Anti-leishmania antibodies in cerebrospinal fluid from dogs with visceral leishmaniasis

Visceral leishmaniasis in Brazil is caused by Leishmania (Leishmania) chagasi and the dog is its most important reservoir. The clinical features in dogs include loss of weight, lymphadenopathy, renal failure, skin lesions, fever, hypergammaglobulinemia, hepatosplenomegaly, anemia, and, rarely, neurological symptoms. Most infected animals develop active disease, characterized by high anti-leishmania antibody titers and depressed lymphoproliferative ability. Antibody production is not primarily important for protection but might be involved in the pathogenesis of tissue lesions. An ELISA test was used to determine if there is an association between neurological symptoms and the presence of anti-L. chagasi antibodies in cerebrospinal fluid (CSF). Thirty serum and CSF samples from symptomatic mixed breed dogs (three with neurological symptoms) from a region of high incidence of visceral leishmaniasis in Brazil were examined for antibody using total parasite antigen and anti-dog IgG peroxidase conjugate. A high level of L. chagasi antibodies was observed in sera (mean absorbance ± SD, 1.939 ± 0.405; negative control, N = 20, 0.154 ± 0.074) and CSF (1.571 ± 0.532; negative control, N = 10, 0.0195 ± 0.040) from all animals studied. This observation suggests that L. chagasi can cause breakdown of filtration barriers and the transfer of antibodies and antigens from the blood to the CSF compartment. No correlation was observed between antibody titer in CSF and neurological symptoms.

The anti-IRBP IgG1 and IgG2a response does not correlate with susceptibility to experimental autoimmune uveitis

Susceptibility to experimental autoimmune uveitis (EAU) in inbred mice has been associated with a dominant Th1 response. Elevated anti-inter-photoreceptor retinoid-binding protein (anti-IRBP) IgG2a/IgG1 antibody ratios have been implicated as candidate markers to predict disease severity. In the present study, both the anti-IRBP antibody isotype and severity of EAU phenotypes were examined in 4 non-isogenic genetically selected mouse lines to determine if they can be used as general markers of disease. Mice between 8 and 12 weeks old selected for high (H III) or low (L III) antibody response and for maximum (AIR MAX) or minimum (AIR MIN) acute inflammatory reaction (AIR) were immunized with IRBP. Each experiment was performed with at least 5 mice per group. EAU was evaluated by histopathology 21 days after immunization and the minimal criterion was inflammatory cell infiltration of the ciliary body, choroid and retina. Serum IgG1- and IgG2a-specific antibodies were determined by ELISA. EAU was graded by histological examination of the enucleated eyes. The incidence of EAU was lower in AIR MIN mice whereas in the other strains approximately 40% of the animals developed the disease. Low responder animals did not produce anti-IRBP IgG2a antibodies or interferon-gamma. No correlation was observed between susceptibility to EAU and anti-IRBP isotype profiles. Susceptibility to EAU is related to the intrinsic capacity to mount higher inflammatory reactions and increased production of anti-IRBP IgG2a isotype is not necessarily a marker of this immunologic profile.

Use of anti-PGL-1 antibodies to monitor therapy regimes in leprosy patients

The suitability of IgM antibodies to PGL-1 for monitoring the response to multidrug therapy (MDT) was sequentially tested by ELISA in 105 leprosy patients, and bacterial indexes (BI) were also determined. Patients were divided into 3 groups: group 1, 34 multibacillary (MB) patients treated for 12 months with MDT-MB; group 2, 33 MB patients treated for 24 months with MDT-MB, and group 3, 38 paucibacillary (PB) patients treated for 6 months with MDT-PB. Untreated MB patients exhibited higher antibody levels (mean ± SEM): group 1 (6.95 ± 1.35) and group 2 (12.53 ± 2.02) than untreated PB patients (1.28 ± 0.35). There was a significant difference (P < 0.01) in anti-PGL-1 levels in group 1 patients: untreated (6.95 ± 1.35) and treated for 12 months (2.78 ± 0.69) and in group 2 patients: untreated (12.53 ± 2.02) and treated for 24 months (2.62 ± 0.79). There was no significant difference between untreated (1.28 ± 0.35) and treated (0.62 ± 0.12) PB patients. Antibody levels correlated with BI. The correlation coefficient (Pearson’s r) was 0.72 before and 0.23 (P < 0.05) after treatment in group 1 and 0.67 before and 0.96 (P < 0.05) after treatment in group 2. BI was significantly reduced (P < 0.01) after 12 and 24 months on MDT (group 1: 1.26-0.26; group 2: 1.66-0.36). Our data indicate that monitoring anti-PGL-1 levels during MDT may be a sensitive tool for evaluating treatment efficacy. These data also indicate that the control of leprosy infection can be obtained with 12 months of MDT in MB patients.

Pattern of functional antibody activity against Haemophilus influenzae type b (Hib) in infants immunized with diphtheria-tetanus-pertussis/Hib Brazilian combination vaccine

We evaluated the functional activity of Haemophilus influenzae B (Hib) antibodies elicited in a group of infants immunized with the diphtheria-tetanus-pertussis vaccine combined with an Hib vaccine produced totally in Brazil after technological transfer of Hib vaccine production from Glaxo SmithKline, Belgium. Blood samples from immunized infants (N = 985) were collected for the determination of Hib antibodies. Total Ig and IgM and IgG subclasses of antibodies against polyribosyl ribitol phosphate (PRP) were analyzed by ELISA. Almost all vaccinees (97.56%, 961/985) developed a strong anti-PRP IgG antibody response (≥1.0 μg/mL), while an anti-PRP IgM response was observed in 64.24% (634/985) of them (≥0.15 μg/mL). Only 18.88% (186/985) of the infants in the group with high PRP antibody IgG concentrations (≥1.0 μg/mL) developed a high IgM antibody response. Anti-PRP IgG antibody levels were significantly higher than anti-PRP IgM. These results demonstrate the predominance of IgG antibodies over IgM antibodies in response to PRP, with a ratio of 17:1. IgG antibodies were predominantly of the IgG1 subclass. An increase in IgG avidity was also observed during the course of immunization.

