Producción y evaluación del antígeno recombinante TES-30 de Toxocara canis para el inmunodiagnóstico de toxocariasis / Production and evaluation of the recombinant antigen TES-30 of Toxocara canis for the immunodiagnosis of toxocariasis

Introducción. Toxocara canis es un nematodo patógeno de cánidos que accidentalmente puede ser transmitido a los humanos. A pesar de la importancia de la serología para el diagnóstico de esta zoonosis, los kits diagnósticos usan antígenos crudos de excreción-secreción, en su mayoría glucoproteínas que no son específicas de especie, por lo cual pueden presentarse reacciones cruzadas con anticuerpos generados contra otros parásitos. Objetivos. Producir el antígeno recombinante TES-30 de T. canis y evaluarlo para el inmunodiagnóstico de la toxocariasis. Materiales y métodos. Se clonó el gen que codifica TES-30 en el vector de expresión pET28a (+), usando oligonucleótidos de cadena sencilla unidos mediante reacción en cadena de la polimerasa (PCR). La proteína rTES-30 se purificó por cromotografia de afinidad (Ni 2+ ). La reacción serológica de rTES-30 se evaluó mediante immunoblot . Teniendo en cuenta que no existe una prueba de referencia , se observó el comportamiento del antigeno en comparación con la prueba de rutina para el inmunodiagnóstico de la toxocariasis, es decir, la técnica ELISA convencional con antígenos de excreción-secreción. Resultados. El rTES-30 se produjo a partir de un cultivo de Escherichia coli LB, con un rendimiento de 2,25 mg/l y 95 % de pureza. La concordancia de la reacción entre el immunoblot rTES-30 y la ELISA convencional, fue de 73 % (46/63) y de 100 % con los 21 sueros no reactivos. De los 21 sueros con diagnóstico de otras parasitosis, 19 fueron reactivos con ELISA, mientras que tan solo siete fueron positivos con el immunoblot rTES-30. La concordancia entre la ELISA y el immunoblot fue moderada (índice kappa de 0,575; IC 95% 0,41-0,74). Conclusiones. Los datos presentados respaldan la utilidad del immunoblot r TES-3 0 para la confirmación de los posibles positivos por ELISA, no solo en los estudios epidemiológicos, sino también, como candidato para el desarrollo de pruebas diagnósticas de la toxocariasis ocular en Colombia.

Introduction: Toxocara canis is a pathogenic nematode of canines which can be accidentally transmitted to humans. Although serology is the most important diagnostic tool for this zoonosis, diagnostic kits use crude excretion/secretion antigens, most of them being glycoproteins which are not species-specific and may cross-react with antibodies generated against other parasites. Objectives: To produce the rTES-30 recombinant antigen of Toxocara canis and evaluate it in the immunodiagnosis of toxocariasis. Materials and methods: The gene that codes for TES-30 was cloned in the expression vector pET28a (+) using single-stranded oligonucleotides united by PCR. The protein rTES-30 was purified by Ni 2+ affinity chromotography. Seroreactivity of rTES-30 was evaluated by immunoblot. Given that there is no gold standard test, the behaviour of the antigen was compared with the method that is routinely used to immunodiagnose toxocariasis, i.e., the conventional ELISA technique using excretion/secretion antigens. Results: The rTES-30 was produced from an Escherichia coli LB culture which yielded 2.25 mg/L of the antigen with a purity of 95%. The results obtained showed 73% (46/63) concordance of reactivity between the rTES-30 immunoblot and the conventional ELISA, and 100% concordance with the non-reactive sera (21). Nineteen of the 21 sera positive for other parasitoses reacted with ELISA, while only seven of these were positive with the rTES-30 immunoblot. Concordance between the ELISA and the immunoblot was moderate (kappa coefficient: 0.575; 95% CI: 0.41- 0.74). Conclusions: The data presented show the potential of the rTES-30 inmunoblot for confirmation of possible ELISA positives, not only in epidemiological studies, but also as a candidate for the development of diagnostic tests for ocular toxocariasis in Colombia.

Paracoccidioidoyycosis: challenges in the develpment of a vaccine against an eendemic mycosis in the americas / Paracoccidioidomicose: desafios no desenvolvimento de uma vacina contra micose endêmica nas Américas

SUMMARYParacoccidioidomycosis (PCM), caused by Paracoccidioides spp, is an important endemic mycosis in Latin America. There are two recognized Paracoccidioides species, P. brasiliensis and P. lutzii, based on phylogenetic differences; however, the pathogenesis and disease manifestations of both are indistinguishable at present. Approximately 1,853 (~51,2%) of 3,583 confirmed deaths in Brazil due to systemic mycoses from 1996-2006 were caused by PCM. Antifungal treatment is required for patients with PCM. The initial treatment lasts from two to six months and sulfa derivatives, amphotericin B, azoles and terbinafine are used in clinical practice; however, despite prolonged therapy, relapses are still a problem. An effective Th1-biased cellular immune response is essential to control the disease, which can be induced by exogenous antigens or modulated by prophylactic or therapeutic vaccines. Stimulation of B cells or passive transference of monoclonal antibodies are also important means that may be used to improve the efficacy of paracoccidioidomycosis treatment in the future. This review critically details major challenges facing the development of a vaccine to combat PCM.

