Adjuvants influence the immune cell populations present at the injection site granuloma induced by whole-cell inactivated paratuberculosis vaccines in sheep.

Vaccination is the most effective tool for paratuberculosis control. Currently, available vaccines prevent the progression of clinical disease in most animals but do not fully protect them against infection and induce the formation of an injection site granuloma. The precise mechanisms that operate in response to vaccination and granuloma development, as well as the effect that adjuvants could trigger, have not been fully investigated. Therefore, this study aimed to investigate the injection site granulomas induced by two inactivated paratuberculosis vaccines, which differ in the adjuvant employed. Two groups of 45-day-old lambs were immunized with two commercially available vaccines-one (n = 4) with Gudair® and the other (n = 4) with Silirum®. A third group (n = 4) was not vaccinated and served as control. The peripheral humoral response was assessed throughout the study by a commercial anti-Mycobacterium avium subspecies paratuberculosis (Map) antibody indirect ELISA, and the cellular immune response was assessed similarly by the IFN-γ release and comparative intradermal tests. The injection site granulomas were measured during the experiment and sampled at 75 days post-vaccination (dpv) when the animals were euthanized. The tissue damage, antigen and adjuvant distribution, and the presence and amount of immune cells were then determined and assessed by immunohistochemical methods. Antibodies against Map antigens; a general macrophage marker (Iba1), M1 (iNOS), and M2 (CD204) macrophages; T (CD3), B (CD20), and γδ T lymphocytes, proteins MHC-II and NRAMP1, and cytokines IL-4, IL-10, TNF, and IFN-γ were employed. Silirum® elicited a stronger peripheral cellular immune response than Gudair®, while the latter induced larger granulomas and more tissue damage at the site of injection. Additionally, adjuvant and Map antigen distribution throughout the granulomatous inflammatory infiltrate, as well as the NRAMP1 cell expression, which is linked to antigen phagocytosis, were highly irregular. In Silirum® induced granulomas, a higher number of MHC-II and TNF-expressing cells and a lower number of M2 macrophages suggested an improved antigen presentation, which could be due to the better antigen distribution and reduced tissue damage induced by this vaccine.

Phenotypic Characterization of Encephalitis and Immune Response in the Brains of Lambs Experimentally Infected with Spanish Goat Encephalitis Virus.

Spanish goat encephalitis virus (SGEV), a novel subtype of tick-borne flavivirus closely related to louping ill virus, causes a neurological disease in experimentally infected goats and lambs. Here, the distribution of microglia, T and B lymphocytes, and astrocytes was determined in the encephalon and spinal cord of eight Assaf lambs subcutaneously infected with SGEV. Cells were identified based on immunohistochemical staining against Iba1 (microglia), CD3 (T lymphocytes), CD20 (B lymphocytes), and glial fibrillary acidic protein (astrocytes). In glial foci and perivascular cuffing areas, microglia were the most abundant cell type (45.4% of immunostained cells), followed by T lymphocytes (18.6%) and B lymphocytes (4.4%). Thalamus, hypothalamus, corpus callosum, and medulla oblongata contained the largest areas occupied by glial foci. Reactive astrogliosis occurred to a greater extent in the lumbosacral spinal cord than in other regions of the central nervous system. Lesions were more frequent on the side of the animal experimentally infected with the virus. Lesions were more severe in lambs than in goats, suggesting that lambs may be more susceptible to SGEV, which may be due to species differences or to interindividual differences in the immune response, rather than to differences in the relative proportions of immune cells. Larger studies that monitor natural or experimental infections may help clarify local immune responses to this flavivirus subtype in the central nervous system.

Clostridium sordellii in a brown bear (Ursus arctos) from Spain.

