Development and Bayesian validation of a competitive inhibition ELISA for detection of antibodies against Brucella abortus in cattle.

Bovine brucellosis is a zoonotic disease caused by Brucella abortus, responsible for abortions in cows. It is endemic in low- and middle-income countries, where the brucellosis control and eradication programs are based on compulsory vaccination, detection of infected cattle through serologic assays, and culling of infected animals at slaughterhouses. The development of high sensitivity and specificity, and low-cost serologic assays guarantee their implementation in countries where the disease is endemic. The aim of the present study was to develop and validate a competitive inhibition enzyme-linked immune assay (ciELISA) to detect anti-B. abortus antibodies in sera from cattle. The developed ciELISA was validated using 2833 serum samples from dairy and beef cattle. From these, 1515 sera were from uninfected cows that belonged to free of brucellosis herds and 1318 were from infected cows that belonged positive to brucellosis herds. Sera were analyzed with the developed ciELISA, the buffer plate antigen (BPA) test, and the complement fixation test (CFT). The brucellosis status of the herds was officially established according to the country legislation and consistent for at least 5 years and was defined for each cow using the CFT as gold standard. The cutoff for the ciELISA was calculated using a ROC curve and its sensitivity and specificity were analyzed using the Bayesian Latent Class Model (BLCM) approach. The agreement among tests was calculated using the kappa (κ) value. In addition, 15 calves were vaccinated with 3 × 1010 viable cells of B. abortus Strain 19 vaccine, and the dynamics of antibodies were measured by CFT, buffered plate antigen (BPA) test, and the developed ciELISA. The obtained cutoff for ciELISA was ≥ 47 percentage of inhibition (% I), at the BLCM approach the sensitivity was 99.01 % (95 % CI: 97.55-100) and the specificity 98.74 % (95 % CI: 97.68-99.8). The κ between the ciELISA and BPA was κ = 0.88 and between the ciELISA and CFT κ = 0.95. Antibodies against B. abortus were detected in all the vaccinated calves 7 days after vaccination (AV) by the three assays, at day 135 AV all the calves were negative to CFT (15/15), 93.3 % (14/15) to ciELISA and 73.3 % (11/15) to BPA, and at day 190 AV all the calves were negative to the three assays. The developed ciELISA showed a very good performance, could detect the majority of vaccinated animals as negative after 135 days and could be used for the detection of anti-B. abortus antibodies in serum samples for the brucellosis control and eradication program.

Construction of recombinant Omp25 or EipB protein loaded PLGA nanovaccines for Brucellosis protection.

Safe and effective vaccine candidates are needed to address the limitations of existing vaccines against Brucellosis, a disease responsible for substantial economic losses in livestock. The present study aimed to encapsulate recombinant Omp25 and EipB proteins, knowledged antigen properties, into PLGA nanoparticles, characterize synthesized nanoparticles with different methods, and assessed theirin vitro/in vivoimmunostimulatory activities to develop new vaccine candidates. The recombinant Omp25 and EipB proteins produced with recombinant DNA technology were encapsulated into PLGA nanoparticles by double emulsion solvent evaporation technique. The nanoparticles were characterized using FE-SEM, Zeta-sizer, and FT-IR instruments to determine size, morphology, zeta potentials, and polydispersity index values, as well as to analyze functional groups chemically. Additionally, the release profiles and encapsulation efficiencies were assessed using UV-Vis spectroscopy. After loading with recombinant proteins, O-NPs reached sizes of 221.2 ± 5.21 nm, while E-NPs reached sizes of 274.4 ± 9.51 nm. The cumulative release rates of the antigens, monitored until the end of day 14, were determined to be 90.39% for O-NPs and 56.1% for E-NPs. Following the assessment of thein vitrocytotoxicity and immunostimulatory effects of both proteins and nanoparticles on the J774 murine macrophage cells,in vivoimmunization experiments were conducted using concentrations of 16µg ml-1for each protein. Both free antigens and antigen-containing nanoparticles excessively induced humoral immunity by increasing producedBrucella-specific IgG antibody levels for 3 times in contrast to control. Furthermore, it was also demonstrated that vaccine candidates stimulated Th1-mediated cellular immunity as well since they significantly raised IFN-gamma and IL-12 cytokine levels in murine splenocytes rather than IL-4 following to immunization. Additionally, the vaccine candidates conferred higher than 90% protection from the infection according to challenge results. Our findings reveal that PLGA nanoparticles constructed with the encapsulation of recombinant Omp25 or EipB proteins possess great potential to triggerBrucella-specific humoral and cellular immune response.

