Induction of Petite Colonies in Candida glabrate via Rose Bengal-Mediated Photodynamic Therapy

Facing a 40% mortality rate in candidemia patients, drug-resistant Candida and their petite mutants remain a major treatment challenge. Antimicrobial photodynamic therapy (aPDT) targets multiple fungal structures, unlike antibiotics/antifungals, potentially thwarting resistance. Traditional methods for inducing petite colonies rely on ethidium bromide or fluconazole, which can influence drug susceptibility and stress responses. This study investigated the application of green light (peak 520 nm) and rose bengal (RB) photosensitizer to combat a drug-resistant Candida glabrata isolate. The findings revealed that aPDT treatment significantly inhibited cell growth (≥99.9% reduction) and effectively induced petite colony formation, as evidenced by reduced size and loss of mitochondrial redox indicator staining. This study provides initial evidence that aPDT can induce petite colonies in a multidrug-resistant C. glabrata strain in vitro, offering a potentially transformative approach for combating resistant fungal infections.

Novel SLC5A6 mutations lead to B lymphocyte maturation defects with metabolic abnormality rescuable by biotin replenishment

We characterized a family diagnosed with immunodeficiency disease presenting with low immunoglobulin levels and skin dyskeratosis. Exome sequencing revealed compound heterozygous missense variants in SLC5A6, the gene encoding a cellular sodium-dependent multivitamin transporter (SMVT) responsible for transporting vitamins, including biotin (vitamin B7). We showed that the biotin deficiency was caused by the SLC5A6 variants resulting in defective B cell differentiation and antibody deficiency. Altered cellular metabolic profiles, including aberrant mitochondrial respiration and reliance on glycolysis, may underlie the failure in plasma cell maturation. Replenishment of biotin improved plasma cell maturation and recovered the antibody producing activity in the patient and in a CRISPR-Cas9 gene-edited mouse model bearing a patient-specific SLC5A6 variant. Our results demonstrate the critical role of metabolic reprogramming in the maturation of plasma cells and nominate SLC5A6 as a causative gene for immunodeficiency that may be treated by biotin replenishment.

Progenitor Cells Derived from Drain Waste Product of Open-Heart Surgery in Children

Human cardiac progenitor cells isolated from the same host may have advantages over other sources of stem cells. The aim of this study is to establish a new source of human progenitor cells collected from a waste product, pericardiac effusion fluid, after open-heart surgery in children with congenital heart diseases. The fluid was collected every 24 h for 2 days after surgery in 37 children. Mononuclear cells were isolated and expanded in vitro. These pericardial effusion-derived progenitor cells (PEPCs) exhibiting cardiogenic lineage markers, were highly proliferative and enhanced angiogenesis in vitro. Three weeks after stem cell transplantation into the ischemic heart in mice, cardiac ejection fraction was improved significantly without detectable progenitor cells. Gene expression profiles of the repaired hearts revealed activation of several known repair mechanisms including paracrine effects, cell migration, and angiogenesis. These progenitor cells may have the potential for heart regeneration.

Enterovirus 71 virion-associated galectin-1 facilitates viral replication and stability

Enterovirus 71 (EV71) infection causes a myriad of diseases from mild hand-foot-and-mouth disease or herpangina to fatal brain stem encephalitis complicated with pulmonary edema. Several severe EV71 endemics have occurred in Asia-Pacific region, including Taiwan, and have become a serious threat to children’s health. EV71 infection is initiated by the attachment of the virion to the target cell surface. Although this process relies primarily upon interaction between viruses and cell surface receptors, soluble factors may also influence the binding of EV71 to host cells.Galectin-1 has been reported to participate in several virus infections, but is not addressed in EV71. In this study, we found that the serum levels of galectin-1 in EV71-infected children were higher than those in non-infected people. In EV71 infected cells, galectin-1 was found to be associated with the EV71 VP1 and VP3 via carbohydrate residues and subsequently released and bound to another cell surface along with the virus. EV71 propagated from galectin-1 knockdown SK-N-SH cells exhibited lower infectivity in cultured cells and less pathogenicity in mice than the virus propagated from parental cells. In addition, this galectin-1-free EV71 virus was sensitive to high temperature and lost its viability after long-term storage, which could be restored following supplement of recombinant galectin-1. Taken together, our findings uncover a new role of galectin-1 in facilitating EV71 virus infection.

Animal models of enterovirus 71 infection: applications and limitations

Human enterovirus 71 (EV71) has emerged as a neuroinvasive virus that is responsible for several outbreaks in the Asia-Pacific region over the past 15 years. Appropriate animal models are needed to understand EV71 neuropathogenesis better and to facilitate the development of effective vaccines and drugs. Non-human primate models have been used to characterize and evaluate the neurovirulence of EV71 after the early outbreaks in late 1990s. However, these models were not suitable for assessing the neurovirulence level of the virus and were associated with ethical and economic difficulties in terms of broad application. Several strategies have been applied to develop mouse models of EV71 infection, including strategies that employ virus adaption and immunodeficient hosts. Although these mouse models do not closely mimic human disease, they have been applied to determine the pathogenesis of and treatment and prevention of the disease. EV71 receptor-transgenic mouse models have recently been developed and have significantly advanced our understanding of the biological features of the virus and the host-parasite interactions. Overall, each of these models has advantages and disadvantages, and these models are differentially suited for studies of EV71 pathogenesis and/or the pre-clinical testing of antiviral drugs and vaccines. In this paper, we review the characteristics, applications and limitation of these EV71 animal models, including non-human primate and mouse models.

Prostaglandin E₂ promotes post-infarction cardiomyocyte replenishment by endogenous stem cells

Although self-renewal ability of adult mammalian heart has been reported, few pharmacological treatments are known to promote cardiomyocyte regeneration after injury. In this study, we demonstrate that the critical period of stem/progenitor cell-mediated cardiomyocyte replenishment is initiated within 7 days and saturates on day 10 post-infarction. Moreover, blocking the inflammatory reaction with COX-2 inhibitors may also reduce the capability of endogenous stem/progenitor cells to repopulate lost cells. Injection of the COX-2 product PGE₂ enhances cardiomyocyte replenishment in young mice and recovers cell renewal through attenuating TGF-β1 signaling in aged mice. Further analyses suggest that cardiac stem cells are PGE₂-responsive and that PGE₂ may regulate stem cell activity directly through the EP2 receptor or indirectly by modulating its micro-environment in vivo. Our findings provide evidence that PGE₂ holds great potential for cardiac regeneration.

Effects of vaginal septa on the reproductive performance of BALB/cByJNarl mice

From March through December 2010, the incidence of vaginal septa in our SPF breeding colony of BALB/cByJNarl mice was 14.2%. In general, septa obstructed half of the vaginal orifice. Here we sought to determine the effect of this defect by comparing the reproductive performance of affected (septate) mice with that of unaffected (nonseptate) mice. Our results showed that the rates of both copulatory plugs and pregnancy were significantly lower in septate mice than in nonseptate mice. Specifically, 23 of 45 bred septate female mice (51%) had vaginal plugs compared with 49 of 68 bred nonseptate females (72%). Only 12 septate female mice (27%) had successful pregnancies, compared with 37 nonseptate females (54%). Septate mice had a 1-logfold fewer intrauterine sperm after mating than did nonseptate mice. Three cases of dystocia were noted among septate mice whereas none occurred in nonseptate mice. Septate dams had a higher percentage of septate pups (15.5%) than did nonseptate dams (6.1%). Our findings indicate that vaginal septa affect the reproductive performance of laboratory mice and that such a defect should be considered as an exclusion criterion for the selection of future breeders in a mouse colony.

