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1.
Huda A Lind P Christoffersen AB Jungersen G 《Veterinary immunology and immunopathology》2003,94(3-4):95-103
A total of 315 cattle were tested for infection with Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) at three consecutive samplings, using the interferon-gamma (IFN-gamma) test on whole blood and bacteriological culture of faecal samples. Of 205 cattle from 10 infected herds 99 (48%) were positive in the IFN-gamma test on at least one sampling using "IDEXX-criteria" for interpretation, and of 110 cattle from five non-infected herds three (3%) were positive. Forty-four animals from infected and one from non-infected herds tested positive at all three samplings. Although support for the specificity of the IFN-gamma test was provided by these results, they also indicate problems with false positives. Approximately half of the positive animals did not give the same result at all three samplings, indicating that repeated testing increases the chance of detecting reactors. Changing, or fluctuating, IFN-gamma test results occurred most frequently in animals younger than 1 year, indicating that the IFN-gamma test should be applied only to animals 1 year and older. M. paratuberculosis was isolated from 16 (4%) of 371 cattle, all from infected herds. Fifteen culture-positive cattle tested positive at least once in the IFN-gamma test. It was not possible to predict from the IFN-gamma test result the number of animals that would eventually develop disease. However, the test may be useful to detect animals that have been exposed to M. paratuberculosis earlier in their lives, and the testing of young cattle could be included in a control program to check for the effectiveness of preventing transmission of infection to calves and to identify animals at risk of developing disease later in their lives. 相似文献
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Andersen CB Ballut L Johansen JS Chamieh H Nielsen KH Oliveira CL Pedersen JS Séraphin B Le Hir H Andersen GR 《Science (New York, N.Y.)》2006,313(5795):1968-1972
In higher eukaryotes, a multiprotein exon junction complex is deposited on spliced messenger RNAs. The complex is organized around a stable core, which serves as a binding platform for numerous factors that influence messenger RNA function. Here, we present the crystal structure of a tetrameric exon junction core complex containing the DEAD-box adenosine triphosphatase (ATPase) eukaryotic initiation factor 4AIII (eIF4AIII) bound to an ATP analog, MAGOH, Y14, a fragment of MLN51, and a polyuracil mRNA mimic. eIF4AIII interacts with the phosphate-ribose backbone of six consecutive nucleotides and prevents part of the bound RNA from being double stranded. The MAGOH and Y14 subunits lock eIF4AIII in a prehydrolysis state, and activation of the ATPase probably requires only modest conformational changes in eIF4AIII motif I. 相似文献
3.
Thomsen VT Nielsen SS Thakur A Jungersen G 《Veterinary immunology and immunopathology》2012,145(1-2):316-322
Vaccination of cattle against Mycobacterium avium subsp. paratuberculosis (MAP) provides partial protection by delayed shedding of MAP and reduced numbers of clinically affected animals. The duration of vaccine induced immune response is not known. The primary objective of this study was therefore to characterize the long-term effect of whole-cell based vaccination against MAP on the immune response. A secondary objective was to evaluate whether immunodiagnosis of MAP and Mycobacterium bovis infections is affected by MAP vaccination. Two studies were performed: (1) A retrospective longitudinal study including 895 vaccinated and 2526 non-vaccinated dairy cows in 9 Danish dairy herds aiming at characterizing the long-term antibody-response to vaccination; and (2) a cross-sectional study of responses in the IFN-γ assay carried out in 140 vaccinated animals in two herds to evaluate the effect of vaccination on the cell-mediated immune response and to evaluate a possible interference with the diagnosis of M. bovis infections. The results showed that 37% of samples from vaccinated animals and 5% of samples from non-vaccinated animals, respectively, were test positive in the milk antibody ELISA. The prevalence of antibody responses of the vaccinated animals was relatively constant from 2 to 6 years of age, but decreased in older animals. Among the 140 vaccinated animals 88% tested positive with the IFN-γ test to johnin PPD and 50% responded to PPDb with IFN-γ production above a similar cut-off. Although Denmark is free of M. bovis, two of the vaccinated animals responded with higher IFN-γ levels when cultured with PPDb compared to PPDa. In conclusion, immunization with whole-cell MAP vaccines elicits both humoral and cell-mediated immune reactions, which may interfere with surveillance and diagnosis of both MAP and M. bovis infections using currently available tests. 相似文献
