Viral Inclusion Bodies Research Articles

Nonsuppurative Meningoencephalitis in a Laboratory Beagle Dog

We encountered a case of nonsuppurative meningoencephalitis with neurologic signs of depression, tremor, and ataxic gait in a 15-month-old vaccinated male beagle dog. Hematologic and biochemical parameters indicated no significant changes except for some findings suggesting dehydration and anorexia. Microscopically, the main features consisted of nonsuppurative meningoencephalitis with disseminated foci of perivascular cuffing of mononuclear cell in the leptomeninges and gray matter of the cerebrum and cerebellum. Some glial nodules, which were characterized by accumulation of microglia, were seen in the molecular layer of the cerebellum. Demyelination and neuronal necrosis were not observed in the central nervous system. Although the dog had a slightly elevated serum antibody titer to canine distemper virus (CDV), neither viral inclusion bodies, nor CDV antigens were detected in the brain tissue. The cause of disease in this case remained unclear.

Soil‐borne wheat mosaic virus inclusion bodies: structural, compositional and staining properties

SummaryAnatomy and cytochemistry of inclusion bodies induced by Soil‐borne wheat mosaic virus infection were studied in roots and leaves to learn more about the nature of inclusions and their roles in pathogenesis. Acid Fuchsin, Giemsa stain, Toluidine Blue and Trypan Blue stains facilitated visualization of inclusion bodies. Combined, simultaneous staining with Acid Fuchsin and Toluidine Blue clearly differentiated inclusion bodies from host nuclei. The overall anatomy, composition and structure of virus inclusions in leaves and roots were generally similar, as shown by phase contrast, differential interference contrast, epifluorescence, laser scanning confocal and transmission electron microscopy. Both were often closely associated with host nuclei; both were comprised of intertwined masses of tubular material, presumably endoplasmic reticulum, and in which varied numbers and sizes of vacuolar cavities occurred. Leaf inclusions, however, were typically larger and more vacuolate than those in roots. Lipids were found to be significant constituents of both the tubular and vacuolar components of inclusions, indicated by positive staining with Nile Red and Sudan Black. Inclusion bodies in both leaves and roots lost their structural and compositional integrity, eventually becoming disorganized and devoid of clearly identifiable components as host tissue aged and symptom expression advanced. Significant results of this study include the first published examination of virus inclusion bodies in root tissue, the degree of structural detail of inclusion body anatomy revealed by laser scanning confocal microscopy and the presence of an extensive lipid component in virus inclusion bodies.

The clinical pathology of severe acute respiratory syndrome (SARS): a report from China.

In order to investigate the clinical pathology of severe acute respiratory syndrome (SARS), the autopsies of three patients who died from SARS in Nan Fang Hospital Guangdong, China were studied retrospectively. Routine haematoxylin and eosin (H&E) staining was used to study all of the tissues from the three cases. The lung tissue specimens were studied further with Macchiavello staining, viral inclusion body staining, reticulin staining, PAS staining, immunohistochemistry, ultrathin sectioning and staining, light microscopy, and transmission electron microscopy. The first symptom was hyperpyrexia in all three cases, followed by progressive dyspnoea and lung field shadowing. The pulmonary lesions included bilateral extensive consolidation, localized haemorrhage and necrosis, desquamative pulmonary alveolitis and bronchitis, proliferation and desquamation of alveolar epithelial cells, exudation of protein and monocytes, lymphocytes and plasma cells in alveoli, hyaline membrane formation, and viral inclusion bodies in alveolar epithelial cells. There was also massive necrosis of splenic lymphoid tissue and localized necrosis in lymph nodes. Systemic vasculitis included oedema, localized fibrinoid necrosis, and infiltration of monocytes, lymphocytes, and plasma cells into vessel walls in the heart, lung, liver, kidney, adrenal gland, and the stroma of striated muscles. Thrombosis was present in small veins. Systemic toxic changes included degeneration and necrosis of the parenchyma cells in the lung, liver, kidney, heart, and adrenal gland. Electron microscopy demonstrated clusters of viral particles, consistent with coronavirus, in lung tissue. SARS is a systemic disease that injures many organs. The lungs, immune organs, and systemic small vessels are the main targets of virus attack, so that extensive consolidation of the lung, diffuse alveolar damage with hyaline membrane formation, respiratory distress, and decreased immune function are the main causes of death. Copyright © 2003 John Wiley & Sons, Ltd.

