Biomedical subjects

C S Goldsmith

Publications and source records attributed to C S Goldsmith.

28 records · Page 2Linked to original sources

PubMed1992

Further analyses of the orthopoxviruses volepox virus and raccoon poxvirus.

Volepox virus (VPX) from skin lesions on a vole and a piñon mouse caught in California and raccoon poxvirus (RCN) from raccoons trapped in Maryland were examined to begin elucidating their relationship to other orthopoxviruses, most of which are not known to be indigenous to the Americas. VPX and RCN produced pinpoint, nonhemorrhagic pocks on chick embryo chorioallantoic membranes. In cell cultures both viruses produced 1-mm diameter, irregular plaques, A-type inclusions (ATIs), and despite production of hemagglutinin, both viruses caused syncytia formation. Considerable cross-hybridization was seen between VPX and RCN DNA and the DNAs of other orthopoxviruses; however, HindIII cleavage site maps showed marked central and terminal region differences between VPX (222.8 kbp) and RCN (224.8 kbp) DNA and mapped DNAs of other orthopoxviruses. Cognate DNAs of the ATI 160-kDa protein and 38-kDa serine protease inhibitor homologue of cowpox virus (CPV) and the 14-kDa fusion protein of vaccinia virus (VAC) were present within the right end of VPX and RCN DNA, matching their location in CPV and VAC. VPX and RCN, respectively, expressed a 150- and a 155-kDa ATI major protein and a 20- and an 18-kDa fusion protein. Low stringency annealing suggested that cognate DNAs for the VAC growth factor and the alpha-amanitin target protein were present within the left end of VPX and RCN DNA, matching their location in VAC. Terminal tandem repeat sequences of VAC and RCN did not cross-hybridize with each other or with VPX DNA end fragments. Together, the data suggested that VPX and RCN are phylogenetically rather distant from orthopoxviruses not indigenous to the Americas, although genetic information is arranged as in other examined orthopoxviruses.

Animals↗

PubMed1992

Pathogenic potential of filoviruses: role of geographic origin of primate host and virus strain.

African filoviruses have caused outbreaks of fulminating hemorrhagic fever among humans. In 1989, related filoviruses were isolated from cynomolgus monkeys imported into the United States from the Philippines. The pathogenic potential of these new filoviruses was compared in 16 Asian monkeys (Macaca fascicularis-cynomolgus) and 16 African monkeys (Cercopithecus aethiops-African green) using African filoviruses from Zaire (Ebola virus) and Sudan or Asian filoviruses (Reston and Pennsylvania). African filovirus infections resulted in earlier death (P = .005), had a shorter duration of disease and median incubation period (3-4 vs. 7 days), and had earlier peak viremia (5-7 vs. 7-9 days). African green monkeys showed significantly higher survival than cynomolgus monkeys (P less than .01), and some were asymptomatic as have been humans accidentally infected with Asian filovirus. Rechallenge experiments showed that protection in survivors of filovirus infections against fatal challenge with Ebola (Zaire) virus is unpredictable. The minimal clinical disease observed in humans infected with the Reston strain is consistent with host- and virus-dependent pathogenicity.

Africa↗

PubMed1991

Cytokine enhancement of simian immunodeficiency virus (SIV/mac) from a chronically infected cloned T-cell line (HuT-78).

Simian immunodeficiency viruses (SIV) are a family of primate lentiviruses similar to human immunodeficiency viruses (HIV) in their genetic sequence and pathogenesis. However, host-derived cofactors which may determine the extent of viral replication are not clearly defined for SIV or HIV infections. A HuT-78 cell line chronically infected with SIV/mac strain 251, was biologically cloned and characterized for the ability to produce infectious viral particles, viral structural protein profile, cellular antigen surface phenotype and tested to determine the effects of recombinant cytokines on SIV replication. Reverse transcriptase (RT) assay was used to measure the replication of SIV/mac in response to various concentrations of recombinant cytokines (1-1000 units/ml). We report that tumor necrosis factor-alpha (rTNF-alpha), gamma-interferon (rIFN-gamma), interleukin 2 (rIL-2), and granulocyte-macrophage colony stimulating factor (rGM-CSF) induced approximately a 2 to 3 fold increase in virus RT activity compared with untreated SIV-infected HuT-78 cells. In contrast, viral replication was not enhanced or minimally enhanced by interleukin 1 (rIL-1), interleukin 3 (rIL-3), or interleukin 4 (rIL-4) at similar dosages. Furthermore, SIV replication in response to rTNF-alpha and rIFN-gamma occurred in a dose dependent fashion. These data suggest that SIV-infected T-lymphocyte lines are responsive to particular cytokines resulting in increased virus production.