Subneutralizing antibodies to enterovirus 71 induce antibody-dependent enhancement of infection in newborn mice

Antibody-dependent enhancement (ADE) of virus infections can be induced by subneutralizing concentrations of specific antibodies. We recently demonstrated ADE in human monocytes infected with enterovirus 71 (EV71). The current study was designed to extend these observations by determining the effect of ADE on the pathogenesis of EV71 infection in newborn mice. We compared the clinical manifestations, mortality, virus titer, histopathology, and serum levels of cytokines and chemokines in newborn mice pretreated with subneutralizing antibodies to EV71 or normal mouse IgG with and without virus. Seven-day-old ICR mice were pretreated with a wide range of mouse anti-EV71 IgG 24 h prior to intraperitoneal injection of EV71. Mice were protected from infection by neutralizing doses of anti-EV71 IgG ranging from 6.43 × 10⁻¹ to 329.6 μg/ml. Subneutralizing doses ranging from 2.01 × 10⁻² to 3.21 × 10⁻¹ μg/ml were found to significantly increase 14-day mortality compared to virus alone. The ADE effect was not evident at lower doses. Histopathological examination of mice given a subneutralizing dose of 8.04 × 10⁻² μg/ml revealed extensive neuronal and muscular damage compared to untreated infected controls. Higher serum levels of interferon (IFN)-γ and monocyte chemoattractant protein (MCP)-1 were noted in mice pretreated with subneutralizing doses than untreated infected controls. These findings support the concept that subneutralizing antibodies directed enhance EV71 induce ADE in newborn mice.

Enterovirus 71 blocks selectively type I interferon production through the 3C viral protein in mice

Type I interferons (IFNs) represent an essential innate defense mechanism for controlling enterovirus 71 (EV 71) infection. Mice inoculated with EV 71 produced a significantly lower amount of type I IFNs than those inoculated with poly (I:C), adenovirus type V, or coxsackievirus B3 (CB3). EV 71 infection, however, mounted a proinflammatory response with a significant increase in the levels of serum and brain interleukin (IL)-6, monocyte chemoattractant protein-1, tumor necrosis factor, and IFN-γ. EV 71 infection abolished both poly (I:C)- and CB3-induced type I IFN production of mice. Such effect was not extended to other enteroviruses including coxsackievirus A24, B2, B3, and echovirus 9, as mice infected with these viruses retained type I IFN responsiveness upon poly (I:C) challenge. In addition, EV 71-infected RAW264.7 cells produced significantly lower amount of type I IFNs than non-infected cells upon poly (I:C) stimulation. The inhibitory effect of EV 71 on type I IFN production was attributed to the viral protein 3C, which was confirmed using over-expression systems in both mice and RAW264.7 cells. The 3C over-expression, however, did not interfere with poly (I:C)-induced proinflammatory cytokine production. These findings indicate that EV 71 can hamper the host innate defense by blocking selectively type I IFN synthesis through the 3C viral protein.

Cell surface sialylation affects binding of enterovirus 71 to rhabdomyosarcoma and neuroblastoma cells

BACKGROUND

Enterovirus 71 (EV71) is a major causative agent of hand-foot-and-mouth disease (HFMD), and infection of EV71 to central nerve system (CNS) may result in a high mortality in children less than 2 years old. Although there are two highly glycosylated membrane proteins, SCARB2 and PSGL-1, which have been identified as the cellular and functional receptors of EV71, the role of glycosylation in EV71 infection is still unclear.

RESULTS

We demonstrated that the attachment of EV71 to RD and SK-N-SH cells was diminished after the removal of cell surface sialic acids by neuraminidase. Sialic acid specific lectins, Maackia amurensis (MAA) and Sambucus Nigra (SNA), could compete with EV71 and restrained the binding of EV71 significantly. Preincubation of RD cells with fetuin also reduced the binding of EV71. In addition, we found that SCARB2 was a sialylated glycoprotein and interaction between SCARB2 and EV71 was retarded after desialylation.

CONCLUSIONS

In this study, we demonstrated that cell surface sialic acids assist in the attachment of EV71 to host cells. Cell surface sialylation should be a key regulator that facilitates the binding and infection of EV71 to RD and SK-N-SH cells.

Exogenous interleukin-6, interleukin-13, and interferon-γ provoke pulmonary abnormality with mild edema in enterovirus 71-infected mice

Background

Neonatal mice developed neurological disease and pulmonary dysfunction after an infection with a mouse-adapted human Enterovirus 71 (EV71) strain MP4. However, the hallmark of severe human EV71 infection, pulmonary edema (PE), was not evident.

Methods

To test whether EV71-induced PE required a proinflammatory cytokine response, exogenous pro-inflammatory cytokines were administered to EV71-infected mice during the late stage of infection.

Results

After intracranial infection of EV71/MP4, 7-day-old mice developed hind-limb paralysis, pulmonary dysfunction, and emphysema. A transient increase was observed in serum IL-6, IL-10, IL-13, and IFN-γ, but not noradrenaline. At day 3 post infection, treatment with IL-6, IL-13, and IFN-γ provoked mild PE and severe emphysema that were accompanied by pulmonary dysfunction in EV71-infected, but not herpes simplex virus-1 (HSV-1)-infected control mice. Adult mice did not develop PE after an intracerebral microinjection of EV71 into the nucleus tractus solitarii (NTS). While viral antigen accumulated in the ventral medulla and the NTS of intracerebrally injected mice, neuronal loss was observed in the ventral medulla only.

Conclusions

Exogenous IL-6, IL-13, and IFN-γ treatment could induce mild PE and exacerbate pulmonary abnormality of EV71-infected mice. However, other factors such as over-activation of the sympathetic nervous system may also be required for the development of classic PE symptoms.

A single nucleotide in stem loop II of 5'-untranslated region contributes to virulence of enterovirus 71 in mice

Background

Enterovirus 71 (EV71) has emerged as a neuroinvasive virus responsible for several large outbreaks in the Asia-Pacific region while virulence determinant remains unexplored.

Principal Findings

In this report, we investigated increased virulence of unadapted EV71 clinical isolate 237 as compared with isolate 4643 in mice. A fragment 12 nucleotides in length in stem loop (SL) II of 237 5′-untranslated region (UTR) visibly reduced survival time and rate in mice was identified by constructing a series of infectious clones harboring chimeric 5′-UTR. In cells transfected with bicistronic plasmids, and replicon RNAs, the 12-nt fragment of isolate 237 enhanced translational activities and accelerated replication of subgenomic EV71. Finally, single nucleotide change from cytosine to uridine at base 158 in this short fragment of 5′-UTR was proven to reduce viral translation and EV71 virulence in mice. Results collectively indicated a pivotal role of novel virulence determinant C158 on virus translation in vitro and EV71 virulence in vivo.

Conclusions

These results presented the first reported virulence determinant in EV71 5′-UTR and first position discovered from unadapted isolates.