“From Qatar to the World” Abstracts Presented at International Conferences

One month after renal transplantation, a 60-year-old man developed acute allograft dysfunction associated with gross hematuria and dysuria. Urinary cytological examination showed viral inclusion-bearing epithelial cells. A renal transplant biopsy specimen showed granulomatous interstitial nephritis, tubular necrosis, and ground glass-like intranuclear viral inclusion bodies in tubular cells caused by an adenovirus (ADV) infection. A reduction in baseline immunosuppressive therapy resulted in rapid normalization of allograft function and ultimately viral clearance. We report this case not only to illustrate an exceptional manifestation of an ADV infection in a renal allograft, but also to highlight the beneficial effect of reduction in immunosuppressive therapy on viral replication and clinical outcome.

Cytomegalovirus infection in the brain of liver transplant recipients: Do pathologically occult infections matter clinically?

Cytomegalovirus (CMV) infection remains a highly prevalent systemic complication following orthotopic liver transplantation (LT), accounting for a significant increase in morbidity and affiliated costs. However, unlike other immunosuppressed groups of population, CMV infection of the central nervous system in LT is rarely diagnosed, either clinically or postmortem. Furthermore, in 20% of the LT patients who develop preterminal neurological complications, the etiology remains undetermined. With the hypothesis that at least some of these cases could be related to an occult CMV infection, we examined brain tissue from 83 unselected autopsies of LT patients by morphological, immunohistochemical (IHC), in situ hybridization (ISH), and nested polymerase chain reaction (nested PCR) techniques. Microglial nodules were observed in 17 brains of the LT group (20.4%) but in none of the 36 controls. Isolated positive cells by either IHC, ISH, or both techniques, were identified in 11 LT patients (13.2%) and in 2 controls (5.5%). CMV DNA amplification was obtained from paraffin embedded tissues in 41 of 81 LT cases (50.6%), and in 5 controls (13.8%) (P=0.00017). Viral inclusion bodies, inflammatory infiltrates, or necrotizing changes were not identified in any case. Our findings indicate an increased susceptibility of the brain of LT patients to occult infection by CMV and suggest that a latent or low-grade infection of the central nervous system could operate as a reservoir of the CMV and play a role in some of the unexplained neurological symptoms that appear in the postoperative period. (Virchows Arch 2002;440:166-171.)

Adenovirus infection of a renal allograft

One month after renal transplantation, a 60-year-old man developed acute allograft dysfunction associated with gross hematuria and dysuria. Urinary cytological examination showed viral inclusion-bearing epithelial cells. A renal transplant biopsy specimen showed granulomatous interstitial nephritis, tubular necrosis, and ground glass-like intranuclear viral inclusion bodies in tubular cells caused by an adenovirus (ADV) infection. A reduction in baseline immunosuppressive therapy resulted in rapid normalization of allograft function and ultimately viral clearance. We report this case not only to illustrate an exceptional manifestation of an ADV infection in a renal allograft, but also to highlight the beneficial effect of reduction in immunosuppressive therapy on viral replication and clinical outcome. Am J Kidney Dis 41:696-701. © 2003 by the National Kidney Foundation, Inc.

BK Polyomavirus Interstitial Nephritis in a Renal Allograft Recipient

Human polyomavirus (PV) interstitial nephritis has recently been recognized as a cause of severe renal allograft dysfunction. It occurs in immunosuppressed patients after reactivation of the latent virus PV type BK (BK virus) in the renal epithelium. BK disease is defined as a morphologically manifest renal infection with cytopathic signs accompanied by varying degrees of interstitial inflammatory cell infiltrates and functional impairment. It is also identified by the presence of cells containing viral inclusion bodies (decoy cells) in the urine. The authors report a case of BK PV interstitial nephritis in a 36-year-old renal allograft recipient. Under light microscopy the chief diagnostic indicator was detection of intranuclear viral inclusions, which were found exclusively in tubular epithelial cells. Cells with viral changes were often enlarged with nuclear atypia and chromatin basophilia. Widespread interstitial plasma cell infiltrates associated with tubulitis were present. Intranuclear paracrystalline arrays of virus particles 35-38 nm in diameter were present as characteristic ultrastructural indicators. Urine samples revealed decoy cells with ground-glass-type intranuclear inclusions positive for BK virus by electron microcopy.

