Monoclonal antibodies against sporangia and spores of Marteilla sp. (Protozoa: Ascetospora)

6 pages, 4 figures.Digestive glands of mussels Mytilus edulis from Brittany, France, infected with Marteilia sp. (Ascetospora) were used to purify the parasite. A modification of a previously used punfication protocol increased purification efficiency, permitting sporangial primordia and sporangia of Marteilia sp. to be obtained. Mouse (Balb/c) monoclonal antibodies were generated against this parasite. From the fusion, 26 monoclonal antibodies against Marteilia sp. were obtained. Antibodies from 6 clones reacted only with Marteilia sp. cells and not with normal host tissues. Four of these antibodies (1/1-3, 3/1-1, 4/1-1 and 6/2-3) reacted with the sporangia wall and two with the spore cytoplasm (9/1-1 and 12/5-1), Antibodies cross-reacted with Marteilia refringens from Mytilus galloprovincialis obtained in the Ría de Vigo, Spain.J.A.F.R. acknowledges Xunta de Galicia, Spain, for his with research fellowship at the IIM-CSIC and Caixa Galicia for his research fellowship at IFREMER - La Tremblade.Peer reviewe

First amyloid β1-42 certified reference material for re-calibrating commercial immunoassays

INTRODUCTION: Reference materials based on human cerebrospinal fluid were certified for the mass concentration of amyloid beta (Aβ)1-42 (Aβ42 ). They are intended to be used to calibrate diagnostic assays for Aβ42 . METHODS: The three certified reference materials (CRMs), ERM-DA480/IFCC, ERM-DA481/IFCC and ERM-DA482/IFCC, were prepared at three concentration levels and characterized using isotope dilution mass spectrometry methods. Roche, EUROIMMUN, and Fujirebio used the three CRMs to re-calibrate their immunoassays. RESULTS: The certified Aβ42 mass concentrations in ERM-DA480/IFCC, ERM-DA481/IFCC, and ERM-DA482/IFCC are 0.45, 0.72, and 1.22 μg/L, respectively, with expanded uncertainties (k = 2) of 0.07, 0.11, and 0.18 μg/L, respectively. Before re-calibration, a good correlation (Pearson's r > 0.97), yet large biases, were observed between results from different commercial assays. After re-calibration the between-assay bias was reduced to < 5%. DISCUSSION: The Aβ42 CRMs can ensure the equivalence of results between methods and across platforms for the measurement of Aβ42

An innate defense peptide BPIFA1/SPLUNC1 restricts influenza A virus infection

The airway epithelium secretes proteins that function in innate defense against infection. BPI fold-containing family member A1 (BPIFA1) is secreted into airways and has a protective role during bacterial infections, but it is not known whether it also has an antiviral role. To determine a role in host defense against influenza A virus (IAV) infection and to find the underlying defense mechanism we developed transgenic mouse models that are deficient in BPIFA1 and used these, in combination with in vitro 3D mouse tracheal epithelial cell (mTEC) cultures, to investigate its antiviral properties. We show that BPIFA1 has a significant role in mucosal defense against IAV infection. BPIFA1 secretion was highly modulated after IAV infection. Mice deficient in BPIFA1 lost more weight after infection, supported a higher viral load and virus reached the peripheral lung earlier, indicative of a defect in the control of infection. Further analysis using mTEC cultures showed that BPIFA1-deficient cells bound more virus particles, displayed increased nuclear import of IAV ribonucleoprotein complexes and supported higher levels of viral replication. Our results identify a critical role for BPIFA1 in the initial phase of infection by inhibiting the binding and entry of IAV into airway epithelial cells