Formaldehyde-inactivated human enterovirus 71 vaccine is compatible for co-immunization with a commercial pentavalent vaccine

In this study we tested the effectiveness of a formaldehyde-inactivated EV71 vaccine and its compatibility for co-immunization with a pentavalent vaccine that contained inactivated poliovirus (PV) vaccine. The inactivated EV71 vaccine (C2 genogroup) elicited an antibody response which broadly neutralized homologous and heterologous genogroups, including B4, C4, and B5. Pups from vaccinated dams were resistant to the EV71 challenge and had a high survival rate and a low tissue viral burden when compared to those from non-vaccinated counterparts. Co-immunization with pentavalent and inactivated EV71 vaccines elicited antibodies against the major components of the pentavalent vaccine including the PV, Bordetella pertussis, Haemophilus influenzae type b, diphtheria toxoid, and tetanus toxoid at the same levels as in mice immunized with pentavalent vaccine alone. Likewise, EV71 neutralizing antibody titers were comparable between EV71-vaccinated mice and mice co-immunized with the two vaccines. These results indicate that formaldehyde-inactivated whole virus EV71 vaccine is feasible for designing multivalent vaccines.

Passive protection effect of chicken egg yolk immunoglobulins on enterovirus 71 infected mice

The objective of this study is to evaluate the passive protective efficiency of immunoglobulin in yolk (IgY) specific against human enterovirus type 71 (EV71). The antibody was raised by intramuscular immunization to 10 White Leghorn hens, with inactivated human EV71 serving as the antigen. The titer and specificity of the antibody were analyzed from purified IgY in the egg yolks of immunized hens. Results indicate that the titer of IgY specific against EV71 increased from the third week after the first immunization. The content of total IgY was 190 ± 26 mg/yolk, with an average concentration of specific IgY of 6.34 ± 3.38 mg/yolk in the eggs from 3 to 18 wk after immunization. The results of the neutralization effect of specific IgY in EV71-challenged mice demonstrate that the EV71-specific IgY, either by intraperitoneal injection or oral administration, was able to significantly reduce the morbidity and mortality in EV71 infected mice pups.

Methylene blue-mediated photodynamic inactivation as a novel disinfectant of enterovirus 71

OBJECTIVES

We tested whether methylene blue, an inexpensive and safe photosensitizer, is feasible for photodynamic inactivation of enterovirus 71 (EV71) in the environment.

METHODS

By escalating light doses and photosensitizer concentrations, photoinactivation of EV71 and other enteroviruses was examined in vitro. Viral transmission in the environment was simulated with a neonatal mouse model in vivo. Possible mechanisms were analysed with alterations of viral DNA and proteins after treatments.

RESULTS

Photodynamic inactivation of EV71 in suspensions occurred in a dose-dependent manner. The optimal condition for photoinactivating EV71 required a light dose of 200 J/cm(2) in the presence of methylene blue. This photodynamic condition was also able to inactivate other enteroviruses, including poliovirus 1 and coxsackieviruses A2, A3, A16 and B3. In an imitation environment, EV71 spread on a solid surface was inactivated by methylene blue-mediated photodynamic inactivation and prevented EV71 transmission to mice. Western blot and RT-PCR analysis indicated that both the viral proteins and the genome were disrupted after photodynamic inactivation.

CONCLUSIONS

Methylene blue-mediated photodynamic inactivation may provide a novel way to eliminate environmentally contaminated sources of EV71 to prevent infection.

Microbial contaminations of laboratory mice and rats in Taiwan from 2004 to 2007

Limited data are available on the pathogen status of contemporary rodent colonies in Taiwan. Here we summarized the rodent pathogen diagnostic records of the Taiwan National Laboratory Animal Center during a 4-y period that representing approximately 10% of the rodent colonies in Taiwan. Demand for pathogen diagnostic service increased continuously from 2004 to 2007, with a 20% increase each year. In 2007, more than 20% of the mouse colonies were positive for mouse parvovirus, mouse hepatitis virus, Theiler murine encephalomyelitis virus, and Mycoplasma pulmonis, with fewer colonies diagnosed as having infections of pneumonia virus of mice, mouse adenovirus, lymphocytic choriomeningitis virus, and reovirus. Almost 40% of tested rat colonies were positive for Mycoplasma pulmonis and rat parvovirus, with fewer colonies containing Kilham rat virus, sialodacryoadenitis virus, pneumonia virus of mice, Sendai virus, and Syphacia spp. These data provide a sound overall picture of the health status of mouse and rat colonies in Taiwan.

Ribavirin reduces mortality in enterovirus 71-infected mice by decreasing viral replication

Enterovirus 71 (EV71) causes fatal encephalitis in young children. However, there is no effective antiviral drug available for infected patients. Ribavirin is currently used for the treatment of several RNA virus infections clinically, so its anti-EV71 efficacy was evaluated. In vitro results showed that ribavirin effectively reduced the viral yields (with an IC₅₀ of 65 μg/mL) and virus-induced cytopathic effect in human and mouse cell lines. In vivo results showed that ribavirin reduced the mortality, morbidity, and subsequent paralysis sequelae in infected mice by decreasing viral loads in tissues. Thus, ribavirin could be a potential anti-EV71 drug

Enterovirus 71 triggering of neuronal apoptosis through activation of Abl-Cdk5 signalling

The molecular mechanism behind what causes an infection of Enterovirus 71 (EV71) in young children to result in severe neurological diseases is unclear. Herein, we show that Cdk5, a critical signalling effector of various neurotoxic insults in the brain, is activated by EV71 infection of neuronal cells. EV71-induced neuronal apoptosis could be effectively repressed by blocking either Cdk5 kinase activity or its protein expression. Moreover, EV71-induced Cdk5 activation was modulated by c-Abl. The suppression of c-Abl kinase activity by STI571 notably repressed both the Cdk5 activation and neuronal apoptosis in cells infected with EV71. Although EV71 also induces apoptosis in non-neuronal cells, it did not affect Abl and Cdk5 activities in several non-neuronal cell lines. Intriguingly, coxsackievirus A16 (CA16), a genetically closely related serotype to EV71 that usually does not induce severe neurological disorders, could only weakly stimulate Abl, but not Cdk5 kinase activity. Taken together, our data suggest a serotype- and cell type-specific mechanism, by which EV71 induces Abl kinase activity, which in turn triggers Cdk5-signalling for neuronal apoptosis.

Remifentanil preconditioning confers delayed cardioprotection in the rat †

BACKGROUND

Preconditioning with remifentanil (RPC) provides immediate cardioprotection in rats via all three types of opioid (OP) receptor. This study sought to investigate whether remifentanil also confers delayed cardioprotection via OP receptors.

METHODS

Male rats received preconditioning either by ischaemia (IPC; 5 min occlusion, 5 min reperfusion x 3) or with remifentanil (RPC; 1, 5, 10, and 20 microg kg(-1) min(-1), 20 min infusion). After 24 h, all animals were subjected to 30 min occlusion of the left coronary artery and 2 h of reperfusion. Subsequently, the time-course effect of RPC (10 microg kg(-1) min(-1), 20 min infusion) was determined at 12, 16, 24, 32, 36, and 48 h intervals, using the same experimental procedure. The effect of RPC (10 microg kg(-1) min(-1), 20 min infusion) and IPC in the presence of selective OP receptor antagonists was evaluated at the 24 h interval. Infarct size (IS), as a percentage of the area at risk (AAR), was determined.

RESULTS

Pre-treatment with remifentanil at 1, 5, 10, and 20 microg kg(-1) min(-1) significantly reduced the IS/AAR at 24 h with the maximum effect at 10 microg kg(-1) min(-1). Remifentanil at 10 microg kg(-1) min(-1) significantly reduced the IS at 12 h [32.5 (sd 9.1)%]; 16 h [26.1 (2.8)%]; 24 h [19.5 (5.0)%]; 32 h [31.2 (9.1)%]; and 36 h [36.4 (9.4)%] after drug administration. The maximal reduction in IS was seen at 24 h and the effect completely disappeared at 48 h [36.4 (9.4)%]. The protective effect of RPC was abolished or significantly attenuated by blockade of any of the three OP receptors with selective antagonists.