RESUMOA paracoccidioidomicose (PCM), causada por Paracoccidioides spp, é importante micose endêmica na América Latina. Com base em diferenças filogenéticas, existem duas espécies reconhecidas de Paracoccidioides, P. brasiliensis e P. lutzii, no entanto, a patogênese e as manifestações clínicas de ambas são indistinguíveis atualmente. Aproximadamente 1853 (~51,2%) de 3583 mortes confirmadas, atribuídas a micoses sistêmicas de 1996-2006, no Brasil foram causadas por PCM. Tratamento antifúngico é necessário para pacientes com PCM. O tratamento inicial dura de dois a seis meses e derivados de sulfa, anfotericina B, azóis e terbinafina são utilizados na prática clínica; no entanto, apesar da terapêutica prolongada, as recaídas ainda são um problema. Uma resposta imune celular eficaz, tendendo a Th1, é essencial para controlar a doença que pode ser induzida por antígenos exógenos, ou moduladas por vacinas profiláticas ou terapêuticas. A estimulação de células B ou a transferência passiva de anticorpos monoclonais também são meios importantes que podem ser utilizados para melhorar a eficácia do tratamento da paracoccidioidomicose no futuro. Esta revisão detalha criticamente os principais desafios que o desenvolvimento de uma vacina para combater a PCM enfrenta.

Chemokines and immunity / Quimiocinas e imunidade

Chemokines are a large family of small cytokines and generally have low molecular weight ranging from 7 to 15kDa. Chemokines and their receptors are able to control the migration and residence of all immune cells. Some chemokines are considered pro-inflammatory, and their release can be induced during an immune response at a site of infection, while others are considered homeostatic and are involved in controlling of cells migration during tissue development or maintenance. The physiologic importance of this family of mediators is resulting from their specificity − members of the chemokine family induce recruitment of well-defined leukocyte subsets. There are two major chemokine sub-families based upon cysteine residues position: CXC and CC. As a general rule, members of the CXC chemokines are chemotactic for neutrophils, and CC chemokines are chemotactic for monocytes and sub-set of lymphocytes, although there are some exceptions. This review discusses the potential role of chemokines in inflammation focusing on the two best-characterized chemokines: monocyte chemoattractant protein-1, a CC chemokine, and interleukin-8, a member of the CXC chemokine sub-family.

Quimiocinas são uma grande família de pequenas citocinas e seu peso molecular varia de 7 a 15kDa. As quimiocinas e seus receptores são capazes de controlar a migração e a residência de células imunes. Algumas quimiocinas são consideradas pró-inflamatórias e podem ser induzidas durante a resposta imune no sítio de infecção, enquanto outras são consideradas homeostáticas e estão envolvidas no controle da migração celular durante o desenvolvimento ou a manutenção dos tecidos. A importância fisiológica dessa família de mediadores é resultado de sua especificidade − os membros da família de quimiocinas induzem ao recrutamento de subtipos bem definidos de leucócitos. Existem duas grandes subfamílias de quimiocinas baseadas na posição dos resíduos de cisteínas: CXC e CC. Como regra geral, membros da família de quimiocinas CXC são quimiotáticos de neutrófilos, e as quimiocinas CC são quimiotáticos de monócitos e subtipos de linfócitos, apesar de existirem algumas exceções. Esta revisão discute o potencial papel das quimiocinas na inflamação focando nas duas quimiocinas mais bem caracterizadas: a proteína quimioatraente de monócitos-1, uma quimiocina CC, e a interleucina 8, uma quimiocina membro da subfamília CXC.

Avaliação dos estudantes de enfermagem sobre a aprendizagem com a simulação clínica / Evaluación de los estudiantes de enfermería sobre el aprendizaje con la simulación clínica / Evaluation of nursing students about learning with clinical simulation

RESUMO Objetivo: descrever as contribuições da simulação clínica para aprendizagem de atributos cognitivos e procedimentais, por meio do debriefing, na perspectiva dos estudantes de enfermagem. Método: estudo descritivo exploratório. Participaram 20 estudantes de Graduação em Enfermagem de uma universidade do interior paulista. Na coleta de dados, realizada na etapa do debriefing, foi registrada a percepção do aluno sobre a simulação, aspectos positivos e o que poderia ser feito de forma diferente. Os relatos foram agrupados em categorias temáticas centrais, segundo referencial de análise de conteúdo de Bardin (2011), analisadas por meio de estatística descritiva. Resultados: identificada valorização da aprendizagem ativa, crítica e reflexiva (47,5%) em decorrência da aproximação à realidade assistencial (20,3%), manifestação dos sentimentos vivenciados durante a simulação (16,9%) e composição do cenário (15,3%). Conclusão: a simulação clínica seguida do debriefing favorece a compreensão da relação entre ação e resultados alcançados na aprendizagem. .

