SulTlmaryThe ligand for CD40 (CD40L) is expressed on the surface of activated CD4 + T cells and its role in T-B cell collaborations and thymus-dependent humoral immunity is well established. Recently, by generating CD40L-knockout mice, we have confirmed its previously described role in humoral immunity and defined another important function of this molecule in the in vivo clonal expansion of antigen-specific CD4 + T cells. Here, we investigated the potential in vivo role of CD40L in antiviral immunity by examining the immune response mounted by CD40L-deficient mice following infection with lymphocytic choriomeningitis virus (LCMV), Pichinde virus, or vesicular stomatitis virus. Humoral immune responses of CD40L-deficient mice to these viruses were severely compromised, although moderate titres of antiviral IgM and some IgG2a were produced by virus-infected CD40L-deficient mice by a CD4 + T cell-independent mechanism. By contrast, CD40L-deficient mice made strong primary CTL responses to all three viruses. Interestingly however, although memory CTL activity was detectable in CD40L-deficient mice two months after infection with LCMV, the memory CTL response was much less efficient than in wild-type mice. Together, the results show that CD40-CD40L interactions are required for strong antiviral humoral immune responses, and reveal a novel role for CD40L in the establishment and/or maintenance of CD8 + CTL memory.

BackgroundLeptin and its receptor play a role in several disease processes such as pancreatitis and heart disease. However, their association with gallbladder mucocele (GBM) in dogs has not been reported.Hypothesis/ObjectivesTo evaluate differences in the expression of leptin and leptin receptor between dogs with and without GBM.AnimalsTwenty‐five healthy dogs, including 9 laboratory beagle dogs, and 22 client‐owned dogs with GBM.MethodsSerum leptin concentration was determined in blood samples of all dogs by ELISA. Canine gallbladder samples were collected from 9 dogs with GBM that underwent surgery for therapeutic purposes and from 9 healthy laboratory beagle dogs as a normal control group. Samples were analyzed for leptin and leptin receptor mRNA by real‐time polymerase chain reaction.ResultsSerum leptin concentration was significantly higher in dogs with GBM than in healthy dogs (medians of 7.03 and 2.18 ng/mL, respectively; P < .001). Patients with GBM that had undergone surgery had significantly higher serum leptin concentrations than those that had not (medians of 12.2 and 4.09 ng/mL, respectively; P = .001). However, no difference in serum leptin concentration was found between dogs with GBM with or without endocrinopathies. The mRNA expression levels of leptin and its receptor were significantly increased in the gallbladder tissues of dogs with GBM.Conclusions and Clinical ImportanceDysregulation of leptin might be involved in the pathophysiology of GBM, and leptin concentrations might be associated with GBM severity.

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This 10-day (D) study was conducted to evaluate changes in traditional and newer kidney safety biomarker expression levels in dogs. Animals received cisplatin (CDDP, 0.75 mg per kg per day) or 0.9% Saline (vehicle) for 5 days. Serum/urine samples were collected at various time points. Cage-side observations included emesis (D1-2/D4-D5/D7-9), absence of stool (D5-9/D11), soft stool (D4-7/D12), excessive salivation (D1/D3/D5-6), decreased food consumption (D5-8), decreased activity (D7-8) and/or dehydration (D7). Animals were necropsied when serum creatinine (sCr) levels measured at ≥1.9 mg dL, indicating significant loss of renal function; or at the end of the study (D11). When compared to controls, increases in BUN/sCr were detected on D3, D5 and/or D8. Increases in urinary total protein (Ur TP) were noted on D6. The moribund dog that was euthanized early on D7 showed insignificant increases in urinary osteopontin (Ur OPN), urinary neutrophil gelatinase-associated lipocalin (Ur NGAL), urinary clusterin (Ur CLU), sCr, serum cystatin C (sCYS C) and urinary cystatin C (Ur CYS C) on D5 when compared to controls. Insignificant increases in urinary albumin (Ur ALB) were observed from an animal that was euthanized on D7 and 1 : 2 surviving animals on D8 relative to baseline. From three dogs that were euthanized on D9, increases in Ur CLU, and/or sCYS C were noted on D8 relative to baseline. The two surviving dogs showed elevated Ur CLU and 1 : 2 surviving dogs showed elevated Ur CYS C. Decreased urinary kidney injury molecule 1 (Ur KIM-1) on D3/D5 was evident ( baseline and controls). CDDP-induced cortico-medullary lesions were characterized as minimal to mild tubule degeneration/necrosis, dilatation, regeneration, cell alteration, intratubular casts, interstitial inflammation and vacuolization. Increased Ur OPN and Ur CLU correlated with enhanced OPN and CLU immunopositive staining in damaged cortical epithelium in the proximal tubules. Enhanced KIM-1 staining in damaged cortico-medullary tubular epithelium appeared in the absence of rises in Ur KIM-1. This study showed changes in kidney safety protein biomarkers associated with CDDP nephrotoxicity in dogs and possibly in humans.

