title: Growth of mouse hepatitis and other indigenous mouse viruses in tracheal organ cultures

text: Organ cultures of mouse trachea were infected with some indigenous mouse viruses. Mengovirus and reovirus type 3 grew to high titer; inocula of, respectively, 10(2) and 10(3) TCID(50) were required to initiate infection. Organ cultures supported also the growth of mouse hepatitis viruses, MHV-3 and MHV-S, though to a lesser extent. Viral production was noted for periods of as long as two weeks. None of the viruses had a noticeable effect on the ciliary activity or acquired such capacity on serial passage in organ cultures.


title: Plaque formation by avian infectious bronchitis virus in primary chick embryo fibroblast cells in the presence of trypsin

text: Ten strains of avian infectious bronchitis virus (IBV) were titrated as plaqueforming units in primary chick embryo fibroblast cells. In the absence of trypsin, plaques were only formed by Beaudette-42 and Iowa-609 strains. When trypsin was incorporated in the overlay medium of cell monolayers, all the IBV strains tested produced plaques within 4 days after inoculation. Incorporation of 20–40 µg of trypsin per ml of the overlay medium seemed to be suitable for plaque formation of IBV. A preliminary investigation was made of the mode of action of trypsin.


docid: rhkrmftn

title: Isolation and characterization of a canine rotavirus

text: Canine rotavirus particles were visualized by direct electron microscopy in the feces from a clinically normal dog. The virus was subsequently propagated in cell cultures; it was chracterized and compared with rotaviruses from other species. Replication of the virus in cell culture was found to be less dependent upon trypsin than that of human, bovine and porcine rotaviruses. Reproducible, sharp-edged plaques of various sizes were produced by the canine rotavirus in an established cell line of fetal rhesus monkey kidney, MA104, under overlays of carboxymethyl cellulose or agarose. Intracytoplasmic inclusion bodies of different sizes and shapes were produced in infected MA104 cells. By plaque reduction neutralization assay, a two-way antigenic relationship was found between the canine (CU-1) and simian (rhesus MMU 18006 and SA-11) rotaviruses. The canine rotavirus had a one-way antigenic relationship with feline (Taka), bovine (NCDV), and porcine (OSU) rotaviruses.


title: Selective vulnerability of neural cells and age-related susceptibility to OC43 virus in mice

text: Suckling CD1 mice infected intracerebrally or extraneurally with OC43 virus developed a lethal neurotropic infection with high titres of virus in the brain. Examination of infected brain by routine H & E staining revealed no necrosis even in extensively infected tissue. Resistance to infection developed with increasing age, and by 20 days of age mice were completely insusceptible to i. c. inoculation. Virus replication was also demonstrable by FA staining, in spinal cord, dorsal root ganglia and retina. All other tissues were insusceptible and in particular, macrophages from both susceptible and resistant mice were found to be resistant to infection bothin vivo andin vitro. Immunosuppression rendered 15 day old mice more susceptible to infection but adult mice remained insusceptible. The transfer of immune or non immune spleen cells from resistant mice did not confer resistance to newborn mice. Treatment of resistant mice with anti interferon globulin (AIG) did not render them more susceptible. These results indicate that the immune response is partially responsible for the development of resistance to OC43 infection but that it is only partially protective and other factors must also be required. The basis for the unique susceptibility of neural tissues in suckling mice is being investigated.


title: Aetiology of community-acquired pneumonia in children treated in hospital

text: Viral and bacterial antigen and antibody assays were prospectively applied to study the microbial actiology of community-acquired pneumonia in 195 hospitalised children during a surveillance period of 12 months. A viral infection alone was indicated in 37 (19%), a bacterial infection alone in 30 (15%) and a mixed viral-bacterial infection in 32 (16%) patients. Thus, 46% of the 69 patients with viral infection and 52% of the 62 patients with bacterial infection had a mixed viral and bacterial aetiology. Respiratory syncytial virus (RSV) was identified in 52 patients andStreptococcus pneumoniae in 41 patients. The next common agents in order were non-classifiedHaemophilus influenzae (17 cases), adenoviruses (10 cases) andChlamydia species (8 cases). The diagnosis of an RSV infection was based on detecting viral antigen in nasopharyngeal secretions in 79% of the cases. Pneumococcal infections were in most cases identified by antibody assays; in 39% they were indicated by demonstrating pneumococcal antigen in acute phase serum. An alveolar infiltrate was present in 53 (27%) and an interstitial infiltrate in 108 (55%) of the 195 patients. The remaining 34 patients had probable pneumonia. C-reactive protein (CRP), erythrocyte sedimentation rate and total white blood cell count were elevated in 25%, 40% and 36% of the patients, respectively, CRP was more often elevated in patients with bacterial infection alone than in those with viral or mixed viral-bacterial infections. No other correlation was seen between the radiological or laboratory findings and serologically identified viral, bacterial or mixed viralbacterial infections. By using a comprehensive serological panel, the causative agent could be found in over 50% of patients with pneumonia. We conclude that RSV and pneumococcus are the two most common organisms causing pneumonia in children. Our results suggest that mixed viral-bacterial aetiology is common in lower respiratory tract infections affecting children.


title: Ultrastructure of newly recognized caliciviruses of the dog and mink

text: Two recently recognized viruses obtained from a dog with glossitis and from mink with hemorrhagic pneumonia were characterized by electron microscopy. The results of the negative-stained preparations indicated that the viruses were structurally compatible with the calicivirus group.


docid: hliujvbz

title: The virology and pathogenesis of feline infectious peritonitis


docid: ecfwnphv

title: Immunogenicity of the S protein of transmissible gastroenteritis virus expressed in baculovirus

text: Seven fragments of the spike (S) gene cDNA of transmissible gastroenteritis virus (TGEV), as well as the full length cDNA, were cloned and expressed in baculovirus vectors. Piglets were immunized with cells infected with the recombinant viruses. Each of the recombinants induced TGEV-specific antibodies detected in a fixed cell enzyme immunoassay. The amino terminal half of the S protein, containing all four major antigenic sites (A, B, C and D), and encoded by a 2.2 kb fragment of the S gene, induced virus neutralizing (VN) antibody titers comparable with those induced by the complete S protein. Recombinant proteins lacking the A antigenic site, or with a deletion including the putative receptor binding sites and the D antigenic site, were not capable of inducing levels of VN antibodies similar to those induced by the whole S protein.


title: Detection of equine arteritis virus (EAV) by polymerase chain reaction (PCR) and differentiation of EAV strains by restriction enzyme analysis of PCR products

text: A polymerase chain reaction (PCR) based assay capable of detecting and differentiating seven strains of equine arteritis virus (EAV) from around the world was developed. The primers for the PCR were chosen from the ORF 6 gene encoding the unglycosylated membrane protein (M). Viral RNA from cell culture fluids infected with each of the seven EAV strains and RNA from the live vaccine, Arvac, was detected by PCR using four sets of primers. The sensitivity of detection was increased from 100 to 1000 times by performing nested PCR enabling the detection of RNA at a level of 0.5–5 PFU. Differentiation among the virus strains and the live vaccine was achieved by cutting the PCR-amplified products from three sets of primers with six restriction endonucleases. Using this procedure it was possible to distinguish among the seven EAV strains used.


title: Molecular characterization of a novel recombinant strain of human astrovirus associated with gastroenteritis in children

text: We report a naturally occurring human astrovirus (HAstV) strain detected in two different geographic locations. We identified two isolates of this strain in a diarrhea outbreak at a child care center in Houston, Texas; and two isolates in diarrhea stool samples from two children in Mexico City. All four isolates were detected in stool samples by enzyme immunoassay (EIA). One of the Mexican isolates was typed by EIA and all four isolates were HAstV-5 by typing RT-PCR. The four isolates were >97% nucleotide-identical in two different genomic regions: ORF1a (246nt), and the 3′ end of the genome (471nt). One isolate from each geographic location was further sequenced in the transition region from ORF1b to ORF2 (1255nt) and this region of the two isolates showed ≥ 99% nt identity. Phylogenetic analyses of sequences of eight HAstV antigenic types and the novel strain in the transition region demonstrated the new strain being closely related to HAstV-3 in ORF1b, but closest to HAstV-5 in ORF2. These results and high sequence identity among all HAstV antigenic types in the transition region and RNA structural predictions supported a potential recombination site at the ORF1b/ORF2 junction. This is the first evidence that recombination occurs among human astroviruses.


title: S1 glycoprotein gene analysis of infectious bronchitis viruses isolated in Korea

text: Fifteen isolates of Infectious bronchitis virus (IBV) were obtained from the kidney, trachea, and cecal tonsil of IB suspected chickens between 2001 and 2002 years in Korea. The S1 glycoprotein gene of IBV isolates were amplified by reverse transcriptase – polymerase chain reaction (RT-PCR) and analyzed by restriction fragment length polymorphism (RFLP) analysis. Fifteen Korean IBV isolates were classified into 4 groups by their RFLP patterns using restriction enzymes, HaeIII, BstYI, and XcmI. The RFLP patterns for 3, 1, and 1 of 15 isolates corresponded to the patterns of IBV Arkansas, Connecticut, and Massachusetts strains, respectively. Ten of 15 isolates generated unique KM91 RFLP pattern that was observed in the IBV KM 91 strain previously isolated in Korea. To confirm genetic diversity in the S1 genes of IBV isolates, viral RNAs of representative 9 of 15 IBV isolates were amplified, cloned, sequenced and compared with published sequences for non-Korean IBV strains. Korean IBV isolates showed amino acid sequence similarity between 61.8% (K446-01 and K161-02) and 96.1% (K281-01 and K210-02) with each other and they showed amino acid sequence similarity between 42.9% (K161-02 and GA980470) and 96.5% (K203-02 and KB8523) compared to non-Korean IBV strains. By phylogenetic tree analysis, Korean IBV field isolates were branched into five clusters in which 3 clusters were differentiated from non-Korean IBV strains. Especially, Korean IBV isolates K069-01, K507-01, K774-01 and K142-02 formed a separate cluster. It seems that IBVs continue to evolve and IBVs showing various genetic differences may cocirculate in Korea.


title: Feline calicivirus protein synthesis investigated by Western blotting

text: We have used Western blotting to examine the accumulation of feline calicivirus proteins within the infected cell. Experiments using elevated growth temperature to block post-translational cleavage have demonstrated two additional high molecular weight protein bands 125 kd and 123 kd respectively which may be precursor polyproteins. Inhibition of proteolytic processing withp-fluorophenylalanine led to the accumulation of several additional protein species which may represent intermediates in the protein processing pathway. None of these proteins were related to the 62 kd major capsid protein (cP 62) of the virus as judged by reaction with monoclonal antibodies. The production of a 76 kd capsid precursor protein (cpP 76) was demonstrated for the first time in FCV-infected cells. The pathway by which calicivirus polypeptides are made thus appears highly complex and may involve temporal regulation of protein synthesis as well as protein processing. Tentative identification of primary, intermediate and mature forms of virus proteins is discussed.