Clostridium sordellii is found in the environment and occasionally in animal (including human) intestines and may cause myonecrosis and large outbreaks of enterotoxemia. A few cases of fatal clostridial infection in bears (Ursus spp.) have been described worldwide but none attributed to C. sordellii. We describe a fatal case of septicemia caused by C. sordellii in an illegally trapped brown bear (Ursus arctos). At necropsy, acute gangrenous myositis was the primary lesion. Serohemorrhagic edema was observed in the abdominal cavity, thorax, pericardium, and skeletal muscle, mostly affecting femoral, humeral, and scapular muscles. Hemorrhage was observed in the heart, skeletal muscles, stomach, and intestine. Liver, spleen, and kidney appeared with loss of consistency, hemorrhages, and edema. Microscopically, primary lesions were in skeletal muscle, stomach, and small intestine, with gram-positive, clostridial-like bacilli. Biochemical and molecular tests identified C. sordellii in cultures from liver, muscle, and intestine. Sequences showed a homology of >99% with the 16S rRNA gene sequence of C. sordellii. The severity of effects of the C. sordellii infection reveal the importance of this pathogen as a wildlife health risk with conservation concerns, as well as the need to consider possible infection with this pathogen in management actions involving immobilization, stress, or severe muscular activity of wild brown bears.

Perivascular inflammatory cells in ovine Visna/maedi encephalitis and their possible role in virus infection and lesion progression.

We examined the distribution in the perivascular spaces of Visna/maedi antigen, T cells (CD3+, CD4+ and CD8+), B cells and macrophages by immunohistochemistry in 22 natural cases of Visna/maedi encephalitis. Sheep showed lymphocytic or histiocytic lesions. In mild lymphocytic lesions, the viral antigen was detected in perivascular cuffs where CD8+ T cells predominated, but in severe lymphocytic lesions, sparse antigen was identified, and CD8+/CD4+ T cells appeared in a similar proportion in multilayer perivascular sleeves. In histiocytic lesions, vessels were surrounded by macrophages with abundant viral antigen, with CD8+/CD4+ T cells and B cells in the periphery. These results could reflect different stages of virus neuroinvasion and clarify the neuropathogenesis of Visna/maedi encephalitis.

Louping ill in goats, Spain, 2011.

Although louping ill affects mainly sheep, a 2011 outbreak in northern Spain occurred among goats. Histopathologic lesions and molecular genetics identified a new strain of louping ill virus, 94% identical to the strain from Britain. Surveillance is needed to minimize risk to domestic and wildlife species and humans.

Endothelialization of nonapposed stent struts located over the origin of a side branch: results with different carbofilm-coated stents.

OBJECTIVE: To evaluate the degree of endothelialization of the nonapposed struts located at the ostia of side branches. BACKGROUND: Endothelialization of coronary stents has got considerable relevance because of the phenomenon of late thrombosis. Bifurcation location and incomplete stent apposition have been linked to this complication. METHODS: Domestic pigs (n = 11; weight: 25 +/- 3 kg) were anesthetized and had one stent per coronary artery implanted: one stainless steel (Tecnic), one cobalt-chromium (Chrono), and one tacrolimus-eluting stent (Janus), all of them being Carbofilm-coated (Sorin). One, three, or seven days postprocedure, the pigs were sacrificed, the hearts explanted, and longitudinal sections examined by surface electron microscopy to quantify the percentage of the strut endothelialized over the branches and in the total surface. RESULTS: Forty-four side branches (25 stents) that had stent struts over their origin were evaluated. Different patterns of endothelialization were observed, from the total absence to the complete endothelialization. There were no significant differences in relation to type of stent or to the artery treated. The predictors of higher percentage of endothelialization were the ratio of metal to branch diameter (P = 0.04) and better endothelialization in the rest of the stent (P = 0.0002), only this parameter maintaining significant correlation (P = 0.03) in multivariate analysis. CONCLUSIONS: Carbofilm-coated stent struts located over the origin of side branches follow the pattern of endothelialization for the rest of the stent, even in the case of tacrolimus-eluting stent.