Cell Line↗

PubMed1991

Simultaneous expression of the Lassa virus N and GPC genes from a single recombinant vaccinia virus.

A new transfer vector was constructed that directs the insertion of two heterologous genes into the vaccinia virus thymidine kinase (TK) gene during a single recombination event. This vector, pDAVAC2, contains bidirectional vaccinia P7.5 early/late promoter elements and two unique cloning sites. cDNA clones containing the complete coding sequences for the Lassa virus (Josiah strain) nucleoprotein (N) and glycoprotein (GPC) genes were inserted into the vaccinia TK gene using this transfer vector. The recombinant virus, V-LSGN-II, expressed proteins in cell culture that appeared to be authentic with respect to electrophoretic mobility, glycosylation, and post-translational cleavage. Indirect immunofluorescence (IFA) of recombinant virus-infected cells demonstrated both the bright granular and diffuse patterns of staining characteristic of the Lassa nucleoprotein and glycoprotein, respectively. Electron-dense inclusion bodies typical of arenavirus-infected cells were observed by electron microscopy in V-LSN and V-LSGN-II-infected cells, but not in V-LSGPC-infected cells. Mice inoculated with V-LSGN-II by intraperitoneal injection developed serum antibodies that reacted with authentic Lassa proteins in immunofluorescence and radioimmune precipitation assays. This recombinant virus represents an additional candidate for a Lassa fever vaccine and demonstrates the feasibility of expressing any two genes of interest in a single recombinant vaccinia virus through the use of the transfer vector pDAVAC2.

Animals↗

PubMed1991

Isolation and characterization of an Ehrlichia sp. from a patient diagnosed with human ehrlichiosis.

A new disease was recognized in the United States in 1986. The etiologic agent, although not previously isolated from a human, appeared to be serologically related to Ehrlichia canis, a canine leukotropic rickettsia. We obtained blood specimens from 27 febrile patients with a history of tick exposure. Leukocytes from 24 patients not treated with tetracycline were placed onto a monolayer of DH82 cells. We performed indirect immunofluorescence on sera from all 27 febrile patients as well as sera from 12 patients with previously diagnosed ehrlichiosis. Intractoplasmic inclusions were first observed in culture 35 days after the addition of infected blood from one patient. Partial sequencing of the rRNAs from the human isolate and E. canis indicated that they are 98.7% related. Positive indirect immunofluorescence reactions to the human isolate were obtained for all 12 previously diagnosed patients and for 33% of the 27 febrile patients. Two patients were seropositive for the human isolate but not for E. canis. No sera were positive for E. canis and negative for the human isolate. We report the isolation of a previously unrecognized Ehrlichia sp. that appears to be the etiologic agent of human ehrlichiosis. Serologic data (range of antibody titers, 256 to 32,768) in combination with rRNA sequencing indicated that the newly isolated Ehrlichia sp. is similar, but not identical, to E. canis.

Adult↗

PubMed1989

Studies on Tanapox virus.

Virus characterization studies were performed to meliorate the taxonomic status of three currently unclassified, serologically related viruses: Tanapox virus (causes vesicular skin lesions in humans), Yaba-like disease (YLD) virus (causes vesicular skin lesions in monkeys), and Yaba monkey tumor virus (YMTV, causes epidermal histiocytoma). These studies included (1) microscopic observations of Tanapox virus cytopathic effect and morphogenesis during its 6-day cytolytic-type growth at 35 degrees in CV-1 monkey kidney cells; (2) resolution of Tanapox virion proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of nonenveloped and double-enveloped virus particles purified by velocity sedimentation in sucrose and CsCl density gradients; and (3) restriction endonuclease DNA comparison of the three viruses. DNA analysis showed that six recent Tanapox virus isolates from patients in Zaire, Africa, were identical to Tanapox virus, Kenya strain, from 1957 from a patient in the Tana River Valley. In addition, BamHI, MluI, and PstI cleavage sites mapped on the DNA of Kenya Tanapox virus, and PstI sites mapped on DNA of YLD virus differentiated YLD and Tanapox viruses as separate strains. On the other hand, YMTV shared few restriction endonuclease sites with Tanapox and YLD viruses, although all three cross-hybridized extensively. These studies along with published viral characteristics, support the formation of a new poxvirus genus: the suggested name is Yatapoxvirus, and the genus currently comprises two species, Tanapox virus and YMTV.