RESUMEN Objetivo: describir las contribuciones de simulación clínica para aprender atributos cognitivos y de procedimiento, a través de debriefing, desde la perspectiva de los estudiantes de enfermería. Método: estudio exploratorio descriptivo. 20 estudiantes participaron en el Pregrado en Enfermería de una universidad de São Paulo. Durante la recolección de datos, que se aplicó durante el debriefing, fue grabado en la percepción de los estudiantes de la simulación, los aspectos positivos y lo que podría hacerse de otra manera. Los informes de los estudiantes se agrupan de acuerdo a los temas centrales, según el referencial de análisis de contenido de Bardin (2011) y analizados mediante estadística descriptiva. Resultados: identificado la mejora de aprendizaje activo, crítico y reflexivo (47,5%) debido a la aproximación a la realidad en la atención de enfermería (20,3%), un resultado de la composición del escenario (16,9%), lo que favorece el desarrollo de sentimientos experimentados durante la simulación (15,3%). Conclusión: la simulación clínica seguida de debriefing favorece la comprensión de la relación entre la acción y los resultados obtenidos en el aprendizaje. .

ABSTRACT Objective: to describe the contributions of clinical simulation for learning cognitive and procedural attributes through debriefi ng, from the perspective of nursing students. Method: descriptive exploratory study. Twenty nursing undergraduate students from a university in the interior of the state of São Paulo participated in this study. Data collection was performed at the debriefi ng stage. Student’s perceptions about the simulation, positive aspects and what they could have done differently were registered. The students’ statements were grouped according to the central themes and the framework of Bardin’s content analysis (2011) and were analyzed using descriptive statistics. Results: enhancement of active, critical and refl ective learning (47.5%) was identifi ed due to the closeness to reality in nursing care (20.3%), manifestation of feelings experienced during the simulation (15.3%) and composition of the scenario (15.3%). Conclusion: the clinical simulation followed by debriefi ng promotes the understanding of the link between action and achievements in learning. .

Production and evaluation of chicken antibodies against a synthetic peptide from glial growth factor / Producción y evaluación de anticuerpos de gallinas contra un péptido sintético del factor de crecimiento glial

Neuregulins (NRG) are proteins that belong to the family of epidermal growth factors. It is well established that these factors are essential for the development and maintenance of the nervous system. Due to the difficulty of purifying enough quantities of these factors and the lack of specificity from commercially available antibodies, the aim of this work was to produce antibodies against a synthetic peptide capable to detect and identify neuregulin GGFb isoforms. To accomplish this goal, polyclonal antibodies were raised in hens against a synthetic peptide designed from the GGFb1 extracellular sequence. The sequence analysis was made using different epitope-predicting programs. Our results showed that the peptide sequence selected was immunogenic because it was capable of inducing a specific type B immune response in the experimental animal model. These antibodies were also capable of recognizing a recombinant GGF protein and GGF isoforms present in different samples. Our results suggest that the development of immunoglobulin Y (IgY) using synthetic peptides represents, a valuable tool for neuroscience research.

Las Neuregulinas (NRG) son proteínas que pertenecen a la familia de los factores de crecimiento epidermal. Se ha demostrado que estos factores son esenciales para el desarrollo y mantenimiento de la funcionalidad del sistema nervioso. Debido a la dificultad para purificar estas proteínas y la falta de especificidad de los anticuerpos disponibles comercialmente, el objetivo de este trabajo fue producir anticuerpos contra un péptido sintético capaz de detectar e identificar una isoforma de la Neuregulina (GGFb). Para lograr este objetivo, se desarrollaron anticuerpos en gallinas (IgY) contra un péptido sintético diseñado a partir de la secuencia aminoacídica de la región extracelular de GGFb, utilizando programas de predicción de epítopes. Los resultados demuestran que el péptido seleccionado fue immunogénico debido a que estimuló una respuesta inmune específica tipo B en el modelo utilizado. Estos anticuerpos fueron también capaces de reconocer una proteína recombinante e isoformas de GGF presentes en diferentes muestras biológicas. Nuestros resultados demuestran el potencial valor de las inmunoglobulinas Y (IgY) contra péptidos sintéticos como una herramienta de aplicación para la investigación en neurociencia.

