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At least 1,351 records · Page 75Linked to original sources
PubMed1995

Characterization of the mode of Hantaan virus infection in adult mice using a nested reverse transcriptase polymerase chain reaction: transient virus replication in adult mice.

A polymerase chain reaction (PCR) for the detection of hantavirus genome was established and applied to analyze the mode of infection of Hantaan virus in adult ICR mice. The cDNA for the S genome segment of Hantaan virus was reverse-transcribed from the total RNA of organs of the infected mice. The sequence in the S genome segment of Hantaan virus was successfully amplified by reverse transcriptase (RT)-PCR followed by nested PCR. In 5-week-old ICR mice inoculated intraperitoneally with Hantaan virus, strain 76-118 (1.3 x 10(5) FFU/mouse), the virus was detected in clots and lungs from 3 to 10 days post-inoculation (p.i.) by nested PCR and virus-isolation techniques. No virus was detected in any specimens collected on 1 day and after 28 days p.i., and in spleens and brains through the observation period by both methods. The antibody which was measured by indirect immunofluorescence antibody assay (IFA) appeared at 7 days p.i. and the geometric mean titer was elevated to its maximum level of 1:203 at 10 days p.i., maintaining the same level until 35 days p.i. These results suggest that adult mice are transiently infected with Hantaan virus.

Animals↗
PubMed1979

[Effect of 5-iodo-2-deoxyuridine (IDU) on Newcastle disease virus replication in cell cultures].

In chick embryo fibroblasts and in mouse fibroblasts of established L line, grown in the presence of IDU, the multiplication of Newcastle Disease virus was better and the CPE more distinct than in control cell cultures. In calf kidney cells only the CPE was enhanced. The most pronounced influence of IDU on virus multiplication was found after adding the analogue in maximum tolerated dose to the medium at the moment of cell culture preparation. The growth curve of virus in chick embryo fibroblasts grown in the presence of IDU shows the most distinct influence of this analogue with regard to LaSota strain. Already two days after inoculation with a smaller dose the titer was 2 log higher than in control cultures and the maximum difference of 3 log was found on the 5th day. In reference to Roakin strain the influence of IDU was weaker--maximum difference of 1,2 log on the fifth day after inoculation. Also the difference between the titers of virus in L cells grown in the presence of IDU and in the control ones, inoculated with LaSota strain was greater (about 1,5 lg during 2-8 days) than in the case of Roakin strain. In chick embryos treated with IDU intraallantoically at 24 and 48 hours before the inoculation with LaSota strain (only this was used) the enhancement of virus multiplication was much poorer than in chick embryo fibroblasts.

Animals↗
PubMed1998

A comparison between permissive and restricted infections with Aleutian mink disease parvovirus (ADV): characterization of the viral protein composition at nuclear sites of virus replication.

We used three-color fluorescent labeling and confocal microscopy to compare the permissive and the antibody-mediated, restricted replication of Aleutian mink disease parvovirus (ADV). In both permissive (CRFK cells) and restricted (K562 cells) situations, both ADV non-structural proteins (NS1 and NS2) concentrated at focal sites in the nucleus, which also contained viral DNA. Bromodeoxyuridine labeling demonstrated that these sites also supported active ADV single-strand DNA synthesis, indicating that they were replication compartments. ADV capsid proteins were located in intranuclear shells surrounding the replication compartments. At later time points, NS2 was readily detected in the cytoplasm of permissively infected CRFK cells, whereas the cytoplasmic presence of NS2 was much less pronounced in the K562 cells. These results showed that both permissive and restricted ADV replication are associated with a tight nuclear subcompartmentalization of viral products. Furthermore, differences between the permissive and restricted virus-cell interactions were noted, suggesting that there may be a morphological basis for examining the outcome of ADV infection.

Aleutian Mink Disease Virus↗
PubMedDate not supplied

[Differential ultrastructural elements in human cytomegalovirus and Herpes simplex virus replication in cultures of human cells].

Differential ultrastructural features in the replicative cycle between a strain of human cytomegalovirus (CMV) and two strains (types 1 and 2) of herpes simplex virus (HSV) have been studied by electron microscopy. Either on the same or different host cell system four differential aspects have been constantly observed: a) presence in CMV infected cells of a large nuclear inclusion, lacking in HSV infected cells; b) envelopment of CMV capsids by microvescicular systems near the nuclear membrane, whereas HSV (types 1 and 2) takes envelope from the inner lamina of the nuclear membrane; c) presence in the cytoplasm of CMV infected cells of homogeneous dense material and dense microbodies, lacking in HSV infected cells; d) in extracellular space homogenous dense microbodies are present only in CMV infected cell cultures. Diagnostic usefulness of the above reported ultrastructural differences and their meaning on the basis of most recent data of the literature are discussed, with special concern to envelopment of two viruses and to the nature of homogeneous dense material observed in CMV infected cells.