Parvovirus B19: a pathogen responsible for more than hematologic disorders

The clinical and pathomorphological patterns of parvovirus B19 (PVB19)-associated diseases is the result of a balance between virus, host target cells and immune response. It is a characteristic feature of PVB19 that in patients with various other preexisting diseases, e.g., many hemolytic anemias, immune complex-mediated vasculitic disorders, and primary or secondary immunodeficiencies, the underlying diseases can be triggered, aggravated or complicated by severe organ manifestations. Identification of PVB19 by means of routine histology and immunohistology is only given in lytic infections occurring in transient aplastic anemia or nonimmune hydrops fetalis by the detection of viral inclusion bodies in erythroid precursor cells. In all other PVB19-associated diseases, molecular pathological methods must be applied. In this report, quantitative real-time polymerase chain reaction was used to determine the viral load in formalin-fixed and paraffin-embedded tissues derived from various organs. Using in situ hybridization it was demonstrated that endothelial cells of the microcirculatory periphery of the heart and hepatobiliar system in lytic infections are PVB19-specific target cells in children and adults. Because treatment of lytic PVB19 infection has been successfully applied, the pathologist should be alerted to include PVB19 into the diagnostic spectrum of viral disease, especially in immunocompromised patients.

Seroprevalence of an Endometriotropic Bovine Herpes Virus-4 in a Georgia Dairy

The University of Georgia Veterinary Diagnostic Laboratory has now confirmed more than 60 cases of suppurative, ulcerative endometritis associated with Bovine Herpesvirus-4 (BHV-4) in postparturient dairy cows. These cases have a clinical pattern of metritis that occurs 3 to 28 days postpartum. Beginning at 3 to 7 days postpartum, the uterus is characterized by necrotic, ulcerated endometrial mucosa with only mild inflammation in the lamina propria and submucosa. Over the ensuing 21 days, the ulcers become confluent/diffuse and epithelium is replaced by fibrinonecrotic, suppurative mats resulting in severe bacterial pyometra by day 24, usually involving Arcanobacterium pyogenes or Escherichia coli. In addition to the gross pathology, histopathologic evidence demonstrates viral inclusion bodies and virus detection techniques yield positive results for BHV-4.3 Before 1999, BHV-4-associated endometritis had rarely been recognized in the United States,4 but a syndrome of epizootic metritis similar in timing, course and outcome attributed to BHV-4 was reported in Europe in the 1980s.1,2,6 Significant seroconversion to BHV-4 occurs in affected herds. The viral sequence of this endometriotropic strain of BHV-4 differs from the BHV-4 strain that is associated with mild respiratory disease (DN599).3 Herds affected by this endometriotropic strain of BHV-4 have experienced high morbidity and mortality rates.3 One endemic dairy herd had a period mortality rate of 70% due to BHV-4- associated metritis (7 of 10 dead in one two-week interval). Due to concurrent or subsequent bacterial metritis associated with this viral infection, large economic losses are incurred from death, delayed breeding and infertility, discarded milk from antibiotic therapy, and decreased milk production from systemic effects of the metritis. Similar reports from other diagnostic laboratories indicate BHV-4 appears to be an emerging cause of endometritis in cattle throughout the southern and midwestern United States.

Reovirus core protein mu2 determines the filamentous morphology of viral inclusion bodies by interacting with and stabilizing microtubules.

Cells infected with mammalian reoviruses often contain large perinuclear inclusion bodies, or "factories," where viral replication and assembly are thought to occur. Here, we report a viral strain difference in the morphology of these inclusions: filamentous inclusions formed in cells infected with reovirus type 1 Lang (T1L), whereas globular inclusions formed in cells infected with our laboratory's isolate of reovirus type 3 Dearing (T3D). Examination by immunofluorescence microscopy revealed the filamentous inclusions to be colinear with microtubules (MTs). The filamentous distribution was dependent on an intact MT network, as depolymerization of MTs early after infection caused globular inclusions to form. The inclusion phenotypes of T1L x T3D reassortant viruses identified the viral M1 genome segment as the primary genetic determinant of the strain difference in inclusion morphology. Filamentous inclusions were seen with 21 of 22 other reovirus strains, including an isolate of T3D obtained from another laboratory. When the mu2 proteins derived from T1L and the other laboratory's T3D isolate were expressed after transfection of their cloned M1 genes, they associated with filamentous structures that colocalized with MTs, whereas the mu2 protein derived from our laboratory's T3D isolate did not. MTs were stabilized in cells infected with the viruses that induced filamentous inclusions and after transfection with the M1 genes derived from those viruses. Evidence for MT stabilization included bundling and hyperacetylation of alpha-tubulin, changes characteristically seen when MT-associated proteins (MAPs) are overexpressed. Sequencing of the M1 segments from the different T1L and T3D isolates revealed that a single-amino-acid difference at position 208 correlated with the inclusion morphology. Two mutant forms of mu2 with the changes Pro-208 to Ser in a background of T1L mu2 and Ser-208 to Pro in a background of T3D mu2 had MT association phenotypes opposite to those of the respective wild-type proteins. We conclude that the mu2 protein of most reovirus strains is a viral MAP and that it plays a key role in the formation and structural organization of reovirus inclusion bodies.