Anticuerpo anticitrulina y manifestaciones extra articulares en artritis reumatoidea / Anticitrulin antibody and the extra-articular manifestations in rheumatoid arthritis

Los pacientes con artritis reumatidea (AR) pueden desarrollar manifestaciones extra articulares (MExA), relacionadas a su morbi-mortalidad. Los anticuerpos anti-péptidos citrulinados cíclicos (ACCP) son específicos para la AR y estan relacionados con el daño articular; y podrían tener rol patogénico en las MExA. Nuestro objetivo fue determinar la relación entre los anticuerpos ACCP y MExA en pacientes con AR. Se incluyeron 74 pacientes con diagnóstico de AR (ACR 1987) mayores de 18 años, de más de 6 meses de evolución, con MExA, y un control apareado por sexo y edad sin MExA por cada paciente. Las variables demográficas, clínicas y de laboratorio se compararon con test t, chi cuadrado o Mann-Whitney. Se realizó análisis multivariado; p ≤ 0.05. Los pacientes con MExA presentaron mayor título de anticuerpo ACCP (116 vs. 34, p < 0.01) y de factor reumatoideo (FR) (108 vs. 34.5, p < 0.01). En el análisis multivariado hubo asociación entre la presencia de MExA y tabaquismo activo (p = 0.02, OR: 3.78, IC 95%: 1.17-12.2), FR positivo (p = 0.04, OR: 3.23, IC95%: 1.04-11.8) y anticuerpo ACCP positivo (p = 0.04, OR: 3.23, IC 95%: 1.04-10). Presentaron mayor título de anticuerpo ACCP que los controles los pacientes con xerostomía (109 vs. 34, p = 0.04), xeroftalmia (150 vs. 34, p < 0.01), nódulos sub-cutáneos (NSC) (141 vs. 34, p < 0.01) y fibrosis pulmonar (158 vs. 34, p = 0.04). En conclusión, el anticuerpo ACCP positivo, el FR positivo y el tabaquismo activo fueron factores de riesgo independientes para el desarrollo de MExA.

A large proportion of rheumatoid arthritis (RA) patients develop extra-articular manifestations (EAM), which are associated with morbidity and early mortality. Anti cyclic citrullinated peptide (ACCP) antibody has proven to be highly specific for the diagnosis of RA, associated with severe joint damage and may have some role in the pathogenesis of EAM. The aim of this study was to determine the relationship between ACCP antibody and the presence of EAM in RA patients. Seventy four RA patients (ACR 1987) with EAM, > 18 years, more than 6 months duration were included, and an EAM free control, matched by sex and age, for each patient. Demographic, clinical and laboratory variables were compared using t-test, chi-square or Mann-Whitney test. Multivariate analysis was performed: p ≤ 0.05. Patients with EAM presented a greater value of ACCP antibody (116 vs. 34, p < 0.01) and rheumatoid factor (108 vs. 34.5, p < 0.01). Independent association with current smoking habit (p = 0.02, OR = 3.78, 95%: 1.17-12.2), RF positive (p = 0.04, OR 3.23, CI 95%: 1.04 to 11.8) and ACCP antibody positive (p = 0.04, OR 3.23, 95% CI: 1.04-10) was found. The patients with xerostomia (109 vs. 34, p = 0.04), xerophthalmia (150 vs. 34, p < 0.01), subcutaneous nodules (141 vs. 34, p < 0.01) and pulmonary fibrosis (158 vs. 34, p = 0.04) had a higher degree of the ACCP antibody, than controls. In conclusion, ACCP antibody positive, RF positive and smoking were independent risk factors for the development of MEXA.

Mycobacterium leprae virulence-associated peptides are indicators of exposure to M: leprae in Brazil, Ethiopia and Nepal

Silent transmission of Mycobacterium leprae, as evidenced by stable leprosy incidence rates in various countries, remains a health challenge despite the implementation of multidrug therapy worldwide. Therefore, the development of tools for the early diagnosis of M. leprae infection should be emphasised in leprosy research. As part of the continuing effort to identify antigens that have diagnostic potential, unique M. leprae peptides derived from predicted virulence-associated proteins (group IV.A) were identified using advanced genome pattern programs and bioinformatics. Based on human leukocyte antigen (HLA)-binding motifs, we selected 21 peptides that were predicted to be promiscuous HLA-class I T-cell epitopes and eight peptides that were predicted to be HLA-class II restricted T-cell epitopes for field-testing in Brazil, Ethiopia and Nepal. High levels of interferon (IFN)-γ were induced when peripheral blood mononuclear cells (PBMCs) from tuberculoid/borderline tuberculoid leprosy patients located in Brazil and Ethiopia were stimulated with the ML2055 p35 peptide. PBMCs that were isolated from healthy endemic controls living in areas with high leprosy prevalence (EChigh) in Ethiopia also responded to the ML2055 p35 peptide. The Brazilian EChigh group recognised the ML1358 p20 and ML1358 p24 peptides. None of the peptides were recognised by PBMCs from healthy controls living in non-endemic region. In Nepal, mixtures of these peptides induced the production of IFN-γ by the PBMCs of leprosy patients and EChigh. Therefore, the M. leprae virulence-associated peptides identified in this study may be useful for identifying exposure to M. leprae in population with differing HLA polymorphisms.

