Effect of maternally acquired Aujeszky's disease (pseudorabies) virus-specific antibody in pigs on establishment of latency and seroconversion to differential glycoproteins after low dose challenge

This study investigated whether (1) passively immune pigs could become latently infected after challenge with low doses of wild type pseudorabies virus (PRV) and (2) if seroconversion to PRV could be consistently detected using two commercially available differential diagnostic ELISAs. Three litters of piglets with passively acquired PRV serum neutralizing (SN) antibody (geometric mean titers 47.03 to 95.10) were challenged at 6 to 12 days of age with 236 to 500 TCID50 of Shope strain virus; pigs were vaccinated at 11 weeks of age with a commercially available genetically engineered vaccine (TK- gE- gG- Iowa S62 strain PRV). Vaccination was intended to reduce the risk of reactivation of latent infection resulting in spread of virulent PRV infection to previously uninfected pigs during the experiment. Vaccination at this age also approximated common field practices in infected herds. After 15 weeks, all challenged pigs were seropositive on the PRV glycoprotein (g or gp) E differential ELISA but were seronegative on the gG differential ELISA. All three challenge groups had pigs that were latently infected as evidenced by the detection of PRV DNA by polymerase chain reaction (PCR) assay of their trigeminal ganglia (TG). There was a significant inverse relationship observed for age at challenge and the proportion of PCR positive pigs in the group 15 weeks postchallenge (p = 0.0004). This trend was independent of the passively acquired PRV SN antibody titers at challenge. In this study, passively acquired antibody did not provide protection against establishment of latent infection in piglets after exposure to low doses of virulent PRV. These latent infections were detected serologically by only one of two available differential diagnostic ELISA.     

Different patterns of neuronal infection after intracerebral injection of two strains of pseudorabies virus

Pseudorabies virus (PRV), a swine neurotropic alphaherpesvirus, is known to invade the central nervous system (CNS) of a variety of animal species through peripherally projecting axons, replicate in the parent neurons, and then pass transsynaptically to infect other neurons of a circuit. Studies of the human pathogen herpes simplex virus type 1 have reported differences in the direction of transport of two strains of this virus after direct injection into the primate motor cortex. In the present study we examined the direction of transport of virulent and attenuated strains of PRV, utilizing injections into the rat prefrontal cortex to evaluate specific movement of virus through CNS circuitry. The data demonstrate strain-dependent patterns of infection consistent with bidirectional (anterograde and retrograde) transport of virulent virus and unidirectional (retrograde) transport of attenuated PRV from the site of injection. The distribution of infected neurons and the extent of transsynaptic passage also suggest that a release defect in the attenuated strain reduces the apparent rate of viral transport through neuronal circuitry. Finally, injection of different concentrations of virus influenced the onset of replication within a neural circuit. Taken together, these data suggest that viral envelope glycoproteins and virus concentration at the site of injection are important determinants of the rate and direction of viral transport through a multisynaptic circuit in the CNS.     

Experimental infection of chimpanzees with hepatitis C virus of genotype 5a: genetic analysis of the virus and generation of a standardized challenge pool

Six major genotypes (genotypes 1-6) of hepatitis C virus (HCV) have been identified. These genetic variants are being transmitted to chimpanzees, the only recognized animal model for the study of HCV. Genotype 5a (strain SA13), a variant found primarily in South Africa, has been transmitted to chimpanzees for the first time. Experimental infection of 2 chimpanzees was characterized by early appearance of viremia and peak virus titers of 10(5)-10(6) genome equivalents/mL. The HCV infection was resolved by week 15 after inoculation in 1 chimpanzee and persisted in the other. Both chimpanzees became anti-HCV-positive by week 14 after inoculation. Both chimpanzees developed viral hepatitis. The infectivity titer of a genotype 5a challenge pool prepared from the first passage of HCV in a chimpanzee was approximately 10(4) infectious doses/mL. Finally, sequence analysis of strain SA13 confirmed that genotype 5a is genetically distinct from other genotypes of HCV.     

