933,816 research outputs found

    Primary vs. Secondary Antibody Deficiency: Clinical Features and Infection Outcomes of Immunoglobulin Replacement

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    <div><p>Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.</p></div

    Antibody Conjugation and Formulation

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    In an era where ultra-high antibody concentrations, high viscosities, low volumes, auto-injectors, and long storage requirements are already complex problems with the current unconjugated monoclonal antibodies on the market the formulation demands for antibody-drug conjugates (ADCs) are significant. Antibodies have historically been administered at relatively low concentrations through intravenous (IV) infusion due to their large size and the inability to formulate for oral delivery. Due to the high demands associated with IV infusion and the development of novel antibody targets and unique antibody conjugates more accessible routes of administration such as intramuscular (IM), and subcutaneous (SC) are being explored. This review will summarize various site-specific and non-site-specific antibody conjugation techniques in the context of antibody-drug conjugates (ADCs) and the demands of formulation for high concentration clinical implementation

    Insights into antibody catalysis: Structure of an oxygenation catalyst at 1.9-Å resolution

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    The x-ray crystal structures of the sulfide oxidase antibody 28B4 and of antibody 28B4 complexed with hapten have been solved at 2.2-Å and 1.9-Å resolution, respectively. To our knowledge, these structures are the highest resolution catalytic antibody structures to date and provide insight into the molecular mechanism of this antibody-catalyzed monooxygenation reaction. Specifically, the data suggest that entropic restriction plays a fundamental role in catalysis through the precise alignment of the thioether substrate and oxidant. The antibody active site also stabilizes developing charge on both sulfur and periodate in the transition state via cation-pi and electrostatic interactions, respectively. In addition to demonstrating that the active site of antibody 28B4 does indeed reflect the mechanistic information programmed in the aminophosphonic acid hapten, these high-resolution structures provide a basis for enhancing turnover rates through mutagenesis and improved hapten design

    Tropomyosin antibody: the specific localization of tropomyosin in nonmuscle cells

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    An antibody against purified chicken skeletal muscle tropomyosin is used in indirect immunofluorescence to visualize the localization of tropomyosin in a variety of nonmuscle cells. The antibody produces a fluorescent pattern which is very similar to that obtained with an actin-specific antibody. This pattern is composed of fluorescent fibers which are shown to be coincident with the fibers seen with phase-contrast optics. High resolution epifluorescent microscopy reveals that fibers stained with the actin antibody show a continuous fluorescence, while fibers reacted with the tropomyosin antibody show a periodic fluorescence. Measurements indicate that the lengths of the fluorescent segments are variable with an average of 1.2 μm while the spacing between segments is approximately 0.4 μm

    Combined DNA extraction and antibody elution from filter papers for the assessment of malaria transmission intensity in epidemiological studies.

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    BACKGROUND: Informing and evaluating malaria control efforts relies on knowledge of local transmission dynamics. Serological and molecular tools have demonstrated great sensitivity to quantify transmission intensity in low endemic settings where the sensitivity of traditional methods is limited. Filter paper blood spots are commonly used a source of both DNA and antibodies. To enhance the operational practicability of malaria surveys, a method is presented for combined DNA extraction and antibody elution. METHODS: Filter paper blood spots were collected as part of a large cross-sectional survey in the Kenyan highlands. DNA was extracted using a saponin/chelex method. The eluate of the first wash during the DNA extraction process was used for antibody detection and compared with previously validated antibody elution procedures. Antibody elution efficiency was assessed by total IgG ELISA for malaria antigens apical membrane antigen-1 (AMA-1) and merozoite-surface protein-1 (MSP-142). The sensitivity of nested 18S rRNA and cytochrome b PCR assays and the impact of doubling filter paper material for PCR sensitivity were determined. The distribution of cell material and antibodies throughout filter paper blood spots were examined using luminescent and fluorescent reporter assays. RESULTS: Antibody levels measured after the combined antibody/DNA extraction technique were strongly correlated to those measured after standard antibody elution (p < 0.0001). Antibody levels for both AMA-1 and MSP-142 were generally slightly lower (11.3-21.4%) but age-seroprevalence patterns were indistinguishable. The proportion of parasite positive samples ranged from 12.9% to 19.2% in the different PCR assays. Despite strong agreement between outcomes of different PCR assays, none of the assays detected all parasite-positive individuals. For all assays doubling filter paper material for DNA extraction increased sensitivity. The concentration of cell and antibody material was not homogenously distributed throughout blood spots. CONCLUSION: Combined DNA extraction and antibody elution is an operationally attractive approach for high throughput assessment of cumulative malaria exposure and current infection prevalence in endemic settings. Estimates of antibody prevalence are unaffected by the combined extraction and elution procedure. The choice of target gene and the amount and source of filter paper material for DNA extraction can have a marked impact on PCR sensitivity

