between epsilon antitoxin titers in rabbit sera, determined by the ToBI test and serum neutralization in mice, ranged from 0.222% to 0.452% in polyvalent vaccines and from 0.154% to 0.387% in monovalent vaccines. Interplate coefficients of variation were not significant, reaching 0.350% in polyvalent vaccines and 0.400% in monovalent vaccines, indicating high homogeneity. In conclusion, the ToBI test in vitro is suitable for assessing the potency of clostridial vaccines and may be used as an alternative method able to replace current in vivo tests.


Assuntos
Antitoxinas/sangue , Toxinas Bacterianas/antagonistas & inibidores , Clostridium perfringens/imunologia , Testes Sorológicos/métodos , Animais , Toxinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Vacinas Bacterianas/normas , Infecções por Clostridium/diagnóstico , Infecções por Clostridium/imunologia , Infecções por Clostridium/prevenção & controle , Enterotoxemia/diagnóstico , Enterotoxemia/imunologia , Enterotoxemia/prevenção & controle , Imunização , Técnicas In Vitro , Camundongos , Testes de Neutralização/métodos , Controle de Qualidade , Coelhos , Testes Sorológicos/normas
8.
Vet Rec ; 167(1): 13-22, 2010 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-20605954

RESUMO

Cattle enterotoxaemia is one of numerous pathologies caused by Clostridium perfringens. These anaerobic Gram-positive bacteria are naturally present in the intestinal flora of mammals, but their uncontrolled multiplication under certain conditions results in the overproduction of toxins in the intestinal tract. Major clinical signs are induced by the systemic spread of these toxins in the blood and tissues. Enterotoxaemia may be acute or peracute, and sudden death is often reported in rapidly growing, apparently healthy cattle. Enterotoxaemia can be prevented only with better understanding of its risk factors and pathogenesis. This paper provides an up-to-date overview of knowledge concerning the aetiology of the syndrome, its epidemiological context, pathogenesis, clinical signs and lesions, the diagnostic procedures and prophylactic tools, with specific attention to field aspects that are directly relevant to practitioners and clinical researchers.


Assuntos
Doenças dos Bovinos/microbiologia , Infecções por Clostridium/veterinária , Clostridium perfringens , Enterotoxemia/microbiologia , Animais , Antibioticoprofilaxia/veterinária , Bovinos , Doenças dos Bovinos/diagnóstico , Doenças dos Bovinos/prevenção & controle , Infecções por Clostridium/diagnóstico , Infecções por Clostridium/prevenção & controle , Clostridium perfringens/classificação , Clostridium perfringens/crescimento & desenvolvimento , Clostridium perfringens/patogenicidade , Contagem de Colônia Microbiana/veterinária , Enterotoxemia/diagnóstico , Enterotoxemia/prevenção & controle , Mucosa Intestinal/microbiologia , Fatores de Risco
9.
Vaccine ; 28(38): 6125-7, 2010 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-20670910

RESUMO

Enterotoxemia, a disease that affects domestic ruminants, is caused mainly by the epsilon toxin from Clostridium perfringens type D. Its eradication is virtually impossible, control and prophylaxis are based on systematic vaccination of herds with epsilon toxoids that are efficient in inducing protective antibody production. The use of recombinant toxins is one of the most promising of these strategies. This work evaluates the potency of a Cl. perfringens type D epsilon toxoid expressed by Escherichia coli administered to goats, sheep, and cattle. The etx gene was cloned into the pET-11a plasmid of E. coli strain BL21 to produce the recombinant toxin. Rabbits (n=8), goats, sheep, and cattle (n=5 for each species) were immunized with 0.2mg of the insoluble recombinant protein fraction to evaluate vaccine potency of the epsilon toxoid studied. Antibody titers were 40, 14.3, 26, and 13.1 IU/mL in the rabbit, goat, sheep, and cattle serum pools, respectively. The epsilon toxoid produced and tested in this work is adequate for immunization of ruminants against enterotoxemia.