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Mycobacterium avium subsp. paratuberculosis (MAP) is a slow growing bacterium that can infect ruminants and remain latent for years without development of any clinical signs or disease. Diagnosis is often based on detection of MAP antibodies in milk or serum samples or culture of bacteria from faeces; however, these diagnostic tools are often not applicable until years after infection. Detection of MAP specific cell-mediated immune (CMI) responses can serve as an alternative and be implemented in a diagnostic tool. CMI responses can be measured at an early stage of infection, prior to development of antibodies and shedding of detectable amounts of MAP. At present, available diagnostic assays are limited by the lack of MAP specific antigens included in these assays resulting in poor specificity. The objective of this review is to provide a systematic overview of diagnostic MAP antigen candidates described to date with special emphasis on antigen candidates tested for CMI responses. Relevant information on 115 different MAP antigens was systematically extracted from literature and summarized in 6 tables of CMI antigens, secreted antigens, cell wall and membrane antigens, lipoprotein antigens, heat shock antigens and hypothetical antigens. Strategies for evaluation of novel antigen candidates are discussed critically. Relatively few of the described antigens were evaluated for their use in CMI based diagnostic assays and so far, no obvious candidate has been identified for this application. Most of the novel diagnostic candidates were evaluated in few animals and it is recommended that an appropriate sample size is included for evaluation of antigen candidates in future studies. 相似文献
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Nielsen EO Lauritsen KT Friis NF Enøe C Hagedorn-Olsen T Jungersen G 《Veterinary microbiology》2005,111(1-2):41-50
A novel indirect ELISA test using deoxycholate extracted antigens coated onto a hydrophobic polystyrene surface for measurement of serum antibodies specific for Mycoplasma hyosynoviae was developed. Sensitivity and specificity of the test were found to be superior to previous ELISAs as tested on porcine serum following experimental Mycoplasma infections as well as by analysis of samples from one Danish herd known to be free of M. hyosynoviae and samples from two Norwegian herds without clinical suspicion of M. hyosynoviae infections since their establishment. The epidemiology of M. hyosynoviae infection was then investigated in Danish pig herds with evidence of clinical M. hyosynoviae arthritis (MhA herds, n = 4) and in herds with M. hyosynoviae-carriers among slaughter pigs, but with limited clinical lameness (MhC herds, n = 4). M. hyosynoviae bacteriaemia and tonsil-carrier state were determined by culture of cross-sectional samples of whole-blood (n = 238) and tonsil scrapings (n = 322), respectively. Levels of serum antibodies (n = 396) were measured by the novel indirect ELISA test. There was no significant difference in the ELISA results between the MhA and the MhC herds. Pigs that were tonsil-carriers had a significantly higher response in the ELISA test (P < 0.001) than non-carriers. Slaughter pigs showed higher ELISA values (P < 0.001) and they were more prone to be tonsil-carriers (P < 0.001). The most critical period for spread of the infection seems to be the nursery period (4-12 weeks). The results indicate that M. hyosynoviae infection progresses similarly in herds irrespective of the presence of clinical arthritis. Thus, clinical arthritis due to M. hyosynoviae is probably triggered by other host or herd factors than low levels of serum antibodies or by differences in virulence factors between M. hyosynoviae strains. 相似文献
8.