Obtención y evaluación preliminar de un virus canarypox recombinante como candidato a vacuna antirrábica / Development and preliminary assessment of a recombinant canarypox virus as an antirabic vaccine candidate

En la Argentina, la rabia está circunscripta a algunas provincias del norte. La disponibilidad de nuevas vacunas que eliminen la manipulación del virus rábico y que permitan el control de la enfermedad es de importancia estratégica nacional y regional. Las vacunas basadas en poxvirus recombinantes se han utilizado con éxito como vacunas antirrábicas a nivel mundial. SI bien estos sistemas no están disponibles comercialmente, la plataforma de obtención de virus canarypox (CNPV) recombinantes ya ha sido implementada en nuestro laboratorio. El objetivo de este trabajo fue obtener y evaluar un candidato a vacuna antirrábica basado en CNPV recombinantes que expresan la glicoproteína G (RG) del virus rábico (RV). Se construyó un virus recombinante que expresa la secuencia codificante de RG (CNPV-RG). La inoculación de ratones con este virus indujo altos títulos de anticuerpos seroneutralizantes de RV (3,58 y 9,76 Ul/ml después de una o dos inmunizaciones, respectivamente) y protegió al 78 % de los animales desafiados intracerebralmente con RV. Además, se determinó que el CNPV-RG posee una potencia relativa de 3,5 Ul/ml. Los resultados obtenidos constituyen la primera etapa en la evaluación del CNPV-RG como candidato a vacuna antirrábica. Se requerirán nuevos ensayos para confirmar su utilidad en especies de interés veterinario.

In Argentina, rabies is limited to some northern provinces. Availability of new vaccines abolishing the handling of the rabies virus and allowing disease control has regional and national strategic importance. Vaccines based on recombinant poxviruses have been successfully used as antirabic vaccines worldwide. Although these systems are not commercially available, the platform to obtain recombinant canarypox viruses (CNPV) has been previously set up in our laboratory. The aim of this work was the development and evaluation of an antirabic vaccine candidate based on recombinant CNPV expressing the rabies virus (RV) glycoprotein G (RG). A recombinant virus (CNPV-RG) expressing the RG coding sequence was designed. Inoculation of mice with this virus induced high RV seroneutralizing antibodies (3.58 and 9.76 lU/ml after 1 or 2 immunizations, respectively) and protected 78% of intracerebrally RV-challenged animals. In addition, it was determined that CNPV-RG has a relative potency of 3.5 lU/ml. The obtained results constituted the first stage of CNPV-RG evaluation as antirabic vaccine candidate. Further assays will be necessary to confirm its utility in species of veterinary Interest.

In silico binding predictions for identification of HLA-DR-promiscuous regions and epitopes of mycobacterium tuberculosis protein MPT64 [Rv1980c] and their recognition by human Th1 cells

To identify HLA-promiscuous regions and epitopes of MPT64 [Rv1980c], a major secreted antigen of Mycobacterium tuberculosis, by in silico analysis for binding to HLA-DR molecules. The sequence of mature MPT64 protein [aa 1-205] was analyzed in silico for HLA-DR binding regions and T cell epitopes using ProPred, a web-based prediction server. The prediction results were experimentally verified by testing 20-mer synthetic peptides corresponding to the predicted HLA-DR binding regions and epitopes with T cell lines established from peripheral blood mononuclear cells of PPD-positive and HLA-heterogeneous healthy subjects in Th1 cell assays [antigen-induced proliferation and IFN-gamma secretion]. The in silico analysis for binding of the mature MPT64 sequence to HLA-DR molecules suggested that it could bind to molecules expressed from all HLA-DR alleles [n=51] included in ProPred. Furthermore, ProPred identified 26 epitopes and 8 nonoverlapping HLA-DR binding regions [9-35 aa in length] in the Rv1980c sequence, with 5 regions [aa 20-44, aa 68-102, aa 132-146, aa 164-186 and aa 194-202] being HLA-DR-promiscuous. By using synthetic peptides and T cell lines in Th1 cell assays, 4 peptides of MPT64 [aa 21-40, aa 81-100, aa 171-190 and aa 191-20], from 4 of the 5 HLA-DR-promiscuous regions predicted by ProPred, were experimentally verified to be HLA-DR-promiscuous and to have immunodominant epitopes. The in silico method [ProPred] suggested promiscuous HLA-DR-binding of mature MPT64 and identified HLA-promiscuous and immunodominant regions and epitopes of this protein

Recombinant in vitro assembled hepatitis C virus core particles induce strong specific immunity enhanced by formulation with an oil-based adjuvant

In the present work, immunogenicity of recombinant in vitro assembled hepatitis C virus core particles, HCcAg.120-VLPs, either alone or in combination with different adjuvants was evaluated in BALB/c mice. HCcAg.120-VLPs induced high titers of anti-HCcAg.120 antibodies and virus-specific cellular immune responses. Particularly, HCcAg.120-VLPs induced specific delayed type hypersensitivity, and generated a predominant T helper 1 cytokine pro file in immunized mice. In addition, HCcAg.120-VLPs prime splenocytes proliferate in vitro against different HCcAg.120-specific peptides, depending on either the immunization route or the adjuvant used. Remarkably, immunization with HCcAg.120-VLPs/Montanide ISA888 formulation resulted in a significant control of vaccinia virus titer in mice after challenge with a recombinant vaccinia virus expressing HCV core protein, vvCore. Animals immunized with this formulation had a marked increase in the number of IFN-γ producing spleen cells, after stimulation with P815 cells infected with vvCore. These results suggest the use of recombinant HCV core particles as components of therapeutic or preventive vaccine candidates against HCV.