Assuntos
Toxinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Enterotoxemia/prevenção & controle , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Neutralizantes/sangue , Toxinas Bacterianas/genética , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/prevenção & controle , Enterotoxemia/imunologia , Escherichia coli/genética , Escherichia coli/metabolismo , Doenças das Cabras/imunologia , Doenças das Cabras/prevenção & controle , Cabras , Coelhos , Proteínas Recombinantes/imunologia , Ovinos , Doenças dos Ovinos/imunologia , Doenças dos Ovinos/prevenção & controle
10.
Clin Vaccine Immunol ; 17(6): 1013-6, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20427629

RESUMO

Sheep pox and enterotoxemia are important diseases of sheep, and these diseases cause severe economic losses to sheep farmers. The present study was undertaken to evaluate the potential of formaldehyde-inactivated recombinant epsilon toxin as a vaccine candidate. The potency of the recombinant epsilon toxoid with aluminum hydroxide as an adjuvant in sheep was determined. Vaccinated sheep were protected against enterotoxemia, with potency values of >5 IU being protective. Further, the use of this construct in a combination vaccine against sheep pox resulted in the sheep being protected against both sheep pox and enterotoxemia.


Assuntos
Toxinas Bacterianas/imunologia , Capripoxvirus/imunologia , Enterotoxemia/prevenção & controle , Infecções por Poxviridae/veterinária , Doenças dos Ovinos/prevenção & controle , Toxoides/imunologia , Vacinas Sintéticas/imunologia , Animais , Toxinas Bacterianas/genética , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/imunologia , Enterotoxemia/imunologia , Formaldeído/farmacologia , Infecções por Poxviridae/imunologia , Infecções por Poxviridae/prevenção & controle , Infecções por Poxviridae/virologia , Ovinos , Doenças dos Ovinos/imunologia , Doenças dos Ovinos/microbiologia , Doenças dos Ovinos/virologia , Vacinas Atenuadas/imunologia , Vacinas Combinadas , Vacinas Sintéticas/administração & dosagem , Vacinas Virais/administração & dosagem , Vacinas Virais/imunologia
11.
J Infect Dev Ctries ; 3(8): 624-7, 2009 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-19801806

RESUMO

BACKGROUND: Enterotoxaemia produced by Clostridium perfringens A, C and D is an important cause of mortality in young llamas. There is no data on antibody responses following vaccination with epsilon toxin. METHODOLOGY: Twenty-six L. glama crias were divided into four groups which were vaccinated with a commercial vaccine (Mancha Gangrena Enterotoxemia, Instituto Rosembusch Sociedad Anónima, Argentina) on days 0, 21 and 42 or left as unvaccinated controls. An indirect ELISA was compared with the mouse neutralization test (MNT) for measuring titers to C. perfringens type D epsilon toxin and used to determine titers in sera taken before vaccination and 16, 28, 49, 59, and 93 days later. RESULTS: The ELISA gave comparable results to the MNT and showed animals vaccinated once failed to develop raised titers. A week following a second vaccination, mean antibody titers rose significantly (P < 0.05) and 7/12 animals developed high titers which were present in only one animal at the end of the study (day 93). A third vaccination resulted in a decrease in mean antibody titers a week later. CONCLUSIONS: Llamas develop antibodies to Clostridium perfringens type D epsilon toxin after two vaccinations at a 21-day interval. Further studies are indicated to determine if these inoculations protect against enterotoxemia and the most appropriate vaccination schedule.


Assuntos
Toxinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Camelídeos Americanos/imunologia , Clostridium perfringens/imunologia , Enterotoxemia/prevenção & controle , Vacinação/veterinária , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Toxinas Bacterianas/administração & dosagem , Vacinas Bacterianas/administração & dosagem , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Injeções Subcutâneas , Camundongos , Testes de Neutralização
12.
Arq. bras. med. vet. zootec ; 58(5): 952-954, out. 2006.
Artigo em Português | LILACS | ID: lil-441549

RESUMO

This report describes a case of bovine enterotoxaemia in Morro da Garça, Minas Gerais, Brazil. Clostridium perfringens type D was isolated in pure culture and was characterized by biochemical reactions and PCR. By the mouse neutralization test, the presence of epsilon toxin from intestinal content was detected.