Cells, Cultured↗

PubMed1989

Growth properties of human herpesvirus-6 strain Z29.

Experiments performed to optimize the growth conditions of HHV-6(Z29) revealed that the virus grows best in phytohemagglutinin-stimulated umbilical cord blood lymphocytes (CBL) cultured in media containing 32 units/ml interleukin-2 and 0.01 mg/ml hydrocortisone. The titer of maternal antibody in the plasma of the cord blood cells does not affect the ability of the cells to support virus growth. DEAE-dextran and polybrene do not increase virus growth in umbilical cord blood lymphocytes. Phorbol myristate acetate abolishes virus growth. The HHV-6(Z29) growth cycle in CBL was approximately 5 days; capsids were not seen before day 3, and mature virions were not seen before day 5.

Cells, Cultured↗

PubMed1988

Ultrastructure of human retroviruses.

We compared the ultrastructure of the human retroviruses by thin-section electron microscopy of infected lymphocytes. Virus particles form at the plasma membrane without involvement of a cytoplasmic precursor. Budding forms of human T-cell leukemia virus types I and II (HTLV-I and -II) consist of a crescent-shaped nucleoid separated from the envelope by an intermediate layer. Mature forms of these viruses are about 100 nm in diameter. The nucleoid is electron lucent and almost completely fills the virion. There is about a 10-nm space between the envelope and nucleoid. The envelope has fuzzy surface projections. HTLV-I and -II resemble other type C retroviruses in morphology. Budding forms of human immunodeficiency virus (HIV, LAV, HTLV-III) also have a crescent-shaped nucleoid but not an intermediate layer between the core and envelope. The envelope has rod-shaped surface projections. Mature forms of HIV have an electron-dense nucleoid that is eccentric and bar- or cone-shaped. Particles have the same ultrastructure as retroviruses of the Lentivirus genus. HIV is readily distinguishable from HTLV-I and -II by thin-section electron microscopy. HIV is usually found in extracellular spaces by transmission electron microscopy of thin sections, and scanning electron microscopy of HIV-infected T4 lymphocytes also shows many particles on the surface of these cells. Lymphadenopathy-associated virus type II (LAV-II) has the same internal ultrastructure as HIV, but its surface projections are more prominent, being about three times the length of those of HIV. Human T lymphotropic virus type IV (HTLV-IV) has the same morphology as LAV-II.

Deltaretrovirus↗

PubMed1988

Studies on human immunodeficiency virus-induced cytopathic effects: use of human rhabdomyosarcoma (RD) cells.

A full-length molecular clone of human immunodeficiency virus (HIV) proviral DNA was transferred to human rhabdomyosarcoma (RD) cells by gene transfer method. RD cells released infectious virus within 12 hours after transfection and the viral particles present in the culture medium could be quantitated by monitoring reverse transcriptase activity. Chronic low level viral producer cell lines of RD were also established. Southern hybridization analysis revealed the presence of HIV sequences in transfected RD cells. Electron microscopic studies of the transfected cell revealed intracellular budding of HIV and also showed structural abnormalities such as giant cell phenotype and vacuolation. These features qualify RD cells as a useful system for studying the regulation and cytopathic effects of HIV.

Cytopathogenic Effect, Viral↗

PubMed1987

Rodent and primate monolayer cells support the expression and assembly of viral particles directed by human immunodeficiency virus (HIV) proviral DNA.

A molecular clone of human immunodeficiency virus (HIV) was transferred to rodent and primate monolayer cells by DNA transfection. Of the cell lines tested, all of them released viral particles as shown by reverse transcriptase assay and dot-blot hybridization. The viruses released from transfected cultures were able to establish infection of human T-cell line HUT 78. These results suggest that factors present in cells of non-lymphoid origin support the expression and assembly of HIV. Thus, transfection with cloned HIV DNA provides an approach to analyse the consequences of viral gene expression in cell types which lack a mechanism for efficient uptake of HIV particles.

Animals↗