title: Identification of amino acids involved in a serotype and neutralization specific epitope with in the s1 subunit of avian infectious bronchitis virus

text: Localization of neutralizing, serotype specific epitopes of infectious bronchitis virus has been difficult because these epitopes are conformationally dependent. We identified amino acids involved in a serotype specific, conformationally dependent epitope by analysis of the S1 gene of 13 monoclonal antibody-neutralization-resistant mutants. Substitutions in the predicted amino acid sequence of these mutants were located at residues 304 and/or 386. Most of the substitutions at residue 304 were from threonine to isoleucine, whereas the substitutions at residue 386 were from arginine to proline, histidine, cysteine, or tryptophan. Based on this data, it appears that AA residues at 304 and 386 on the S1 glycoprotein are involved in a virus neutralizing serotype specific epitope.


title: Low levels of poliovirus replication in primary human monocytes: possible interactions with lymphocytes

text: To investigate the molecular mediators of poliovirus tissue tropism, the correlation between poliovirus replication and poliovirus receptor expression was examined in a primary human tissue system. Earlier work [M. Freistadt, H. Fleit, and E. Wimmer, Virology 195: 798–803 (1993)] showed that the cellular receptor for poliovirus is present in 87% of primary human monocytes and that peripheral blood mononuclear cells support poliovirus replication. In the current work, monocytes, obtained by adherence or by a novel negative selection procedure using specific monoclonal antibodies to lymphocyte surface antigens, supported poliovirus replication. However, total virus yield was low and infectious centers assays revealed that a minority (6%) of monocytes become productively infected. Viral yield from monocytes was lower than from the heterogeneous mononuclear cells; however, when uninfected lymphocytes were added back to infected monocytes, the higher viral yield was restored. The purity of the cells did not significantly affect the number of cells infected. These results suggest that more poliovirus is produced per cell from activated rather than unactivated monocytes. Furthermore, poliovirus replication in monocytes may reflect genuine in vivo replication and comprise a system in which to determine molecular mediators of poliovirus tissue tropism.


title: Complete nucleotide sequence and genome organization of Pelargonium line pattern virus and its relationship with the family Tombusviridae

text: The complete nucleotide sequence of Pelargonium line pattern virus (PLPV) has been determined. The PLPV genomic RNA comprises 3884 nt and contains six open reading frames (ORFs) potentially encoding proteins of 27 (p27), 13 (p13), 87 (p87), 7 (p7), 6 (p6), and 37 kDa (p37), respectively. The arrangement of these ORFs on the PLPV genome closely resembles that of members of the genus Carmovirus in the family Tombusviridae and, moreover, most of the putative PLPV gene products showed high identity with proteins of this viral group. However, several striking differences were noticed. Carmoviruses generate two subgenomic RNAs whereas PLPV produces a single one. In addition, only p7 showed similarity with movement proteins of carmoviruses whereas p6 (as p13) has no viral (or other) homologs. This protein might be expressed from a non-canonical start codon or, alternatively, through a −1 frameshift (FS) mechanism. Both, the production of one subgenomic RNA and the likely involvement of a −1 FS for expression of an internal ORF parallel the translation strategies reported for the unique species of the genus Panicovirus, belonging also to the family Tombusviridae. Overall, the results support the placement of PLPV in this family although its peculiar characteristics preclude its direct assignment to any of the current genera.


title: The ribonucleic acid of infectious bronchitis virus

text: Analysis of the nucleic acid of infectious bronchitis virus by SDS polyacrylamide gel electrophoresis revealed an RNA of molecular weight 9.0×10(6) Daltons. The RNA was shown to have a sedimentation coefficient of 50.


title: Nosocomial necrotising enterocolitis outbreaks: epidemiology and control measures

text: Necrotising enterocolitis (NEC) is one of the most serious gastrointestinal diseases among newborns and it mainly affects those in intensive care units. The aetiology of the disease has been reported to be multifactorial and both sporadic cases and nosocomial outbreaks have occurred. In this report, we review 17 epidemics of NEC reported in the literature between 1973 and 1999. The number of confirmed cases ranged from 1 to 32 with an average of 10.5 confirmed cases. On average, 16.15% of cases required surgery (range 0–66.6%). The average mortality rate was 6.25% (range 0–87.5%). The mean age at disease onset was 9.5 days (range 6.6–29 days). Most of the infants had low birth weight (median weight 1,395 g; range 1,112–2,788 g, calculated on the reported mean weights). The main risk factors associated with NEC were: low birth weight, low gestational age, low Apgar score, perinatal complications, hyaline membrane disease, and umbilical catheterisation. The bacteria involved often included Enterobacteriaceae, particularly Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae type 3305573. The causative role of Clostridia in NEC is controversial. With regard to viral agents, coronarovirus, rotavirus and enterovirus, such as echovirus type 22, were isolated during some of the epidemics. The recommended control measures for NEC epidemics are those used for epidemics of other orofaecally transmitted infections. Conclusion Understanding the epidemiology of necrotising enterocolitis is fundamental if adequate preventive control measures are to be developed and applied.


title: Protective role of antigenic sites on the envelope protein of Hantaan virus defined by monoclonal antibodies

text: To investigate the role of Hantaan virus envelope glycoprotein in infection, a panel of monoclonal antibodies (MAbs) was examined in vitro with several serological tests and in vivo by passive transfer experiments in mice. An antigenic site, specific for the inhibition of infected cell focus was detected with the focus inhibition neutralization test (FINT), in addition to the neutralization related antigenic sites, which were revealed by the ordinary focus reduction neutralization test (FRNT). Suckling mice were given the MAbs by passive transfer followed by lethal Hantaan virus challenge. All neutralizing MAbs detected by either FRNT or FINT protected all mice from lethal infection, confirming the importance of the antigenic sites as a protective antigen. Mice given non-neutralizing MAbs by passive transfer, however, began to die earlier than the control group; mean time to death (18.2±2.1 to 21.5±2.8 days) being significantly shorter than that of the control group (25.8±1.8, p<0.01, Mann-Whitney,U probability test). Virus titers in brains of mice which died early, were about 10 times higher than those of control mice. These results indicated the early death phenomenon of mice which was mediated by the antivirus antibody.


title: Mapping of viral epitopes with prokaryotic expression products

text: Several systems are available for the expression of foreign gene sequences inEscherichia coli. We describe the use of prokaryotic expression products of viral gene fragments in order to identify the regions that specify the binding sites of antibodies. This approach is particulary successful if the antigenicity does not depend on the native protein, but only on the amino acid sequence, i.e., if the epitope is sequential. Combining prokaryotic expression with the use of synthetic peptides often permits a fast and accurate mapping of an epitope. The occurrence of immunodominant sequential epitopes on the surface of viruses seems to be a widespread phenomenon.


On the relative merits of italics, Latin and binomial nomenclature in virus taxonomy


title: High-flow nasal cannula oxygen for bronchiolitis in a pediatric ward: a pilot study

text: High-flow nasal cannula (HFNC) is a widely used ventilatory support in children with bronchiolitis in the intensive care setting. No data is available on HFNC use in the general pediatric ward. The aim of this study was to evaluate the feasibility of HFNC oxygen therapy in infants hospitalized in a pediatric ward for moderate–severe bronchiolitis and to assess the changes in ventilatory parameters before and after starting HFNC support. This prospective observational pilot study was carried out during the bronchiolitis season 2011–2012 in a pediatric tertiary care academic center in Italy. Interruptions of HFNC therapy and possible side effects or escalation to other forms of respiratory support were recorded. Oxygen saturation (SpO(2)), end-tidal carbon dioxide (ETCO(2)), and respiratory rate (RR), measured for a baseline period of 1 h before and at specific time intervals in 48 h after the start of HFNC were recorded. Twenty-seven infants were included (median age 1.3 months; absolute range 0.3–8.5). No adverse events, no premature HFNC therapy termination, and no escalation to other forms of respiratory support were recorded. Median SpO(2) significantly increased by 1–2 points after changing from standard oxygen to HFNC (p <0.001). Median ETCO(2) and RR rapidly decreased by 6–8 mmHg and 13–20 breaths per minute, respectively, in the first 3 h of HFNC therapy (p <0.001) and remained steady thereafter. Conclusions: Use of HFNC for oxygen administration is feasible for infants with moderate–severe bronchiolitis in a general pediatric ward. In these children, HFNC therapy improves oxygen saturation levels and seems to be associated with a decrease in both ETCO(2) and RR.


title: Treatment of multiple sclerosis with anti-measles cow colostrum

text: Previous virological and immunological studies have suggested that multiple sclerosis (MS) is an auto-immune disease triggered by a virus infection. In order to inhibit the growth of measles virus in the patient's jejunum, we obtained an IgA-rich cow colostrum containing anti-measles lactoglobulin resistant to proteases. This colostrum was orally administered to patients with MS to investigate its effect on the course of the disease. Measles-positive antibody colostrum was orally administered every morning to 15 patients with MS at a daily dosage of 100 ml for 30 days. Similarly, measles-negative antibody (< 8) control colostrum was orally administered to 5 patients. As a clinical assessment, disability scores developed by the International Federation of Multiple Sclerosis Societies were used. As a result, of 7 high NT titre (512–5120) anti-measles colostrum recipients 5 patients improved and 2 remained unchanged. Among 8 low NT titre (8–32) anti-measles colostrum recipients 5 patients improved and 3 remained unchanged. However, of 5 negative NT titre (< 8) colostrum recipients 2 patients remained unchanged and 3 worsened. No side-effects were observed in colostrum recipients. These findings suggest the efficacy of orally administered anti-measles colostrum in improving the condition of MS patients (P < 0.05).