Mikkelsen H Aagaard C Nielsen SS Jungersen G 《Veterinary immunology and immunopathology》2011,143(1-2):46-54
Paratuberculosis is a chronic infection of the intestine of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Early stage MAP infection can be detected by measuring specific cell mediated immune responses, using the whole blood interferon-γ (IFN-γ) assay. Available IFN-γ assays use purified protein derivative of MAP (PPDj) which are complex antigen mixtures with low specificity. The objectives of this study were to evaluate immunogenicity and specificity of 14 novel recombinant antigens for use in the IFN-γ assay and to assess the consistency of IFN-γ responses. The study included blood samples from 26 heifers from a MAP infected herd, collected three times with four to five-week intervals, and blood samples from 60 heifers of a non-infected herd collected once. Heifers of the non-infected herd were used to establish cut-off values for each antigen. The case definition was an animal with ≥ 2 positive tests for ≥ 4 antigens, resulting in 13 cases and 13 non-cases. IFN-γ levels of cases were higher compared to IFN-γ levels of non-cases (P<0.05). The results of the IFN-γ assay using PPDj did not correlate well with the results using the novel antigens. PPDj produced elevated IFN-γ responses of samples from both the non-infected and the MAP infected herd, indicating unspecific IFN-γ responses and showed low consistency. Three latency proteins, LATP-1, LATP-2 and LATP-3 gave positive IFN-γ tests that correlated very well with the case definition suggesting high immunogenicity. Three tested antigens, LATP-2, MAP-1 and MAP-2 have no homologue in the M. avium subsp. avium or M. bovis genome and could be promising diagnostic antigens, especially LATP-2 correlated highly with the case definition. 相似文献
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Liselotte Rothmann Norup Tina S. Dalgaard Janne Pleidrup Anders Permin Torben W. Schou Gregers Jungersen Dorte R. Fink Helle R. Juul-Madsen 《Veterinary parasitology》2013,191(1-2):187-190
Increasingly large numbers of poultry are held in production systems with access to outdoor areas. In these systems intestinal helminths are found with flock prevalences of up to 100%. Helminth infections influence chicken health negatively, which is why the following investigation has been performed.In the present experiment, 20 chickens of two inbred chicken lines containing the major histocompatibility complex (MHC) haplotypes, B14 and R5, were inoculated with 500 embryonated Ascaridia galli eggs. The A. galli-specific IgG titres of serum samples and the excretion of A. galli eggs in chicken faeces were measured for a period of 81 weeks.The level of excreted A. galli eggs measured as eggs per gram chicken faeces (EPG) varied greatly between chickens in each line. Significant differences were found between the two lines and with the R5 chickens reaching the highest levels. Likewise, the A. galli-specific IgG titres in serum differed significantly between the two lines, and an inverse relationship between infection level (EPG) and antibody titres was found. Although this inverse relationship suggests that humoral immunity may be involved in protection against A. galli infection, the high antibody titres did not prevent continued infection. 相似文献
10.
Mikkelsen H Aagaard C Nielsen SS Jungersen G 《Veterinary immunology and immunopathology》2012,147(1-2):69-76
Paratuberculosis is a chronic infection of the intestine of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Early stage MAP infection can be detected by measuring cell-mediated immune responses using the interferon gamma (IFN-γ) assay. Whole blood samples are cultured overnight with specific MAP antigens followed by quantification of IFN-γ by ELISA. It is recommended that the time interval from sampling to culture does not exceed eight hours but addition of the co-stimulating cytokine interleukin 12 (IL-12) or anti-IL-10 antibodies to culture have been demonstrated to enhance IFN-γ responses of cultures stimulated with Johnin purified protein derivative (PPDj). Here we examined the correlation of IFN-γ production in response to PPDj and 15 recombinant antigens in day-old blood samples from heifers 10-21 months of age from a MAP infected herd with addition of either recombinant bovine IL-12 or anti-bovine IL-10 antibody with IFN-γ production in sample day samples. IFN-γ responses of sample day samples showed high correlation with responses to some antigens in day-old samples with addition of IL-12 or anti-IL-10 antibodies to cultures, indicating that day-old protocols can be applied as an alternative to the conventional IFN-γ protocol. Immunogenicity of the novel antigens was generally low for day-old samples. The most promising antigen using the day-old protocol with addition of IL-12 was latency protein LATP-2 as correlations, immunogenicity and diagnostic specificity collectively was high. The latency protein LATP-1 was the most promising antigen in the day-old protocol with addition of anti-IL-10 antibodies. 相似文献