Anti-Leishmania titers and positive skin tests in patients cured of kala-azar

Visceral leishmaniasis (VL), also known as kala-azar, is an important public health problem. If not treated, virtually all clinically symptomatic patients die within months. The diagnosis is based on the Montenegro skin test (MST) and anti-Leishmania titers. Nevertheless, the time required for cured individuals living in a leishmaniasis-endemic area to present a positive skin test and negative anti-Leishmania serology is known. To determine the cellular and humoral immune response profile in relation to different times post-VL cure, a cross-sectional study was conducted on subjects from a kala-azar endemic area in Paço do Lumiar, MA, Brazil, on the basis of 1995-2005 notifications reported by the National Health Foundation/Regional Coordination of Maranhão. We visited cured individuals with a history of VL within the last 10 years. Seventy-four subjects (30 females) ranging in age from 1 to 44 years were included, all of them symptom free at the time of the study. A cellular immune response was observed in 73 (98.6%) subjects, whereas no significant antibody titers were detected by indirect immunofluorescence (IIF) in the sera of 69 (93.2%) cases. Ten years post-cure, 39 (52%) subjects had a positive MST and negative IIF reaction, while in one subject the skin and anti-Leishmania serology tests were negative. Two other subjects were positive in both tests 1 year after cure. These data suggest that a cellular immune response may still be present in subjects cured of VL regardless of post-cure time, and that the parasite persists in the host after clinical cure of the disease. This would explain the persistence of significant Leishmania sp antibody titers in some subjects after treatment.

Expression, production, and renaturation of a functional single-chain variable antibody fragment (scFv) against human ICAM-1

Intercellular adhesion molecule-1 (ICAM-1) is an important factor in the progression of inflammatory responses in vivo. To develop a new anti-inflammatory drug to block the biological activity of ICAM-1, we produced a monoclonal antibody (Ka=4.19×10−8 M) against human ICAM-1. The anti-ICAM-1 single-chain variable antibody fragment (scFv) was expressed at a high level as inclusion bodies in Escherichia coli. We refolded the scFv (Ka=2.35×10−7 M) by ion-exchange chromatography, dialysis, and dilution. The results showed that column chromatography refolding by high-performance Q Sepharose had remarkable advantages over conventional dilution and dialysis methods. Furthermore, the anti-ICAM-1 scFv yield of about 60 mg/L was higher with this method. The purity of the final product was greater than 90%, as shown by denaturing gel electrophoresis. Enzyme-linked immunosorbent assay, cell culture, and animal experiments were used to assess the immunological properties and biological activities of the renatured scFv.

El escepticismo radical de Pierre Gassendi contra la filosofía natural de los aristotélicos

Este artículo tiene como objetivo dar cuenta del escepticismo radical de Pierre Gassendi propuesto en el Exercitationes paradoxicae Adversus Aristoteleos (Disertaciones paradójicas contra los aristotélicos). Para dar cuenta de ello nuestro artículo se divide en tres momentos: Primero, damos cuenta de la estructura de la obra; segundo, se presentan los argumentos centrales propuestos por Gassendi para comprender su actitud crítica al escolasticismo. Y tercero, se muestra la crítica que realiza a la lógica aristotélica. La idea fundamental que sostenemos en este trabajo es que la actitud crítica y de libre pensador que caracterizó a Gassendi tuvo su origen directo en la actitud escéptica. Además, revisar su obra de juventud y su actitud filosófica nos permite comprender una parte importante del alcance del escepticismo en la reforma de la filosofía natural del siglo XVII.

Los momentos políticos de Lévinas: desde una trama "anti-política" hasta su estado justo e igualitario

En varios pasajes de la obra de Lévinas vemos que su manera de presentarse frente a lo político es ambigua. O bien, resulta mejor decir que solo en apariencia el "objeto" de lo político en sus reflexiones sobre la justicia y el Estado resultan claras; hay una suerte de equívoco que vale la pena precisar y distinguir. Así, el objetivo central de este trabajo es describir dos momentos políticos en Lévinas leídos en clave Estado, como una figura posible de la política; desentrañamos así la trama anti-política en tanto crítica política al Estado, para llegar a la trama del Estado justo e igualitario, lo que abre nuevas puertas para pensar lo político. A partir de esta descripción reflexionamos, por un lado, una postura crítica frente a las ideas sobre el Estado de Lévinas desde las vinculaciones ético-políticas que hace, tal como la de Alberto Sucasas. Y por otro, en contraposición a éstas, las interesantes y extravagantes lecturas que hace Miguel Abensour de Lévinas creyendo que las relaciones ético-políticas levinasianas aportan a renovar críticamente una nueva figura de Estado dejando el terreno político y estatal abierto a nuevas reflexiones.

L'Anti-libelle, en vers burlesques

[Mazarinade. 1649]

Tercer informe de seguimiento a la política anticíclica del Gobierno Nacional en el eje de infraestructura de transporte

Gestión del conocimiento

Inducción de anticuerpos policlonales anti-hormonas esteroides para su aplicación en radioinmunoanalisis (por) Martha Merino Ruíz

Tesis (Maestría en Ciencias, con especialidad en Biología de la Reproducción) U.A.N.L.