Light and electron immunohistochemical assays on paramyxean parasites

6 pages, 3 figures.[EN] An indirect fluorescent antibody test (IFAT) incorporating a polyclonal antibody to Marteilia sydneyi recognized spornlating stages of M. sydneyi from Saccostrea commercialis but not those of Marteilia refringens, M. maurini, Marteilia sp. and Marteilioides branchialis from Ostrea edulis, Mytilus galloprovincialis, Mytilus edulis and Saccostrea commercialis respectively. This indicates that the antibody had a high specificity and that the other parasites were immunologically distinct from M. sydneyi. Immunoelectron microscopy was used to investigate background labelling and the specificity of the antibody to antigenic sites. It showed that though most immunoglobulins were specific to parasite epitopes, some reacted to host tissue. IFAT's based on three monoclonal antibodies raised against Marteilia sp. did not recognise spores or other stages of M. sydneyi. An immunogold-silver staining technique using the polyclonal antibody to M. sydneyi failed to identify the presumed presporulation stage of M. sydneyi in the connective tissue of a recently infected host. This suggests the antigens were stage-specific. Thus a DNA probe rather than immunohistochemical tests may be more useful in investigating the life cycle of this parasite.[FR] Dans un test en immunofluorescence indirecte, des anticorps polyclonaux spécifiques de Marteilia sydneyi ont réagi positivement contre les formes sporulées de ce parasite associé à l'huître Saccostrea commercialis. Par contre, aucune réaction n'a été observée avec les formes sporulées de Marteilia refringens, M. maurini, Marteilia sp. et Marteilioides branchialis qui sont respectivement associées à Ostrea edulis, Mytilus galloprovincialis, Mytilus edulis et Saccostrea commercialis. Ces résultats ont montré que les anticorps polyclonaux sont hautement spécifiques et que les autres parasites sont immunologiquement différents de M. sydneyi. La réactivité des anticorps a été étudiée en microscopie électronique, ce qui a révélé que la majorité des immunoglobulines sont spécifiques d'épitopes parasitaires, certaines réagissant avec les tissus de l'hôte. Par ailleurs, trois anticorps monoclonaux spécifiques de Marteilia sp., parasite de Mytilus edulis se sont révélés négatifs en immunofluorescence indirecte vis-à-vis des spores et des autres stades de M. sydneyi. Selon la technique d'immunogold, les anticorps polyclonaux spécifiques de M. sydneyi n'ont pas permis d'identifier le stade présporal présumé de ce parasite dans le tissu conjonctif d'un hôte récemment infecté. Ceci suggère que ces anticorps sont spécifiques de certains stades. Ainsi, un test utilisant une sonde ADN pourrait être mieux adapté que des tests immunologiques pour étudier le cycle de développement de ce parasite.This paper represents part of doctoral dissertation of the senior author whilst supported by an Australian Postgraduate Research Award.Peer reviewe

Characterisation of shrimp haemocytes and plasma components by monoclonal antibodies

Characterisation of shrimp haemocytes and plasma components by monoclonal antibodie

First evidence of the activation of Cg-timp, an immune response component of pacific oysters, through a damage-associated molecular pattern pathway

International audienc

Transient expression assays with the proximal promoter of a newly characterized actin gene from the oyster Crassostrea gigas11The sequences have been deposited in the GenBank database under accession number AF026063.

AbstractWe undertook the characterization of an actin gene and its proximal promoter in the oyster Crassostrea gigas. A complete actin cDNA was identified, sequenced and its amino acid sequence deduced. Comparative analysis showed a high homology with actin of other species and that this gene is closer to the cytoplasmic form of actins than to the muscle type. A probe derived from the 5′-untranslated region of the cDNA was then used to isolate the actin gene from a genomic library. The gene was sequenced and shown to contain a single 643 bp intron. A 1670 bp fragment upstream from the open reading frame was isolated and sequenced. This upstream region displays typical features of actins such as a serum response element (CarG box). This fragment was cloned into the promoterless vector pGL3-basic and the resulting construct was transfected into cells of dissociated oyster heart primary cultures. Its capacity to express the luciferase in this in vitro homologous system was monitored and showed high expression levels. This is the first complete actin sequence reported so far for the oyster C. gigas and its promoter is the first available among bivalves

Aquaporin molecular characterization in the sea bass (Dicentrarchus labrax): The effect of salinity on AQP1 and AQP3 expression

Euryhaline fish possess the ability to compensate for environmental salinity changes through hydro-mineral regulation. A number of proteins have been studied in order to understand water and ion exchanges, known as fish osmoregulation. Sea-bass (Dicentrarchus labrax) cDNA sequences encoding a homologue of mammalian aquaporin (termed AQP1) and a homologue of mammalian aquaglyceroporin (termed AQP3) have been isolated and sequenced. The aquaporin amino acid sequences share respectively more than 60% and 65% identity with other known aquaporins. We have shown that salinity influences aquaporin expression levels in the gill, kidney and digestive tract, the main osmoregulatory organs. AQP1 may have a major osmoregulatory role in water transport in kidney and gut in SW-acclimated fish, whereas AQP3 could be implicated in gill water transport in FW-acclimated fish. (c) 2007 Elsevier Inc. All rights reserved.</p