YB-1 Relocates to the Nucleus in Adenovirus-infected Cells and Facilitates Viral Replication by Inducing E2 Gene Expression through the E2 Late Promoter

The adenovirus early proteins E1A and E1B-55kDa are key regulators of viral DNA replication, and it was thought that targeting of p53 by E1B-55kDa is essential for this process. Here we have identified a previously unrecognized function of E1B for adenovirus replication. We found that E1B-55kDa is involved in targeting the transcription factor YB-1 to the nuclei of adenovirus type 5-infected cells where it is associated with viral inclusion bodies believed to be sites of viral transcription and replication. We show that YB-1 facilitates E2 gene expression through the E2 late promoter thus controlling E2 gene activity at later stages of infection. The role of YB-1 for adenovirus replication was demonstrated with an E1-minus adenovirus vector containing a YB-1 transgene. In infected cells, AdYB-1 efficiently replicated and produced infectious progeny particles. Thus, adenovirus E1B-55kDa protein and the host cell factor YB-1 act jointly to facilitate adenovirus replication in the late phase of infection.

Usefulness of dead shrimp specimens in studying the epidemiology of white spot syndrome virus (WSSV) and chronic bacterial infection.

This paper describes the utility of dead shrimp samples in epidemiological investigations of the white spot syndrome virus (WSSV) and chronic bacterial infections. A longitudinal observational study was undertaken in shrimp farms in Kundapur, Karnataka, India, from September 1999 to April 2000 to identify risk factors associated with outbreaks of white spot disease (WSD) in cultured Penaeus monodon. As a part of the larger study, farmers were trained to collect and preserve dead and moribund shrimp (when observed) during the production cycle. At the end of the production cycle, 73 samples from 50 ponds had been collected for histopathology and 55 samples from 44 ponds for PCR. Intranuclear viral inclusion bodies diagnostic of WSSV infection were detected in dead samples from 32 ponds (64 %). Samples of dead shrimp from 18 ponds (36%) showed no histopathological evidence of WSSV infection. However, of these, samples from 13 ponds (26%) showed clear evidence of shell, oral, enteric and systemic chronic inflammatory lesions (CIL) in the form of haemocytic nodules, typical of bacterial infection. Samples from 5 ponds (10%) were negative for both WSSV and CIL. Samples from 8 ponds had dual WSSV and CIL, although both WSSV and CIL were only observed in the same shrimp from 1 pond. Useful information was obtained from these shrimp despite the presence of post-mortem changes. Samples from 19 ponds (43%) tested positive for WSSV by 1-step PCR and samples from an additional 10 ponds (22.7%) were positive by 2-step nested PCR. Samples from 15 ponds (34.1%) were negative for WSSV by 2-step nested PCR. There was moderate to substantial agreement between PCR and histopathology in the diagnosis of WSSV infection in dead shrimp. WSSV infection in dead shrimp was significantly associated with crop failures as defined by a shorter length of the production cycle (<90 d) and lower average weight at harvest (<22 g). WSSV infection was also associated with lower survival (<50%), but this was not significant. Ponds with CIL did not experience any crop failures, and the presence of CIL was significantly associated with successful crops. The study demonstrates that samples of dead shrimp can provide useful information for disease surveillance and epidemiological investigations of WSSV and chronic bacterial infections.

Detection of Porcine Circovirus 2 (PCV-2) DNA by Nested PCR from Formalin-Fixed Tissues of Post-Weaning Multisystemic Wasting Syndrome (PMWS) Pigs in Thailand.

A retrospective study for the detection of porcine circovirus 2 (PCV-2) DNA was conducted by nested PCR method in 16 cases of swine post-weaning multisystemic wasting syndrome (PMWS) in Thailand. Histopathology showed characteristic lesions of PMWS and intracytoplasmic viral inclusion bodies in macrophages infiltrating in lymphoid tissues. PCV-2 DNA was detected from formalin-fixed and/or formalin-fixed paraffin-embedded tissues from all pigs with PMWS. The amplified products were digested with Hae III.

