Interferon-gamma response of PBMC indicates productive pseudorabies virus (PRV) infection in swine

In Chinese Meishan/German Landrace cross-bred swine F2 generation interferon gamma (IFN-gamma) production by peripheral blood mononuclear cells (PBMC) was determined directly ex vivo at different time points after survival of a virulent pseudorabies virus (PRV) infection. This reactivity was compared with the reactivity of na?ve PBMC. Significant IFN-gamma production was determined in ELISA and ELISPOT only after in vitro PBMC re-stimulation with PRV and not with the closely related bovine herpesvirus BHV-1. The PRV-specific IFN-gamma secretion from re-stimulated PBMC showed high levels 6 days after infection, before the presence of serum antibodies, and it persisted at a high level over a 3 months period. The response of a group of eight piglets infected intranasally with PRV varied. Only two animals showed the expected typical fever response. PRV specific IFN-gamma production by PBMC clearly indicated that infection had occurred. Early significant IFN-gamma production by primed PBMC turned out to be a reliable and specific ex vivo marker for cellular response against productive PRV infection in swine before antibody formation.     

Biological variation in random and leukotriene B4-directed migration of canine neutrophils

Seasonal, sexual, parental and age-related effects on peripheral blood neutrophil migration were studied in 25 dogs. Random and chemotactic movements were estimated by measuring migration towards buffer and leukotriene B4, respectively. Significant effects were seen only in the comparison between the two sexes. Neutrophils from bitches exhibited 19% greater random migration but 10% smaller chemotactic responsiveness than neutrophils from male dogs. A progesterone-mediated suppression of chemotaxis is hypothesized in metoestral bitches. It is concluded that the observed differences are probably too subtle to play any role in combatting bacterial infections, but may constitute a source of bias in the evaluation of isolated cases of disease-associated defective chemotaxis.     

Immune response in pigs to Aujeszky's disease viruses defective in glycoprotein g1 or gX.

Two Aujeszky's disease virus glycoprotein genes, gX and g1, have been used to produce deletion mutants which have then been developed into vaccines. These deletions then allow differentiation between pigs infected with wild type virus and those given the vaccine. It is not clear whether the glycoproteins encoded for by these genes are needed to induce a full protective immune response, in which case deletion mutants would suffer from lack of potency. To test this, commercially available Aujeszky's virus vaccines which lacked either gX or g1 were compared and isogenic constructs were made which differed only in the absence or presence of gX and, or, g1. These constructs and vaccines were used to vaccinate the natural host of Aujeszky's disease, the pig, and potency was measured using challenge with wild type virus. In all cases vaccines which lacked g1 performed significantly less well than those in which g1 was present, whereas deletions of gX had no significant effect on vaccine performance.     

Clinical and pathologic responses of American crows (Corvus brachyrhynchos) and fish crows (C ossifragus) to experimental West Nile virus infection

West Nile virus (WNV)-associated disease has a range of clinical manifestations among avian taxa, the reasons for which are not known. Species susceptibility varies within the avian family Corvidae, with estimated mortality rates ranging from 50 to 100%. We examined and compared virologic, immunologic, pathologic, and clinical responses in 2 corvid species, the American crow (Corvus brachyrhynchos) and the fish crow (C ossifragus), following experimental WNV inoculation. Unlike fish crows, which remained clinically normal throughout the study, American crows succumbed to WNV infection subsequent to dehydration, electrolyte and pH imbalances, and delayed or depressed humoral immune responses concurrent with marked, widespread virus replication. Viral titers were approximately 3,000 times greater in blood and 30,000 to 50,000 times greater in other tissues (eg, pancreas and small intestine) in American crows versus fish crows. Histologic lesion patterns and antigen deposition supported the differing clinical outcomes, with greater severity and distribution of lesions and WNV antigen in American crows. Both crow species had multiorgan necrosis and inflammation, although lesions were more frequent, severe, and widespread in American crows, in which the most commonly affected tissues were small intestine, spleen, and liver. American crows also had inflammation of vessels and nerves in multiple tissues, including heart, kidney, and the gastrointestinal tract. WNV antigen was most commonly observed within monocytes, macrophages, and other cells of the reticuloendothelial system of affected tissues. Collectively, the data support that WNV-infected American crows experience uncontrolled systemic infection leading to multiorgan failure and rapid death.     

Herd-level risk factors for the mortality of cows in Danish dairy herds

The factors affecting the mortality of cows in Danish dairy herds were investigated by analysing data from 6839 herds. The mean risk of mortality during the first 100 days of lactation was 2.5 per cent. The risk of mortality increased with increasing herd size (odds ratio [OR] 1.05 for an increase in herd size of 50 cows), with the proportion of purchased cows (OR 1.05 for an increase in the proportion of purchased cows of 0.1), and with increases in the somatic cell count (OR 1.16 for an increase in average weighted mean somatic cell count of 100,000 cells/ml). The risk decreased with increasing average milk yield per cow (OR 0.93 for an increase in mean yield per cow-year of 1000 kg). The risk was lower in free-stall barns with deep litter (OR 0.79) than in barns with cubicles (OR 1) or tie-stalls (OR 1.04). Herds with Danish Holstein (OR 1) or Danish Jersey (OR 0.93) cows as the predominant breed had a higher risk of mortality than herds of the Danish red dairy breed (OR 0.67). The risk of mortality was lower in organic herds (OR 1) than in conventional herds (OR 1.17), and lower in herds that grazed pasture during the summer (OR 0.78).     