A novel vaccine strategy against Brucellosis using Brucella abortus multi-epitope OMPs vaccine based on Lactococcus lactis live bacterial vectors.

Brucella infections typically occur in mucosal membranes, emphasizing the need for mucosal vaccinations. This study evaluated the effectiveness of orally administering Lactococcus lactis (L. lactis) for producing the Brucella abortus multi-epitope OMPs peptide. A multi-epitope plasmid was generated through a reverse vaccinology method, and mice were administered the genetically modified L. lactis orally as a vaccine. The plasmid underwent digestion, synthesizing a 39 kDa-sized protein known as OMPs by the target group. The sera of mice that were administered the pNZ8124-OMPs-L. lactis vaccine exhibited a notable presence of IgG1 antibodies specific to outer membrane proteins (OMPs), heightened levels of interferon (IFN-λ) and tumor necrosis factor alpha (TNF-α), and enhanced transcription rates of interleukin 4 (IL-4) and interleukin 10 (IL-10). The spleen sections from the pNZ8124-OMPs-L. lactis and IRIBA group had less morphological damage associated with inflammation, infiltration of lymphocytes, and lesions to the spleen. The findings present a novel approach to utilizing the food-grade, non-pathogenic L. lactis as a protein cell factory to synthesize innovative immunological candidate OMPs. This approach offers a distinctive way to evaluate experimental medicinal items' practicality, safety, affordability, and long-term sustainability.

The immunostimulatory roles of gold nanoparticles in immunization and vaccination against Brucella abortus antigens.

One effective antigen carrier proposed for use in immunization and vaccination is gold nanoparticles. Prior work has shown that gold nanoparticles themselves have adjuvant properties. Currently, gold nanoparticles are used to design new diagnostic tests and vaccines against viral, bacterial, and parasitic infections. We investigated the use of gold nanoparticles as immunomodulators in immunization and vaccination with an antigen isolated from Brucella abortus. Gold nanoparticles with a diameter of 15 nm were synthesized for immunization of animals and were then conjugated to the isolated antigen. The conjugates were used to immunize white BALB/c mice. As a result, high-titer (1:10240) antibodies were produced. The respiratory and proliferative activities of immune cells were increased, as were the serum interleukin concentrations. The minimum antigen amount detected with the produced antibodies was âˆ¼ 0.5 pg. The mice immunized with gold nanoparticles complexed with the B. abortus antigen were more resistant to B. abortus strain 82 than were the mice immunized through other schemes. This fact indicates that animal immunization with this conjugate enhances the effectiveness of the immune response. The results of this study are expected to be used in further work to examine the protective effect of gold nanoparticles complexed with the B. abortus antigen on immunized animals and to develop test systems for diagnosing brucellosis in the laboratory and in the field.

Inmunopatología de la brucelosis osteoarticular / Immunopathology of osteoarticular brucelosis

