Paola Dall'Ara

Seroepidemiological and clinical survey of feline immunodeficiency virus infection in Northern Italy

Abstract Four hundred and thirty-nine feline serum samples from cats with different living conditions in the north of Italy were tested for antibodies to feline immunodeficiency virus (FIV) and for antigen of Feline Leukemia Virus by enzyme-linked immunosorbent assay. A Western blot technique was also used on the positive sera in order to confirm the presence of specific antibodies to FIV. The Western blot enabled the detection of a false positive serum. The prevalence of FIV infection in this population was 12.5% and among the seropositive cats a greater proportion was male (74.5%) than female (25.5%). A correlation between the clinical status and the evolution of the pathology is described together with a score based on the severity of the stomatitis in infected cats. The Western blot patterns of positive samples were then compared with the stage of the pathology. Statistical analysis on the distribution of FIV in stray cats, cats with garden and courtyard access and strictly house-confined cats showed a highly significant risk of the infection in the first group.

Therapeutic activity of inhibition of the soluble epoxide hydrolase in a mouse model of scrapie.

AIMS The misfolding and the aggregation of specific proteins are key features of neurodegenerative diseases, specifically Transmissible Spongiform Encephalopathies (TSEs). In TSEs, neuronal loss and inflammation are associated with the accumulation of the misfolded isoform (PrP(sc)) of the cellular prion protein (PrP(c)). Therefore we tested the hypothesis that augmenting a natural anti-inflammatory pathway mediated by epoxygenated fatty acids (EpFAs) will delay lethality. EpFAs are highly potent but enzymatically labile molecules produced by the actions of a number of cytochrome P450 enzymes. Stabilization of these bioactive lipids by inhibiting their degradation mediated by the soluble epoxide hydrolase (sEH) results in potent anti-inflammatory effects in multiple disease models. MAIN METHODS Mice were infected with the mouse-adapted RML strain of scrapie by intracerebral or intraperitoneal routes. Animals received the sEH inhibitor, by oral route, administrated in drinking water or vehicle (PEG400). Infected mice were euthanized at a standard clinical end point. Histopathological, immunohistochemical and Western blot analyses of brain tissue confirmed the presence of pathology related to prion infection. KEY FINDINGS Oral administration of the sEHI did not affect the very short survival time of the intracerebral prion infection group. However, mice infected by intraperitoneal route and treated with t-AUCB survived significantly longer than the control group mice (p<0.001). SIGNIFICANCE These findings support the idea that inhibition of sEH or augmentation of the natural EpFA signaling in the brain offers a potential and different route to understand prion diseases and may become a therapeutic strategy for diseases involving neuroinflammation.

Genetic immunization with the immunodominant antigen P48 of Mycoplasma agalactiae stimulates a mixed adaptive immune response in BALBc mice

A DNA vaccine against contagious agalactia was developed for the first time, encoding the P48 of Mycoplasma agalactiae. Specific immune responses elicited in BALB/c mice were evaluated. Both total IgG and IgG1 were detected in mice vaccinated with pVAX1/P48. Proliferation of mononuclear cells of the spleen, levels of gamma interferon, interleukin-12, and interleukin-2 mRNAs were enhanced in immunized animals. Results indicate that pVAX1/P48 vaccination induced both T(h)1 and T(h)2 immune responses. Nucleic acid immunization could be a new strategy against M. agalactiae infections and may be potentially used to develop vaccines for other Mycoplasma diseases.

Diets with different lipid contents do not modify the neuronal membrane lipid raft profile in a scrapie murine model

UNLABELLED In Transmissible Spongiform Encephalopathies (TSEs), the localization of the prion protein in the neuronal membrane lipid rafts (LR) seems to play a role in sustaining the protein misfolding. Changes in membrane properties, due to altered lipid composition, affect their organization and interaction between lipids and protein therein, and consequently also membrane resident protein functionality; dietary polyunsaturated fatty acids (PUFAs), gangliosides and cholesterol seem to influence these processes. AIMS In this work, the influence of administration of different feed, able to change the composition of lipid membrane, on the clinical progression of prion disease was studied. MAIN METHODS The activity of three diets (hyperlipidic with 6% fats; hypolipidic with 0.1% fats; and purified with 4% fats) was tested in CD1 mouse model experimentally infected with RML scrapie strain. Presence and distribution of typical central nervous system (CNS) lesions and deposits of PrP(sc) were evaluated by histopathological analysis and immunohistochemistry. Analysis of lipids was performed in homogenate and insoluble brain fraction of the neuronal membrane rich in LR. KEY FINDINGS Results show that a diet with a different lipid level has not a significant role in the development of the scrapie disease. All infected mice fed with different diets died in the same time span. Histology, immunohistochemistry, and neuropathological analyses of the infected brains did not show significant differences between animals subjected to different diets. SIGNIFICANCE Independently of the diet, the infection induced a significant modification of the lipid composition in homogenates, and a less noticeable one in insoluble brain fraction.

Detection of PrPres in the spleen of hamsters used as an in vivo model for experimental TSE

The pathogenesis of TSE has still not been completely clarified and discussed. In fact, in some animal species, other than neuroinvasion, accumulation of PrPre in extraneural tissues has also been found, suggesting the possibility of concomitant lymphoinvasion. In particular, in experimentally infected mice, the lymphoreticular system and the spleen are infected for a long before neuroinvasion. Moreover, infection can be detected in the spleen 1 hour after intraperitoneal infection, suggesting that amplification of the pathogen in the spleen is necessary before neuroinvasion, at least for some scrapie strains (Beringue et al., 2000). In a study on prion diffusion in the hamster model, in animals intraperitoneally (i.p.) infected with the scrapie strain 263K, it was possible to identify a small amount of PrPres in the spleen of the hamsters. Nevertheless, the concentration of PrPres in the spleen showed no correlation with the level of PrPres accumulation in any segment of the brain tissue. According to the authors, the spleen appeared to play a potential but non-essential role in pathogenesis after intraperitoneal infection in the hamster model (Baldauf et al., 1997). The aim of this work was to improve and validate an extraction method useful for quantification of the PrPres in the spleen of prion-infected hamsters.