CONCLUSIONS

Like IPC, remifentanil produces delayed cardioprotection in anaesthetized rats 12-36 h after administration. The protective effect is mediated via all three OP receptors.

Immunity to avirulent enterovirus 71 and coxsackie A16 virus protects against enterovirus 71 infection in mice

In this study, we sought to determine whether intratypic and intertypic cross-reactivity protected against enterovirus 71 (EV71) infection in a murine infection model. We demonstrate that active immunization of 1-day-old mice with avirulent EV71 strain or coxsackie A16 virus (CA16) by the oral route developed anti-EV71 antibodies with neutralizing activity (1:16 and 1:2, respectively). Splenocytes from both EV71- and CA16-immunized mice proliferated upon EV71 or CA16, but not coxsackie B3 virus (CB3), antigen stimulation. Immunized mice became more resistant to virulent EV71 strain challenge than nonimmunized mice. There was an increase in the percentage of activated splenic T cells and B cells in the immunized mice 2 days after EV71 challenge. The CA16 immune serum reacted with EV71 antigens in an enzyme-linked immunosorbent assay and neutralized EV71 but not CB3 or poliovirus at a titer of 1:4. Passive immunization with the CA16 immune serum reduced the clinical score, diminished the organ viral load, and increased the survival rate of mice upon EV71 challenge. CB3 neither shared in vitro cross-reactivity with EV71 nor provided in vivo protection after both active and passive immunization. These results illustrated that live vaccine is feasible for EV71 and that intertypic cross-reactivity of enteroviruses may provide a way to determine the prevalence of EV71.

Retrograde axonal transport: a major transmission route of enterovirus 71 in mice

Inoculation of enterovirus 71 (EV71) by the oral (p.o.), intramuscular (i.m.), or intracranial route resulted in brain infection, flaccid paralysis, pulmonary dysfunction, and death of 7-day-old mice. The lag time of disease progression indicated that neuroinvasion from the inoculation sites was a prerequisite for the development of the clinical signs. Although EV71 p.o. inoculation led to a persistent viremia and a transient increase in blood-brain barrier permeability at the early stage of the infection, only low levels of virus, which led to neither severe infection nor clinical illness, could be detected in the brain, suggesting that hematogenous transport might not represent a major transmission route. In the spinal cord, following both p.o. and hind limb i.m. inoculation, the virus first appeared and increased rapidly in the lower segments, especially at the anterior horn areas, and then spread to the upper segments and brain in the presence of viremia. A reverse pattern, with the virus being first detected in the upper segment, was observed when the virus was i.m. inoculated in the forelimb. Colchicine, a fast axonal transport inhibitor, but not sciatic nerve transection reduced EV71 neuroinvasion in a dose-dependent manner, indicating a neuronal transmission of the virus.

A Non-biotin Polymerized Horseradish-peroxidase Method for the Immunohistochemical Diagnosis of Canine Distemper

This report describes a modified non-biotin polymerized horseradish peroxidase (HRP) immunohistochemical method for the diagnosis of canine distemper virus (CDV) infection from formalin-fixed, paraffin wax-embedded tissues. This method confirmed infection in seven of eight (87.5%) suspected cases. Labelled CDV antigen was observed in the following sites: cerebrum, cerebellum, meninges, glial cells, neurons, vascular endothelium, periventricular areas and pericytes, and choroid plexus; grey and white matter and central canal of the spinal cord; renal pelvis and tubular epithelium, and urinary bladder epithelium; macrophages and lymphocytes in splenic white pulp and lymph nodes; skin epidermis; bronchiolar epithelium and alveolar macrophages; hepatic Kupffer cells, and gastric and intestinal mucosal epithelium; stratified squamous epithelium of the tongue and oesophagus. With the non-biotin HRP detection system, pretreatment by autoclaving followed by microwave heating gave better labelling results than did microwave pretreatment alone. No obvious difference was noted between the labelling results produced by the non-biotin HRP detection system and the Super Sensitive Link-Label IHC detection system.

Modulation of cytokine production by intravenous immunoglobulin in patients with enterovirus 71-associated brainstem encephalitis

BACKGROUND

Several epidemics of enterovirus 71 (EV71) infections occurred in Taiwan since 1998.

OBJECTIVES

We performed the study to determine the changes in cytokine profiles associated with administration of intravenous immunoglobulin (IVIG) in patients with EV71-associated brainstem encephalitis complicated by autonomic nervous system (ANS) dysfunction and pulmonary edema.

STUDY DESIGN

Plasma cytokine concentrations (IL-1beta, IL-6, IL-8, IFN-gamma, TNF-alpha, IL-2, IL-4, IL-5, IL-10, and IL-13) were monitored on admission and within 12-24h after administration of IVIG in a cohort of children (n=22) with virologically confirmed EV71 infection, from March 2000 through April 2004.

RESULT

Plasma levels of IFN-gamma, IL-6, IL-8, IL-10, and IL-13 levels significantly decreased in patients with pulmonary edema after administration of IVIG, P<0.05. Plasma levels of IL-6 and IL-8 were significantly decreased in patients with ANS dysregulation after administration of IVIG, P<0.05. Administration of IVIG was not associated with significant changes in plasma concentration of IL-1beta, IL-2, IL-4, IL-5 IL-10, IL-13 and TNF-alpha in patients with ANS dysregulation.

CONCLUSIONS

These findings suggest that IVIG might be considered to have a therapeutic role in EV71-associated brainstem encephalitis. A clinical trial is needed to support this hypothesis.

Enterovirus 71 infection induces Fas ligand expression and apoptosis of Jurkat cells

T-cell depletion is found in enterovirus 71 (EV71)-infected patients with pulmonary edema. However, the mechanism that causes T-cell depletion is unclear. To address this question, the effects of EV71 infection on the cell viability of human Jurkat T cells were studied. Viable viruses were recovered from both the culture supernatant and the cell lysate of Jurkat cells after EV71 infection. Results from reverse-transcription polymerase chain reaction (RT-PCR) and immunofluorescence assay confirmed further the presence of EV71 negative-strand RNA and antigen, respectively, in EV71-infected Jurkat cells. The viability of the Jurkat cells decreased after 48 hr of EV71 infection. Both terminal transferase end labeling (TUNEL) and DNA fragmentation assays demonstrated that the apoptosis of EV71-infected Jurkat cells had increased. In addition, the expression of Fas ligand (FasL) in EV71-infected Jurkat cells increased at both mRNA and surface expression levels. Taken together, these results confirmed that EV71 infected T cells and induced FasL expression, which may contribute to T-cell apoptosis during EV71 infection.

Serine protease inhibitors nafamostat mesilate and gabexate mesilate attenuate allergen-induced airway inflammation and eosinophilia in a murine model of asthma

BACKGROUND

Serine proteases such as mast cell tryptase and certain allergens are important in the pathogenesis of allergic inflammation of asthma.

OBJECTIVE

We sought to investigate the effects of serine protease inhibitors nafamostat mesilate (FUT), gabexate mesilate (FOY), and ulinastatin (UTI) on airway inflammation in a mouse model of allergic asthma.

METHODS

BALB/c mice were sensitized to Dermatophagoides pteronyssinus (Der p) and intratracheally challenged with Der p (0.5 mg/mL). Therapeutic doses of FUT (0.0625 mg/kg), FOY (20 mg/kg), and UTI (10,000 U/kg) were intra-peritoneally injected into 3 corresponding sensitized mice during the sensitization phase (protocol 1) or 24 hours after allergen challenge (protocol 2).