First Report of Tomato yellow leaf curl virus in Mississippi.

Tomato yellow leaf curl virus (TYLCV) is a begomovirus (family Geminiviridae) that causes severe chlorosis, stunting, and cupping of leaves in tomato (Lycopersicon esculentum) throughout the world. The disease was first reported in the United States in Florida in 1997 (2). In 2000, TYLCV was confirmed as the cause of severe chlorosis, stunting, and cupping of leaves in tomato in Louisiana (3). In January of 2001, mild symptoms consistent with TYLCV were observed in a greenhouse-tomato production operation in east-central Mississippi. Whiteflies (Bremisia tabaci) were present in the greenhouse during the previous month, but in relatively low numbers. Symptom severity slightly increased over time with chlorosis in the terminal, reduction in terminal leaf size, and upward cupping of leaves observed. Approximately 4% of plants in the greenhouse developed symptoms. Yield reductions are thought to be negligible since the tomato plants harbored most fruit for that growing season. Terminal growth was halted, and no additional flower production was observed. No symptoms were observed on mature fruit; however, fruit set after leaf symptoms developed remained stunted. A representative sample of symptomatic tissue was submitted to an independent lab (Agdia, Inc., Elkhart, IN), screened for whitefly-transmitted geminiviruses, and the results were positive. Additional symptomatic tomato tissue was submitted to the University Diagnostics Lab, University of Florida, Gainesville, and was observed for viral inclusion bodies. This test was positive for TYLCV based on morphology of virus particles located in the nucleus of tomato cells (1). Total DNA was extracted from the symptomatic plants for polymerase chain reaction (PCR) assay (2). Results from the PCR assay indicated the presence of TYLCV in symptomatic tomato tissue. The strain of the virus was not determined. To our knowledge, this is the first report of TYLCV in Mississippi.

The 3-week sulphasalazine syndrome strikes again

A 34-year-old lady developed a constellation of dermatitis, fever, lymphadenopathy and hepatitis, beginning on the 17th day of a course of oral sulphasalazine for sero-negative rheumatoid arthritis. Cervical and inguinal lymph node biopsies showed the features of severe necrotising lymphadenitis, associated with erythrophagocytosis and prominent eosinophilic infiltrates, without viral inclusion bodies, suggestive of an adverse drug reaction. A week later, fulminant drug-induced hepatitis, associated with the presence of anti-nuclear autoantibodies (but not with other markers of autoimmunity), and accompanied by multi-organ failure and sepsis, supervened. She subsequently died some 5 weeks after the commencement of her drug therapy. Post-mortem examination showed evidence of massive hepatocellular necrosis, acute hypersensitivity myocarditis, focal acute tubulo-interstitial nephritis and extensive bone marrow necrosis, with no evidence of malignancy. It is thought that the clinico-pathological features and chronology of this case bore the hallmarks of the so-called “3-week sulphasalazine syndrome”, a rare, but often fatal, immunoallergic reaction to sulphasalazine.

Presence of occult cytomegalovirus infection in the brain after orthotopic liver transplantation. An autopsy study of 83 cases.

Cytomegalovirus (CMV) infection remains a highly prevalent systemic complication following orthotopic liver transplantation (LT), accounting for a significant increase in morbidity and affiliated costs. However, unlike other immunosuppressed groups of population, CMV infection of the central nervous system in LT is rarely diagnosed, either clinically or postmortem. Furthermore, in 20% of the LT patients who develop preterminal neurological complications, the etiology remains undetermined. With the hypothesis that at least some of these cases could be related to an occult CMV infection, we examined brain tissue from 83 unselected autopsies of LT patients by morphological, immunohistochemical (IHC), in situ hybridization (ISH), and nested polymerase chain reaction (nested PCR) techniques. Microglial nodules were observed in 17 brains of the LT group (20.4%) but in none of the 36 controls. Isolated positive cells by either IHC, ISH, or both techniques, were identified in 11 LT patients (13.2%) and in 2 controls (5.5%). CMV DNA amplification was obtained from paraffin-embedded tissues in 41 of 81 LT cases (50.6%), and in 5 controls (13.8%) (P=0.00017). Viral inclusion bodies, inflammatory infiltrates, or necrotizing changes were not identified in any case. Our findings indicate an increased susceptibility of the brain of LT patients to occult infection by CMV and suggest that a latent or low-grade infection of the central nervous system could operate as a reservoir of the CMV and play a role in some of the unexplained neurological symptoms that appear in the postoperative period.