La brucelosis es una de las enfermedades zoonóticas más importantes a nivel mundial capaz de producir enfermedad crónica en los seres humanos. La localización osteoarticular es la presentación más común de la enfermedad activa en el hombre. Sin embargo, algunos de los mecanismos moleculares implicados en la enfermedad osteoarticular han comenzado a dilucidarse recientemente. Brucella abortus induce daño óseo a través de diversos mecanismos en los cuales están implicados TNF-α y RANKL. En estos procesos participan células inflamatorias que incluyen monocitos/macrófagos, neutrófilos, linfocitos T del tipo Th17 y linfocitos B. Además, B. abortus puede afectar directamente las células osteoarticulares. La bacteria inhibe la deposición de la matriz ósea por los osteoblastos y modifica el fenotipo de estas células para producir metaloproteinasas de matriz (MMPs) y la secreción de citoquinas que contribuyen a la degradación del hueso. Por otro lado, la infección por B. abortus induce un aumento en la osteoclastogénesis, lo que aumenta la resorción de la matriz ósea orgánica y mineral y contribuye al daño óseo. Dado que la patología inducida por Brucella afecta el tejido articular, se estudió el efecto de la infección sobre los sinoviocitos. Estos estudios revelaron que, además de inducir la activación de estas células para secretar quemoquinas, citoquinas proinflamatorias y MMPs, la infección inhibe la muerte por apoptosis de los sinoviocitos. Brucella es una bacteria intracelular que se replica en el retículo endoplásmico de los macrófagos. El análisis de los sinoviocitos infectados con B. abortus indicó que las bacterias también se multiplican en el retículo endoplasmático, lo que sugiere que la bacteria podría usar este tipo celular para la multiplicación intracelular durante la localización osteoarticular de la enfermedad. Los hallazgos presentados en esta revisión intentan responder a preguntas sobre los mediadores inflamatorios implicados en el daño osteoarticular causado por Brucella. (AU)

Brucellosis is one of the most important zoonotic diseases that can produce chronic disease in humans worldwide. Osteoarticular involvement is the most common presentation of human active disease. The molecular mechanisms implicated in bone damage have started to be elucidated. B. abortus induces bone damage through diverse mechanisms in which TNF-α and RANKL are implicated. These processes are driven by inflammatory cells, including monocytes/macrophages, neutrophils, Th17 lymphocytes and B cells. Also, Brucella abortus (B. abortus) can directly affect osteoarticular cells. The bacterium inhibits bone matrix deposition by osteoblast and modifies the phenotype of these cells to produce matrix methalloproteinases (MMPs) and cytokine secretion that contribute to bone matrix degradation. B. abortus also affects osteoclast increasing mineral and organic bone matrix resorption and contributing to bone damage. Since the pathology induced by Brucella species involves joint tissue, experiments conducted in sinoviocytes revealed that besides inducing the activation of these cells to secrete chemokines, proinflammatory cytokines and MMPS, the infection also inhibits sinoviocyte apoptosis. Brucella is an intracellular bacterium that replicate in the endoplasmic reticulum of macrophages. The analysis of B. abortus infected sinoviocytes indicated that bacteria also replicate in their reticulum suggesting that the bacterium could use this cell type for intracellular replication during the osteoarticular localization of the disease. The findings presented in this review try to answer key questions about the inflammatory mediators involved in osteoarticular damage caused by Brucella. (AU)

Evaluation of dot-blot test for serological diagnosis of bovine brucellosis

Abstract The objective of this study was to standardize and validate the dot-blot test for the serological diagnosis of bovine brucellosis, compare the results with those found in the 2-mercaptoethanol (2-ME) and complement fixation test (CF), and estimate the relative sensitivity and specificity of the dot-blot compared to these tests. Fifty bovine blood serum samples were used for the test standardization, and 1315 samples were used for evaluation and comparison between the tests; the results were compared using the Kappa indicator. At the end of standardization, it was established as optimal for the antigen obtained from Brucella abortus B19 after passing through a microorganism rupture process, the blood serum samples diluted at 1:100, and the conjugate at 1:30,000. The comparison of the dot-blot results with 2-ME showed Kappa index of 0.9939, sensitivity of 99.48%, and specificity 99.91%, with CF, Kappa index of 0.8226, sensitivity 100% and specificity 95.32%. Using the combination of the test results 2-ME and CF to establish the true condition of the animal, the dot-blot showed relative sensitivity of 100%, and relative specificity of 99.91%. The evaluated test proved to be effective and reliable, besides being easy to handle and interpret the results.