docid: pjearubt

title: Coxsackievirus-cell interactions that initiate infection in porcine ileal explants

text: Coxsackievirus B 5 (CB 5) labeled with tritiated uridine was used to trace the interaction of the virus with explant cultures of porcine ileum. Similarly labeled human poliovirus 1 (PO 1), which is not specifically retained by porcine tissue, was used as a control. The explant procedure employed could maintain ileal tissue in a differentiated state for up to 48 hours. Porcine ileum was acquired from both young (4–6 week-old) and adult (9–11 month-old) animals. Inoculated explants of either absorptive or lymphoid tissue were incubated at temperatures selected to permit either viral adsorption or penetration and elution to occur. Retention of radioactive virus was quantitated by liquid scintillation counting and localized by autoradiography. Only in absorptive tissue explants from young animals did adsorption of CB 5 at 6°C exceed penetration at 37°C. This suggested that incubation at 6°C may not be an appropriate condition for studying enterovirus adsorption in explants. CB 5 penetrated most efficiently into lymphoid tissue explants from young animals, indicating that these tissues could discriminate between CB 5 and PO 1. In explants from adults, CB 5 penetrated equally well into lymphoid and absorptive tissues. Virus penetrated into the absorptive epithelial cells and, possibly, the lamina propria near the villous tips. Low efficiency of penetration, and the non-critical function of these target cells, may help account for the characteristic lack of gastrointestinal symptoms in enterovirus infections.


title: A study on the mechanism of antibody-dependent enhancement of feline infectious peritonitis virus infection in feline macrophages by monoclonal antibodies

text: Enhancement of feline infectious peritonitis virus (FIPV) infection of feline macrophages was studied using monoclonal antibodies (MAbs) to the FIPV strain 79-1146. Adherent cells recovered from the feline lung and peritoneal cavity phagocytosed fixed red blood cells, and formed Fc-mediated rosettes. Enhancement of virus infection by MAb was investigated by inoculating alveolar macrophages with a mixtures of viral suspension and MAb, and examining the cells for intracellular viral antigen by the immunofluorescence assay and the amount of infectious virus in the supernatant fluid after incubation. The replication of FIPV in macrophages was enhanced by non-neutralizing MAbs recognizing peplomer protein (S) and transmembrane protein (M) of the virus. Even among the MAbs having the ability to neutralize FIPV strain 79-1146, some reversely enhanced virus infection when they were diluted. The enhancement was suppressed by pretreatment of the MAb with protein A. The enhancement was reduced by the use of F(ab′)(2) fragment of MAb. These results demonstrated antibody-dependent enhancement (ADE) of FIPV infection in macrophage. The replication of FIPV 79-1146 strain in macrophages from FIPV antibody-positive cats was more enhanced than in those from antibody-negative cats.


title: The effect of prior inoculation with an enterovirus (LEV 4) on rhinovirus infection of volunteers

text: Twenty-four volunteers at the Common Cold Unit were divided into two groups of twelve. One group was vaccinated orally with an enterovirus (LEV 4) and the other with nutrient broth. Both groups were challenged three days later with intranasal rhinovirus 4 and they were observed clinically and monitored by laboratory tests to see if any modification of the rhinovirus infection occurred. All the vaccinated volunteers were successfully infected with LEV 4 and were excreting the enterovirus in the faeces at near maximum titres at the time of the rhinovirus infection, following which 67 per cent of the volunteers were infected and 29 per cent developed symptoms. However, the vaccinated group did not differ from the unvaccinated in respect of the illness induced, the excretion of rhinovirus type 4 or the rise of RV 4 antibody titre. LEV 4 was isolated from the nasopharynx of some of the volunteers, but the rhinovirus infection was not modified even in these. Interferon was present in the serum and nasal washings of nine volunteers in all, of whom only 3 had received the LEV 4 vaccination. Two additional volunteers were shown to be insusceptible to reinfection with LEV4. It was concluded that live enterovirus vaccination does not induce viral interference.


docid: cdvnqfjz

title: The entry of Junin virus into Vero cells

text: The entry mechanism of Junin virus (JV) into Vero cells was studied analyzing the effect of lysosomotropic compounds and acid pH on JV infection. Ammonium chloride, amantadine, chlorpheniramine and procaine inhibited JV production. The action of ammonium chloride was exerted at early times of infection. Virus internalization was inhibited and viral protein expression was not detected. When the extracellular medium was buffered at low pH, the ammonium chloride induced block on JV infection was overcome. Furthermore, JV was able to induce fusion of infected cells at pH 5.5 leading to polykaryoctye formation. Taken together, these results demonstrate that JV entry occurs through an endocytic mechanism requiring a low pH dependent membrane fusion.


title: Glycosylation of dengue virus glycoproteins and their interactions with carbohydrate receptors: possible targets for antiviral therapy

text: Dengue virus, an RNA virus belonging to the genus Flavivirus, affects 50 million individuals annually, and approximately 500,000–1,000,000 of these infections lead to dengue hemorrhagic fever or dengue shock syndrome. With no licensed vaccine or specific antiviral treatments available to prevent dengue infection, dengue is considered a major public health problem in subtropical and tropical regions. The virus, like other enveloped viruses, uses the host’s cellular enzymes to synthesize its structural (C, E, and prM/M) and nonstructural proteins (NS1–5) and, subsequently, to glycosylate these proteins to produce complete and functional glycoproteins. The structural glycoproteins, specifically the E protein, are known to interact with the host’s carbohydrate receptors through the viral proteins’ N-glycosylation sites and thus mediate the viral invasion of cells. This review focuses on the involvement of dengue glycoproteins in the course of infection and the virus’ exploitation of the host’s glycans, especially the interactions between host receptors and carbohydrate moieties. We also discuss the recent developments in antiviral therapies that target these processes and interactions, focusing specifically on the use of carbohydrate-binding agents derived from plants, commonly known as lectins, to inhibit the progression of infection.


Report on an ICTV-sponsored symposium on Virus Evolution


docid: kjhzqhbo

title: The S1 glycoprotein but not the N or M proteins of avian infectious bronchitis virus induces protection in vaccinated chickens

text: The S1, N and M proteins, obtained from the nephropathogenic N1/62 strain of infectious bronchitis virus (IBV) by immunoaffinity purification with monoclonal antibodies, were used for immunization of chickens. For all three antigens multiple immunizations were necessary for induction of an antibody response. Protection of chickens vaccinated with the S1 glycoprotein against virulent challenge was demonstrated by the complete absence of virus in tracheas and kidneys of vaccinated chickens. Following four immunizations with the S1 glycoprotein 71% and 86% of chickens were protected at the level of tracheas and kidneys, respectively. Three immunizations with the S1 glycoprotein protected 70% and 10% of chickens at the level of kidney and trachea, respectively. Neither the N nor the M antigen induced protection to a virulent challenge with the nephropathogenic N1/62 strain of IBV after four immunizations. Virus neutralizing, haemagglutination inhibiting and ELISA antibodies were detected in chickens immunized with the S1 glycoprotein and inactivated N1/62 virus, however there was no correlation between the presence of any of these antibodies and protection.


The rotaviruses


title: In vitro cultivation of cells from the chorioallantoic membrane of chick embryos

text: By treatment of chorioallantoic membranes from embryonated eggs with collagenase and hyaluronidase before the conventional application of trypsin cells could be grown in culture which supported growth of a large variety of myxoviruses, herpesviruses, avian reoviruses and the infectious bronchitis virus of chickens. The cultures could be used for sensitive plaque assays and neutralization tests.


title: A novel method for the detection of early events in cell-cell fusion of Semliki Forest virus infected cells growing in monolayer cultures

text: Semliki Forest virus infected Aedes albopictus cells were used to investigate virus induced cell-cell fusion. It was shown by a novel method that cell-cell fusion was completed within approximately 5 minutes after triggering the fusion event by low pH. This method consists of fixing fusing cells with glutaraldehyde and microinjecting the highly fluroescent and rapidly diffusing dye Lucifer yellow. In contrast, polykaryon formation, the usually used criterion to measure cell-cell fusion occurred only within 30 minutes. Furthermore, it was shown that potassium cyanide, a potent inhibitor of polykaryon formation in the described system, inhibits an early step of membrane-membrane fusion of neighbouring cells.


title: Serum interferon assay as a possible test for virus infections of man

text: Acute phase serum gave positive results in an interferon assay when collected from 17 out of 45 (38 per cent) patients with proven virus infection, and from none of 43 patients with other disease and none of 61 healthy subjects. Sera from 11 of 43 (26 per cent) patients with suspected virus infection were also positive. Interferon was detected in the sera of volunteers infected with respiratory viruses in strict isolation. It is suggested that the test might be used to supplement conventional tests for virus infections, and with modification may provide a useful diagnostic aid.


title: In vitro growth characteristics and heterogeneity of mouse hepatitis virus type 3

text: Thein vitro virus yield of MHV3 reached 10(7) PFU/ml in mouse DBT cells infected with a virus suspension in HEPES-buffered medium containing DEAE-dextran. The virus titer was 10(6) PFU/ml in the presence of 10 µg actinomycin D/ml. MHV3 grown in DBT cells gave three peaks of density (1.10–1.14 g/cm(3), 1.18–1.20 g/cm(3), and 1.25–1.31 g/cm(3)) in sucrose gradients. All these peaks retained infectivity.


title: Adaptation of transmissible gastroenteritis virus to growth in non-permissive Vero cells

text: The CPK cells derived from swine kidney were infected with the attenuated TO-163 strain of transmissible gastroenteritis (TGE) virus, and fused with uninfected Vero cells in the presence of polyethylene glycol. Repeated cocultivation of the fused cells with uninfected Vero cells rendered the virus to grow in Vero cells. The Vero cell-adapted virus acquired the ability to infect and produce cytopathic effects in several other non-permissive cell lines of non-porcine origin. No major differences in viral polypeptides were shown between the Vero cell-adapted TO-163 strain and its parent strain by indirect immunofluorescence and Western blotting using monoclonal and polyclonal antibodies to TGE virus.


title: Effect of in ovo bursectomy on the course of an infectious bronchitis virus infection in line C White Leghorn chickens

text: White Leghorn line C chicks were surgically bursectomised (Bx) in ovo to eliminate antibody production. After inoculation with infectious bronchitis virus (IBV) at 14 days after hatching, Bx chicks experienced a more severe and longer lasting infection than intact chicks. The severity and duration of clinical infection in the Bx chicks resembled that previously observed in the highly susceptible line 15 I chicks, however no increase in mortality was observed, in contrast to the high levels of mortality recorded in IBV-inoculated line 15 I chicks. After secondary challenge the degree of damage to the ciliated epithelium of the trachea was greater in the Bx chicks than in the intact chicks. The results indicate that, although antibodies play an important role in recovery from IBV infection, other immunological factor(s) may also be involved.