Assuntos
Animais , Feminino , Bovinos , Clostridium perfringens/isolamento & purificação , Enterotoxemia/diagnóstico , Enterotoxemia/prevenção & controle
13.
Pesqui. vet. bras ; 26(1): 51-54, jan.-mar. 2006. tab, graf
Artigo em Inglês | LILACS | ID: lil-423931

RESUMO

Foi avaliada a resposta sorológica de vacina experimental contra a enterotoxemia em quatro grupos de caprinos. O Grupo 1 recebeu colostro de vacas não vacinadas e nenhuma dose de vacina. Os Grupos 2, 3 e 4 receberam colostro de vacas vacinadas, e uma dose de vacina aos 80 dias de idade nos Grupos 3 e 4. O Grupo 4 recebeu a segunda dose de vacina aos 120 dias de idade. Os níveis de anticorpos séricos foram avaliados pelo ELISA nas vacas antes e depois do parto e nos caprinos aos 3, 80, 120 e 160 dias de idade. Não houve diferença significativa nos níveis de anticorpos séricos das vacas vacinadas e não vacinadas, assim como entre os quatro grupos de caprinos avaliados aos três dias de vida. Os Grupos 3 e 4 apresentaram títulos médios de anticorpos de 0,6 UI/mL e 1,1 UI/mL, respectivamente, aos 40 dias após a primovacinação. A resposta vacinal do grupo 4, 40 dias após o reforço, foi de 1,8 UI/mL, superior ao Grupo 3 que foi de 0,2 UI/mL. Portanto, no esquema proposto, o uso de colostro não induziu a imunização passiva dos cabritos. No entanto, a primovacinação e reforço 40 dias após desencadearam níveis de anticorpos considerados satisfatórios.


Assuntos
Colostro , Clostridium perfringens/isolamento & purificação , Enterotoxemia/diagnóstico , Enterotoxemia/prevenção & controle , Cabras , Vacinas , Ensaio de Imunoadsorção Enzimática
15.
Vet Clin North Am Food Anim Pract ; 20(2): 379-91, vii-viii, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15203231

RESUMO

Clostridial infections are found worldwide in almost all species of animals and may involve a variety of body systems and present with a diversity of clinical signs. Most damage done through clostridial infections is due to the action of toxins released from the bacteria.Thus, disease caused by Clostridium spp should more correctly be called intoxication. Two prominent clostridial infections are associated with neurologic signs: Clostridium botulinum and C tetani. In both infections, the mechanism that is responsible for causing the problem is similar, despite the remarkable difference in clinical presentation. In addition, neurologic signs are described with C perfringens types C and D but are not the dominant feature of these diseases.


Assuntos
Botulismo/veterinária , Enterotoxemia/diagnóstico , Ruminantes , Tétano/veterinária , Animais , Botulismo/diagnóstico , Botulismo/prevenção & controle , Enterotoxemia/prevenção & controle , Tétano/diagnóstico , Tétano/prevenção & controle
16.
ALTEX ; 21 Suppl 3: 65-9, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15057410

RESUMO

Clostridium (C.) perfringens is a Gram-positive anaerobic spore-forming bacterium. Disease caused by C. perfringens infection is called enterotoxaemia. C. perfringens strains are classified on the basis of the lethal exotoxins formed by the bacteria. Epsilon toxin is one of the major lethal toxins and is formed by C. perfringens types B and D. C. perfringens is an ubiquitous bacterium. Infection occurs via food, water, animal litter or soil. Affected animals include mainly sheep, pigs and cattle. C. perfringens infection manifests as pulpy kidney disease and diarrhoea in suckling lambs. Enterotoxaemia development is peracute in most cases. Animals die suddenly while grazing on the pasture, without any prior signs of disease. Therefore, treatment is possible only in very rare cases. Suitable immunoprophylactic measures are the treatment of choice to combat the disease: Vaccines and immunosera have therefore been used extensively for a long time. The requirements for quality, efficacy and safety testing of the inactivated vaccines are laid down in the Ph. Eur. in the monograph: Clostridium perfringens vaccines for veterinary use. After a marketing authorisation is attained, the product batches must be tested in laboratory animal models for their potency against all vaccine components (Pharmeuropa, 1997). For potency testing (batch control) of C. perfringens types B and D, the induction of specific antibodies against epsilon toxin in rabbits must be verified. For this purpose, 10 rabbits are immunised twice with the product to be tested. Their blood is taken 14 days after the last immunisation and the serum is pooled. The pooled serum is then tested for its protective effect. This is done by means of the toxin neutralisation test in mice (optionally also in guinea pigs) in comparison with an international reference serum. The evaluation criterion is the death rate of the mice in the test and reference groups after administration of lethal doses of epsilon toxin. The exact efficacy of the test serum is given in International Units (IU). The tested serum must show a minimum content of 5 IU. This in vivo method requires a very high number of experimental animals. Approximately 400 mice (or 50 guinea pigs) are used per vaccine batch. The monograph for C. perfringens vaccines, which has recently been revised, expressly indicates that a validated serological method may be used for batch testing. In addition, a reference serum known as clostridium multicomponent serum has been available since 2000. The objective is to test vaccine batches against this reference and by means of a competitive ELISA developed in the precursor project, using a monoclonal antibody for direct determination of specific antitoxins in rabbit sera. This ELISA method was subjected to an international validation to verify whether the protocol and the precision can be transferred within and between the participating laboratories.