Occurrence of antibodies anti -Toxoplasma gondii, Neospora caninum and Leptospira interrogans in a captive deer herd in Southern Brazil / Ocorrência de anticorpos anti -Toxoplasma gondii, Neospora caninum e Leptospira interrogans em um rebanho de cervídeos de cativeiro do sul do Brasil

Abstract A large number of Brazilian zoos keep many endangered species of deer, however, very few disease surveillance studies have been conducted among captive cervids. Blood samples from 32 Brazilian deer (Blastocerus dichotomus, Mazama nana and Mazama americana) kept in captivity at Bela Vista Biological Sanctuary (Foz do Iguaçu, Brazil) were investigated for 10 ruminant pathogens, with the aims of monitoring deer health status and evaluating any potential zoonotic risk. Deer serum samples were tested for Brucella abortus, Leptospira (23 serovars), Toxoplasma gondii, Neospora caninum, bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, foot-and-mouth disease virus, western equine encephalitis virus, eastern equine encephalitis virus and Venezuelan equine encephalitis virus. Antibodies against T. gondii (15.6%), N. caninum (6.2%) and L. interrogans serogroup Serjoe (3.1%) were detected. The serological results for all other infectious agents were negative. The deer were considered to be clinically healthy and asymptomatic regarding any disease. Compared with studies on free-ranging deer, the prevalences of the same agents tested among the captive deer kept at the Sanctuary were lower, thus indicating good sanitary conditions and high-quality management practices at the zoo.

Resumo Um grande número de zoológicos brasileiros abriga espécies de cervídeos ameaçados de extinção, entretanto, estudos de vigilância de doenças em cervídeos de cativeiro são escassos. Amostras de sangue de 32 cervídeos brasileiros (Blastocerus dichotomus, Mazama nana e Mazama americana), mantidos em cativeiro no Refúgio Biológico Bela Vista (Foz do Iguaçu, Brasil), foram investigados para 10 patógenos de ruminantes, visando monitorar o estado de saúde dos cervídeos e avaliar a presença de agentes zoonóticos. As amostras de soro foram testadas para Brucella abortus, Leptospira (23 sorovares), Toxoplasma gondii, Neospora caninum, diarreia viral bovina, rinotraqueíte infecciosa bovina, febre aftosa, encefalomielite equina do oeste, encefalomielite equina do leste e encefalomielite equina venezuelana. Foram detectados anticorpos para T. gondii (15,6%), N. caninum (6,2%) e para L. interrogans sorogrupo Serjoe (3,1%). As sorologias apresentaram resultado negativo para as demais doenças. Os cervídeos foram considerados clinicamente sadios e assintomáticos para doenças. Comparados aos estudos de populações de vida livre, as soroprevalências para os mesmos agentes testados foram menores para os cervídeos mantidos no Refúgio, indicando as boas condições sanitárias e a qualidade das práticas de manejo no zoológico.

Serosurvey of Leptospira interrogans, Brucella abortus and Chlamydophila abortus infection in free-ranging giant anteaters (Myrmecophaga tridactyla) from Brazil / Inquérito sorológico de Leptospira interrogans, Brucella abortus e Chlamydophila abortus em tamanduás-bandeira (Myrmecophaga tridactyla) de vida livre no Brasil

A serological survey for antibodies against Leptospira interrogans, Brucella abortus, and Chlamydophila abortus was conducted in 21 clinically healthy, free-ranging giant ant- eaters (Myrmecophaga tridactyla) from Parque Nacional das Emas (Goiás State, Brazil; n=6), Parque Nacional da Serra da Canastra (Minas Gerais State, Brazil; n=9), and RPPN SESC Pantanal (Mato Grosso State, Brazil; n=6) between July 2001 and September 2006. Sera were screened for antibodies against 22 serovars of Leptospira interrogans with a microscopic agglutination test. Twelve tested positive for L. interrogansserovars sentot (n=5 in PN Emas, n=2 in PN Serra da Canastra), butembo (n=2 in PN Serra da Canastra), autumnalis, bataviae, and shermani/icterohaemorrhagiae(n=1 each in SESC Pantanal)One adult female tested positive for B. abortus with the buffered plate antigen test. All sera were negative for C. abortususing the complement fixation text. This is the first report of pathogens that may interfere with the reproduction and population dynamics of free-ranging giant anteaters.