title: Functional and topographical analyses of epitopes on bovine herpesvirus type 1 glycoprotein IV

text: Bovine herpesvirus type 1 (BHV-1) glycoprotein gIV was purified by affinity chromatography. Purified preparations showed two distinct components of 71 K and 140 K following electrophoresis in sodium dodecyl sulphate polyacrylamide gels. The polypeptides were separated, excised from the gel and used to immunize rabbits; the resulting antisera showed a high degree of cross reactivity indicating that these polypeptides represent monomeric and dimeric forms of the same glycoprotein. Purified gIV was also used to develop a gIV-specific panel of monoclonal antibodies. Neutralizing monoclonal antibodies directed against gIV were conjugated to horseradish peroxidase and subjected to competition binding assays by ELISA. Three distinct neutralizing antigenic domains on gIV were identified. Domain 1 comprised two overlapping epitopes, whereas domain 2 was represented by a single monoclonal antibody. The third antigenic domain was made up of a complex of four identical or overlapping epitopes designated 3a, b, c, and d. Evidence is presented suggesting that domain 1 of gIV may be involved in penetration of the virus into the cell.


title: Silencing E1A mRNA by RNA interference inhibits adenovirus replication

text: The adenovirus family contains 51 human serotypes, and most human adenoviruses cause widespread respiratory tract infections. Adenovirus infections can result in severe complications in some cases, such as in adenovirus type 11 infection in immunocompromised patients. However, effective treatment methods for adenovirus infections are currently unavailable. This prompted the search for antiviral agents effective against adenovirus infections. In the present study, adenovirus E1A was targeted by RNA interference (RNAi) using synthetic small interfering RNAs (siRNAs) in an attempt to inhibit viral replication, since adenovirus E1A proteins are known to be involved in the transcriptional activation of the viral and cellular genes necessary for controlling the cell cycle and viral replication. The results indicated that the siRNAs effectively reduced the amount of adenovirus E1A mRNA and the levels of replicative intermediates. Additionally, siRNA-mediated gene silencing inhibited adenovirus replication by suppressing the E1A mRNA. These results suggest that the RNAi-mediated targeting of adenovirus E1A may have a potentially therapeutic effect in controlling adenovirus infections.


title: Sequence analysis of open reading frames (ORFs) 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus

text: The sequence of ORFs 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus (PRRSV), ATCC VR2385, was determined by analysis of a cDNA λ library. The cDNA clones containing PRRSV specific sequences were selected using a VR2385 ORF 4 specific PCR probe and sequenced. The ORFs 2, 3 and 4 overlapped each other and encoded polypeptides with predicted M(r) of 29.5 kDa (ORF 2), 28.7 kDa (ORF 3) and 19.5 kDa (ORF 4), respectively. No overlap was found between ORFs 4 and 5, and instead there was a 10 bp sequence which separated these two ORFs. The nucleic acid homology with corresponding ORFs of the European PRRSV isolate Lelystad virus (LV) was 65% for ORF 2, 64% for ORF 3 and 66% for ORF 4. Comparison of the ORF 4 sequences of VR2385 with that of another U.S. isolate MN-1b revealed only 86% amino acid sequence homology and the presence of deletions in the ORF 4 of MN-1b. Our results further strengthen the observation that there is sequence variation between US and European PRRSV isolates.


title: Cultivation of avian rotaviruses in chicken lymphocytes and lymphoblastoid cell lines

text: Avian rotavirus isolates were used to infect normal chicken spleen cells, lymphoblastoid T cell lines transformed by Marke's disease virus, an avian leukosis virus-transformed B cell line, and a reticuloendotheliosis virus-transformed line, which is a pre-B, pre-T cell line. All five isolates tested were able to infect spleen cells and the three types of lymphoblastoid cell lines, suggesting that avian rotaviruses can infect both B and T cells. Splenic lymphocytes were considerably less susceptible to infection than chick kidney cells. Lymphoblastoid cell lines remained virus-positive during a 10-day culture period. Virus was neutralized by the addition of low dilutions of normal chicken serum and high dilutions of chicken anti-rotavirus serum.


title: Development of real-time RT-PCR for detection of human metapneumovirus and genetic analysis of circulating strains (2009-2011) in Pune, India

text: Human metapneumovirus (HMPV) is an important respiratory virus implicated in respiratory infections. The purpose of this study was to develop a one-step real-time RT-PCR assay that can detect all four lineages of HMPV and to identify the HMPV lineages circulating in Pune, India. Conserved regions of the nucleoprotein gene were used to design real-time primers and a probe. A total of 224 clinical samples that were positive for different respiratory viruses (including 51 samples that were positive for HMPV) were tested using the real time RT-PCR assay, and the specificity of the assay was observed to be 100 %. Using in vitro-synthesized RNA, the sensitivity of the assay was ascertained to be 100 copies of the target gene per reaction. Phylogenetic analysis of the nucleoprotein (N) and attachment glycoprotein (G) genes confirmed that this assay detected all lineages of HMPV. A2, B1 and B2 strains were observed during the study period. Our assay is highly sensitive and specific for all known lineages of HMPV, making it a valuable tool for rapid detection of the virus. A2 and B2 were the predominant subtypes circulating in Pune, Western India.


title: Herpesvirus strigis, a new avian herpesvirus: II. Biochemical and biophysical properties

text: A virus (HSIS) originating from dead owls was successfully cultivated in chicken embryo fibroblasts. Its replication was inhibited by IUDR. Tissue cultured virus proved sensitive to ether, chloroform, 0.5 per cent trypsin, and to pH levels of 4.0 or lower. Infectivity was rapidly destroyed at 56° C. Negatively stained naked virions of 100 nm average diameter were seen, and enveloped virions with 160–250 nm size. The capsid was built up of hollow cyclindrical capsomeres, arranged in equilateral triangles, carrying 5 capsomeres along each edge. Cubical symmetry and icosahedron structure yielded a total number of 162 capsomeres. All these biochemical and biophysical data lead to classification of HSIS virus into the genus herpesvirus. Biological properties described in a foregoing paper sustained such grouping, and indicated that the agent was a new avian herpesvirus for which the nameherpesvirus strigis was proposed.


title: Feline CD 4 molecules expressed on feline non-lymphoid cell lines are not enough for productive infection of highly lymphotropic feline immunodeficiency virus isolates

text: To investigate whether the feline CD 4 (fCD 4) molecules are involved in infections of highly lymphotropic feline immunodeficiency virus (FIV) isolates, we expressed fCD 4 stably on Crandell feline kidney cells andFelis catus whole foetus 4 cells by transfection of a cDNA encoding the fCD 4 glycoprotein, and then infected them with TM 1 and TM 2 strains of FIV, which are unable to infect these cells productively. In spite of fCD 4 being expressed on these cells, no virus production was observed. This result indicates that fCD 4 expression alone cannot induce a productive infection of the FIV TM 1 and TM 2 strains.


title: Studies on avian infectious bronchitis virus (IBV): I. Resistance of IBV to chemical and physical treatments

text: The resistance of avian infectious bronchitis virus (IBV) to several chemical and physical treatments was studied. Ten strains, including four Japanese strains, were used. 1. All strains were sensitive to heating at 56° C for 15 minutes; although two of them, KH and Massachusetts-41, were resistant to heating at 45° C for 90 minutes. 2. All strains were resistant to pH 3.0 and most of the strains were sensitive to pH 11.0. 3. All strains were completely inactivated by chloroform and sodium deoxycholate and all except Beaudette-42 and Connaught were relatively stable to ether. 4. All strains rapidly lost their infectivities upon ultraviolet irradiation. 5. Trypsin did not affect the infectivity of any strain. 6. From these results, the ten strains were classified into three groups based on their stabilities to exposure to heating at 45° C for 90 minutes and to ether.


title: Activation of toll-like receptor signaling pathways leading to nitric oxide-mediated antiviral responses

text: Toll-like receptors (TLRs), well-characterized pattern-recognizing receptors of the innate arm of the immune system, are vital in detecting pathogen-associated molecular patterns (PAMPs). The TLR-PAMP interaction initiates an intracellular signaling cascade, predominantly culminating in upregulation of antiviral components, including inducible nitric oxide synthase (iNOS). After activation, various TLR pathways can promote iNOS production via the myeloid differentiation primary response-88 (MyD-88) adapter protein. Subsequently, iNOS facilitates production of nitric oxide (NO), a highly reactive and potent antiviral molecule that can inhibit replication of RNA and DNA viruses. Furthermore, NO can diffuse freely across cell membranes and elicit antiviral mechanisms in various ways, including direct and indirect damage to viral genomes. This review emphasizes current knowledge of NO-mediated antiviral responses elicited after activation of TLR signaling pathways.


docid: umbumcya

title: Biological properties of mengovirus: Characterization of avirulent, hemagglutination-defective mutants

text: Biological properties of two mengovirus mutants, 205 and 280, were compared to those of wild-type virus. The mutants exhibited alterations in plaque morphology, hemagglutination, and virulence in mice, but were not temperature-sensitive. Agglutination of human erythrocytes by mengovirus was dependent on the presence of sialic acid on the erythrocyte surface; however, free sialic acid failed to inhibit hemagglutination. Glycophorin, the major sialoglycoprotein of human erythrocyte membranes, exhibited receptor specificity for wild-type virus, but not for mutants 205 or 280. Cross-linking studies indicated that glycophorin exhibited binding specificity for the alpha (1 D) structural protein. The LD(50) titers for wild-type mengovirus were 7 and 1500 plaque forming units (PFU) in mice infected intracranially (IC) and intraperitoneally (IP), respectively. However, mice infected IC or IP with 10(6) or 10(7) PFU of mutant 205 or 280 did not exhibit symptoms indicative of virus infection. Revertants were isolated from the brains of mice infected with mutant 205, but not from the brains of mice infected with mutant 280. The biological characterization of the revertants indicated that hemagglutination and virulence may be phenotypically-linked traits.


title: Failure of oral 4′, 6-dichloroflavan to protect against rhinovirus infection in man

text: 4′, 6-Dichloroflavan, a potent inhibitor of rhinovirus replicationin vitro, was tested in a double-blind placebo controlled volunteer trial for its protective effect against experimental rhinovirus infection. Dichloroflavan was given orally (1 mg/kg, 3 times per day) for 3 doses before, and 13 doses after intransasal challenge with rhinovirus type 9, a type known to be highly sensitive in tissue culture. A total of 63 volunteers were included in the analysis for efficacy. Dichloroflavan did not produce any consistent or significant reduction in quantitative clinical or laboratory evidence of infection, and there was no apparent negative correlation of such data with drug concentrations in plasma. It is concluded that administration of dichloroflavan in the oral formulation tested is not of value in the treatment of human rhinovirus infection.


