Genetic parameters for�resistance to the Salmonella abortusovis vaccinal strain Rv6 in sheep

An experimental population (1216 lambs from 30 sires) of the Inra401 sheep was created in an Inra flock to allow QTL detection for susceptibility to Salmonella infection, wool and carcass traits. The Inra401 is a sheep composite line developed from two breeds: Berrichon du Cher and Romanov. At 113 days of age on average, the lambs were inoculated intravenously with 10(8 )Salmonella abortusovis Rv6 (vaccinal strain). They were slaughtered 10 days after the inoculation. Several traits were measured at inoculation and/or slaughtering to estimate the genetic resistance of the lambs to Salmonella infection: specific IgM and IgG1 antibody titres, body weight loss, spleen and pre-scapular node weights and counts of viable Salmonella persisting in these organs. This paper presents a quantitative analysis of the genetic variability of the traits related to salmonellosis susceptibility. The heritabilities of the traits varied between 0.10 and 0.64 (significantly different from zero). Thus, in sheep as well as in other species, the determinism of resistance to Salmonella infection is under genetic control. Moreover, the correlations between the traits are in agreement with the known immune mechanisms. The genetic variability observed should help QTL detection

Towards the Establishment of a Porcine Model to Study Human Amebiasis

BACKGROUND: Entamoeba histolytica is an important parasite of the human intestine. Its life cycle is monoxenous with two stages: (i) the trophozoite, growing in the intestine and (ii) the cyst corresponding to the dissemination stage. The trophozoite in the intestine can live as a commensal leading to asymptomatic infection or as a tissue invasive form producing mucosal ulcers and liver abscesses. There is no animal model mimicking the whole disease cycle. Most of the biological information on E. histolytica has been obtained from trophozoite adapted to axenic culture. The reproduction of intestinal amebiasis in an animal model is difficult while for liver amebiasis there are well-described rodent models. During this study, we worked on the assessment of pigs as a new potential model to study amebiasis. METHODOLOGY/PRINCIPAL FINDINGS: We first co-cultured trophozoites of E. histolytica with porcine colonic fragments and observed a disruption of the mucosal architecture. Then, we showed that outbred pigs can be used to reproduce some lesions associated with human amebiasis. A detailed analysis was performed using a washed closed-jejunal loops model. In loops inoculated with virulent amebas a severe acute ulcerative jejunitis was observed with large hemorrhagic lesions 14 days post-inoculation associated with the presence of the trophozoites in the depth of the mucosa in two out four animals. Furthermore, typical large sized hepatic abscesses were observed in the liver of one animal 7 days post-injection in the portal vein and the liver parenchyma. CONCLUSIONS: The pig model could help with simultaneously studying intestinal and extraintestinal lesion development

A compilation of global bio-optical in situ data for ocean-colour satellite applications - version three

A global in situ data set for validation of ocean colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data set comprises in situ observations of the following variables: spectral remote-sensing reflectance, concentration of chlorophyll-a, spectral inherent optical properties, spectral diffuse attenuation coefficient, and total suspended matter. Data were obtained from multi-project archives acquired via open internet services or from individual projects acquired directly from data providers. Methodologies were implemented for homogenization, quality control, and merging of all data. Minimal changes were made on the original data, other than conversion to a standard format, elimination of some points, after quality control and averaging of observations that were close in time and space. The result is a merged table available in text format. Overall, the size of the data set grew with 148 432 rows, with each row representing a unique station in space and time (cf. 136 250 rows in previous version; Valente et al., 2019). Observations of remote-sensing reflectance increased to 68 641 (cf. 59 781 in previous version; Valente et al., 2019). There was also a near tenfold increase in chlorophyll data since 2016. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) are included in the final table. By making the metadata available, provenance is better documented and it is also possible to analyse each set of data separately. The compiled data are available at https://doi.org/10.1594/PANGAEA.941318 (Valente et al., 2022)

A compilation of global bio-optical in situ data for ocean colour satellite applications – version three