Down syndrome critical region 1 enhances the proteolytic cleavage of calcineurin

Down syndrome critical region 1 (DSCR1), an oxidative stress-response gene, interacts with calcineurin and represses its phosphatase activity. Recently it was shown that hydrogen peroxide inactivates calcineurin by proteolytic cleavage. Based on these facts, we investigated whether oxidative stress affects DSCR1-mediated inactivation of calcineurin. We determined that overexpression of DSCR1 leads to increased proteolytic cleavage of calcineurin. Convertsely, knockdown of DSCR1 abolished calcineurin cleavage upon treatment with hydrogen peroxide. The PXIIXT motif in the COOH-terminus of DSCR1 is responsible for both binding and cleavage of calcineurin. The knockdown of overexpressed DSCR1 in DS fibroblast cells also abrogated calcineurin proteolysis by hydrogen peroxide. These results suggest that DSCR1 has the ability to inactivate calcineurin by inducing proteolytic cleavage of calcineurin upon oxidative stress.

Murine monoclonal antibodies neutralizing the cytotoxic activity of diphtheria toxin.

In this study, murine monoclonal antibodies that specifically bound to the A and B subunits of diphtheria toxin (DT) were produced by conventional hybridoma technology using the spleens of BALB/c mice immunized with diphtheria DTP vaccine and CRM197. Monoclonal antibodies specific to the A subunit, i.e. clone AC5, as well as those specific to the B subunit, i.e. clone BB7, could neutralize the DT-mediated cytotoxicity to Vero cells in microcultures. The DT neutralizing mechanisms have yet to be determined. The MAbBB7 is hypothesized to either interfere with the DT receptor binding or with the pore forming function of the T domain of the B subunit. The MAbAC5 could neutralize the DT mediated cytotoxicity when mixed with the DT before adding to the Vero cell culture thus suggesting that the antibody interfered with the translocation of the A subunit. The A subunit-antibody complex might be too large to pass through the membrane channel formed by the T domain and thus prevent the accessibility of the A subunit to the cytosolic target. It is also possible that the MAb AC5 blocked the enzymatic active site of the enzyme catalytic subunit. While further experiments are needed to localize the epitopes of the two MAbs on the holo-DT in order to reveal the DT neutralizing mechanisms, both MAbs in their humanized forms have a high potential as human therapeutic antibodies for diphtheria.

Anti-malaria humoral responses in children exposed to Plasmodium falciparum and Schistosoma haematobium

Antibody responses directed against the Plasmodium falciparum antigens, total extract, anti-merozoite surface protein-3 (MSP3b) and glutamate-rich protein (Glurp-R0) were studied in 42 children exposed to both Schistosoma haematobium and P. falciparum infections. The association between levels of the anti-malaria IgG subclasses and IgM with host age, sex, schistosome infection intensity and schistosome specific antibodies was studied before chemotherapeutic treatment of schistosome infections. This showed a significant negative association between schistosome infection intensity and levels of IgG1, IgG3, and IgG4 directed against malaria total extract antigen, and a positive association between levels of anti-schistosome soluble egg antigen IgG2, IgG3, and IgG4 and levels of the same subclasses directed against malaria total extract antigens. The effect of treating schistosome infections with praziquantel on malaria specific responses was also studied. This treatment resulted in increases in significant IgG4 levels against MSP3b and IgM against Glurp R0. Treatment also resulted in a significant decrease in IgG4 levels against Glurp R0. Host age, sex or pre-treatment infection intensity was not associated with the magnitude of change in the two IgG4 responses while males showed a significantly higher increase in levels of IgM. The results suggest cross reactivity between schistosome and malaria antigens in this population.

Plasmodium vivax thrombospondin related adhesion protein: immunogenicity and protective efficacy in rodents and Aotus monkeys

The thrombospondin related adhesion protein (TRAP) is a malaria pre-erythrocytic antigen currently pursued as malaria vaccine candidate to Plasmodium falciparum. In this study, a long synthetic peptide (LSP) representing a P. vivax TRAP fragment involved in hepatocyte invasion was formulated in both Freund and Montanide ISA 720 adjutants and administered by IM and subcutaneous routes to BALB/c mice and Aotus monkeys. We measured specific humoral immune responses in both animal species and performed a sporozoite challenge in Aotus monkeys to assess the protective efficacy of the vaccine. After immunization both mice and Aotus seroconverted as shown by ELISA, and the specific anti-peptide antibodies cross reacted with the parasite in IFAT assays. Only two out of six immunized animals became infected after P. vivax sporozoite challenge as compared with four out of six animals from the control group. These results suggest that this TRAP fragment has protective potential against P. vivax malaria and deserves further studies as vaccine candidate.

