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Biomedical subjects

R E Shope

Publications and source records attributed to R E Shope.

At least 55 records · Page 3Linked to original sources
PubMed1993

Evaluation of vero cell lysate antigen for the ELISA of flaviviruses.

The vero cell lysate antigen for the enzyme-linked immunosorbent assay (ELISA) of flaviviruses was evaluated for sensitivity, specificity including cross-reactions, and background by comparing with the standard ELISA. Human sera, in serial dilutions, were taken from subjects 14, 35, and 210 days postvaccination with 17D antigen. Early after injection, high sensitivity (82.9%) was shown by the cell lysate antigen method. Late after infection, high sensitivity was achieved by the standard method (96.2% and 94%), with significant difference (P = 0.0001). However, sensitivity achieved by the cell lysate antigen method was also acceptable (91.7% & 88.9%). The cell lysate antigen method showed high specificity and low cross reactivity early after infection. At 35 days postvaccination, no difference in specificity was observed between the two methods, but higher cross-reactions were observed for the standard method. This pattern continued at 210 days postvaccination, with significantly higher cross-reactions with the standard ELISA. The optical density differences by the two methods did not show significant relationship with the serial dilutions of human sera. No difference was observed in early and late infections in the background values of the negative control (Western equine encephalitis) between the two methods. The ELISA by the cell lysate antigen, within the limits of the experiments done, was found to be a good replacement for the ELISA by the standard method.

Animals↗
PubMed1993

A rapid diagnostic assay for eastern equine encephalomyelitis viral RNA.

Eastern equine encephalomyelitis virus (EEEV) has been a low-frequency, but serious human and veterinary health problem. Increased frequency of this mosquito-borne virus is anticipated as wetlands are maintained and re-established. Control of EEEV has depended on mosquito abatement in response to increasing frequency of EEEV in the environment. A coupled reverse transcription/polymerase chain reaction assay was designed to rapidly, sensitively, and specifically detect EEEV RNA. The assay successfully detected the viral RNA in a single-blind study of a set of field samples composed of either pooled mosquitoes or bird tissue. These results suggest that it would be practical to use this assay for deciding when and where to implement mosquito abatement.

Animals↗
PubMed1993

Prevalence of atretic corpora lutea in ovaries of bovine fetuses.

Both ovaries from 88 bovine fetuses in the fifth month or later of gestation were studied histologically to determine the prevalence, origin, and time of appearance of atretic corpora lutea (ACL). Ovaries from 36 (41%) fetuses had ACL; fetuses < 6 months of gestation did not have ACL. Six fetuses had more than 25 ACL, but there was no apparent relationship between fetal age and number of ACL. Formation of ACL involved disintegration of the stratum granulosum of secondary follicles, concomitant with proliferation and invasion by vascularized elements of the theca. Fully developed ACL consisted of a large primary oocyte surrounded by a prominent zona pellucida and encased in a well-vascularized, largely thecal, fibrocellular wall. They measured approximately 0.5 to 1.0 mm in diameter. Empty, collapsed zona pellucidas were seen in many of the degenerating ACL.

Animals↗
PubMed1992

Recombinant vaccinia virus producing the prM and E proteins of yellow fever virus protects mice from lethal yellow fever encephalitis.

Four recombinant vaccinia viruses were constructed for expression of different portions of the 17D yellow fever virus (YFV-17D) open reading frame. A recombinant, vP869, expressing prM and E induced high titers of neutralizing and hemagglutination inhibiting antibodies in mice and was protective against intracranial challenge with the French neurotropic strain of YFV. Levels of protection were equivalent to those achieved by immunization with the YFV-17D vaccine virus. Recombinant vaccinia viruses expressing E and NS1, C prM, E, NS1, or only NS1 failed to protect mice against challenge with YFV despite eliciting antibodies to NS1. The vP869-infected HeLa cells produced a particulate extracellular hemagglutinin (HA) similar to that produced by YFV-infected cells, supporting previous studies with Japanese encephalitis virus (Mason et al., 1991), suggesting that the ability of recombinant vaccinia virus to produce extracellular HA particles is important for effective flavivirus immunity.

Animals↗
PubMed1992

Mice immunized with a subviral particle containing the Japanese encephalitis virus prM/M and E proteins are protected from lethal JEV infection.

Extracellular subviral particles produced by HeLa cells infected with a recombinant vaccinia virus encoding the prM and E genes of Japanese encephalitis virus (JEV) were purified and characterized. These particles contained the JEV prM/M and E proteins embedded in a lipid bilayer, and RNA was not detected in particles using the polymerase chain reaction and primers recognizing a part of the JEV E gene. The particles were uniformly spherical with a 20-nm diameter and had 5-nm projections on their surface. Mice that received a single inoculation of the purified extracellular particles emulsified with Freund's complete adjuvant were fully protected against 4.9 x 10(5) LD50 of JEV. Comparison of the neutralizing and hemagglutination-inhibiting antibody titers and radioimmunoprecipitation data showed that immunization with the particles induced an immune response similar to that following inoculation with the recombinant vaccinia virus.