Inquéritos sorológicos para detecção de anticorpos contra Leptospira interrogans, Brucella abortus, e Chlamydophila abortus foram realizados em 21 tamanduás-bandeira (Myrmecophaga tridactyla) de vida livre do Parque Nacional das Emas (Goiás, Brasil, n=6), o Parque Nacional da Serra da Canastra (Minas Gerais, Brasil, n=9) e RPPN SESC Pantanal (Mato Grosso, Brasil, n=6) entre julho de 2001 e setembro de 2006. Os sor os foram testados para anticorpos contra 22 sorotipos de Leptospira interrogans com um teste de aglutinação microscópica. Doze animais foram considerados positivos para L. interrogans sorovares sentot (n=5 em PN Emas, n=2 em PN Serra da Canastra), butembo (n=2 em PN Serra da Canastra), autumnalis, bataviae e shermani/icterohaemorrhagiae(n=1 para cada sorovar em SESC Pantanal). Uma fêmea adulta testou positivo para B. abortuscom o teste do antígeno tamponado. Todos os soros se mostraram negativos para C. abortusatravés do teste de fixação do complemento. Este é o primeiro relato de patógenos que podem interferir na dinâmica reprodutiva de populações de tamanduás em estado selvagem.

Outbreak of laboratory-acquired Brucella abortus in Brazil: a case report

Human brucellosis is an occupational disease affecting workers in slaughterhouses, butcher shops and the milk and dairy product industry as well as individuals who work in clinical or research laboratories. We report the first outbreak of a Brucella abortus infection in a Brazilian laboratory and compare the data obtained with reports available in the literature. Exposure was a result of damage to a biological safety cabinet and failure of the unidirectional airflow ventilation system. An epidemiological investigation identified 3 seroconverted individuals, 1 of whom had clinical manifestations and laboratory results compatible with infection at the time of exposure (n=11; attack rate=9.1%).

Prevalência de anticorpos anti-Brucella ovis e anti-Brucella abortus em ovinos do município de Colinas, Tocantins, Brasil / Prevalence of anti-Brucella ovis and anti-Brucella abortus in sheep in the city of Colinas, Tocantins, Brazil

A brucelose é uma enfermidade infecciosa, causada por bactérias do gênero Brucella spp. responsáveis por desordens reprodutivas nos animais, especialmente nos ruminantes. Este trabalho objetivou determinar a presença de anticorpos anti-Brucella ovis e anti-Brucella abortus em ovinosde 14 propriedades cadastradas na Associação de Ovinocultores do município de Colinas, Tocantins,Brasil. Para isso, amostras de soro de 450 ovinos foram analisadas por meio da aglutinação rápida em placa com Antígeno Acidificado e Tamponado (AAT) e, quando reagentes, foram realizados os testes de Aglutinação Lenta em Tubos (SAT) e 2-Mercaptoetanol (2-ME) para pesquisar cepas lisas (B. abortus). Para a pesquisa de cepas rugosas (B. ovis), foi realizada a Imunodifusão em Gel de Ágar (IDGA) e, quando reagente, foi realizada a Fixação de Complemento (FC). Das amostras analisadas,142 (31,6por cento) reagiram ao teste de IDGA, dentre estas, apenas 4 (2,8por cento) foram confirmadas na FC.Ante o AAT, apenas 20 (4,4por cento) se mostraram positivas, das quais 14 (70por cento) foram confirmadas noSAT/2-ME. Os resultados obtidos nos testes de FC e SAT/2-ME e analisados pelo Teste de Fisher e OR demonstraram significância estatística entre a positividade e a faixa etária, sendo maior a chance de um animal em reprodução ser positivo para brucelose.