Cien años de la enfermedad de Alzheimer: La inmunoterapia ¿una esperanza? / One hundred years of Alzheimer's disease: Immunotherapy a hope?

In 1906 Alois Alzheimer, described the cerebral lesions characteristic of the disorder that received his name: senile plaques and neurofibrillary tangles. Alzheimer's disease (AD) is now, 100 years after, the most prevalent form of dementia in the world. The longer life expectancy and aging of the population renders it as a serious public health problem of the future. Urgent methods of diagnosis and treatment are required, since the definitive diagnosis of AD continues to be neuropathologic. In the last 30 years several drugs have been approved to retard the progression of the disease; however, there are still no curative or preventive treatments. Although still in experimentation, the visualization of amyloid deposition by positron emission tomography or magnetic resonance imaging will allow in vivo diagnosis of AD. In addition, experiments with the amyloid vaccine are still ongoing, and very recent data suggest that intravenous gammaglobulins may be beneficial and safe for the treatment of AD.

Direct Detection of Reactive Nitrogen Species in Experimental Autoimmune Uveitis

PURPOSE: Demonstrate unequivocally the generation of nitric oxide in experimental autoimmune uveoretinitis by electron spin resonance spectroscopy (ESR) using ferrous iron complex of N-methyl-D-glucamine dithiocarbamate, (MGD)2-Fe2+, as a spin trap. METHODS: Experimental autoimmune uveitis was induced in Lewis rats, and at the peak of the intraocular inflammation, the animals received intravitreous injections of the spin trap. The retina and choroid dissected from the enucleated globes were subjected to ESR. Similarly, the retina and choroid obtained at the peak of experimental autoimmune uveo-retinitis (EAU) were placed in a vial containing luminal, and chemiluminescence was counted on a Packard liquid scintillation analyzer. RESULTS: The ESR three-line spectrum (g=2.04; a(N)=12.5 G) obtained was characteristic of the adduct [(MGD)2-Fe2+-NO]. The majority of this signal was eliminated by the inducible nitric oxide synthase (iNOS) specific inhibitor aminoguanidine injected inflamed retina was detected when compared with that of the non inflamed controls. The chemiluminescent activity was further increased two-fold by the addition of bicarbonate to the inflamed retina; the phenomenon is attributable only to the presence of a high steady-state concentration of peroxynitrite. CONCLUSIONS: The study shows an unequivocal presence of nitric oxide in EAU retina and choroid and the generation of peroxynitrite. High levels of these reactive nitrogen species generated in the inflamed retina and choroids are certain to cause irreversible tissue damage, especially at the susceptible sites such as photoreceptors.

Evolution of PTH assays / Evolução dos ensaios para paratormônio

PTH metabolism is complex and the circulating forms include the intact 1-84 molecule as well as several carboxyl-terminal fragments. The first generation of PTH assays included several types of competitive assays, with specificities that spanned carboxyl, mid-region and amino-terminal portions of the molecule. The limitations of these assays and the methodological evolution led to the description of 2nd generation non-competitive immunometric assays for PTH in the late 80's, based on the recognition of the PTH molecule by two different antibodies, one directed against de amino-terminal and other against the carboxyl-terminal segments. The observation that in some circumstances "long" carboxyl-terminal segments were also measured by 2nd generation assays led to the development of 3rd generation assays based on amino-terminal specific antibodies that are specific for the first amino acids, measuring only the molecular forms that activate PTH1R. The practical and cost-benefit advantages of these assays are still debatable. The recent observation that carboxyl-terminal fragments of PTH have biological activity via a distinct receptor than PTH1R, points to the future need of more than one assay in order to evaluate parathyroid hormone function.

O metabolismo do PTH e complexo e as formas circulantes incluem o PTH 1-84, assim como fragmentos C-terminal. A primeira geração de ensaios para o PTH incluía vários ensaios competitivos com especificidades para as regiões carboxi, meio da molécula e amino-terminal. A limitação destes ensaios e a evolução metodológica, levaram ao desenvolvimento dos ensaios não competitivos de 2ª. geração no final dos anos 80, baseados no reconhecimento por dois anticorpos diferentes, contra a porção amino e carboxi-terminal respectivamente. A observação que em algumas circunstâncias segmentos carboxiterminais longos também eram detectados, levou ao desenvolvimento dos ensaios de 3ª. geração, baseados em anticorpos específicos para a porção aminoterminal com maior especificidade para os primeiros aminoácidos, e assim mensurando apenas a forma molecular que ativa o PTH1R. As vantagens práticas e o custo-benefício deste ensaio ainda e motivo de debate. A observação recente de que fragmentos carboxiterminais têm atividade biológica via receptor distinto, aponta para a necessidade futura de mais de um ensaio para avaliar a função do paratormônio.