RESULTS

Both FUT-treated and FOY-treated sensitized mice had reduced mast cells activation, airway hyperresponsiveness, attenuated eosinophils infiltrations, and decreased Der p-induced IL-4 and TNF-alpha, but increased IL-12 cytokine production in bronchoalveolar lavage fluid compared with nontreated mice. Furthermore, FUT treatment downregulated the expression of IL-1beta, TNF-alpha, IL-6, eotaxin, inducible NO synthase, CD86, and nuclear factor-kappaB activation, but enhanced the expression of IL-12 and IL-10 in Der p-stimulated alveolar macrophages. UTI-treated mice have no significant change of the aforementioned measurements compared with nontreated sensitized mice.

CONCLUSION

Nafamostat mesilate and FOY exerting the therapeutic effect in allergen-induced airway inflammation was a result not only of their inhibitory action in the early phase of mast cells activation but also of immunoregulatory function in the late phase of allergic inflammation. Such properties of FUT and FOY might be a potential therapeutic approach for asthma.

CLINICAL IMPLICATIONS

The clinical used of serine protease inhibitors FUT and FOY may also have implications for treating airway inflammation of asthma.

Type I interferons protect mice against enterovirus 71 infection

In this study, the contribution of type I interferons (IFNs) to protection against infection with enterovirus 71 (EV71) was investigated using a murine model where the virus was administrated to neonatal Institute of Cancer Research (ICR) mice by either the intraperitoneal (i.p.) or the oral route. In i.p. inoculated mice, post-infection treatment of dexamethasone (5 mg kg(-1) at 2 or 3 days after infection) exacerbated clinical symptoms and increased the tissue viral titre. In contrast, polyriboinosinic : polyribocytidylic acid [poly(I : C); 10 or 100 microg per mouse at 12 h before infection], a potent IFN inducer, improved the survival rate and decreased the tissue viral titres after EV71 challenge, which correlated with an increase in serum IFN-alpha concentration, the percentage of dendritic cells, their expression of major histocompatibility complex class II molecule and IFN-alpha in spleen. Treatment with a neutralizing antibody for type I IFNs (10(4) neutralizing units per mouse, 6 h before and 12 h after infection) resulted in frequent deaths and higher tissue viral load in infected mice compared with control mice. In contrast, an early administration of recombinant mouse IFN-alphaA (10(4) U per mouse for 3 days starting at 0, 1 or 3 days after infection) protected the mice against EV71 infection. In vitro analysis of virus-induced death in three human cell lines showed that human type I IFNs exerted a direct protective effect on EV71. It was concluded that type I IFNs play an important role in controlling EV71 infection and replication.

Delayed diagnosis of cervical cancer in young women

This study aims to determine whether women under 35 years presenting with cervical cancer experience delays between presentation and diagnosis. All women referred with cervical cancer to the gynaecological cancer centre for the North London Cancer Network from January 2002 to December 2004 were identified retrospectively. Clinical presentation and time interval from symptoms to diagnosis were compared between women under and women over 35 years. A total of 105 women were included. Median age at diagnosis was 45 years (range 23--88). Twenty-two women (19%) were under 35 years at presentation and 17 had persistent symptoms prior to diagnosis. Median time from initial presentation to diagnosis in this group was 9 months (range 3--24 months); significantly longer than in the older group (9 vs 2 months; p=0.0009). Although cervical cancer is relatively rare in young women, diagnosis should be considered in symptomatic women as delay can limit treatment options.

Lactoferrin inhibits enterovirus 71 infection by binding to VP1 protein and host cells

The antiviral activities of bovine lactoferrin (LF) against enterovirus 71 (EV71) were studied both in vitro and in vivo. LF protected both human rhabdomyosarcoma and neuroblastoma SK-N-SH cell lines from EV71 infection when it was added at the same time, before, or within 30min after EV71 infection. Using enzyme-linked immunosorbent assay-based binding assay and indirect fluorescent stain, we found that LF could bind to the target cells. Furthermore, it was found that LF could bind to the VP1 protein of EV71, which was blocked in the presence of anti-VP1 antibody. In addition, LF could induce IFN-alpha expression of SK-N-SH cells and inhibit EV71-induced IL-6 production. Finally, LF protected mice against lethal EV71 challenge. Taken together, these results suggest that LF can inhibit EV71 infection by interacting with both EV71 and host cells.

IL-19 induced Th2 cytokines and was up-regulated in asthma patients

IL-19 belongs to the IL-10 family, which includes IL-10, IL-19, IL-20, IL-22, melanoma differentiation-associated gene-7 (IL-24), and AK155 (IL-26). IL-10 has been shown to inhibit allergen-induced airway hyperreactivity and inflammation. To determine whether IL-19 was also associated with asthma, we used ELISA to analyze the serum level of IL-19 in patients with asthma and found that their serum IL-19 levels were twice those of healthy controls. Patients with a high level of IL-19 also had high levels of IL-4 and IL-13. In a dust mite-induced murine model of asthma, we found that IL-19 level in asthmatic BALB/cJ mice was also twice that of healthy control mice. IL-19 transcript was also induced in the lungs of asthmatic mice. Electroporation i.m. of the IL-19 gene into healthy mice up-regulated IL-4 and IL-5, but not IL-13. However, IL-19 up-regulated IL-13 in asthmatic mice. In vitro, IL-19 induced IL-4, IL-5, IL-10, and IL-13 production by activated T cells. Activation of T cells was required for induction of IL-13 because IL-19 did not induce IL-13 production on nonstimulated T cells. Taken together, these results demonstrated that IL-19 up-regulates Th2 cytokines on activated T cells and might play an important role in the pathogenesis of asthma.

Human endothelial cell activation and apoptosis induced by enterovirus 71 infection

Enterovirus 71 (EV71), a neurotropic virus, its infection is transmitted mainly by the oral-fecal route. However, it is unclear how EV71 is disseminated/spread from initial replication sites to the central nervous system. Since endothelial cells form the interface between blood and tissues throughout the body, it is likely that EV71 can infect and then exit endothelial cells to establish infection. In this study, human endothelial cells were examined for susceptibility to EV71 infection using human microvascular endothelial cell line (HMEC-1 cell). Immunofluorescence assay confirmed EV71 infection of HMEC-1. Viable viruses were cultured from both the culture supernatant and the cell lysate. Live but not UV-inactivated EV71 induced HMEC-1 to secrete IL-6, macrophage migration inhibition factor, and macrophage chemo-attractant protein 1, and to express toll-like receptor 4. In addition, EV71 decreased the viability and increased the apoptosis of HMEC-1 cells after 36-48 hr of infection. These results demonstrate that EV71 is able to infect, activate, and induce apoptosis of endothelial cells, which may play a role in the pathogenesis of EV71 infection.

