Emma J. O'Neill

Role for IL-10 in Suppression Mediated by Peptide-Induced Regulatory T Cells In Vivo

Regulatory CD4+ T cells were induced in the Tg4 TCR transgenic mouse specific for the N-terminal peptide (Ac1-9) of myelin basic protein by intranasal administration of a high-affinity MHC-binding analog (Ac1-9[4Y]). Peptide-induced tolerant cells (PItol) were anergic, failed to produce IL-2, but responded to Ag by secretion of IL-10. PItol cells were predominantly CD25− and CTLA-4+ and their anergic state was reversed by addition of IL-2 in vitro. PItol cells suppressed the response of naive Tg4 cells both in vitro and in vivo. The in vitro suppression mediated by these cells was not reversed by cytokine neutralization and was cell-cell contact-dependent. However, suppression of proliferation and IL-2 production by PItol cells in vivo was abrogated by neutralization of IL-10. These results emphasize an important role for IL-10 in the function of peptide-induced regulatory T cells in vivo and highlight the caution required in extrapolating mechanisms of T regulatory cell function from in vitro studies.

IL-10 is essential for disease protection following intranasal peptide administration in the C57BL/6 model of EAE.

We have shown previously that intranasal administration of encephalitogenic peptides in soluble form to H-2u and H-2s mice affords protection from experimental autoimmune encephalomyelitis (EAE). Here we demonstrate that this method of disease protection can be induced in C57BL/6 mice by administration of the soluble peptide 35-55 from myelin oligodendrocyte glycoprotein. This protective effect was demonstrated by the evaluation of both clinical EAE scores and central nervous system histopathology; the latter showing minimal inflammatory infiltrates in treated mice. The employment of an IL-10-/- congenic strain allowed an appraisal of the involvement of IL-10 in this process. The lack of disease protection in these mice clearly demonstrates the non-redundant role of IL-10 in this process.

Comparison of survival after surgical or medical treatment in dogs with a congenital portosystemic shunt

OBJECTIVE To compare survival of dogs with a congenital portosystemic shunt (CPSS) that received medical or surgical treatment. DESIGN Prospective cohort study. ANIMALS 126 client-owned dogs with a single CPSS. PROCEDURES Dogs were examined at 1 of 3 referral clinics, and a single CPSS was diagnosed in each. Dogs received medical or surgical treatment without regard to signalment, clinical signs, or results of hematologic or biochemical analysis. Survival data were analyzed via a Cox regression model. RESULTS During a median follow-up period of 579 days, 18 of 126 dogs died as a result of CPSS. Dogs treated via surgical intervention survived significantly longer than did those treated medically. Hazard ratio for medical versus surgical treatment of CPSS (for the treatment-only model) was 2.9 (95% confidence interval, 1.1 to 7.2). Age at CPSS diagnosis did not affect survival. CONCLUSIONS AND CLINICAL RELEVANCE Both medical and surgical treatment can be used to achieve long-term survival of dogs with CPSS, although results of statistical analysis supported the widely held belief that surgery is preferable to medical treatment. However, the study population consisted of dogs at referral clinics, which suggested that efficacy of medical treatment may have been underestimated. Although surgical intervention was associated with a better chance of long-term survival, medical management provided an acceptable first-line option. Age at examination did not affect survival, which implied that early surgical intervention was not essential. Dogs with CPSS that do not achieve acceptable resolution with medical treatment can subsequently be treated surgically.

Natural and Induced Regulatory T Cells

Abstract: Mucosal antigen delivery can induce tolerance, as shown by suppression of subsequent responses to antigen. Our previous work showed that both intranasal and oral routes of antigen delivery were effective but indicated that the intranasal route might be more reliable. Intranasal peptide administration induced cells that could mediate bystander suppression of responses to associated antigenic epitopes. Here, we discuss further investigation into the nature of intranasal, peptide‐induced tolerance. Cells from mice treated with intranasal peptide became anergic and shut down secretion of cytokines such as IL‐2, but still secreted IL‐10. This latter cytokine was required for suppression of immune responses in vivo even though suppression of responses in vitro was IL‐10 independent. Intranasal peptide induced a subset of CD25−, CTLA‐4+ regulatory cells that suppressed naive cell function in vitro and in vivo. We provide evidence that these cells arise from CD25− precursors and differentiate independently from natural CD25+ regulatory cells. IL‐10‐secreting regulatory cells are also found in the peripheral blood of humans and can be induced by soluble peptide administration. This route of tolerance induction offers promise as a means of antigen‐specific immunotherapy of allergic and autoimmune conditions in humans.