Antigen-binding Characteristics of Circulating IgG Autoantibodies to Cytokeratin 18 Protein in Patients with Nonallergic Asthma

Cytokeratin 18 (CK18) protein was identified as an airway epithelial cell autoantigen associated with nonallergic asthma. Cleavage of CK18 protein by caspase-3 is a marker of early apoptosis in epithelial cells. It has been shown that the expression of active caspase-3 was increased in bronchial epithelial cells of asthmatic patients, when compared with healthy controls. To investigate the antigen-binding characteristics of IgG autoantibodies to CK18 protein in nonallergic asthma, the bindings of IgG autoantibodies to the fragments of CK18 protein cleaved by caspase-3 were analyzed by Western blot using serum samples from three patients with nonallergic asthma. Recombinant human CK18 protein was treated by caspase-3 and cleaved into N-terminal fragment (1-397 amino acids) and C-terminal fragment (398-430 amino acids). The binding capacity of IgG autoantibodies to N-terminal fragment of CK18 was maintained in one patient and reduced in other two patients. IgG autoantibodies from all three patients did not bind to C-terminal fragment of CK 18. In conclusion, IgG autoantibodies to CK18 protein from patients with nonallergic asthma seems to preferentially bind to the whole molecule of CK18 protein and their antigen-binding characteristics were heterogeneous among the patients with nonallergic asthma.

Human immunodeficiency virus type 1 neutralization by plasma from B or F genotype infected individuals

Anti-human immunodeficiency virus type 1 (HIV-1) "binding antibodies" (antibodies capable of binding to synthetic peptides or proteins) occur throughout HIV-1 infection, are high-titered and highly cross-reactive, as confirmed in this study by analyzing plasma from B and F genotype HIV-1 infected individuals. Plasma from individuals infected with clade F HIV-1 displayed the most frequent cross-reactivity, in high titers, while Bbr plasma showed much higher specificity. Similarly, neutralization of a reference HIV-1 isolate (HIV-1 MN) was more frequently observed by plasma from F than B genotype infected individuals. No significant difference was seen in neutralization susceptibility of primary B, Bbr or F clade HIV-1 by plasma from individuals infected with the classical B (GPGR) or F HIV-1, but Bbr (GWGR) plasma were less likely to neutralize the F genotype primary HIV-1 isolates. The data indicate that both B and F genotype derived vaccines would be equally effective against B and F HIV-1 infection, with a slightly more probable effectiveness for F than B genotype. Although the Bbr variant appears to induce a much more specific humoral immune response, the susceptibility in neutralizing the Brazilian HIV-1 B genotype Bbr variant is similar to that observed with the classical B genotype HIV-1.

Antibody recognition of synthetic peptides mimicking immunodominant regions of HIV-1 p24 and p17 proteins / Reconocimiento por anticuerpos de péptidos sintéticos que imitan regiones inmunodominantes de las proteínas p24 y p17 de VIH-1

The gag gene of HIV-1 encodes a single open reading frame of 55 kDa that contains three subdomains: the matrix domain (p17), the capsid domain (p24) and the nucleocapsid domain (p15). The p24 and p17 proteins have a predominant a-helical structure and perform important functions throughout thevirallife-cycle. The determination of gag-specific antibodies is important because declining titers of these antibodies herald clinical deterioration.In this work we present the results obtained on immunoreactiviy of synthetic peptides that mimic immunogenic a-helical regions of p24 and p17. The influence on the immunoreactivity of structural modifications in native sequences, including the addition of non immunogenic side chains: AAAC- and -CAAA on both side of minimal epitopes was evaluated in indirect and competitive enzymeimmunoassays. The conformational characteristcs to the peptides were analysed by circular dichroism and these results were correlated with that obtained in the immunoassays. It was shown that the reactivity of peptides mimicking short a-helical regions of p24 and p17 is improved by adding short non immunogenic chains on both N- and C- terminus. These modifications enhanced the immobilization of the peptides onto the solid support and allowed more accesibility to the minimal epitopes byspecific antibodies, in solution.

El gen gag del VIH-1 codifica una región de 55kDA que contiene tres subdominios: matriz (p17), cápside (p24) y nucleocápside (p15). Las proteínas p24 y p17 tienen una estructura predominante helicoidal y cumplen un rol importante en el ciclo de vida del virus. En este trabajo presentamos los resultados de inmunorreactividad de péptidos sintéticos que imitan regiones helicoidales de p24 y p17. Utilizando enzimoinmunoensayos se evaluó la influencia de modificaciones en las secuencias nativas sobre la capacidad de reconocimiento de anticuerpos específicos en solución y en fase sólida, incluyendo el agregado de cadenas no inmunogénicas en ambos extremos de los epitopes mínimos. La conformación de los péptidos se determinó por dicroísmo circular y los resultados se correlacionaron con los de inmunorreactividad. Se observó que la capacidad de reconocimiento de anticuerpos por péptidos pequeños que imitan estructuras helicoidales de p24 y p17 mejoró con el agregado de cadenas no inmunogénicas en ambos extremos de los epitopes. Estas modificaciones mejoran la inmovilización sobre las superficies sólidas y permiten una mayor accesibilidad de los anticuerpos a los epitopes mínimos en solución.