A mouse-adapted enterovirus 71 strain causes neurological disease in mice after oral infection

A mouse-adapted enterovirus 71 (EV71) strain with increased virulence in mice, MP4, was generated after four serial passages of the parental EV71 strain 4643 in mice. Strain MP4 exhibited a larger plaque size, grew more rapidly, and was more cytotoxic in vitro than strain 4643. Although strains 4643 and MP4 both induced apoptosis of SK-N-SH human neuroblastoma cells, MP4 was more virulent than 4643 in 1-day-old mice (50% lethal doses, 10(2) and 10(4) PFU/mouse, respectively). Strain MP4 (5 x 10(6) PFU/mouse), but not 4643, could orally infect 7-day-old mice, resulting in rear-limb paralysis followed by death 5 to 9 days after inoculation with the virus. Histopathologically, neuronal loss and apoptosis were evident in the spinal cords as well as the brain stems of the infected mice. The limb muscles displayed massive necrosis. There was early and transient virus replication in the intestines, whereas the spinal cord, brain, and muscle became the sites of viral replication during the late phase of the infection. Virus transmission occurred among infected and noninfected cagemates, as demonstrated by the occurrence of seroconversion and the presence of viable viruses in the stool samples of the latter. Protection against EV71 challenge was demonstrated following administration of hyperimmune serum 1 day after inoculation with the virus. Nucleotide sequence analysis of the genome of EV71 strain MP4 revealed four nucleotide changes on the 5' untranslated region, three on the VP2 region, and eight on the 2C region, resulting in one and four amino acid substitutions in the VP2 and 2C proteins, respectively.

Activation of mast cells is essential for development of house dust mite Dermatophagoides farinae-induced allergic airway inflammation in mice

In this study, we demonstrate that Dermatophagoides farinae (Der f), a major source of airborne allergens, but not OVA, could rapidly activate mast cells in mice. This was indicated by an elevation of serum mouse mast cell protease 1, a mast cell-specific proteinase, as early as 30 min after intratracheal challenge. Administration of sodium cromoglycate (40 mg/kg, i.p., 1 h before Der f instillation), a mast cell stabilizer, not only suppressed acute mouse mast cell protease 1 production but also attenuated the allergic airway inflammation provoked by repetitive Der f challenge in mice (five times at 1-wk interval). Der f induced the expression of mRNA for TNF-alpha, IL-1beta, IL-4, IL-6, IL-9, and IL-13 in mastocytoma P815 cells and stimulated both P815 cells and bone marrow-derived mast cells to produce IL-4, IL-6, and TNF-alpha in a dose- and time-dependent manner. Cycloheximide as well as sodium cromoglycate blocked the Der f-induced IL-4 production, indicating a de novo protein synthesis process. Supernatants of Der f-stimulated mast cells chemoattracted monocytes and T lymphocytes; they up-regulated the expression of costimulatory B7 molecules, eotaxin, RANTES, monocyte chemoattractant protein 1, and IFN-inducible protein 10 mRNA of alveolar macrophages; they supported PHA-induced T cell proliferation; and they promoted Th2 cell development. Our data indicate that mast cells may be an important cell type during the initiation of Der f sensitization in the airway by modulating the function of alveolar macrophages and T cells.

A murine oral enterovirus 71 infection model with central nervous system involvement

Enterovirus 71 (EV71) infection causes a myriad of diseases from mild hand-foot-and-mouth disease or herpangina to fatal meningoencephalitis complicated with neurogenic pulmonary oedema. Its pathogenesis, especially the CNS involvement, is not clearly understood. The aim of this study was to set up a mouse EV71 infection model with CNS involvement. EV71 virus was administrated orally to neonatal mice. The EV71-infected mice manifested a skin rash at an early stage and hind limb paralysis or death at a later stage. Immunohistochemical staining and virus isolation demonstrated that EV71 replicated in the small intestine, induced viraemia and spread to various organs. Kinetic studies showed that EV71 antigen was first detected in the intestine at 6 h, in the thoracic spinal cord at 24 h, in the cervical spinal cord at 50 h and in the brain stem at 78 h post-infection. Leukocyte infiltration was evident in the spinal cord and brain stem. Furthermore, EV71 virus could be transmitted to littermates within the same cage.

Pathogenesis of enterovirus 71 brainstem encephalitis in pediatric patients: roles of cytokines and cellular immune activation in patients with pulmonary edema

Taiwan experienced several epidemics of enterovirus 71 (EV71) infections, which were associated with brainstem encephalitis (BE) and pulmonary edema (PE). To elucidate the role of immune mechanisms in the pathogenesis of BE caused by EV71 and its fatal complication, PE, we analyzed the laboratory findings, cytokine, and immunophenotypes of 73 EV71-infected patients with BE. Patients were stratified by disease: PE (n=14), autonomic nervous system (ANS) dysregulation (n=25), and isolated BE (n=34). The mortality rate for PE was 64.3%. Leukocytosis and thrombocytosis were significantly more frequent among patients with PE. A significant elevation of plasma interleukin (IL)-10, IL-13, and interferon (IFN)-gamma levels observed in patients with PE. Patients with PE also had lower circulating CD4(+) T cells, CD8(+) T cells, and natural killer (NK) cells. An extensive peripheral and central nervous system inflammatory response with abnormal IL-10, IL-13, and IFN-gamma cytokine production and lymphocyte depletion appears to be responsible for the pathogenesis of EV71-associated PE.

House dust mite Dermatophagoides farinae augments proinflammatory mediator productions and accessory function of alveolar macrophages: implications for allergic sensitization and inflammation

In this study, we examine the effects of Dermatophagoides farinae (Der f), a major source of airborne allergens, on alveolar macrophages (AMs), and we also test its contribution to allergic responses in mice. Der f activated NF-kappaB of AMs and, unlike OVA or LPS stimulation, up-regulated IL-6, TNF-alpha, and NO. In addition, it down-regulated antioxidants, but affected neither the expression nor production of IL-12. Der f-stimulated AMs expressed enhanced levels of costimulatory B7 molecules, supported T cell proliferation, and promoted Th2 cell development. The enhanced accessory function was suppressed by blockade mAbs to B7.2, IL-6, and TNF-alpha and by N-monomethyl-L-arginine, an NO synthase inhibitor, and N-acetylcysteine, a thiol antioxidant, whereas it was augmented by (+/-)-S-nitroso-N-acetylpenicillamine, an NO donor. Arg-Gly-Asp-Ser peptide and neo-glycoproteins galactose-BSA and mannose-BSA inhibited the Der f-induced IL-6 and TNF-alpha productions and enhanced accessory function of AMs. Der f was more potent than OVA for inducing pulmonary eosinophilic inflammation, NO, and serum allergen-specific IgG1 Ab production in mice. AMs from Der f-challenged mice expressed enhanced levels of B7 and augmented T cell proliferation ex vivo. In Der f-challenged mice, respiratory syncytial virus infection (5 x 10(5) pfu; 3 days before Der f instillation) augmented Der f-specific Ab production, whereas dexamethasone (50 mg/kg; 1 h before Der f instillation) diminished the allergic airway inflammation and Ab response. We conclude that AMs are sensitive targets for Der f and that the Der f-induced proinflammatory responses may represent an important mechanism in mediating the development of allergic sensitization and inflammation.

Dehydroepiandrosterone attenuates allergic airway inflammation in Dermatophagoides farinae-sensitized mice

Dehydroepiandrosterone, an androgen abundant in circulation, has important immunomodulating effects. In this study the therapeutic effect of dehydroepiandrosterone on established allergic inflammation was examined in a dust mite (Dermatophagoides farinae)-induced asthma model. Airway inflammation was provoked in D. farinae-sensitized BALB/c mice by repetitive intratracheal challenge (3 times, once a week). Three days after the first challenge, mice were fed a diet incorporated with 1.5% (w/w) dehydroepiandrosterone and were examined at days 3 and 6 after the last challenge. Airway challenge resulted in pulmonary eosinophilic inflammation accompanied by elevated blood eosinophil counts and elevated serum and bronchoalveolar lavage immunoglobulin E antibody levels in control diet-fed mice. However, the D. farinae-induced airway inflammation and blood eosinophilia was significantly reduced in dehydroepiandrosterone-fed mice, which was associated with a decrease in serum interleukin-4, interleukin-5, and interferon-gamma levels. Total immunoglobulin E antibody concentrations in serum and bronchoalveolar lavage fluids were not affected by the dehydroepiandrosterone treatment. These results demonstrated that dehydroepiandrosterone could suppress preexisting allergic airway inflammation.