First Report of Peanut stripe virus (Family Potyviridae) in South Korea.

Severe mosaic symptoms resembling those reported for a blotch isolate of Peanut stripe virus (PStV) (1) were observed in the year 1998 in Suwon, South Korea, on several peanut cultivars. The incidence of the virus was as high as 100% in cv. Daekwang. The virus was seed transmitted to varying degrees depending on the cultivar and a maximum seed transmission of 15.7% was observed in cv. Aul. Electron microscopic examination of leaf dip preparations showed filamentous rods having modal length of 720 nm. Viral inclusion bodies in infected cells were of pinwheel, scroll, and laminated aggregates. The 3' terminal region of the viral genome was amplified using degenerate primers (2) and the resulting approximately 700 bp fragment was cloned and sequenced. GenBank searches using the 709 nucleotides consisting of the complete 3'-untranslated region and a part of the coat protein gene showed that the virus shared 98% sequence identity with the currently known PStV isolates. To our knowledge, this is the first report of PStV in the Republic of Korea.

Multimers of the Bluetongue Virus Nonstructural Protein, NS2, Possess Nucleotidyl Phosphatase Activity: Similarities between NS2 and Rotavirus NSP2

The nonstructural protein, NS2, of bluetongue virus is a nonspecific single- stranded RNA-binding protein that forms large homomultimers and accumulates in viral inclusion bodies of infected cells. NS2 shares these features with the nonstructural protein, NSP2, of rotavirus, which like BTV is a member of the family Reoviridae. Recently, NSP2 was shown to have an NTPase activity and an autokinase activity that catalyzed its phosphorylation in vitro. To examine NS2 for similar enzymatic activities, the protein was expressed in bacteria with a C-terminal His-tag and purified to homogeneity. Recombinant (r)NS2 possessed nonspecific RNA-binding activity and formed 8–10S homomultimers of the same approximate size as rNSP2 homomultimers. Notably, enzymatic assays performed with rNS2 showed that the protein hydrolyzed the α, β, and γ phosphodiester bonds of all four NTPs. Therefore, rNS2 possesses a nucleotidyl phosphatase activity instead of the NTPase activity of NSP2, which only hydrolyzes the γ phosphodiester bonds of NTPs. NS2 did not exhibit any autokinase activity in vitro, unlike NSP2. However, both NS2 and NSP2 were phosphorylated in vitro by cellular kinases. Although the nature of the enzymatic activities differs significantly, the fact that both NS2 and NSP2 hydrolyze NTPs, undergo phosphorylation, bind RNA, and assemble into multimers consisting of 6 ± 2 subunits suggests that they are functional homologs.

Fatal Disseminated Adenoviral Infection Associated with Thrombotic Thrombocytopenic Purpura after Allogeneic Bone Marrow Transplantation

Adenoviruses are increasingly recognized as a significant cause of morbidity and mortality in immunocompromised patients. We report on a patient who, approximately 4 weeks after allogeneic stem cell transplantation, developed fever, new liver lesions and thrombotic microangiopathy. Adenovirus type 2 was isolated from blood and urine samples. Liver biopsy showed parenchymal necrosis with intranuclear viral inclusion bodies. Immunohistochemistry was positive for adenovirus. In addition, on electron microscopy the morphologic pattern was highly suggestive of adenovirus. The patient died on post-transplant day 40. The relatively early post-transplant presentation of disseminated adenoviral disease and its possible association with a TTP-like picture are rather unusual after allogeneic transplantation.

NTP binding and phosphohydrolase activity associated with purified bluetongue virus non-structural protein NS2.

The bluetongue virus ssRNA-binding protein, NS2, is a phosphoprotein that forms viral inclusion bodies in infected cells. Recombinant NS2 was expressed in the baculovirus expression system and purified to homogeneity from insect cells. Purified NS2 bound nucleosides. Further investigation revealed that the protein bound ATP and GTP and could hydrolyse both nucleosides to their corresponding NMPs, with a higher efficiency for the hydrolysis of ATP. The increased efficiency of hydrolysis of ATP correlated with a higher binding affinity of NS2 for ATP than GTP. Ca(2+), Mg(2+) and Mn(2+) were able to function as the required divalent cation in the reactions. The phosphohydrolase activity was not sensitive to ouabain, an inhibitor of cellular ATPases, suggesting that this activity was not the result of a cellular contaminant.