Assuntos
Toxinas Bacterianas/imunologia , Vacinas Bacterianas/normas , Clostridium perfringens/imunologia , Enterotoxemia/prevenção & controle , Ensaio de Imunoadsorção Enzimática/métodos , Testes de Neutralização/métodos , Alternativas aos Testes com Animais , Animais , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/sangue , Anticorpos Monoclonais/sangue , Anticorpos Monoclonais/imunologia , Enterotoxemia/sangue , Cobaias , Camundongos , Controle de Qualidade , Coelhos , Reprodutibilidade dos Testes , Segurança , Sensibilidade e Especificidade , Resultado do Tratamento , Vacinas de Produtos Inativados/normas
17.
Berl Munch Tierarztl Wochenschr ; 113(1): 9-13, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10684178

RESUMO

In order to study the prophylactic and metaphylactic effect of antomicrobial growth promoters and ionophorous anticoccidials on the incidence of Cl. perfringens enterotoxaemia in chickens, experimental attempts were performed with 675 chickens in 27 trials. The birds were intraduodenally infected with Cl. perfringens type A (ATCC 3624). The following antimicrobial growth promoters and ionophore anticoccidials were used either on their own or in combination: avilamycin, narasin, monensin and tylosin. While infected and non-medicated trials showed an average incubation period of 1 week, clinical symptoms occurred 2-4 days later in infected and medicated birds. Avilamycin medicated birds had the longest incubation period. In the infected and non-medicated trials, a mortality rate of 16%-36% was noted within 3 weeks post infection. The avilamycin trials showed a mortality rate of 0-8% (0-2 birds died) and the narasin and monensin a mortality rate of 0-8%, respectively. In the combination groups (monensin + avilamycin or narasin + avilamycin), the mortality rate ranged from 0 to 4%. Tylosin showed a very good metaphylactic/therapeutic effect against Cl. perfringens enterotoxaemia. Following infection, medicated birds showed a significantly better bodyweight gain than the chickens, whose feeds had not been supplemented. From epidemiological point of view, the systematic prevention of coccidiosis is a key in the control of Cl. perfringens enterotoxaemia in chickens.


Assuntos
Antibioticoprofilaxia/veterinária , Infecções por Clostridium/veterinária , Clostridium perfringens , Enterotoxemia/prevenção & controle , Oligossacarídeos/uso terapêutico , Doenças das Aves Domésticas/prevenção & controle , Tilosina/uso terapêutico , Animais , Antibacterianos/uso terapêutico , Galinhas , Infecções por Clostridium/mortalidade , Infecções por Clostridium/prevenção & controle , Enterotoxemia/mortalidade , Feminino , Masculino , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/mortalidade
19.
Vet Rec ; 142(26): 722-5, 1998 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-9682431