Multicenter screening for pre-eclampsia and fetal growth restriction by transvaginal uterine artery Doppler at 23 weeks of gestation

OBJECTIVE

To determine the value of transvaginal color Doppler assessment of the uterine arteries at 23 weeks of gestation in predicting the subsequent development of pre-eclampsia and fetal growth restriction.

PATIENTS AND METHODS

Women with singleton pregnancies attending for routine ultrasound examination at 23 weeks in any one of seven hospitals underwent Doppler assessment of the uterine arteries. The presence of an early diastolic notch in the waveform was noted, and the mean pulsatility index of the two arteries was calculated. Screening characteristics in the prediction of pre-eclampsia and the delivery of a low birth-weight infant were calculated.

RESULTS

Doppler examination of the uterine arteries was attempted in 8335 consecutive singleton pregnancies, satisfactory waveforms were obtained from both vessels in 8202 (98.4%) cases and complete outcome data were available in 7851 (95.7%) of these. The mean gestational age was 23 (range, 22-24) weeks. The mean uterine artery pulsatility index did not change significantly with gestation (r = -0.0078; P = 0.483); the median value was 1.04 and the 95th centile was 1.63. In 9.3% of cases early diastolic notches in the waveform from both uterine arteries were present and in an additional 11.1% of cases there were notches unilaterally. Pre-eclampsia with fetal growth restriction occurred in 42 (0.5%) cases, pre-eclampsia without fetal growth restriction in 71 (0.9%) and fetal growth restriction without pre-eclampsia in 698 (8.9%). The sensitivity of increased pulsatility index above the 95th centile (1.63) for pre-eclampsia with fetal growth restriction was 69%, for pre-eclampsia without fetal growth restriction was 24%, for fetal growth restriction without pre-eclampsia was 13%, for pre-eclampsia irrespective of fetal growth restriction was 41% and for fetal growth restriction irrespective of pre-eclampsia was 16%. The sensitivity of fetal growth restriction defined by the 5th rather than the 10th centile was higher (19% vs. 16%). The sensitivity for both pre-eclampsia and fetal growth restriction was inversely related to the gestational age at delivery; when delivery occurred before 32 weeks, the sensitivity for all cases of pre-eclampsia with fetal growth restriction, pre-eclampsia without fetal growth restriction and fetal growth restriction without pre-eclampsia increased to 93%, 80% and 56%, respectively. The sensitivity of bilateral notches in predicting pre-eclampsia and/or fetal growth restriction was similar to that of increased pulsatility index but the screen-positive rate with notches (9.3%) was much higher than that with increased pulsatility index (5.1%).

CONCLUSIONS

A one-stage color Doppler screening program at 23 weeks identifies most women who subsequently develop severe pre-eclampsia and/or fetal growth restriction.

Repeatability of measurement of uterine artery pulsatility index using transvaginal color Doppler

OBJECTIVE

To assess the repeatability of measuring the pulsatility index of the uterine arteries using transvaginal color Doppler at 23 weeks of gestation.

PATIENTS AND METHODS

The pulsatility index was measured in 100 women with singleton pregnancies attending for routine transvaginal Doppler examination of the uterine arteries at 23 weeks. To assess the repeatability of different components of variability, six measurements of the uterine artery pulsatility index were made on one of the uterine arteries in each patient.

RESULTS

Six measurements of the pulsatility index were successfully measured in all 100 patients, resulting in a total of 600 measurements. The repeatability was unrelated to the pulsatility index. On 95% of occasions the intraobserver, interobserver and waveform tracing repeatability was less than 0.24, 0.27 and 0.14, respectively.

CONCLUSIONS

Measurement of the pulsatility index using transvaginal color Doppler is highly reproducible when the examination is carried out by well-trained operators.

Complete genome analysis of enterovirus 71 isolated from an outbreak in Taiwan and rapid identification of enterovirus 71 and coxsackievirus A16 by RT-PCR

Hand, foot, and mouth disease (HFMD) and encephalomyelitis were two major clinical manifestations during the 1998 enterovirus 71 (EV71) epidemic in Taiwan. To investigate whether different clinical patterns were caused by alterations in EV71 genomes, the complete nucleotide sequences of four EV71 strains associated with HFMD or encephalomyelitis were compared. Among these viral strains, two or three nucleotide differences were found within the 5'-noncoding region, and two or four amino acid differences were found within the regions encoding viral polyproteins; however, none of these differences were correlated with either clinical manifestation. Because coxsackievirus A16 was another major causative agent of HFMD, a reverse transcription-polymerase chain reaction assay, with high sensitivity and specificity for identification of EV71 (both 100%) and coxsackievirus A16 (100 and 98.8%), was developed for the rapid differential identification of these two viruses in HFMD patients.

Isolation and characterization of a Vibrio vulnificus mutant deficient in both extracellular metalloprotease and cytolysin

We isolated a Vibrio vulnificus mutant that was deficient in both metalloprotease and cytolysin by allelic exchange. The virulence of this mutant in mice and its cytotoxicity for HEp-2 cells were comparable to those of the wild-type strain, indicating that neither factor was essential for these properties. The cytolysin, but not the protease, seemed to be important for causing damage in the alimentary tract of the mice.

Allergen-induced bronchial inflammation is associated with decreased levels of surfactant proteins A and D in a murine model of asthma

BACKGROUND

Increasing evidence suggests that pulmonary surfactant protein A (SP-A) and D (SP-D) participate in the lung defence against pathogens. However, the role of surfactant proteins in the pathogenesis of allergen-induced airway inflammation has not been elucidated. In this study we examined the levels and distributions of SP-A and SP-D in a dust mite (Dermatophagoides pteronyssinus, Der p) allergen-induced murine model of asthma.

METHODS

The concentration of SP-A and SP-D in the bronchoalveolar lavage fluid (BALF) and the distribution of surfactant proteins in the lung were assayed by ELISA and immunohistochemistry methods, respectively. The effect of surfactant proteins on allergen-induced pulmonary lymphocyte proliferation was also studied.

RESULTS

We demonstrated that there were marked reductions of SP-A and SP-D levels in the BALF of Der p-sensitized BALB/c mice at 48-72 h after allergen challenge (AC). Both purified SP-A and SP-D were able to suppress, in a dose dependent manner, Der p-stimulated intrapulmonary lymphocyte proliferation of naïve mice with saline or allergen challenge, or of Der p-sensitized mice with saline challenge. On the contrary, this suppressive effect was mild (< 9%) on lymphocytes from sensitized mice after AC.

CONCLUSION

These results indicated the involvement of pulmonary surfactant proteins in the allergic bronchial inflammation of sensitized mice.

The effect of Chinese herbal medicine, xiao-qing-long tang (XQLT), on allergen-induced bronchial inflammation in mite-sensitized mice

BACKGROUND

There are detailed descriptions of the clinical experiences and prescriptions of asthma in traditional Chinese medicine. Xiao-qing-long tang (XQLT), or sho-seiryo-to by its Japanese name, is one of the Chinese herbal medicines used to treat bronchial asthma and allergic rhinitis for centuries. However, the therapeutic mechanisms of this medication are still far from clear. In this study, a house-dust-mite (Dermatophagoides pteronyssinus [Der p])-sensitized murine model of asthma was used to evaluate the immunomodulatory effect of XQLT on the allergen-induced airway inflammation in asthma.

