An Ibero-American inter-laboratory trial to evaluate serological tests for the detection of anti-<i>Neospora caninum</i> antibodies in cattle

We carried out an inter-laboratory trial to compare the serological tests commonly used for the detection of specific Neospora caninum antibodies in cattle in Ibero- American countries. A total of eight laboratories participated from the following countries: Argentina (n = 4), Brazil (n = 1), Peru (n = 1), Mexico (n = 1), and Spain (n = 1). A blind panel of well-characterized cattle sera (n = 143) and sera representative of the target population (n = 351) was tested by seven in-house indirect fluorescent antibody tests (IFATs 1–7) and three enzyme-linked immunosorbent assays (ELISAs 1–3; two in-house and one commercial). Diagnostic performance of the serological tests was calculated and compared according to the following criteria: (1) the BPre-test information,^ which uses previous epidemiological and serological data; (2) the BMajority of tests,^ which classifies a serumas positive or negative according to the results obtained by most tests evaluated. Unexpectedly, six tests showed either sensitivity (Se) or specificity (Sp) values lower than 90%. In contrast, the best tests in terms of Se, Sp, and area under the ROC curve (AUC) values were IFAT 1 and optimized ELISA 1 and ELISA 2. We evaluated a high number of IFATs, which are the most widely used tests in Ibero-America. The significant discordances observed among the tests regardless of the criteria employed hinder control programs and urge the use of a common test or with similar performances to either the optimized IFAT 1 and ELISAs 1 and 2.Facultad de Ciencias Veterinaria

Effectiveness analysis of resistance and tolerance to infection

<p>Abstract</p> <p>Background</p> <p>Tolerance and resistance provide animals with two distinct strategies to fight infectious pathogens and may exhibit different evolutionary dynamics. However, few studies have investigated these mechanisms in the case of animal diseases under commercial constraints.</p> <p>Methods</p> <p>The paper proposes a method to simultaneously describe (1) the dynamics of transmission of a contagious pathogen between animals, (2) the growth and death of the pathogen within infected hosts and (3) the effects on their performances. The effectiveness of increasing individual levels of tolerance and resistance is evaluated by the number of infected animals and the performance at the population level.</p> <p>Results</p> <p>The model is applied to a particular set of parameters and different combinations of values. Given these imputed values, it is shown that higher levels of individual tolerance should be more effective than increased levels of resistance in commercial populations. As a practical example, a method is proposed to measure levels of animal tolerance to bovine mastitis.</p> <p>Conclusions</p> <p>The model provides a general framework and some tools to maximize health and performances of a population under infection. Limits and assumptions of the model are clearly identified so it can be improved for different epidemiological settings.</p

Expression profile of genes associated with mastitis in dairy cattle

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF- α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with and three without mastitis per breed. Gene expression was analyzed by real-time PCR. IL-10 gene expression was higher in the group of BW and Gyr cows with mastitis compared to animals free of infection from both breeds (p < 0.05). It was also higher in BW Holstein animals with clinical mastitis (p < 0.001), but it was not significant when Gyr cows with and without mastitis were compared (0.05 < p < 0.10). Among healthy cows, BW Holstein animals tended to present a higher expression of all genes studied, with a significant difference for the IL-2 and IFN- γ genes (p < 0.001). For animals with mastitis no significant difference in gene expression was observed between the two breeds. These findings suggest that animals with mastitis develop a preferentially cell-mediated immune response. Further studies including larger samples are necessary to better characterize the gene expression profile in cows with mastitis

Androgen Receptor Drives Cellular Senescence

The accepted androgen receptor (AR) role is to promote proliferation and survival of prostate epithelium and thus prostate cancer progression. While growth-inhibitory, tumor-suppressive AR effects have also been documented, the underlying mechanisms are poorly understood. Here, we for the first time link AR anti-cancer action with cell senescence in vitro and in vivo. First, AR-driven senescence was p53-independent. Instead, AR induced p21, which subsequently reduced ΔN isoform of p63. Second, AR activation increased reactive oxygen species (ROS) and thereby suppressed Rb phosphorylation. Both pathways were critical for senescence as was proven by p21 and Rb knock-down and by quenching ROS with N-Acetyl cysteine and p63 silencing also mimicked AR-induced senescence. The two pathways engaged in a cross-talk, likely via PML tumor suppressor, whose localization to senescence-associated chromatin foci was increased by AR activation. All these pathways contributed to growth arrest, which resolved in senescence due to concomitant lack of p53 and high mTOR activity. This is the first demonstration of senescence response caused by a nuclear hormone receptor

An Ibero-American inter-laboratory trial to evaluate serological tests for the detection of anti-<i>Neospora caninum</i> antibodies in cattle

We carried out an inter-laboratory trial to compare the serological tests commonly used for the detection of specific Neospora caninum antibodies in cattle in Ibero- American countries. A total of eight laboratories participated from the following countries: Argentina (n = 4), Brazil (n = 1), Peru (n = 1), Mexico (n = 1), and Spain (n = 1). A blind panel of well-characterized cattle sera (n = 143) and sera representative of the target population (n = 351) was tested by seven in-house indirect fluorescent antibody tests (IFATs 1–7) and three enzyme-linked immunosorbent assays (ELISAs 1–3; two in-house and one commercial). Diagnostic performance of the serological tests was calculated and compared according to the following criteria: (1) the BPre-test information,^ which uses previous epidemiological and serological data; (2) the BMajority of tests,^ which classifies a serumas positive or negative according to the results obtained by most tests evaluated. Unexpectedly, six tests showed either sensitivity (Se) or specificity (Sp) values lower than 90%. In contrast, the best tests in terms of Se, Sp, and area under the ROC curve (AUC) values were IFAT 1 and optimized ELISA 1 and ELISA 2. We evaluated a high number of IFATs, which are the most widely used tests in Ibero-America. The significant discordances observed among the tests regardless of the criteria employed hinder control programs and urge the use of a common test or with similar performances to either the optimized IFAT 1 and ELISAs 1 and 2.Facultad de Ciencias Veterinaria