A global in situ data set for validation of ocean colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data set comprises in situ observations of the following variables: spectral remote-sensing reflectance, concentration of chlorophyll-a, spectral inherent optical properties, spectral diffuse attenuation coefficient, and total suspended matter. Data were obtained from multi-project archives acquired via open internet services or from individual projects acquired directly from data providers. Methodologies were implemented for homogenization, quality control, and merging of all data. Minimal changes were made on the original data, other than conversion to a standard format, elimination of some points, after quality control and averaging of observations that were close in time and space. The result is a merged table available in text format. Overall, the size of the data set grew with 148 432 rows, with each row representing a unique station in space and time (cf. 136 250 rows in previous version; Valente et al., 2019). Observations of remote-sensing reflectance increased to 68 641 (cf. 59 781 in previous version; Valente et al., 2019). There was also a near tenfold increase in chlorophyll data since 2016. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) are included in the final table. By making the metadata available, provenance is better documented and it is also possible to analyse each set of data separately. The compiled data are available at https://doi.org/10.1594/PANGAEA.941318 (Valente et al., 2022)

Induction of IL-17A production during an antigen-specific inflammatory response in the bovine mammary gland

International audienceMammary gland (MG) response to bacterial intrusion is driven by the innate immune system, but can be modulated by the adaptive immunity. The model antigen ovalbumin (OVA) has already been shown to induce an antigen-specific inflammatory response when infused into the MG of cows previously sensitized by a systemic immunization but not of control naive cows. The objective of our study was to characterize this immune response. An overexpression of the genes encoding IL-17A, IL-17F, IL-21, IL-22 and INF-γ was found in milk cells and mammary tissue RNA extracts in the early phase of the inflammatory response following intramammary infusion of OVA. At the protein level, IL-17A was detected in milk as soon as 8 h post-challenge, and both IL-17A and IFN-γ concentrations peaked at 12 to 24 h postchallenge. Expression of IL-17A, as revealed by immunohistochemistry, was located in epithelial cells, in leukocytes in the connective tissue and in association with the epithelium, and in migrated alveolar leukocytes of challenged quarters. In vitro, an OVA-restimulation of PBMC or whole blood of sensitized cows induced the production of IL-17A and IFN-γ. The characterization of the IL-17A-producing leukocytes is underway. These results suggest that a Th17-type immune response can be induced in the MG by immunization to protein antigens, in parallel to a Th1-type response. As IL-17A is known to be involved in the immune defense against extracellular bacteria, and as we previously showed that bovine mammary epithelial cells respond to IL-17A by producing chemokines and antimicrobial peptides, we hypothesize that this cytokine contributes to the defense of the mammary gland against mastitis-causing bacteria

Le point sur l'épidémiologie et la physiopathologie des encéphalopathies spongiformes des ruminants

National audienceThe bovine spongiform encephalopathy epidemic resulted from cattle feeding with contaminated meat and bone meal (MBM). The recycling of infected carcases into MBM amplified the dissemination of the infectious agent, The origin of the disease and the nature of the agent - infectious protein, virus, ... - as web as the possibility of its transmission to humans remain unknown, Most of the current knowledge about spongiform encephalopathies, including the physiopathology of BSE, has been extrapolated from results of many year studies of scrapie in sheep. But some differences exist between diseases according to the host species. One of these differences is the absence of infection in lymphoid tissue of cattle whereas it has been showed to be one of the main features of the disease in sheep, It can then be postulated that dissemination of the agent could occur mainly by the nervous route in the bovine, whereas lymphoid system is likely to be an important and early replication site in sheep, Origin of neuronal death, which could explain symptoms encountered in these conditions, is still poorly understood, PrP, a normal protein found at the membrane of numerous cell types, accumulates in its pathological isoform, PrPsc, in the central nervous system and is strongly involved in the pathological process, since its presence and its genetic polymorphism considerably influences the progress of infection, But PrP is probably not the only protein involved in the transmission and the spread of the agent in the infected host.L’épidémie d’encéphalopathie spongiforme bovine (ESB) résulte de la consommation par les bovins de farines de viandes et d’os contaminées. En recyclant l’agent infectieux, ces farines ont permis d’amplifier la dissémination d’une maladie dont l’origine et l’agent responsable demeurent inconnus. Les hypothèses sur la nature protéique ou/et virale de l’agent sont évoquées, ainsi que l’éventualité d’une transmission à l’homme. Une grande partie de nos connaissances des encéphalopathies spongiformes résulte des études réalisées de longue date sur la tremblante des ovins. En particulier, l’idée que l’on peut se faire de la physiopathologie de l’infection des bovins est en grande partie extrapolée à partir du résultat d’infections expérimentales réalisées chez le mouton. Toutefois, la contamination des tissus lymphoïdes périphériques, qui est la règle au cours de la phase de dissémination dans l’organisme de l’agent de la tremblante, semble absente dans le cas de la maladie bovine. Il est donc possible que ce type de tissus, considéré comme infectieux en matière de tremblante, le soit peu au cours de la phase préclinique dans le cas de l’ESB. L’atteinte du système nerveux central des bovins pourrait alors résulter d’une dissémination empruntant les voies nerveuses. Les mécanismes conduisant à la mort neuronale responsable des symptômes observés restent mal connus. La protéine PrP, protéine normale de la membrane de nombreux types cellulaires, et qui s’accumule sous sa forme pathologique PrPSC au niveau des lésions est indispensable au processus pathologique. Son polymorphisme influence considérablement le devenir de l’infection, mais elle ne peut être tenue pour seule responsable de la transmission de la maladie