title: Virus specificity of the antiviral state induced by IFN gamma correlates with resistance to MHV 3 infection

text: A comparative study was carried out to investigate the correlation between the antiviral effect induced in macrophages by IFN gamma and the resistance of A/J and BALB/c mice to an experimental infection of MHV 3, MHV 4, and MHVA 59. Both mouse strains were resistant to intraperitoneal infection with MHV 4 or MHVA 59 and only the A/J mice showed resistance to MHV 3, the BALB/c mice being fully susceptible to this virus infection. Comparable growth kinetics, for all three viruses, were observed in both mouse strains, except for the MHV 3 growth in BALB/c mice, where the virus titre increased to a peak on day 2, remaining high until day 4 when the mice died of acute hepatitis. The IFN gamma titres in the peritoneum of mice preceded and correlated with the virus growth, higher titres being found in MHV 3 infected BALB/c mice. The highest titre was always observed 24 to 48 h after infection. Among viral strains grown in cultured macrophages, higher titres were always observed in cultures infected with MHVA 59, followed by MHV 3 and the lowest those infected with MHV 4. The macrophage activation by IFN gamma-induced a partial restriction of virus growth only in MHV 3 infected A/J mouse macrophages. A virus specificity of the IFN gamma-induced antiviral state was shown to be in direct correlation with the resistance of mice to MHV 3 infection.


title: Transcription of feline calicivirus RNA

text: We report here the cloning and 3′ sequence determination of feline calicivirus strain F9. Subcloning the 3′ terminus enabled the production of strand specific probes for RNA synthesis. We extend the number of virus specific RNAs detected intracellularly to 8, and show that numbers 1–5 are represented as negative strands which may serve as templates in the synthesis of these RNAs.


title: Temperature dependent replication of porcine parvovirus isolates

text: The replication of four porcine parvovirus isolates, NADL-8, NADL-2, KBSH, and Kresse, in swine testes cells were compared at temperatures of 32, 37, and 39 °C. Replication of the Kresse isolate was restricted at 32 and 37 °C as evidenced by progeny virus, virus polypeptide and viral DNA synthesis, but not at 39 °C. In contrast, replication of KBSH was restricted at 39 °C, but not at 37 or 32 °C. Findings from this study support the contention that replication of KBSH and Kresse isolates are temperature dependent.


title: Physico-chemical properties of murine hepatitis virus, strain A59

text: The infectivity of murine hepatitis virus (MHV-A59) was optimally stable at pH 6.0 and was unaffected by ionic strength or at least 15 cycles of freezing and thawing. It was completely inactivated within 25 minutes at 56° C, but was protected by 1m magnesium chloride or magnesium sulphate. It was completely inactivated within 14 days at 37 and 22°C, but was relatively stable for as long as 72 days at 4°C and optimal pH.


title: Hepatitis C virus

text: HepCV is the major cause of NANB PT hepatitis and is also implicated as the cause in a large proportion of sporadic cases of NANBH. Chronic infection with HepCV has also been linked to the development of hepatocellular carcinoma. Chimpanzees and marmosets are the only animals found to be experimentally infectable and the virus has not been propagated in any cell culture system. HepCV is an enveloped virus with a diameter of 30–60 nm and a 10-kb positive-stranded RNA genome. Its genome organization resembles that of the flaviviruses and pestiviruses. A 5′-untranslated segment of 341 nucleotides precedes a continuous ORF of 9030/9033 nucleotides which is followed by a 54 nucleotides long 3′-non-coding segment. Further work is required to resolve the question of whether the genomic RNA possesses a 3′-poly(U) or poly(A) tail. The genome also carries an internal poly(A) segment towards the 5′-end of its ORF. Genomic RNA is probably translated into a single polyprotein of 3010/3011 amino acids which is processed into functional proteins. The viral proteins have not been identified, but on the basis of the predicted amino acid sequences, hydrophobicity plots, location of potential glycosylation sites and similarities of these properties to those of pesti- and flaviviruses, the following genome organization has been predicted. The predicted viral structural proteins, a nucleocapsid protein and two envelope glycoproteins are located at the aminoterminal end of the polyprotein. They are followed by a highly hydrophobic protein and proteins that exhibit proteinase, helicase and replicase domains and thus are probably involved in RNA replication and protein processing. The replicase domain is located close to the carboxy terminus of the polyprotein. Although the overall nucleotide and amino acid homologies between HepCV and pestiviruses are low, a number of similarities exist that point to a closer ancestral relationship to the latter than the flaviviruses. First, the 5′-untranslated segment of the HepCV genome resembles that of the pestivirus genomes in size and presence of several short ORFs and it contains several segments with high nucleotide homology. Second, the two putative envelope glycoproteins of HepCV resemble two of the three putative envelope glycoproteins of the pestiviruses. Because its genome organization and predicted virion structure closely resemble those of the flaviviruses and pestiviruses, HepCV has been proposed to be placed in the familyFlaviviridae. It has been suggested to be classified as a new third genus in this family because it is only remotely related to the pestiviruses and flaviviruses in nucleotide sequence of its genome and the amino acid sequences of the predicted viral proteins. On the basis of genomic sequence information, an immunoprobe has been devised for screening blood supplies and donors for anti-HepCV antibodies to a non-structural protein of HepCV. The immuno-assay exhibits a high efficiency in detecting infected donors, though one caveat is that antibodies to the test antigen develop in infected individuals only between 2 and 8 months post infection. On the other hand, viral RNA can be detected in plasma by reverse transcription and amplification of the cDNA by PCR within a few days post infection. Thus the latter technique may become more important in the detection of HepCV in blood and tissues once the technique becomes more widely established as a diagnostic tool. The untranslated 5′-segment has been found to be highly conserved in the genomes of different HepCV isolates from various parts of the world. The replicase domain is also highly conserved, but considerable amino acid and nucleotide differences exist in other segments of the long ORFs of various HepCV isolates. Divergence among different isolates is particularly great (up to 30%) in the segment encoding the two putative envelope glycoproteins and the upstream hydrophobic protein. The variability in envelope glycoproteins needs to be considered in the development of immuno-probes and of vaccines for HepCV.


title: Isolation of a murine hepatitis virus from Swiss mice treated with antilymphocyte serum

text: In an attempt to transmit feline malignant lymphoma to mice, a murine hepatitis virus (MHV) was accidentally recovered from conventionally reared Swiss mice receiving prolonged treatment with antilymphocyte serum. In these mice, the virus did not require concomitant infection withEperythrozoon coccoides to produce disease. Tests for antibodies against a variety of viruses were performed on serum from control colony mice and mice that recovered from experimental infection as well as on serum pooled from vaccinated and non-vaccinated mice challenged with the recovered agent. Antibodies to the MHV complement fixing (CF) antigen(s) were demonstrated in only the last mentioned serum. Mice harbouring a hepatitis virus may thus be tolerant to their CF antigen(s) in a situation analogous to oncornavirus infection of their natural hosts. The liver pathology was that of a confluent focal-type necrosis resembling that produced by certain other MHV strains. We have labelled this newly isolated virus MHV (Swiss-Cape Town), abbreviated to MHV (S-CT).


title: Analysis of codon usage in bovine viral diarrhea virus

text: Bovine viral diarrhea virus (BVDV) is a widespread virus in beef and dairy herds. BVDV has been grouped into two genotypes, genotype 1 and genotype 2. In this study, the relative synonymous codon usage (RSCU) values, effective number of codon (ENC) values and nucleotide content were investigated, and a comparative analysis of codon usage patterns for open reading frames (ORFs) of 22 BVDV genomes, including 14 of genotype 1 and 8 of genotype 2, was carried out. A high A+U content and low codon bias were found in BVDV genomes. Depending on the RSCU data, it was found that there was a significant variation in bias of codon usage between the two genotypes, and a geographic factor exists only in genotype-1 of BVDV. The RSCU data have a negative correlation with general average hydrophobicity (GRAVY), aromaticity and nucleotide content. Furthermore, the overall abundance of C and U has no effect on the synonymous codon usage patterns. In contrast, the A and G content showed a significant correlation with the nucleotide content at the third position. In addition, the codon usage patterns of BVDV are similar to those of 22 conserved genes of Bos taurus. Taken together, the genetic characteristics of BVDV possibly result from interactions between natural seclection and mutation pressure. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00705-010-0848-0) contains supplementary material, which is available to authorized users.


title: In vitro activity of R 61837, a new antirhinovirus compound

text: R 61837 or 3-methoxy-6-[4-(3-methylphenyl)-1-piperazinyl]pyridazine is a new and potent inhibitor of rhinoviruses at concentrations not inhibitory to HeLa cell growth. Different rhinovirus serotypes varied widely in their susceptibility to the antiviral agent. The MICs for 50% CPE reduction ranged from 0.004 to 15 µg/ml. The yields of the most susceptible serotypes were reduced by a factor of 1,000 to 10,000 after single round high multiplicity infections in presence of low concentrations of the compound. The inactivation of some but not all serotypes in a time-, concentration- and temperature-dependent way by R 61837 indicated a direct interaction between the drug and the viral particles. The antiviral activity of the compound was confirmed in the human target cells for rhinoviruses by experiments using nasal polyp explant cultures.