Impaired Neutrophil Migration Associated with Specific Bovine CXCR2 Genotypes

Bovine mastitis continues to be the most detrimental factor for profitable dairying. Recent research conducted within our laboratory has identified a genetic marker in the CXCR2 gene associated with mastitis susceptibility. The objective of the present study was to evaluate the migratory ability of neutrophils from cows with different CXCR2 +777 genotypes. Neutrophils isolated from peripheral blood of 30 Holstein cows were tested for in vitro migration and adhesion molecule expression. Cows with the CC or GC genotype at CXCR2 +777 showed significantly lower neutrophil migration to recombinant human interleukin-8 (rhIL-8) than cows with the GG genotype (P < 0.05). Cows with the CC genotype at CXCR2 +777 also showed decreased neutrophil migration to zymosan-activated serum compared to these same cows (P < 0.05). Decreased upregulation of CD18 expression was observed after stimulation with rhIL-8 in cows expressing the CXCR2 +777 CC genotype compared to cows expressing the GG genotype (P < 0.05). A similar trend was observed for CD11b (P < 0.10). However, no difference in CD62 downregulation was observed with respect to genotype. These results provide initial evidence for a phenotypic association between a single nucleotide polymorphism and neutrophil function in dairy cows, as well as potential insight into specific mechanisms affected in cows more susceptible to mastitis

The bovine CXCR1 gene is highly polymorphic

Several single nucleotide polymorphisms (SNP) in the bovine CXCR1 gene have been implicated in resistance to mastitis and milk somatic cell counts in several sample populations of Holstein dairy cows. As such, a more thorough understanding of SNP present in and near the bovine CXCR1 gene is needed. This study identified 36 SNP in the coding region and surrounding sequences of CXCR1 in 88 Holstein dairy cows. Four SNP induced amino acid changes and 1 SNP an early stop codon. Two amino acid changes occur in the third intracellular loop and C-terminus in locations tied to intracellular signaling. The 36 SNP could be subdivided into 4 separate linkage groups. Using representative or 'tag' SNP from each linkage group, haplotypes or the combination of SNP found on a single allele were generated to increase the specificity of an animal's genetic background. Four haplotypes were identified that represented 99% of the sample population. The haplotypes generated using tag SNP agreed with haplotypes generated from SNP causing amino acid changes. In conclusion, the CXCR1 gene is highly polymorphic and has potential implications towards genetic selection and understanding host factors that increase the risk of infection.Fil: Pighetti, Gina M.. University of Tennessee; Estados UnidosFil: Kojima, Cheryl J.. University of Tennessee; Estados UnidosFil: Wojakiewicz, Leszek. University of Tennessee; Estados UnidosFil: Rambeaud, Magdalena. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Isolation of Sarcocystis neurona from an opossum (Didelphis albiventris) in Argentina

Sarcocystis neurona is an Apicomplexan parasite which affects awide range of animal hosts. This protozoan is the main cause ofequine protozoal myeloecephalitis (EPM) inWestern Hemispherehorses. The parasite reproduces sexually in the intestine ofdefinitive hosts (DH) and asexually in tissues of intermediate andaberrant hosts. The geographical distribution of S. neurona isrelated with the distribution its definitive hosts, the opossumsDidelphis virginiana and D. albiventris. A recent serological studyconducted in Argentinean horses using S. neurona antigenrevealed an overall seroprevalence of 26.1%. However, the parasitehas not been isolated in Argentina. Tissues from an opossum (D.albiventris) hunted by dogs in a farm from the central region ofBuenos Aires province were collected. Horses raised in the farmshowed a 50% (10/20) S. neurona seroprevalence. One seropositivehorse developed neurological signs and evidenced clinicalimprovement after a 2 month treatment with Ponazuril. A completenecropsy of the opossum was conducted and the intestinalmucosal scraping was subjected to a parasitological study withsucrose solution. A high amount of Sarcocystis spp. oocysts/sporocystswere observed (Fig. 1). DNA was extracted from concentratedoocysts with a commercial kit (ZR Fecal DNA, ZymoResearch). The sample was identified as S. neurona by specificPCR-restriction fragment length polymorphism (RFLP) and bysequencing of a fragment of the 18S rRNA gene. Approximately 5 x105 oocysts were subjected to a pepsin-HCl digestion followed bya physical disruption. Released sporozoites were used to infectfresh BM cell cultures, maintained by 3 passages during 2 monthsand further preserved in liquid nitrogen. This study represents thefirst isolation of S. neurona in Argentina. Further studies will beconducted in order to identify antigen expression as well as tocompare genetic characteristics between the isolated strain andreference strains.Fil: Moré, Gastón Andrés. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Rambead, M.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; ArgentinaFil: Braun, F.. No especifíca;Fil: Campero, Lucía María. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Walkosksi, A.. No especifíca;Fil: Venturini, M. C.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina10th International Equine Infectious Diseases ConferenceCiudad Autónoma de Buenos AiresArgentinathe Equine Infectious Disease Conferenc