Antigen-Induced IL-10+ Regulatory T Cells Are Independent of CD25+ Regulatory Cells for Their Growth, Differentiation, and Function

Recent studies have emphasized the importance of T cells with regulatory/suppressor properties in controlling autoimmune diseases. A number of different types of regulatory T cells have been described with the best characterized being the CD25+ population. In addition, it has been shown that regulatory T cells can be induced by specific Ag administration. In this study, we investigate the relationship between peptide-induced, CD4+ regulatory T cells and naturally occurring CD4+CD25+ cells derived from the Tg4 TCR-transgenic mouse. Peptide-induced cells were FoxP3− and responded to Ag by secreting IL-10, whereas CD25+ cells failed to secrete this cytokine. Both cell types were able to suppress the proliferation of naive lymphocytes in vitro although with distinct activation sensitivities. Depletion of CD25+ cells did not affect the suppressive properties of peptide-induced regulators. Furthermore, peptide-induced regulatory/suppressor T cells could be generated in RAG−/−, TCR-transgenic mice that do not spontaneously generate CD25+ regulatory cells. These results demonstrate that these natural and induced regulatory cells fall into distinct subsets.

Long-term survival and quality of life in dogs with clinical signs associated with a congenital portosystemic shunt after surgical or medical treatment

OBJECTIVE To compare long-term survival and quality of life data in dogs with clinical signs associated with a congenital portosystemic shunt (CPSS) that underwent medical or surgical treatment. DESIGN Prospective cohort study. ANIMALS 124 client-owned dogs with CPSS. PROCEDURES Dogs received medical or surgical treatment without regard to signalment, clinical signs, or clinicopathologic results. Survival data were analyzed with a Cox regression model. Quality of life information, obtained from owner questionnaires, included frequency of CPSS-associated clinical signs (from which a clinical score was derived), whether owners considered their dog normal, and (for surgically treated dogs) any ongoing medical treatment for CPSS. A Mann-Whitney U test was used to compare mean clinical score data between surgically and medically managed dogs during predetermined follow-up intervals. RESULTS 97 dogs underwent surgical treatment; 27 were managed medically. Median follow-up time for all dogs was 1,936 days. Forty-five dogs (24 medically managed and 21 surgically managed) died or were euthanized during the follow-up period. Survival rate was significantly improved in dogs that underwent surgical treatment (hazard ratio, 8.11; 95% CI, 4.20 to 15.66) than in those treated medically for CPSS. Neither age at diagnosis nor shunt type affected survival rate. Frequency of clinical signs was lower in surgically versus medically managed dogs for all follow-up intervals, with a significant difference between groups at 4 to 7 years after study entry. CONCLUSIONS AND CLINICAL RELEVANCE Surgical treatment of CPSS in dogs resulted in significantly improved survival rate and lower frequency of ongoing clinical signs, compared with medical management. Age at diagnosis did not affect survival rate and should not influence treatment choice.