Infectivity of a pseudorabies virus mutant lacking attachment glycoproteins C and D

Initiation of herpesvirus infection requires attachment of virions to the host cell followed by fusion of virion envelope and cellular cytoplasmic membrane during penetration. In several alphaherpesviruses, glycoprotein C (gC) is the primary attachment protein, interacting with cell-surface heparan sulfate proteoglycans. Secondary binding is mediated by gD, which, normally, is also required for penetration. Recently, we described the isolation of a gD-negative infectious pseudorabies virus (PrV) mutant, PrV gD- Pass (J. Schmidt, B. G. Klupp, A. Karger, and T. C. Mettenleiter, J. Virol. 71:17-24, 1997). In PrV gD- Pass, attachment and penetration occur in the absence of gD. To assess the importance of specific attachment for infectivity of PrV gD- Pass, the gene encoding gC was deleted, resulting in mutant PrV gCD- Pass. Deletion of both known attachment proteins reduced specific infectivity compared to wild-type PrV by more than 10,000-fold. Surprisingly, the virus mutant still retained significant infectivity and could be propagated on normal noncomplementing cells, indicating the presence of another receptor-binding virion protein. Selection of bovine kidney (MDBK) cells resistant to infection by PrV gCD- Pass resulted in the isolation of a cell clone, designated NB, which was susceptible to infection by wild-type PrV but refractory to infection by either PrV gCD- Pass or PrV gD- Pass, a defect which could partially be overcome by polyethylene glycol (PEG)-induced membrane fusion. However, even after PEG-induced infection plaque formation of PrV gCD- Pass or PrV gD- Pass did not ensue in NB cells. Also, phenotypic gD complementation of PrV gCD- Pass or PrV gD- Pass rescued the defect in infection of NB cells but did not restore plaque formation. Glycosaminoglycan analyses of MDBK and NB cells yielded identical results, and NB cells were normally susceptible to infection by other alphaherpesviruses as well as vesicular stomatitis virus. Infectious center assays after PEG-induced infection of NB cells with PrV gD- Pass on MDBK cells indicated efficient exit of virions from infected NB cells. Together, our data suggest the presence of another receptor and receptor-binding virion protein which can mediate PrV entry and cell-to-cell spread in MDBK cells.     

Inadvertent administration of DTP and DT after age six as recorded in the Vaccine Adverse Event Reporting System

OBJECTIVE: Diphtheria and tetanus toxoids and whole-cell pertussis vaccine (DTP) and pediatric diphtheria and tetanus toxoids (DT) are not recommended for individuals > or = 7 years of age due to increased adverse reactions and the low pertussis case-fatality rate. Our objective was to determine if reactions to DTP and DT in individuals > or = 7 years of age were due to administration of pediatric DTP or DT instead of adult tetanus and diphtheria toxoids (Td), after adjusting for database inaccuracies. METHODS: We analyzed data from the Vaccine Adverse Event Reporting System (VAERS) reported from July 1, 1990 through March 31, 1992. Vaccine manufacturers were contacted to verify whether lot numbers indicated DTP or DT. RESULTS: According to VAERS's data, among individuals 7 years of age or older, 26 received DTP and 77 received DT. When lot numbers were compared with manufacturers' records, 8 of the 77 DT doses were confirmed; 11 had incorrect or missing lot numbers; one was a duplicate; 56 were Td; and one was neither DT nor Td. Alleged adverse reactions included fever, headache, and convulsions. CONCLUSION: Individuals > or = 7 years of age are inadvertently receiving DTP or DT and may be unnecessarily experiencing adverse reactions. The 1992 VAERS database offers opportunities to investigate hypotheses but should be interpreted with caution due to inaccuracies in reporting and duplicate entries.     

Direct isolation and identification of recombinant pseudorabies virus strains from tissues of experimentally co-infected swine

Tissue homogenates were obtained from swine co-infected with 2 vaccine strains of pseudorabies virus (PRV). Viral isolates derived by serial plaque purification directly from tissue homogenates, without an intervening step of isolation and amplification on cell cultures, were characterized as recombinant and parental PRV genotypes on the basis of thymidine kinase and glycoprotein X gene combinations. Use of limiting dilutions and recovery of virus isolates as individual plaques minimized the likelihood of in vitro recombination serving as a confounding source of recombinant PRV. The thymidine kinase and glycoprotein X gene sequences were classified as wild-type or deleted, using a battery of polymerase chain reaction assays. Results substantiate the observation that PRV vaccine strains can form genetic recombinants in vivo after experimentally induced co-infection.     