Upfront denileukin diftitox as in vivo regulatory T-cell depletion in order to enhance vaccination effects in a canine allogeneic hematopoietic stem cell transplantation model

Denileukin Diftitox (ONTAK^®, DAB₃₈₉ IL-2) is a recombinant DNA-derived fusion protein depleting cells that express high-affinity IL-2 receptor. Important cell targets are CD4⁺CD25⁺Foxp3⁺ regulatory T cells (T_reg). Elimination of immunosuppressive T_reg by Denileukin Diftitox may provide a way to modulate immune tolerance following stem cell transplantation. Here, we combined T_reg depletion with a vaccination approach to induce donor-specific immune reactions. To investigate this approach we chose the mixed chimerism canine stem cell transplantation model which represents a high state of tolerance between two hematopoietic systems. The aim was therefore to induce a graft versus hematopoiesis effect thereby converting mixed to full donor chimerism. Dog leukocyte antigen identical siblings that had developed a stable mixed chimerism after non-myeloablative stem cell transplantation received a single dose of Denileukin Diftitox (18 μg/kg, i.v.) followed by several cell-lysate vaccinations. Host peripheral blood mononuclear cell lysates combined with CpG-ODN, and Montanide^® ISA 51 were locally applied. In vitro studies demonstrated that canine T_reg are a target of Denileukin Diftitox. The suppression of T-cell proliferation by T_reg was abolished by addition of Denileukin Diftitox (10 nM). An increase of proliferation of median 300% (range: 200%–425%) was observed. No change in donor chimerism was observed after administration of Denileukin Diftitox and vaccination. This study highlights that application of Denileukin Diftitox resulted in a depletion of T_reg followed by an increase of immune response in vitro. This effect could not be confirmed in vivo even if the immune system was stimulated by vaccinations.     

Associations among Haemophilus parasuis,Mycoplasma hyorhinis,and porcine reproductive and respiratory syndrome virus infections in pigs with polyserositis

The objective of this study was to determine the associations among Haemophilus parasuis, Mycoplasma hyorhinis, and porcine reproductive and respiratory syndrome (PRRS) virus (EU-field strain) infections in 95 pigs with polyserositis. A significant association between H. parasuis and M. hyorhinis was identified. H. parasuis and M. hyorhinis were significantly more often detected in PRRS virus positive pigs.     

Unraveling the morphological patterns of a subantarctic eelpout: a geometric morphometric approach

Phenotypic variation in organisms depends on the genotype and the environmental constraints of the habitat that they exploit. Therefore, for marine species inhabiting contrasting aquatic conditions, it is expected to find covariation between the shape and its spatial distribution. We studied the morphology of the head and cephalic sensory canals of the eelpout Austrolycus depressiceps (4.5–22.5 cm TL) across its latitudinal distribution in South Pacific (45°S–55°S). Geometric morphometric analyses show that the shape varied from individuals with larger snout and an extended suborbital canal to individuals with shorter snouts and frontally compressed suborbital canal. There was size variation across the sampled populations, but that size does not have a clear latitudinal gradient. Only 8% of the shape variation relates to this size variation (allometry), represented by a decrease in the relative size of the eye, and a depression of the posterior margin of the head. There were spatial differences in the shape of the head, but these differences were probably caused by allometric effects. Additionally, 2 of the canals of the cephalic lateralis pores and the head shape showed modularity in its development. This study shows that the morphology of marine fish with a shallow distribution varies across distances of hundreds of kilometers (i.e., phenotypic modulation).     

Bovine Leukocyte Adhesion Deficiency in Danish Holstein-Friesian Cattle: I. PCR Screening and Allele Frequency Estimation

Jergensen, C. B., J. S. Agerholm, J. Pedersen and P. D. Thomsen: Bovine leukocyte adhesion deficiency in Danish Holstein-Friesian Cattle I. PCR screening and allele frequency estimation. Acta vet. Scand. 1993,34,231-236.–A screening program for bovine leukocyte adhesion deficiency (BLAD) in Danish Holstein-Friesian cattle has been initiated. During the first months 1611 animals were tested by a PCR based assay. Of these animals 1256, 346, and 8 were assigned normal, BLAD carriers, and BLAD affected animals, respectively One bull, born as a co-twin, showed weak reaction for the BLAD allele on DNA isolated from leukocytes, but a normal genotype on DNA isolated from semen. Chromosome analysis showed that this bull was a blood chimaera. Estimation of the BLAD allele frequency upon the PCR test results showed that around 450 Danish calves born in 1991 might have been affected with the recessive disorder.     

Mapping of quantitative trait loci for lactation persistency traits in German Holstein dairy cattle

A whole genome scan to map quantitative trait loci (QTL) for persistency of milk yield (PMY), persistency of fat yield (PFY), persistency of protein yield (PPY) and persistency of milk energy yield (PEY) was performed in a granddaughter design in the German Holstein dairy cattle population. The analysis included 16 paternal half‐sib families with a total of 872 bulls. The analysis was carried out for the first lactation and for the first three lactations combined using univariate weighted multimarker regression. Controlling the false discovery rate across traits and data sets at a level of 0.15 and treating the four persistency traits as different traits revealed 27 significant QTL. A total of 12 chromosomes showed significant QTL effects on a chromosomewise basis. The DGAT1 effect was highly significant for PPY and protein yield. A haplotype analysis using results of previous studies of the same design revealed a co‐segregation of various persistency QTL and QTL affecting health traits like dystocia and stillbirth and functional traits like non‐return rate 90 and somatic cell score.