METHODS

Three different protocols were designed to evaluate the treatment and/ or long-term prophylactic effect of XQLT in Der p-sensitized mice. XQLT extracts (1 gm/kg) were administered to sensitized mice 1 h before allergen challenge (AC) (group A), 24 h after AC (group B), and every other day six times before AC (group C), respectively. Cellular infiltration and T-cell subsets in the bronchoalveolar lavage fluid (BALF) of allergen-challenged mice were analyzed. Intrapulmonary lymphocytes were also isolated to evaluate their response to allergen stimulation.

RESULTS

When XQLT was administered to the sensitized mice before AC (groups A and C), it suppressed airway inflammation by decreasing the number of total cells and eosinophil infiltration in the BALF, and downregulated the allergen- or mitogen-induced intrapulmonary lymphocyte response of sensitized mice as compared to those of controls. This immunomodulatory effect of XQLT may be exerted through the regulation of T-cell subsets by elevation or activation of the CD8+ and double-negative T-cell population in the lung. However, the administration of XQLT to sensitized mice 24 h after AC (group B) did not have the same inhibitory effect on the airway inflammation as XQLT given before AC.

CONCLUSIONS

The administration of XQLT before AC has the immunomodulatory effect of reducing bronchial inflammation in the allergen-sensitized mice.

Neutralizing antibody provided protection against enterovirus type 71 lethal challenge in neonatal mice

Experimental infection with enterovirus type 71 (EV71) induced death in neonatal mice in an age- and dose-dependent manner. The mortality rate was 100% following intraperitoneal inoculation 1-day-old ICR mice and this gradually decreased as the age at the time of inoculation increased (60% in 3-day-old mice and no deaths occurred in mice older than 6 days of age). A lethal dose greater than 10(8) PFU was necessary. Lethargy, failure to gain weight, rear limb tremors and paralysis were observed in the infected mice before death. EV71 was isolated from various tissues of the dead mice. Using a reverse transcription polymerase chain reaction technique with a specific primer pair, a 332-bp product was detected in the tissues that produced a culture positive for EV71. Protection against EV71 challenge in neonatal mice was demonstrated following passive transfer of serum from actively immunized adult mice 1 day after inoculation with the virus. Pups from hyperimmune dams were resistant to EV71 challenge. Additionally, maternal immunization with a formalin-inactivated whole-virus vaccine prolonged the survival of pups after EV71 lethal challenge.

Propionibacterium acnes induces acute TNFalpha-mediated apoptosis of hepatocytes followed by inflammatory T-cell-mediated granulomatous hepatitis in mice

The CD3+/TCRalphabeta+ T-cell-mediated hepatic inflammation induced by Propionibacterium acnes could be divided into an acute and a chronic phase. The acute phase occurred within 72 h after injection and displayed hepatic apoptosis. Anti-TNFalpha antibody inhibited both the P. acnes-induced hepatic apoptosis and lymphocyte infiltration seen in this phase, indicating the involvement of this cytokine. Thereafter, a chronic phase was manifested from days 7 to 14 after injection. It was characterized as granulomatous inflammation admixed with apoptosis of infiltrating lymphocytes and some hepatocytes. Immunohistochemical staining showed that the infiltrating lymphocytes displayed TNFalpha, TNF type I receptor and a variety of cytokines including IL-1beta, IL-4, IL-6, IL-10, IFNgamma or IL-12. Interestingly, in naive mice, the arteries in the liver constitutively expressed IFNgamma. Its expression appeared to be substantially increased at 48 h, decreased at 72 h, and increased again on day 14 after P. acnes injection. Furthermore, Fas or FasL was only detected on the lymphocytes within the granuloma. We conclude that P. acnes can induce a TNFalpha-mediated acute hepatic apoptosis which subsequently progress to a T-cell-mediated granulomatous hepatitis with increased expression of multiple cytokines and Fas/FasL.

Repeated intratracheal inoculation of house dust mite (Dermatophagoides farinae) induces pulmonary eosinophilic inflammation and IgE antibody production in mice

BACKGROUND

In vitro studies have shown that the biologic activities of dust mite allergens probably contribute to their allergenicity. However, little is known about their in vivo effect, which may lead to allergic inflammation and sensitization.

OBJECTIVE

In this study we characterized the pathologic and immunologic responses of mice after repetitive challenge with dust mite Dermatophagoides farinae.

METHODS

Der f crude extract was intratracheally instilled into female BALB/c mice either once or a total of 10 times at 1-week intervals. The inflammatory responses, morphologic changes, IgE antibody and cytokine levels, and costimulatory molecular B7 expression in the airways were then monitored.

RESULTS

We demonstrated that single Der f challenge provoked an acute neutrophilic inflammation in the airways. After repeated Der f challenge, there was chronic inflammation characterized by increased numbers of lymphocytes and eosinophils in bronchoalveolar lavage (BAL) fluids. Histopathologically, the numbers of goblet cells and mast cells were significantly increased in the airways of these mice. Repetitive challenge elicited Der f-specific IgE antibody, increased IL-5 and IFN-gamma level in BAL fluids, and enhanced costimulatory B7 molecule expression on BAL cells.

CONCLUSIONS

Our findings are in agreement with those of other in vitro studies concerning the properties of dust mite allergens. Prolonged inhalation of Der f without adjuvant may represent an optimal condition to develop experimental animal models of allergic lung diseases.

Attenuation of house dust mite Dermatophagoides farinae-induced airway allergic responses in mice by dehydroepiandrosterone is correlated with down-regulation of TH2 response

BACKGROUND

Dehydroepiandrosterone (DHEA), an abundant androgen in circulation, has important immunomodulating effects on T-cell differentiation; however, it is not known whether this hormone influences allergic responses.

OBJECTIVE

We have established a murine model of airway inflammation induced by house dust mite Dermatophagoides farinae (Der f). Der f challenge of sensitized mice would elicit a pulmonary eosinophilic inflammation. In the present study, we employed this model system to explore the effect of DHEA on allergic responses.

METHODS

Female BALB/c mice were fed with a standard diet incorporated with 1.5% (w/w) of DHEA for 1 week before sensitization and every other day for an additional 2 weeks after sensitization. After intratracheal inoculation of allergen, the Der f-induced airway inflammation, immunoglobulin (Ig)E antibody production, and cytokine expression were compared between control and DHEA-fed mice.

RESULTS

In control mice the Der f-induced eosinophilia in bronchoalveolar lavage (BAL) fluids was accompanied by an increase in production of interleukin (IL)-4, IL-5, and interferon IFN-gamma systemically and locally. DHEA supplementation did not affect the body weight of mice. However, in mice that were receiving DHEA, the numbers of eosinophils and lymphocytes in BAL fluids significantly decreased at days 2 and 6 after challenge as compared with control mice. Concomitantly, total IgE antibody concentrations as well as IL-4, IL-5, and IFN-gamma levels in BAL fluids or serum also significantly reduced. Immunocytochemical staining of BAL cells revealed that there were fewer IL-4-, IL-5-, IL-10-, but not IFN-gamma-positive stained cells in DHEA-fed mice than in mice who consumed unsupplemented diet. Reverse transcription-polymerase chain reaction analysis demonstrated DHEA decreased the expression of IL-5 and IL-10 transcripts in BAL cells.

CONCLUSIONS

Our results showed that administration of DHEA during allergic sensitization could attenuate the subsequent allergic responses elicited by challenge, and that the suppressive effect of DHEA was associated with a down-regulation of TH2 response.