CNS innervation of the urinary bladder demonstrated by immunohistochemical study for c-fos and pseudorabies virus

The aim of the present study is to verify the functional and anatomical neural pathways which innervate the urinary bladder in the central nervous system of the rat. To identify the functional neural pathway, the urinary bladder was stimulated by infusing formalin for 2 h. Then, brain and spinal cord were dissected out and immunohistochemistry was done by using anti-c-fos antibody. Many c-fos immunoreactive (IR) neurons were identified in the telencephalic cortical areas and in several brainstem nuclei, which are known mostly to be related with urinary bladder. In the spinal cord, a number of c-fos IR neurons were found in the lamina I, IIo, dorsal gray commissure, sacral parasympathetic nucleus. To identify the anatomical neural pathway of the urinary bladder, Pseudorabies virus (PRV) was injected into the wall of urinary bladder and was identified with anti-PRV by using immunohistochemistry. Most PRV labeled neurons were found where c-fos IR neurons were identified and few of them were also in the areas where c-fos IR neurons were not found, e.g., prefrontal cortex, agranular insular cortex, and subfornical organ. In the spinal cord, PRV labeled cells were found all over the gray matter. The present study presents morphological evidence demonstrating the supraspinal areas are related with the neural control of the urinary bladder and most functional neural pathway of the urinary bladder is well consistent with the anatomical neural pathway except in some telencephalic cortical areas.     

Pretreatment virus load and multiple amino acid substitutions in the interferon sensitivity-determining region predict the outcome of interferon treatment in patients with chronic genotype 1b hepatitis C virus infection

Behavioral relevance of norepinephrine is associated with neuronal processing underlying arousal, affect, attention, learning and memory, and is associated with beta-adrenergic modifications of neuronal activation in the hippocampal formation. This study utilized l-isoproterenol to initiate pathway-specific activation of afferents to hippocampal CA1 pyramidal cells. The consistent effects of l-isoproterenol on the initiation of action potentials to field CA1 pyramidal neurons to single-pulse stimulation was repeatedly associated with the activation of the Schaffer collateral pathway. In contrast, l-isoproterenol plus single-pulse stimulation never elicited action potential initiation of the perforant pathway to CA1. We interpret these results as indicating that beta-adrenergic modification underlies the augmentation of information processing via the Schaffer collateral pathway in the trisynaptic circuit vs the direct perforant pathway.     

Geographic distribution and genetic variability of hepatitis delta virus genotype I

OBJECTIVES: We sought to determine the prevalence, intensity and evolving changes of myocardial damage detected by myocardial uptake of antimyosin antibodies in patients with alcohol-induced dilated cardiomyopathy, alcohol addicts attending a detoxification unit and healthy subjects with short-term alcohol consumption. BACKGROUND: Evidence of alcohol-induced myocardial damage may be provided by myocardial uptake of indium-111-labeled monoclonal antimyosin antibodies. The spectrum of such damage in patients who are heavy drinkers (> 100 g for > 10 years), with or without cardiomyopathy, and the impact of short-term alcohol ingestion on antimyosin antibody uptake have not been adequately explored. METHODS: One hundred twenty antimyosin studies were performed in 56 patients with dilated cardiomyopathy (group I), 15 alcohol addicts attending a detoxification unit (group II) and 6 volunteers for short-term alcohol ingestion (group III). Estimation of antibody uptake was calculated through a heart/lung ratio (HLR) (normal < 1.55). RESULTS: The 56 patients in group I (54 men, 2 women; mean [+/-SD] age 46 +/- 11 years) had consumed 123 +/- 60 g/day of alcohol for 21 +/- 9 years, for a cumulative intake of 914 +/- 478 kg. Mean duration of symptoms was 46 +/- 49 months. Mean left ventricular end-diastolic diameter was 71 +/- 10 mm, and mean ejection fraction was 28 +/- 12%. No differences in New York Heart Association functional class, ventricular size or ejection fraction were noted between 28 active and 28 past consumers, except for the prevalence and intensity of antibody uptake (75% vs. 32%, p < 0.001) and HLR (1.75 +/- 0.26 vs. 1.49 +/- 0.17, p = 0.0001). In 19 patients in the active group restudied after alcohol withdrawal, antibody uptake decreased (from 1.76 +/- 0.17 to 1.55 +/- 0.19, p < 0.001), and ejection fraction improved (from 30 +/- 12% to 43 +/- 16%, (p < 0.001). No changes occurred in the 15 past consumers restudied. The 15 male patients in group II (mean age 36 +/- 4 years) had consumed 156 +/- 59 g/day for 17 +/- 5 years, for a cumulative alcohol intake of 978 +/- 537 kg, an amount similar to that in patients in group I, but antimyosin antibody uptake was detected in only 3 (20%) of 15 patients. None of six group III subjects developed antibody uptake after short-term ethanol ingestion. Despite the small sample size, the power to detect clinically relevant differences in most variables that did not reach statistical significance was amply sufficient. CONCLUSIONS: In alcohol-induced dilated cardiomyopathy, alcohol withdrawal is associated with the reduction or disappearance of myocardial damage and improvement of function. The difference in prevalence of antimyosin antibody uptake in patients with and without cardiac disease who consume similar amounts of alcohol suggests the presence of those with different myocardial susceptibilities to alcohol. Short-term ethanol ingestion in healthy subjects does not induce detectable uptake of antimyosin antibodies.     