Capsid↗
PubMed1988

Different levels of hepatitis B virus replication among hepatitis Be antigen-positive chronic carriers.

Detection of hepatitis B virus DNA polymerase (HBV DNA-pol) activity and of HBV DNA sequences in serum allowed to distinguish the different degrees of HBV replication in chronic HBsAg carriers. The amount of HBV DNA in the serum of 48 HBsAg and HBeAg positive patients in relation with the presence or absence of HBV DNA-pol was determined by dot-blot hybridization. The HBeAg positive cases with HBV DNA-pol activity had significantly higher HBV DNA levels than those which were DNA-pol negative (p less than 0.001). However, no significant differences with respect to liver function tests (transaminase, albumin, gammaglobulin) or to the histological diagnosis were found between both groups. Quantitative detection of serum HBV DNA in HBsAg chronic carriers may be helpful for learning the natural history of HBV infection and monitoring the antiviral therapy.

Carrier State↗
PubMed2004

Inhibition of infectious pancreatic necrosis virus replication by atlantic salmon Mx1 protein.

Mx proteins form a family of interferon (IFN)-induced GTPases with potent antiviral activity against various single-stranded RNA viruses in mammals and chickens. In fish, alpha/beta IFN has been reported to inhibit the replication of infectious pancreatic necrosis virus (IPNV), but the mode of action has not been elucidated. A correlation between the inhibition of IPNV and Mx protein expression has, however, been observed. To examine whether Atlantic salmon Mx1 protein (ASMx1) possesses antiviral activity against IPNV, CHSE-214 cells constitutively expressing ASMx1 were established. ASMx1 appeared to be localized in the cytoplasm. The ASMx1-expressing clone selected showed a severely reduced IPNV-induced cytopathic effect, which was confirmed by a 500-fold reduction in virus yield. The antiviral activity against IPNV was further confirmed by the inhibition of virus protein synthesis and the reduced accumulation of virus transcripts. The present work further adds to the body of evidence which suggests that antiviral activity is a major functional role of vertebrate Mx proteins. Moreover, the list of viruses inhibited by Mx proteins is extended to include double-stranded RNA viruses.

Animals↗
PubMed1995

Epstein-Barr virus replication studies and their application to vector design.

Vectors containing elements of the Epstein-Barr virus genome are used primarily to maintain cloned DNA inserts as plasmids in mammalian cells. However, Epstein-Bar-virus-based vectors have also been valuable tools in the hands of those studying the life cycle of Epstein-Barr virus. In this article, we discuss those characteristics of Epstein-Barr virus and its life cycle that have been used in vector construction and describe methods that are particularly applicable to the use of Epstein-Barr-virus-based vectors.

DNA Replication↗
PubMed1999

Inhibition of human immunodeficiency virus replication and growth advantage of CD4+ T cells and monocytes derived from CD34+ cells transduced with an intracellular antibody directed against human immunodeficiency virus type 1 Tat.

Current clinical gene therapy protocols for the treatment of human immunodeficiency virus type 1 (HIV-1) infection involve the ex vivo transduction and expansion of CD4+ T cells derived from HIV-positive patients at a late stage in their disease (CD4+ cell count <400 cells/mm3). We examined the efficiency of transduction and transgene expression in adult bone marrow (BM)- and umbilical cord blood (UCB)-derived CD34+ cells induced to differentiate into T cells and monocytes in vitro with an MuLV-based vector encoding the neomycin resistance gene and an intracellular antibody directed against the Tat protein of HIV-1 (sFvtat1-Ckappa). The expression of the marker gene and the effects of antiviral construct on subsequent challenge with monocytotropic and T cell-tropic HIV-1 isolates were monitored in vitro in purified T cells and monocytes generated in culture from the transduced CD34+ cells. Transduction efficiencies of CD34+ cells ranged between 22 and 27%. Differentiation of CD34+ cells into T cells or monocytes was not significantly altered by the transduction process. HIV-1 replication in monocytes and CD4+ T cells derived from CD34+ cells transduced with the intracellular antibody gene was significantly reduced in comparison with the degree of HIV replication seen in monocytes and CD4+ T cells derived from CD34+ cells transduced with the neomycin resistance gene alone. Further, T cells and monocytes derived from CD34+ cells transduced with the intracellular antibody gene were demonstrated to express the sFvtat1-Ckappa transgene by RT-PCR and had a selective growth advantage in cultures that had been challenged with HIV-1. These data demonstrate that sFvtat1-Ckappa inhibits HIV-1 replication in T cells and monocytes developing from CD34+ cells and supports the continuing development of a stem cell gene therapy for the treatment of HIV-1 infection.

Adult↗