GenusTorovirus assigned to theCoronaviridae


Abbreviations for vertebrate virus species names


title: Studies on avian infectious bronchitis virus (IBV): III. Interferon induction by and sensitivity to interferon of IBV

text: The induction of interferon by avian infectious bronchitis virus (IBV) and the sensitivity of IBV to interferon were studied. The results of experiments with ten IBV strains are summarized as follows. 1. All the IBV strains tested induced interferon in chick embryo (CE) cells, chicken kidney (CK) cells and embryonated eggs. The Iowa-609 strain induced about 1000 units of interferon in CE cells while the Beaudette-42 strain induced about 200 units of interferon in embryonated eggs; the interferon titers induced by other strains usually ranged from 5 to 60 units. No IBV strain induced interferon in HeLa or BHK-21 cells. 2. IBV particles inactivated by ultraviolet irradiation or by heating lost their ability to induce interferon. 3. The properties of the interferon produced in the present study are similar to those of other interferons produced in chicken cells. 4. HeLa or BHK-21 cells did not acquire resistance to virus infection, after incubation with interferon produced in CE cells. On the other hand, CK cells acquired the same degree of resistance to virus infection as CE cells after incubation with interferon produced in CE cells. 5. All the IBV strains tested were sensitive to interferon in CK cells. The sensitivities of Massachusetts-41 and Holte strains to interferon were similar to that of vesicular stomatitis virus.


title: Characterization and nuclear localization of the fiber protein encoded by the late region 7 of bovine adenovirus type 3

text: To identify the protein encoded by the L7 region of bovine adenovirus-3 (BAdV-3), specific antisera were raised by immunizing rabbits with bacterial fusion proteins encoding the N-terminus or C-terminus of the BAdV-3 fiber protein. Immunoprecipitation and Western blot analysis confirmed that the fiber is expressed as a 102 kDa glycoprotein, which is localized to the nucleus of infected cells. To identify the nuclear localization signals (NLS), BAdV-3 fiber deletion mutants and GFP/β-galactosidase fusion proteins were expressed in transfected cells, and subcellular localization was visualized by immunofluorescence microscopy. Analysis of deletion mutants localized the NLS to the N-terminal 41 amino acids. Analysis of the N-terminal 41 amino acids identified a cluster of basic residues between amino acid 14 and 20. Substitution of the basic residues ((16)KAKR(19)) with acidic residues ((16)EAEE(19)) resulted in the accumulation of fiber in the cytoplasm. However, (16)KAKR(19) or (12)VYPYKAKRPNI(22) were not sufficient for efficient transport of a cytoplasmic protein GFP/β-galactosidase to the nucleus. The recombinant BAdV-3 expressing mutant fiber containing (16)EAEE(19) instead of (16)KAKR(19) was unable to replicate efficiently in Madin-Darby bovine kidney cells, suggesting that the NLS of fiber carries out important in vivo functions.


title: The spectrum of care for pediatric refugees and asylum seekers at a tertiary health care facility in Switzerland in 2015

text: The aim of this retrospective study was to describe the epidemiology and spectrum of infections of admitted pediatric refugees and asylum seekers in a tertiary referral hospital in a high-income country in Europe. We identified recent refugees and asylum seekers < 18 years of age admitted to the University Children’s Hospital in Basel, Switzerland, in 2015. A retrospective analysis was performed using electronic patient records. We identified 105 admissions in 93 patients with a median age of 5.7 (IQR 2.6–14.5) years. Eritrea, Syria, and Afghanistan were the most frequent countries of origin. The median duration of admission was 4 (IQR 2–6) days with infections and elective surgical interventions being the most common reason (54.8 and 16.1%, respectively). Most infections were airway, skin, and gastrointestinal in 46.4, 20.2, and 11.9%, respectively. The prevalence of tropical infections was 11.9%. The main pathogens identified were influenza A virus (13.8%), Staphylococcus aureus (10.3%), and rhino/enterovirus (10.3%). Previous medical non-infectious conditions were recorded in 13%. Conclusion: The study revealed a high burden of infections in admitted patients mostly caused by well-known pathogens prevalent also in the local population. Both tropical infections and pre-existing non-infectious conditions are also important in admitted patients. Better epidemiological data is required to optimize health care for this medically most vulnerable population in refugee crises.


title: Molecular epidemiology and genetic variation analyses of porcine circovirus type 2 isolated from Yunnan Province in China from 2016-2019

text: BACKGROUND: Porcine circovirus type 2 (PCV2) is the causative agent of porcine circovirus-associated disease (PCVAD). Its prevalence in swine herds was first reported in China in 2000. PCV2 infection causes immunosuppression that leads to multiple diseases, causing serious economic problems for the swine industry in China. Since information on the genetic variation of PCV2 in Yunnan province is limited, this study aims to investigate the molecular epidemiological and evolutionary characteristics of PCV2 from 2016 to 2019. METHODS: A total of 279 clinical samples were collected from different regions of Yunnan between 2016 to 2019, and PCV2 was detected by PCR. We then amplified full genomes from the positive samples, and the sequences were analysed for homology and genetic evolution. RESULTS: Overall, 60.93% (170/279) of the screened swine herd samples were positive for PCV2. We sequenced 15 Yunnan province PCV2 strains from positive samples. Analyses of the complete genomes and Cap genes led to the classification of the 15 Yunnan PCV2 strains into PCV2a (2 of 15), PCV2b (1of 15) and PCV2d (12 of 15). All strains shared 94.3–99.9% of their identities with the nucleotide sequences of complete genomes in this study and shared 94.2–99.9% identity with the reference sequences. All strains share 89.4–100% and 86.8–100% of their identities with the nucleotide and amino acid (aa) sequences of Cap, respectively. CONCLUSIONS: The results of this study provide evidence that PCV2a, PCV2b and PCV2d genotypes coexisted in Yunnan Province from 2016 to 2019, and the priority prevalence genotype was PCV2d. The data provide evidence for the increased genetic diversity and insights into the molecular epidemiology of PCV2. This study also provides basic data for the Yunnan province PCV2 molecular epidemiological survey and accumulates effective materials for the development of PCV2 vaccines.


title: Intrahepatic and portal venous gas detected by ultrasonography

text: During a 3-year period, sonographic evidence of portal venous gas (PVG) was found in 11 patients. Of these, 10 patients were examined for clinically suspected necrotizing enterocolitis (NEC). In the 11th patient, suffering from nephroblastoma, PVG was detected by routine sonography. Radiographic examination, performed in nine of 11 patients did not show any PVG. Intestinal pneumatosis was radiographically identifiable in only four of these children, whereas eight of 11 patients with sonographically detectable PVG also had sonographic evidence of intramural gas. Follow-up examinations in five patients showed cessation of PVG soon after onset of adequate therapy, indicating that ultrasonography is also a reliable method for monitoring NEC. Sonographic evidence of PVG, however, may be limited to the time before onset of therapy.


title: The L1 family of long interspersed repetitive DNA in rabbits: Sequence, copy number, conserved open reading frames, and similarity to keratin

text: The L1 family of long interspersed repetitive DNA in the rabbit genome (L1Oc) has been studied by determining the sequence of the five L1 repeats in the rabbit β-like globin gene cluster and by hybridization analysis of other L1 repeats in the genome. L1Oc repeats have a common 3′ end that terminates in a poly A addition signal and an A-rich tract, but individual repeats have different 5′ ends, indicating a polar truncation from the 5′ end during their synthesis or propagation. As a result of the polar truncations, the 5′ end of L1Oc is present in about 11,000 copies per haploid genome, whereas the 3′ end is present in at least 66,000 copies per haploid genome. One type of L1Oc repeat has internal direct repeats of 78 bp in the 3′ untranslated region, whereas other L1Oc repeats have only one copy of this sequence. The longest repeat sequenced, L1Oc5, is 6.5 kb long, and genomic blot-hybridization data using probes from the 5′ end of L1Oc5 indicate that a full length L1Oc repeat is about 7.5 kb long, extending about 1 kb 5′ to the sequenced region. The L1Oc5 sequence has long open reading frames (ORFs) that correspond to ORF-1 and ORF-2 described in the mouse L1 sequence. In contrast to the overlapping reading frames seen for mouse L1, ORF-1 and ORF-2 are in the same reading frame in rabbit and human L1s, resulting in a discistronic structure. The region between the likely stop codon for ORF-1 and the proposed start codon for ORF-2 is not conserved in interspecies comparisons, which is further evidence that this short region does not encode part of a protein. ORF-1 appears to be a hybrid of sequences, of which the 3′ half is unique to and conserved in mammalian L1 repeats. The 5′ half of ORF-1 is not conserved between mammalian L1 repeats, but this segment of L1Oc is related significantly to type II cytoskeletal keratin.


Lung ultrasound and B-lines quantification inaccuracy: B sure to have the right solution


title: Magnetic resonance imaging of limbic encephalitis

text: In two patients with limbic encephalitis serial magnetic resonance (MR) imaging showed evolution of abnormal high-signal intensity in both hippocampal formations on T2-weighted images.


title: Probable reassortment of genomic elements among elongated RNA-containing plant viruses

text: The relationships of genome organization among elongated (rod-shaped and filamentous) plant viruses have been analyzed. Sequences in coding and noncoding regions of barley stripe mosaic virus (BSMV) RNAs 1, 2, and 3 were compared with those of the monopartite RNA genomes of potato virus X (PVX), white clover mosaic virus (WClMV), and tobacco mosaic virus, the bipartite genome of tobacco rattle virus (TRV), the quadripartite genome of beet necrotic yellow vein virus (BNYVV), and icosahedral tricornaviruses. These plant viruses belong to a supergroup having 5′-capped genomic RNAs. The results suggest that the genomic elements in each BSMV RNA are phylogenetically related to those of different plant RNA viruses. RNA 1 resembles the corresponding RNA 1 of tricornaviruses. The putative proteins encoded in BSMV RNA 2 are related to the products of BNYVV RNA 2, PVX RNA, and WClMV RNA. Amino acid sequence comparisons suggest that BSMV RNA 3 resembles TRV RNA 1. Also, it can be proposed that in the case of monopartite genomes, as a rule, every gene or block of genes retains phylogenetic relationships that are independent of adjacent genomic elements of the same RNA. Such differential evolution of individual elements of one and the same viral genome implies a prominent role for gene reassortment in the formation of viral genetic systems.


title: The cytotoxin of Pseudomonas aeruginosa: Cytotoxicity requires proteolytic activation

text: The primary structure of a cytotoxin from Pseudomonas aeruginosa was determined by sequencing of the structural gene. The cytotoxin (31,700 Mr) lacks an N-terminal signal sequence for bacterial secretion but contains a pentapeptide consensus sequence commonly found in prokaryotic proteins which function in a TonB-dependent manner. The cytotoxin gene has a [G+C]-content of 53.8% which is considerably lower than generally observed for genes from Pseudomonas aeruginosa. The cytotoxin gene was exclusively detected in strain 158 but not in three other clinical isolates, as determined by Southern and Northern hybridization. The latter technique revealed that the toxin is translated from monocistronic mRNA. The promoter of the cytotoxin is inactive in Escherichia coli. Upon site-directed modification of the 5′-noncoding region by the polymerase chain reaction the gene was expressed under control of the trcpromoter. The gene product obtained in Escherichia coli was nontoxic. Toxicity was induced by subsequent treatment with trypsin. [(35)S]methionine-labeled cytotoxin with high specific radioactivity was obtained by in vitro transcription/translation. Like [(125)I] labeled material from Pseudomonas aeruginosa this polypeptide bound to membrane preparations from Ehrlich ascites cells, as evidenced by sedimentation through a sucrose gradient at neutral pH.


title: Fulminant hepatitis

text: In conclusion, evidence exists that cellular and humoral immune-mediated processes result in hepatic necrosis in FH. Activation of the immune coagulation system appears to be an integral part of the inflammatory process resulting in fibrin thrombi which have been demonstrated in the liver, kidneys and lungs of patients with FH. A beneficial role of PG in the treatment of FH has been demonstrated, but controlled trials are required to firmly establish the efficacy of these agents. At present liver transplantation remains the treatment of choice in selected patients with FH. Further studies of the role of the immune system in the pathogenesis of this disease are required to devise more effective therapeutic strategies.