Estradiol's effects on learning and neuronal morphology vary with route of administration.

Estrogen's effects on performance and neuronal morphology are variable, and the reasons for this variability are not yet understood. In this study, the authors compared the effects of 2 delivery routes of 17 β-estradiol on spatial learning and dendritic spine densities in young ovariectomized rats; estradiol was administered by implanted capsules or by daily oral gavage. Estradiol treatment via capsules improved performance in the radial-arm water maze and increased spine densities on dendrites of CA1 pyramidal neurons in the hippocampal formation. In contrast, daily oral administration of estradiol did not affect either measure. These data demonstrate that estradiol delivery is a critical variable in animal studies and that clinical studies comparing the effects of different estradiol treatment routes on cognition are warranted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of Freund's adjuvant and TiterMax in inducing anti-idiotype to idiotypic antibodies against pseudorabies virus antigens

Freund's adjuvant (FA) and TiterMax (TM) were compared for their effectiveness in the induction of the anti-idiotypic antibodies (anti-Id or Ab2) in pigs, goats and mice against swine polyclonal anti-pseudorabies virus (PRV) antibodies (Ab1) by sequential immunization procedures. Both adjuvants had similar effects on inducing anti-swine immunoglobulin antibodies in the animals. However, high levels of the anti-Id were only generated in animals that received FA. Serological characterization of the anti-Id antisera indicated that internal image anti-Id (Ab2 beta) was generated that recognized shared idiotype (IdX) on the antibodies to PRV. The internal image Ab2 was capable of blocking the anti-PRV antibodies from binding to the PRV antigens, and their interaction with anti-PRV antibodies could be inhibited by PRV antigens.     

Subcellular site of expression and route of vaccination influence pulmonary eosinophilia following respiratory syncytial virus challenge in BALB/c mice sensitized to the attachment G protein

The attachment glycoprotein (G) of respiratory syncytial virus (RSV) is synthesized as two mature forms: a membrane-anchored form and a smaller secreted form. Mutant cDNAs were constructed that encoded one or the other form of the protein and were expressed in recombinant vaccinia viruses (rVV). Mice were immunized with rVV by dermal scarification or i.p. injection to determine the contribution of the membrane-anchored and secreted forms of the G protein on the augmentation of pulmonary pathology seen following RSV challenge. Mice scarified with rVV expressing the membrane-anchored G protein had a markedly reduced pulmonary eosinophilic response following RSV challenge compared with mice scarified with rVV expressing either wild-type or secreted G protein. The induction of pulmonary eosinophilia in rVV-primed mice was also dependent upon the route of vaccination. An eosinophilic response was not observed in any groups of mice immunized i.p. with rVV expressing any of the different forms of the G protein. The difference in pulmonary pathology observed between dermal scarification or i.p. vaccinated mice was not reflected in a difference in cytokine production by splenocytes from vaccinated and challenged mice restimulated with RSV in vitro. Both groups produced significant levels of IL-4 and IL-5. These data suggest that the local APCs and lymphoid environment, together with the form of the G protein, influence pulmonary pathology following RSV challenge.     

Plasma pentobarbitone levels. Influence of the preparation, route and method of administration

In fit women plasma pentobarbitone was measured by gas-liquid chromatography after 100 mg given by mouth or intramuscular injection in the buttock using aqueous and organic solutions. Differences in plasma levels with the two solutions were not striking. Considerable inter-administrator difference occurred with significantly higher plasma levels when the drug was injected by a doctor using a 4 cm 21 s.w.g. needle as compared with nurses who used no specified injection technique. The oral route gave significantly higher plasma levels than nurse-given injections.