Immunolocalisation of an ABC transporter, P-glycoprotein, in the eggshells and cuticles of free-living and parasitic stages of <em>Haemonchus contortus</em>

International audienceRecent data have suggested that P-glycoprotein (Pgp), working as membrane efflux “pumps”, plays a major role in the transport of anthelmintic drugs in parasitic nematodes of ruminants. Flow cytometry analyses has shown that active Pgp is probably present in the external layers of Haemonchus contortus eggshells, following staining with the mouse monoclonal anti-human MDR1 antibody UIC2, which binds to Pgp in its active conformation. We evaluated the presence and distribution of this protein in the envelopes (eggshells and cuticles) of H. contortus and compared the various stages (eggs, L1–L2 larvae, L3 larvae, adult male and female worms). Electrophoresis revealed a 170-kDa band, corresponding to the molecular weight of Pgp in all stages. Indirect immunofluorescence staining with UIC2 showed Pgp to be located in the external layer of eggshells or cuticles. Transmission electron microscopy was used to localise Pgp more accurately in the three layers of the eggshells and cuticles. The conformation and biological functions of this protein, which we did not expect to find in such structures, remain to be determined

T helper 17-associated cytokines are produced during antigen-specific inflammation in the mammary gland.

Infectious mastitis cuts down milk production profitability and is a major animal welfare problem. Bacteria-induced inflammation in the mammary gland (MG) is driven by innate immunity, but adaptive immunity can modulate the innate response. Several studies have shown that it is possible to elicit inflammation in the MG by sensitization to an antigen subsequently infused into the lumen of the gland. The objective of our study was to characterize the inflammation triggered in the MG of cows sensitized to ovalbumin, by identifying the cytokines and chemokines likely to play a part in the reaction. Among immunized cows, responders mobilized locally high numbers of leukocytes. An overexpression of the genes encoding IL-17a, IL-17F, IL-21, IL-22 and INF-γ was found in milk cell RNA extracts in the early phase of the inflammatory response. At the protein level, IL-17A was detected in milk as soon as the first sampling time (8 h post-challenge), and both IL-17A and IFN-γ concentrations peaked at 12 to 24 h post-challenge. In mammary tissue from challenged quarters, overexpression of the genes encoding IL-17A, IL-17F, IL-21, IL-22, IL-26 and IFN-γ was observed. Neutrophil-attracting chemokines (CXCL3 and CXCL8) were found in milk, and overexpressed transcripts of chemokines attracting lymphocytes and other mononuclear leukocytes (CXCL10, CCL2, CCL5, CCL20) were detected in mammary tissue. Expression of IL-17A, as revealed by immunohistochemistry, was located in epithelial cells, in leukocytes in the connective tissue and in association with the epithelium, and in migrated alveolar leukocytes of challenged quarters. Altogether, these results show that antigen-specific inflammation in the MG was characterized by the production of IL-17 and IFN-γ. The orientation of the inflammatory response induced by the antigen-specific response has the potential to strongly impact the outcome of bacterial infections of the MG

Imagerie de l’animal à la cellule : stratégies et méthodologies offertes par l’UMR ISP

National audienc