title: Theimunopathogenesis of cronic HBV inducedliver disease

text: In conclusion, until the cellular biology of hepatitis B virus infection is understood and until the technology for the development of suitable virus infected autologous target cells is available, it will not be possible to definitively establish the mechanism involved in the pathogenesis of hepatitis B virus induced hepatocellular injury. Clearly, considerable effort must now be focused on the basic biology of virus infection, replication, and effects on hepatocellular metabolism before it will be possible to perform the definitive experiments to elucidate the role played by the immune system in the pathogenesis of this disease.


title: Preferred apical distribution of glycosyl-phosphatidylinositol (GPI) anchored proteins: A highly conserved feature of the polarized epithelial cell phenotype

text: We use a sensitive biotin polarity assay to survey the surface distribution of glycosyl-phosphatidylinositol (GPI) anchored proteins in five model epithelial cell lines derived from different species (dog, pig, man) and tissues, i.e., kidney (MDCK I, MDCK II, LLC-PK(1)) and intestine (Caco-2 and SK-CO15). After biotinylation of apical or basolateral surfaces of confluent monolayers grown on polycarbonate filters, GPI-anchored proteins are identified by their shift from a Triton X-114 detergent-rich phase to a detergent-poor phase in the presence of phosphatidylinositol-specific phospholipase C. All GPI-anchored proteins detected (3–9 per cell type, at least 13 different proteins) are found to be apically polarized; no GPI-anchored protein is observed preferentially localized to the basal surface. One of the GPI-anchored proteins is identified as carcinoembryonic antigen (CEA). Survey of MDCK II-RCA(r), a mutant cell line with a pleiotropic defect in galactosylation of glycoproteins and glycolipids (that presumably affects GPI anchors) also reveals an apical polarization of all GPI-anchored proteins. In contrast, analysis of MDCK II-ConA′ (a mutant cell line with an unknown defect in glycosylation) revealed five GPI-anchored proteins, two of which appeared relatively unpolarized. Our results indicate that the polarized apical distribution of GPI-anchored proteins is highly conserved across species and tissue-type and may depend on glycosylation.


Antibody and complement-dependent viral neutralization


title: Exchanges of short polymorphic DNA segments predating speciation in feline major histocompatibility complex class I genes

text: Sequence comparisons of 14 distinct MHC class I cDNA clones isolated from species representing the three major taxonomic lineages of Felidae (domestic cat lineage, ocelot lineage, and pantherine lineage) revealed that feline MHC class I alleles have highly mosaic structures with short polymorphic sequence motifs that are rearranged between alleles of individual MHC loci, between MHC class I genes within cat species, and between homologous MHC loci in different species. The pattern of sequence variation in felids supports the role of the following factors in production and maintenance of MHC variation: (1) gradual spontaneous mutation; (2) selective pressure to conserve certain residues but also to vary in hypervariable regions, notably residues that functionally participate in antigen recognition and presentation; and (3) recombination-mediated gene exchange between alleles and between related genes. The overall amount of genetic variation observed among MHC class I genes in the Felidae family is no greater than the amount of variation within any outbred cat species (i.e., domestic cat, ocelot). The occurrence of equivalent levels of polymorphism plus the simultaneous persistence of the same sequence motifs in divergent feline species suggest that most MHC class I nucleotide site polymorphism predated species divergences. Ancient polymorphisms have been transmitted through the speciation events and modern feline MHC class I alleles were derived by recombinational exchange of polymorphic sequence motifs. Moreover, some of these sequence motifs were found in other mammalian MHC class I genes, such as classical human HLA-B5, nonclassical human HLA-E class I genes, and bovine class I genes. These results raise the prospect of an ancient origin for some motifs, although the possibility of convergence in parallel mammalian radiations cannot be excluded.


title: Aberrant expression of Class II major histocompatibility complex molecules by B cells and hyperexpression of Class I major histocompatibility complex molecules by insulin containing islets in Type 1 (insulin-dependent) diabetes mellitus

text: Twenty-three patients with recent onset Type 1 (insulin-dependent) diabetes in whom residual insulin secreting B cells were present and 12 patients with disease of more prolonged duration (maximum 9 years), 8 of whom had residual B cells, were studied. Aberrant expression of Class II major histocompatibility complex molecules was demonstrated immunohistochemically on insulin secreting B cells in 21 out of 23 patients with recent onset disease and 6 of the patients with more prolonged disease. No such expression was seen on glucagon secreting A cells or somatostatin secreting D cells. Islets where there was marked hyperexpression of Class I major histocompatibility complex molecules on islet endocrine cells were seen in all cases in which residual B cells were present. Ninety-two per cent of insulin containing islets but only 1% of insulin deficient islets exhibited this phenomenon (p<0.001, Chi-squared test). There was evidence to suggest that both these abnormalities of major histocompatibility complex expression preceded insulitis within a given islet. They also appeared to be unique to Type 1 diabetes, being absent in pancreases of patients with Type 2 (non-insulin-dependent) diabetes, chronic pancreatitis, cystic fibrosis, graft-versus-host disease and Coxsackie B viral pancreatitis. The development of autoimmunity to B cells in Type 1 diabetes may be a “multistep” process in which abnormalities of major histocompatibility complex expression on islet endocrine cells are crucial events.


Antibody mediated complement dependent lysis of virus infected cells


title: MouseV(k) gene classification by nucleic acid sequence similarity

text: Analyses of immunoglobulin (Ig) variable (V) region gene usage in the immune response, estimates ofV gene germline complexity, and other nucleic acid hybridization-based studies depend on the extent to which such genes are related (i. e., sequence similarity) and their organization in gene families. While mouseIgh heavy chainV region (V (H)) gene families are relatively well-established, a corresponding systematic classification ofIgk light chainV region (V (k)) genes has not been reported. The present analysis, in the course of which we reviewed the known extent of theV (k) germline gene repertoire andV (k) gene usage in a variety of responses to foreign and self antigens, provides a classification of mouseV (k) genes in gene families composed of members with >80% overall nucleic acid sequence similarity. This classification differed in several aspects from that ofV (H) genes: only someV (k) gene families were as clearly separated (by >25% sequence dissimilarity) as typicalV (H) gene families; mostV (k) gene families were closely related and, in several instances, members from different families were very similar (>80%) over large sequence portions; frequently, classification by nucleic acid sequence similarity diverged from existing classifications based on amino-terminal protein sequence similarity. Our data have implications forV (k) gene analyses by nucleic acid hybridization and describe potentially important differences in sequence organization betweenV (H) andV (k) genes.


title: Necrotizing enterocolitis: A continuing problem in the neonate

text: Necrotizing enterocolitis (NEC) is a syndrome of diverse etiologies with a significant mortality rate affecting mostly prematurely born stressed infants. Now recognized as a discrete entity, it had been poorly defined because other conditions seem to represent the same entity. A number of risk factors have been identified that appear to “trigger” NEC, though these have been questioned because they have been present just as frequently in premature and older infants who did not develop NEC as in those that did. Recently, maternal cocaine use has been added to the suspected risk factors. A steady improvement in the survival of babies with NEC has been due largely to a high index of suspicion of the disease and early, aggressive medical management.


title: Relative bioavailability of nicotine from a nasal spray in infectious rhinitis and after use of a topical decongestant

text: The relative bioavailability of nicotine from a nasal spray was assessed in 15 smokers suffering a common cold and rhinitis according to generally accepted criteria. The patients were given a single dose of 2 mg nicotine from the nasal spray with and without concurrent administration of a nasal vasoconstrictor decongestant, xylometazoline, in randomised order. Control session measurements were made in the disease-free state. Applying strict bioequivalence criteria, we found that common cold/rhinitis slightly reduced the bioavailability of nicotine, both in its rate and extent; the geometric mean of the ratio of C(max), AUC and t(max) were 0.81, 0.93 and 1.36, respectively. The nasal vasoconstrictor, xylometazoline, normalised the extent of the bioavailability of nicotine, but further prolonged the time for absorption to almost twice that measured in the disease-free state, increasing the t(max) ratio to 1.72. The results suggest that a minor proportion of people stopping smoking with the help of a nicotine nasal spray may experience a minor reduction in the effect of the spray during common cold/rhinitis. However, the nicotine self-titration behaviour found with most smoking cessation products (except the nicotine patch) will automatically lead to an adjustment of the dosage to achieve the desired effect.


title: Lactate dehydrogenase-elevating virus: an ideal persistent virus?