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Thymus-dependent (T) lymphocytes have recently been associated with a number of functions among which are in vitro cytotoxic activities to cells bearing histoincompatible antigens. In vivo, the presence of T lymphocytes has been detected by immunofluorescence in lesions of delayed hypersensitivity (1) and Marek's disease (2). T lymphocytes have also been shown to be active or present in tissues undergoing rejection by applying less direct means of identification, e.g., by measuring cytotoxicity against tumor target cells (3, 4) or by tracing the localization of labeled cells (5). In this paper we report the flow of T lymphocytes into cellular infiltrates of rejecting renal allografts. T lymphocytes were stained in tissue sections by fluoresceinlabeled horse antisera specific for rat T lymphocytes. Materials and MethodsRats.--18 Lewis (L) rat renal allografts and 12 Brown Norway (BN) rat renal isografts were transplanted heterotopically into BN recipients, as previously described (6). Bladder anastomosis was not performed and both host kidneys remained in place. Recipient and donor rats were males, 4-8 mo of age, and weighed 250-350 g. At daily intervals for 6 days after transplantation, groups of three renal allograft and two renal isograft recipients were sacrificed. One-half of an excised renal transplant was snap frozen in liquid nitrogen and stored at -30°C, while the other half was fixed in Bouin's solution for routine histological study. The nontransplanted donor kidney and a host kidney were excised at the time the grafts were removed, were prepared the same as the grafts, and served as additional controls. Reagents. Fluoresceinated I gG of horse antirat thoracic duct cell antiserum (HART-F) and normal horse serum (NHG-F):The properties of HART-F and its specificity for T cells have been described elsewhere (7). Briefly, horse antirat thoracic duct cell antiserum 1 was inactivated at 56°C for 45 min and an immunoglobulin (Ig) fraction prepared by (NH4)2SO4 precipitation followed by passage through a DEAE-Sephadex A-50 column. An Ig fraction of normal horse serum was similarly prepared. 10 mg of each Ig fraction was conjugated with 2.5 mg of fluorescein * This is publication no. 749 from

ObjectivesTo measure serum leptin concentration in dogs with pituitary‐dependent hyperadrenocorticism and varying degrees of cholestatic disease and determine whether serum levels differed between dogs with pituitary‐dependent hyperadrenocorticism and those with gall bladder mucocoele.Materials and MethodsClient‐owned healthy dogs (n=20), dogs diagnosed with gall bladder mucocoele (n=20) and dogs diagnosed with pituitary‐dependent hyperadrenocorticism (n=60) were enrolled. Only dogs of normal body condition score were included. Dogs with pituitary‐dependent hyperadrenocorticism were divided into three groups according to the severity of cholestatic disease: normal gall bladder (n=20), cholestasis (n=20) and gall bladder mucocoele (n=20). Serum leptin levels were measured using sandwich enzyme‐linked immunosorbent assay.ResultsSerum concentrations of leptin were similar between dogs with gall bladder mucocoele and those with pituitary‐dependent hyperadrenocorticism accompanied by gall bladder mucocoele; these concentrations were significantly higher than those in healthy control dogs. In dogs with pituitary‐dependent hyperadrenocorticism, circulating leptin concentration significantly increased with the severity of cholestasis: higher in the cholestasis group than the normal gall bladder group and higher in the gall bladder mucocoele group than the cholestasis group.Clinical SignificanceElevated circulating leptin concentration was associated with canine pituitary‐dependent hyperadrenocorticism and gall bladder mucocoele. Homeostatic imbalance of leptin concentration might be associated with severity of cholestatic disease in pituitary‐dependent hyperadrenocorticism.