Epidemiological aspects of an infection by Brucella abortus in risk occupational groups in the microregion of Araguaína, Tocantins

The aim of this paper was to study some epidemiological aspects of the infection by Brucella abortus in risk occupational groups in the microregion of Araguaína, Tocantins. For antibody research, 645 serum samples were analyzed by the complement fixation test (CF). A 4.0 percent frequency was found (26/645) in patients' serum and among those 4.1 percent (23/551) were slaughterhouses employees and 8.1 percent (3/37) rural workers. Of the total positive samples, three (2.0 percent) were women and 23 (4.7 percent) men; ten (2.9 percent) were between the ages of 18 and 30, six (3.4 percent) between 31 and 40, and nine (8.0 percent) were above 41 years of age. Risk factors for brucellosis in the study groups were age, background (OR = 2.45; CI 95 percent = 0.98 to 6.10) and previous work conducted with production animals (OR 2.36; CI 95 percent = 0.95 to 6.02). It was concluded that the infection by Brucella abortus is found in some risk occupational groups in the microregion of Araguaína, Tocantins, and control and prophylactic measures must be implemented emphasizing risk factors identified in the study.

Evaluación de la reacción en cadena de la polimerasa para el diagnóstico de la brucelosis en un rebaño lechero infectado con Brucellaspp / Assessment of polymerase chain reaction (PCR) to diagnose brucellosis in a Brucella infected herd

Para el diagnóstico de la brucelosis bovina en muestras de sangre y/o leche, se comparó la reacción en cadena de la polimerasa (PCR) con el aislamiento in vitro de Brucella abortus, las pruebas serológicas defijación del complemento (FC) e inmunoenzimáticas de competición (ELISA-C) en suero e indirecto (ELISA-I) en leche. Se analizaron muestras de vacas lecheras de un rebaño infectado “A”, vacunadas con B. abortus cepa 19 antes de los 8 meses de edad y revacunadas con B. abortus cepa RB51 como adultas (n= 99) y de otro “B”, libre de brucelosis (n=100), como control. En A, la PCR identificó 14 vacas infectadas con B. abortus: nueve con cepa silvestre y cinco con cepa silvestre y RB51. No se identificó B. abortus cepa 19. El biotipo 1 se aisló en un caso. Las 14 vacas infectadas con la cepa silvestre resultaron positivas en las tres pruebas serológicas. En B, por PCR no se identificó Brucella. Las pruebas serológicas mostraron una sensibilidad del 100% respecto de PCR. La especificidad para FC, ELISA-C y ELISA-I fue del 100%, 99% y 95%, respectivamente. Se concluye que la PCR sería útil como complemento de las pruebas serológicas o cuando no hay un resultado concluyente.

The diagnosis of bovine brucellosis using PCR in blood and milk samples from two dairy herds were compared to in vitro isolation, complement fixation test (CF), competitive ELISA (C-ELISA) in serum, and indirect ELISA (I-ELISA) in milk. Samples were obtained from 99 cows vaccinated with Brucella abortus strain 19, from a naturally infected herd (A), whose cows were also vaccinated with B. abortus strain RB51 as adults, and 100 from brucellosis free herd (B). In herd A, PCR identified 14 B. abortus infected cows: nine infected with wild type, and five with wild type and RB51, B. abortus S 19 was not identified. B. abortus biotype 1 was isolated from one cow. All cows infected with a wild strain of B. abortus were positive in serologic tests. Brucella was not found in herd B using PCR. Serological test showed 100% sensitivity related to PCR. The specificity for CF, C-ELISA and I-ELISA was 100%, 99% and 95% respectively. PCR could be useful to identify Brucella biotypes and to complement serologic tests.

Structural, functional and immunological studies on a polymeric bacterial protein

The characterization of proteins from Brucella spp, the causative agent of brucellosis, has been the subject of intensive research. We have described an 18-kDa cytoplasmic protein of Brucella abortus and shown the potential usefulness of this protein as an antigen for the serologic diagnosis of brucellosis. The amino acid sequence of the protein showed a low but significant homology with that of lumazine synthases. Lumazine is an intermediate product in bacterial riboflavin biosynthesis. The recombinant form of the 18-kDa protein (expressed in E. coli) folds like the native Brucella protein and has lumazine-synthase enzymatic activity. Three-dimensional analysis by X-ray crystallography of the homolog Bacillus subtilis lumazine synthase has revealed that the enzyme forms an icosahedral capsid. Recombinant lumazine synthase from B. abortus was crystallized, diffracted X rays to 2.7-A resolution at room temperature, and the structure successfully solved by molecular replacement procedures. The macromolecular assembly of the enzyme differs from that of the enzyme from B. subtilis. The Brucella enzyme remains pentameric (90 kDa) in its crystallographic form. Nonetheless, the active sites of the two enzymes are virtually identical at the structural level, indicating that inhibitors of these enzymes could be viable pharmaceuticals across a broad species range. We describe the structural reasons for the differences in their quaternary arrangement and also discuss the potential use of this protein as a target for the development of acellular vaccines.