    Site-selective multi-porphyrin attachment enables the formation of a next-generation antibody-based photodynamic therapeutic

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    Herein we present a significant step towards next-generation antibody-based photodynamic therapeutics. Site-selective modification of a clinically relevant monoclonal antibody, with a serum-stable linker bearing a strained alkyne, allows for the controlled Cu-free “click” assembly of an in vitro active antibody-based PDT agent using a water soluble azide porpyhrin

    Behaviour of non-donor specific antibodies during rapid re-synthesis of donor specific HLA antibodies after antibody incompatible renal transplantation

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    Background: HLA directed antibodies play an important role in acute and chronic allograft rejection. During viral infection of a patient with HLA antibodies, the HLA antibody levels may rise even though there is no new immunization with antigen. However it is not known whether the converse occurs, and whether changes on non-donor specific antibodies are associated with any outcomes following HLA antibody incompatible renal transplantation. Methods: 55 patients, 31 women and 24 men, who underwent HLAi renal transplant in our center from September 2005 to September 2010 were included in the studies. We analysed the data using two different approaches, based on; i) DSA levels and ii) rejection episode post transplant. HLA antibody levels were measured during the early post transplant period and corresponding CMV, VZV and Anti-HBs IgG antibody levels and blood group IgG, IgM and IgA antibodies were quantified. Results: Despite a significant DSA antibody rise no significant non-donor specific HLA antibody, viral or blood group antibody rise was found. In rejection episode analyses, multiple logistic regression modelling showed that change in the DSA was significantly associated with rejection (p = 0.002), even when adjusted for other antibody levels. No other antibody levels were predictive of rejection. Increase in DSA from pre treatment to a post transplant peak of 1000 was equivalent to an increased chance of rejection with an odds ratio of 1.47 (1.08, 2.00). Conclusion: In spite of increases or decreases in the DSA levels, there were no changes in the viral or the blood group antibodies in these patients. Thus the DSA rise is specific in contrast to the viral, blood group or third party antibodies post transplantation. Increases in the DSA post transplant in comparison to pre-treatment are strongly associated with occurrence of rejection

    Improving sensitivity of oral fluid testing in IgG prevalence studies: application of mixture models to a rubella antibody survey

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    A method for the analysis of age-stratified antibody prevalence surveys is applied to a previously reported survey of antibody to rubella virus using oral fluid samples in which the sensitivity of the assay used was shown to be compromised. The age-specific distribution of the quantitative results of antibody tests using oral fluids is modelled as a mixture of strong positive, weak positive and negative components. This yields maximum likelihood estimates of the prevalence at each age and demonstrates that, when used in conjunction with mixture modelling techniques, the results of antibody prevalence studies using oral fluids accurately reflect those obtained using sera

    Vaccination with complete adjuvant-added inactivated virus vaccine of Japanese encephalitis to swine, rabbits and chicks for preventing viremia (epidemiological study on Japanese encephalitis 25)

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    As a step towards the elimination of Japanese encephalitis virus in natural surroundings, we inoculated pigs, rabbits and chicks with inactivated Japanese encephalitis vaccine supplemented with complete or incomplete Freund's adjuvant twice at one-week interval. Subsequently, we compared HI antibody titers of the groups inoculated with vaccine containing complete Freund's adjuvant (pigs, rabbits, chicks), of the group inoculated with vaccine containing incomplete adjuvant (rabbits), ar;d of the groups inoculated with vaccine containing no adjuvant (pigs, rabbits, chicks), and also observations on changes in the antibody titers due to natural infection. In a certain portion of these animals neutralizing antibody titers were also determined. The results of this study are briefly summarized as follows. 1. In the groups of pigs and rabbits inoculated with vaccine containing complete Freund's adjuvant, titers of HI antibody and neutralizing antibody were higher than those inoculated with vaccine containing no adjuvant and their high titers persisted. Further, in the group of chicks inoculated with inactivated Japanese encephalitis vaccine containing complete Freund's adjuvant, HI antibody titers were higher and persistent as compared with the antibody titers in the chicks inoculated with inactivated Japanese encephalitis vaccine alone. 2. In the rabbits inoculated with inactivated Japanese encephalitis vaccine contammg incomplete adjuvant, HI antibody titers were lower than in those receiving the vaccine with complete adjuvant, but it has been demonstrated clearly that vaccination of inactivated Japanese encephalitis vaccine supplemented with incomplete adjuvant brings about less sideeffects. Hence such a method of vaccination can be applied as the vaccination with least side-effects. 3. With respect to natural infection of swine, on August 27 when the pigs were thought to have been infected, there was observed a rise in antibody titers. And on being infected with Japanese encephalitis, the antibodies formed in those pigs inoculated with inactivated Japanese ence- phalitis vaccine with or without complete adjuvant proved to be all 2-ME resistant type, whereas the antibodies produced in the control groups not receiving such a vaccination were 2-ME sensitive antibody.</p
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