RESUMO

Enterotoxaemia in goats is mainly characterized by enterocolitis, and it has been suggested that the poor efficacy of commercial vaccines in preventing the disease is due to the local action of Clostridium perfringens toxin/s within the intestine, where circulating antibodies might not exert their action. Five goat kids were vaccinated with an incomplete Freund's adjuvant C perfringens type D epsilon toxoid vaccine on three occasions at three-week intervals, four similar kids were vaccinated with a commercial enterotoxaemia vaccine at the same times, and five other unvaccinated kids were used as controls. All the animals were challenged intraduodenally, one week after the last vaccination, with C perfringens type D filtered culture supernatant. At the time of challenge, the level of epsilon toxin antibodies in the serum of the Freund's adjuvant-vaccinated kids ranged between 2.45 and 230 iu/ml, while the kids that received the commercial vaccine had levels between 0.22 and 1.52 iu/ml. No clinical or postmortem changes were observed in the kids that received the Freund's adjuvant-vaccine. Three of the four kids that received the commercial vaccine developed mild, pasty diarrhoea, with a slight reddening of the colonic mucosa being observed postmortem. All the unvaccinated kids developed severe diarrhoea, respiratory distress and central nervous system signs, and were killed humanely between six and 24 hours after challenge. The postmortem changes consisted of pseudomembranous colitis, lung oedema and perivascular oedema of the brain. Moderate to high serum levels of anti-epsilon antibody appeared to protect the goats against both the systemic and the intestinal effects of C perfringens type D toxins.


Assuntos
Anticorpos Antibacterianos/sangue , Vacinas Bacterianas , Clostridium perfringens/imunologia , Enterotoxemia/prevenção & controle , Doenças das Cabras/prevenção & controle , Vacinação/veterinária , Animais , Anticorpos Antibacterianos/imunologia , Adjuvante de Freund/administração & dosagem , Doenças das Cabras/microbiologia , Cabras , Intestinos/imunologia
20.
J Anim Sci ; 75(9): 2328-34, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9303449

RESUMO

The objective of this experiment was to compare vaccination schedules for ewes and their lambs to raise antibody concentrations to epsilon-toxin of Clostridium perfringens, the causative agent of enterotoxemia. Half of 200 Finnsheep x Dorset ewes were vaccinated with C. perfringens type D toxoid vaccine 3 wk before lambing. Serum samples were obtained from 20 ewes that were to be vaccinated and 20 ewes that would remain unvaccinated before treatment and at wk 2, 1, and 0 before the start of lambing. Antibody concentrations in sera of unvaccinated ewes remained at 2 IU/mL, but they peaked in vaccinated ewes at 15 IU/mL by wk 1 before lambing. Lambs from each of the first 13 and the first 14 sets of triplets from vaccinated and unvaccinated ewes, respectively, received one of three vaccination treatments: no vaccine (control), vaccination on d 1 and 21 of age, or vaccination on d 21 and 42 of age. Antibody concentrations declined in sera of vaccinated ewes from 8.5 IU/mL immediately after lambing to 3 IU/mL 12 wk later. Vaccination of lambs did not increase sera antibody concentration. However, prepartum vaccination of ewes significantly increased lamb antibody concentrations (19 IU/mL) compared with lambs reared by unvaccinated ewes (2 IU/mL). Vaccination of ewes resulted in lambs with higher antibody concentrations until wk 10 postpartum. Concentrations declined to .6 IU/mL in all lambs at 12 wk. Because concentrations of .2 IU/mL may be protective, these results indicate that vaccination of ewes before lambing imparts passive protection in lambs to 12 wk of age, whereas vaccination of young lambs provides no added protection.


Assuntos
Anticorpos Antibacterianos/sangue , Toxinas Bacterianas/imunologia , Vacinas Bacterianas/administração & dosagem , Clostridium perfringens/imunologia , Enterotoxemia/prevenção & controle , Doenças dos Ovinos/prevenção & controle , Vacinação/veterinária , Animais , Animais Recém-Nascidos , Anticorpos Antibacterianos/imunologia , Toxinas Bacterianas/sangue , Vacinas Bacterianas/imunologia , Clostridium perfringens/metabolismo , Enterotoxemia/sangue , Enterotoxemia/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Esquemas de Imunização , Tamanho da Ninhada de Vivíparos , Gravidez , Ovinos , Doenças dos Ovinos/sangue , Doenças dos Ovinos/imunologia , Fatores de Tempo , Vacinação/métodos
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