Human brucellosis: immunoblotting analysis of three Brucella abortus antigenic fractions allows the detection of components of diagnostic importance

Se presentan resultados que muestan que el análisis por immunoblotting de la respuesta inmune humoral de pacientes brucelosos permite la caracterización de componentes antigénicso de posible utilidad para el diagnóstico de la enfermedad. Se analizó el suero de 90 pacientes: 20 brucelosos agudos, 23 crónicos y 47 individuos serológicamente positivos sin evidencias clínicas de infección activa al momento del examen (SPI); se utilizó además el suero de 35 personas sanas como control. Todos los sueros fueron ensayados frente a tres fracciones antigéneticas: citoplasmáticas (CYT), membrana externa (OM) y membrana interna (IM). Dichas fracciones, que incluyen virtualmente todas las proteínas bacterianas, fueron preparadas a partir de Brucella abortus 1119/3 por solubilización con detergentes, digestión enzimática y ultracentrifugación. Los resultados obtenidos revelan la existencia de antígenos que permiten detectar a pacientes brucelosos con alta sensibilidad, y diferenciar a éstos del grupo SPI

Vacuna fenol-insoluble contra la brucelosis humana: evaluacion del poder inmunogenico en cobayos / Phenol-insoluble vaccine against human brucellosis: evaluation of the immunogenic power in guinea pigs

Se examino una vacuna diseñada para inmunizar al hombre, preparada con extracto de fenol insoluble, para determinar si protegia a cobayos contra el desafio con la cepa virulenta B. abortus 2308. Se incluyeron en el experimento las vacunas vivas atenuadas B. abortus cepa 19 y B. melitensis Rev. 1, para comparar los resultados. Se vacunaron 93 animales en cada grupo, que fueron subdivididos en subgrupos de 31 y se los desafio con '10 POT. 4', '10 POT. 3' Y '10 POT. 2' unidades formadoras de colonias de la cepa B. abortus 2308 virulenta. El analisis global de los resultados demostro una proteccion del 11.9 por ciento en animales vacunados con el extracto de fenol insoluble, 65 por ciento en los vacunados con B. abortus cepa 19 y 95 por ciento en el grupo que recibio vacuna B. melitensis Rev. 1.

Detección suero bovino de anticuerpos no aglutinantes dirigidos hacia antígenos acultos de Brucella abortus cepa 19 / Detection in bovine serun of non-agglutinating antibodies to occult antigenos of Brucella abortus strain 19

Bovinos hembras de raza Hereford, inoculados con Brucella obortus cepa 19 en fase lisa, elaboraron anticuerpos no aglutinantes que se unieron específicamente a la cepa rugosa 45/20. Los sueros de estos animales, adsorbidos con B. abortus cepa 19 hasta eliminación de los anticuerpos dirigidos contra antígenos de superfície de la cepa lisa, mostraron contener una población no aglutinante de anticuerpos que se unieron a la cepa rugosa 45/20, siendo detectados mediante reacción de Cooms hasta un límite de 1,5 ug. Al margens de los anticuerpos incompletos producidos hacia antígenos externos de cepas lisas de B. abortus, se pone en evidencia este tipo de anticuerpos, con especificidad por antígenos más profundos que también estarían presentes en la superficie de la cepa rugosa. Estos anticuerpos, cuya participación en la depuración sanguínea y degradación del agente etiológico de la brucelosis bovina sería poco significativa, están siendo estudiados minuciosamente con el objeto de establecer la importancia que pudieran tener en el diagnóstico y pronóstico de brucelosis