Bacterial Cholangitis, Cholecystitis, or both in Dogs

Background Bacterial cholangitis and cholecystitis are rarely reported, poorly characterized diseases in the dog. Objectives To characterize the clinical features of these conditions. Animals Twenty‐seven client‐owned dogs with bacterial cholangitis, cholecystitis, or both. Methods Multicenter, retrospective cases series of dogs with bacterial cholangitis, cholecystitis, or both, presenting January 2000 to June 2011 to 4 Veterinary Schools in Ireland/United Kingdom. Interrogation of hospital databases identified all cases with the inclusion criteria; histopathologically confirmed cholangitis or cholecystitis and bile culture/cytology results supporting a bacterial etiology. Results Twenty‐seven dogs met the inclusion criteria with approximately 460 hepatitis cases documented over the same study period. Typical clinical pathology findings were increases in liver enzyme activities (25/26), hyperbilirubinemia (20/26), and an inflammatory leukogram (21/24). Ultrasound findings, although nonspecific, aided decision‐making in 25/26 cases. The most frequent hepatobiliary bacterial isolates were Escherichia coli (n = 17; 16 cases), Enterococcus spp. (n = 8; 6 cases), and Clostridium spp. (n = 5; 5 cases). Antimicrobial resistance was an important feature of aerobic isolates; 10/16 E. coli isolates resistant to 3 or more antimicrobial classes. Biliary tract rupture complicated nearly one third of cases, associated with significant mortality (4/8). Discharged dogs had a guarded to fair prognosis; 17/18 alive at 2 months, although 5/10 re‐evaluated had persistent liver enzyme elevation 2–12 months later. Conclusion and Clinical Significance Bacterial cholangitis and cholecystitis occur more frequently than suggested by current literature and should be considered in dogs presenting with jaundice and fever, abdominal pain, or an inflammatory leukogram or with ultrasonographic evidence of gallbladder abnormalities.

Urinary shedding of spirochaetes in a dog with acute leptospirosis despite treatment

LEPTOSPIROSIS is a zoonosis that is found worldwide and affects most mammalian species, including dogs (Faine and others 1999). The treatment of acute canine leptospirosis often requires intensive management of the affected animal, during which staff may be exposed to Leptospira excreted in the dogs urine. It is commonly assumed that urinary shedding of Leptospira ceases rapidly after the initiation of appropriate antibiotic therapy (Greene 2006). This short communication documents ongoing urinary shedding of spirochaetes in a dog with acute leptospirosis, despite treatment with doxycycline for seven days, highlighting a significant zoonotic risk for carers and owners of infected animals. A five-year-old entire female labrador, with a known history of hunting rats, was presented to the University Veterinary Hospital, Dublin, Ireland with a five-day history of pyrexia, jaundice, inappetence and vomiting. The dog had been treated with intravenous penicillin for four days before referral and was reported as having been vaccinated against leptospirosis in the past six months (the vaccination record was not available). Physical examination of the dog revealed marked jaundice, approximately 5 per cent dehydration and ptyalism. Haematology revealed mild anaemia (packed cell volume 0.36 l/l, reference range 0.37 to 0.55 l/l; haemoglobin 118 g/l, reference range 120 to 180 g/l; red blood cell count 4.97 × 1012/l, reference range 5.5 × 109 to 8.5 × 1012/l) and leucocytosis (white blood cell count 18 × 109/l, reference range 6 × 109 to 17 × 109/l) due to mature neutrophilia (13.5 × 109/l, reference range 3 …

Granulomatous meningoencephalomyelitis in dogs: A review

Granulomatous meningoencephalomyelitis (GME) is an inflammatory disease of the central nervous system in dogs that is characterised by focal or disseminated granulomatous lesions within the brain and/or spinal cord, non-suppurative meningitis and perivascular mononuclear cuffing. The aetiology of the disease remains unknown, although an immune-mediated cause is suspected. This article reviewed the typical history, clinical signs and pathology of the condition along with current opinions on pathogenesis. The potential differential diagnoses for the disease were discussed along with current treatment options.

Geographical distribution of Angiostrongylus vasorum in foxes ( Vulpes vulpes ) in the Republic of Ireland

The reported incidence of the metastrongylid nematode Angiostrongylus vasorum, that infects dogs and other canids, is increasing worldwide outside recognized endemic foci. This apparent expansion of the parasites range is causing concern to veterinary clinicians as the disease caused in dogs can be life threatening and its treatment is not straightforward. The red fox is thought to be a reservoir host for dogs. To investigate the spatial distribution of infection in foxes in Ireland, the hearts and lungs of 542 foxes from all over Ireland were examined. The incidence of infection was found to be 39·9% [95% confidence interval (CI) 35·7-44·1] with positive samples occurring in each of the countrys 26 counties. This report confirms that the parasite is endemic in Ireland and the overall prevalence is the second highest in Europe. This is the first survey of A. vasorum infection in Irish foxes and highlights the potential exposure of the Irish dog population to high risk of cross-infection. Additionally, Crenosoma vulpis was found in seven of the foxes, a parasite not previously reported in the Irish fox.