text: LDV contradicts all commonly held views about mechanisms of virus persistence, namely that persistence is primarily associated with noncytopathic viruses, or the selection of immune escape variants or other mutants, or a decrease in expression of certain viral proteins by infected cells, or replication in “immune-privileged sites”, or a general suppression of the host immune system, etc. [1, 2, 5, 54, 77, 78]. LDV is a highly cytocidal virus that invariably establishes a life-long, viremic, persistence in mice, in spite of normal anti-viral immune responses. One secret of LDV's success in persistence is its specificity for a renewable, nonessential population of cells that is continuously regenerated, namely a subpopulation of macrophages. Since the continuous destruction of these cells is not associated with any obvious health effects, this macrophage population seems nonessential to the well-being of its host. The only function identified for this subpopulation of macrophages is clearance of the muscle type of LDH and some other enzymes [59, 67, 68]. Furthermore, the effects of LDV infection on the host immune system, namely the polyclonal activation of B cells and its associated production of autoantibodies, and the slight impairment of primary and secondary antibody responses also do not seem to be severe enough to cause any clinical consequences. But how does LDV replication in macrophages escape all host defenses? Persistence is not dependent on the seletion of immune escape variants or other mutants ([58] and Palmer, Even and Plagemann, unpublished results). Also, LDV replication is not restricted to immune-privileged sites [5]. LDV replication persists in the liver, lymphoidal tissues and testis [66]. Only the latter could be considered a site not readily accessible to immune surveillance. Most likely, resistance of LDV replication to antiviral immune responses is related to the unique structure of its envelope proteins and the production of large quantities of viral antigens. High titers of anti-LDV antibodies are generated in infected mice but they neutralize LDV infectivity only very inefficiently and, even though the antiviral antibodies are mainly of the IgG2a and IgG2b isotypes, they do not mediate complement lyses of virions [31]. Interaction of the antibodies and complement with the VP-3/VP-2 heterodimers in the viral envelope may be impeded by the exposure of only very short peptide segments of these proteins at the envelope surface and the presence of large oligosaccharide side chains. Furthermore, since LDV maturation is restricted to intracytoplasmic cisternae [59, 71], the question arises of whether any of the viral proteins are available on the surface of infected cells for ADCC. CTLs also fail to control LDV replication. Altough CTLs specific for N/VP-1 are rapidly generated, these have disappeared by 30 days p.i. [26]. The reasons for this loss are unknown, but high-dose clonal exhaustion [41, 51, 77, 78] is a reasonable possibility since, regardless of the infectious dose, large amounts of LDV proteins are present in all the lymphoidal tissues at the time of the induction of the CTL response. Furthermore, after exhaustion of CTLs in the periphery, continuous replication of LDV in the thymus [65] assures that the mice become permanently immunologically tolerant with respect to LDV antigen-specific CTLs as a result of negative selection in the thymus. LDV might be a primary example for the effectiveness of a permanent clonal CTL deletion in adult animals under natural conditions of infection. The presumed modes of transmission of LDV in nature and the events associated with its infection of mice are strikingly similar to those observed during the acute and asymptomatic phases of infection with human immunodeficiency virus (HIV) [24, 29, 74, 78]. These include: (1) primary inefficient transmission via sexual and transplacental routes but effective transmission via blood; (2) primary replication in renewable populations of lymphoidal cells with production of large amounts of virus after the initial infection of the host followed by persistent low level of viremia in spite of antiviral immune responses; (3) persistence, reflecting continuous rounds of productive, cytocidal infection of permissive cells [59, 74] and the rate of generation of permissive cells which may be the main factor in determining the level of virus production (in the case of HIV, the rate of activation of CD4(+) T cells to support a productive HIV replication might be the factor determining the rate of virus production and the progression of the disease); (4) rapid antibody formation but delayed production of neutralizing antibodies with limited neutralizing capacity; (5) rapid but transient generation of virus-specific CTLs; and (6) accumulation of large amounts of virus in newly formed germinal centers in the spleen and lymph nodes concomitant with an initiation of a permanent polyclonal activation of B cells resulting in an elevation of plasma IgG2a. The events described under points 2–6 might be generally associated with natural viremic persistent virus infections. Such persistent viruses, by necessity, have evolved properties that allow them to escape all host defenses and control of their infection by immunological processes is, therefore, difficult, if not impossible. Prevention of infection and chemotherapy may be the only approaches available to combat such virus infections.


title: Effects of angiopeptin on transplant arteriosclerosis in the rat

text: The influence of the somatostatin analogue angiopeptin on transplant arteriosclerosis was investigated using two aortic transplantation rat models. One was characterized by ischemia/reperfusion-induced changes in syngeneic transplants while immunologically induced changes dominated in the other allogeneic model. Angiopeptin, 100 μg/kg per day, was administered continuously until the sacrifice of the rats after 8 weeks. No additional immunosuppression was used in either model. An image analysis system was used to quantify the intimal and medial thicknesses of the grafts. In the syngeneic grafts, the intimal thickness was less than 50% of that of control grafts (P<0.05), but no difference was seen in the allogeneic model. The expression of selected cells, TGF-βs and PDGF and PDGF α-receptors was detected immunohistochemically and displayed a similar picture in control and angiopeptin-treated grafts in both models. We conclude that angiopeptin has no clear immunosuppressive properties but may counteract ischemia-induced transplant arteriosclerosis.


docid: pgyzluwp

title: Programmed cell death


Nucleic acids structure and gene expression


title: Development of ulcerative colitis under the immunosuppressive effect of cyclosporine

text: In recent studies, cyclosporine has been used for the treatment of both ulcerative colitis and Crohn's disease. The results of these studies were variable. We report on a patient who was treated for 6 years with cyclosporine after kidney transplantation. He developed chronic distal colitis with all the features of ulcerative colitis. An infectious etiology of the colitis was carefully excluded. High-dose treatment with methylprednisolone was required to induce remission. This report shows that immunosuppressive therapy with cyclosporine did not prevent the development of ulcerative colitis in this patient.


Relapsing experimental allergic encephalomyelitis an autoimmune model of multiple sclerosis


Cell culture and purification process — purity and safety testing


title: Complement, viruses, and virus-infected cells

text: The attachment of specific antibody to viral glycoproteins and other structures on the surface of a virus or virus-infected cell has a number of potential consequences to the virus or virus-infected cell. Antibody is multivalent and thus able to redistribute or patch surface viral proteins or virus-encoded structures within the lipid bilayer of the viral envelope or the cell membrane. In certain instances, antibody may agglutinate viruses or virus-infected cells. The physical presence of antibody molecules on the virus surface may interfere with the ability of the virus to infect potentially susceptible cells. Antibody on the surface of virus-infected cells may prevent the maturation and release of virus particles; antibody also can alter certain normal cell functions. The Fc portions of antibody molecules bound to virus-infected cells facilitate interactions with effector cells bearing Fc receptors. In the case of lymphocytes and perhaps phagocytic cells, this interaction may lead to antibody-dependent cellular cytotoxicity (ADCC) [51, 58]. The exposed Fc regions may also facilitate attempts at ingestion by monocytes, macrophages, and polymorphonuclear leukocytes.


title: The effects of histamine, pyrilamine, cimetidine, and ranitidine on secretion of lingual lipase and amylase from rat von Ebner's glands

text: Minced von Ebner's glands of rat tongue were incubatedin vitro with histamine and histamine receptor antagonists. At various time intervals, media and homogenates of the tissue were assayed for lingual lipase and amylase activity and percentage secretion calculated. Histamine elicited moderate secretion (≈10%) of lingual lipase and amylase. In contrast, pyrilamine, and H(1) receptor antagonist, elicited>60% secretion. There were statistically significant differences between the percentage secretion of lingual lipase and amylase for basal secretion, as well as for histmine-and pyrilamine-evoked secretion of lingual lipase and amylase for basal secretion, as well as for histamine-and pyrilamine-evoked secretion above basal. The H(2) receptor inhibitors, cimetidine and ranitidine, stimulated secretion of only amylase, but not lingual lipase. When combined with histamine, these antagonists partially inhibited only the secretion of histamine-evoked lingual lipase, but not amylase. The differences in percentage secretion between the two enzymes indicate that exocytosis may not be the only process involved in protein secretion. The anomalous effects of the H(1) and H(2) receptor antagonists necessitate a more detailed characterization of the receptors of von Ebner's glands.


T cell approach to demyelinating diseases


title: The role of proteolytic processing in the morphogenesis of virus particles

text: Proteinases are encoded by many RNA viruses, all retroviruses and several DNA viruses. They play essential roles at various stages in viral replication, including the coordinated assembly and maturation of virions. Most of these enzymes belong to one of three (Ser, Cys or Asp) of the four major classes of proteinases, and have highly substrate-selective and cleavage specific activities. They can be thought of as playing one of two general roles in viral morphogenesis. Structural proteins are encoded by retroviruses and many RNA viruses as part of large polyproteins. Their proteolytic release is a prerequisite to particle assembly; consequent structural rearrangement of the capsid domains serves to regulate and direct association and assembly of capsid subunits. The second general role of proteolysis is in assembly-dependent maturation of virus particles, which is accompanied by the acquisition of infectivity.


title: Experimental immunotherapies for multiple sclerosis

text: Multiple sclerosis (MS) is a chronic demyelinating disease affecting the central nervous system (CNS) principally in young adults. Although its etiology is as yet unknown current evidence suggests that tissue damage is mediated by autoimmune T cells. The examination of an experimental animal model for MS, experimental allergic encephalomyelitis (EAE), has demonstrated that myelin basic protein (MBP)- or proteolipid protein (PLP)-specific T cells mediate the destruction of CNS myelin. In recent years, elegant studies in EAE have shown that encephalitogenic T cells recognize short peptides of MBP or PLP in the context of MHC/HLA-class II molecules, express a restricted number of T cell receptor (TCR) molecules and secrete interferon-γ and tumor necrosis factor-a/β. Understanding the pathogenetic steps in lesion development at the molecular level led to highly specific immunotherapies for EAE targeting each individual molecule. It has been the hope of many investigators that immunological events resembling those in EAE can be found in patients with MS and that the specific immunotherapies effective in EAE could also be applied to MS. However, to date, the evidence for a unique immunological abnormality in MS is notstrong. Although MBP- and PLP-specific T cells with properties similar to those that are encephalitogenic in animals can be isolated from patients, they are not specific for MS and occur with similar frequency in controls. In addition, the variability in specificity and TCR usage has raised questions regarding the relevance of these cells in patients. The importance of the T cell responses to myelin antigens in MS may not be established until the effects of abrogating their activity through specific therapies targeting the trimolecular complex (TMC) have been demonstrated. Consequently, attention has begun to focus on modifying the biology of the MS lesion rather than targeting the initiating event at the level of the TMC, and the success of this approach is reflected by the effect of interferon-β on lesion development in MS. The recent approval for the use of interferon-β for the treatment of relapsing-remitting MS has raised great interest in examining novel strategies for immunotherapies in MS. The basic concepts as well as the current candidates for such new immunotherapies will be outlined in this short review.


title: Effects of T-2 mycotoxin on gastrointestinal tissues: A Review ofin vivo andin vitro models

text: T-2 mycotoxin, a trichothecene, is the principal toxic component ofFusarium sp. Agricultural products and food are frequently contaminated with this toxin. Various animal models have been used to determine its metabolic fate, rate of excretion, and distribution. A modulation effect on cell-mediated immunity and alterations in gastrointestinal propulsion have been demonstrated. The toxin has been shown to produce some similar pathologic alterations in various animal species studied. The consistent alteration appears to mainly affect mitotic cells of the gastrointestinal tract and the lymphoid system. A host of bioassay systems are now being used as alternative methods to the use of animals for testing of the mycotoxin. These tests may accurately assess and define the role of the subject-toxin interactions following consumption of T-2 mycotoxin contaminated food sources. T-2 mycotoxin, as observed above within vivo andin vitro models, promotes a chemically-induced change in structure and function of affected gastrointestinal cells from a transient and reversible aberration in a single enzymatic reaction to cell death. Regardless of the end point measured, the toxic response brought about in cells appears to involve the interactions of virtually all subcellular processes—membrane transport and permeability, chemical metabolism, DNA function, and energy production/expenditure—as cells attempt to maintain their functional integrity while disposing of the toxicant. The variation in the quality of the toxic response with dose suggests that more cellular processes are perturbed as the chemical dose is increased.