Animals↗
PubMed1992

A highly attenuated host range-restricted vaccinia virus strain, NYVAC, encoding the prM, E, and NS1 genes of Japanese encephalitis virus prevents JEV viremia in swine.

A highly attenuated strain of vaccinia virus (NYVAC) was engineered to express the Japanese encephalitis virus (JEV) prM, E, and NS1 genes or the prM and E genes. The recombinant viruses were tested as vaccine candidates in pigs, a natural host of JEV. JEV-neutralizing and hemagglutination-inhibiting antibodies appeared in swine sera 7 days after immunization with 10(8) PFU of the recombinant viruses and increased after a second dose at 28 days. The JEV levels detected in the serum after JEV challenge (d56) of the swine with 2 x 10(5) PFU of JEV were significantly reduced in animals inoculated with the recombinant viruses. These results demonstrate the ability of these NYVAC-vectored recombinants to protect pigs from JEV viremia.

Animals↗
PubMed1992

Use of the polymerase chain reaction for the sensitive detection of St. Louis encephalitis viral RNA.

Polymerase chain reaction (PCR) assays were developed for the detection of RNA from the St. Louis encephalitis (SLE) virus. Using computer-assisted analysis of the MSI-7 strain SLE virus genome, two primer pairs were selected from the capsid-coding and the membrane associated protein-coding genes, and one from the envelope-coding gene. Reverse transcription was primed with either specific oligomers or with random hexamers; these methods were compared for cDNA synthesis and subsequent PCR amplification with the oligomeric pairs. Random hexamers provided more sensitive detection of viral RNA. Each primer pair specifically amplified the expected sized fragment from the Parton SLE strain grown in Aedes albopictus cells, but did not amplify Aedes albopictus cell RNA controls. The technique also detected SLE virus RNA in 1 pg of total cellular RNA added to a background of 1 microgram boiled brain tissue, and in 0.5 pg of total RNA added to homogenized mosquito abdomen. PCR-based assays may be adaptable to detect SLE virus RNA in naturally infected mosquitoes, birds, and human cerebrospinal fluid and brain.

Animals↗
PubMed1991

Venezuelan haemorrhagic fever.

An outbreak of severe haemorrhagic illness began in the municipality of Guanarito, Portuguesa State, Venezuela, in September, 1989. Subsequent detailed study of 15 cases confirmed the presence of a new viral disease, designated Venezuelan haemorrhagic fever. Characteristic features are fever, toxicity, headache, arthralgia, diarrhoea, conjunctivitis, pharyngitis, leucopenia, thrombocytopenia, and haemorrhagic manifestations. Other features include facial oedema, cervical lymphadenopathy, nausea/vomiting, cough, chest or abdominal pain, and convulsions. The patients ranged in age from 6 to 54 years; all were residents of rural areas in central Venezuela, and 9 died. Infection with Guanarito virus, a newly recognised arenavirus, was shown by direct culture or by serological confirmation in all cases. Epidemiological studies suggest that the disease is endemic in some rural areas of central Venezuela and that it is rodent-borne. Venezuelan haemorrhagic fever has many similarities to Lassa fever and to the arenavirus haemorrhagic fevers that occur in Argentina and Bolivia.

Acute Disease↗
PubMed1991

Japanese encephalitis virus-vaccinia recombinants produce particulate forms of the structural membrane proteins and induce high levels of protection against lethal JEV infection.

Four recombinant vaccinia viruses were engineered for expression of different portions of the Japanese encephalitis virus (JEV) open reading frame. All four recombinant vaccinias contained the NS1 and NS2A genes, and each of these viruses specified the synthesis, glycosylation, and secretion of the nonstructural glycoprotein (NS1). All four recombinants also contained the E gene, and each virus correctly directed the synthesis and glycosylation of the envelope glycoprotein (E). Interestingly, two of these viruses (vP555 and vP650), which expressed the prM gene in addition to E and NS1, produced an extracellular hemagglutinin containing M and E that migrated in sucrose gradients similarly to the slowly-sedimenting hemagglutinin found in the culture fluid of JEV-infected cells. Immunization of 3-week-old mice with the recombinant viruses vP555 and vP658 resulted in immune responses to NS1, whereas only the virus that directed the synthesis of extracellular forms of E (vP555) induced an immune response to E. Both viruses provided protection against lethal challenge with JEV. Animals given two inoculations with vP555 were fully protected from greater than 10,000 LD50 of JEV. This high level of protection was correlated with the production of high titers of neutralizing and hemagglutination-inhibiting antibodies.

Animals↗
PubMed1991

Comparison of protective immunity elicited by recombinant vaccinia viruses that synthesize E or NS1 of Japanese encephalitis virus.

Immunization with recombinant vaccinia viruses that specified the synthesis of Japanese encephalitis virus (JEV) glycoproteins protected mice from a lethal intraperitoneal challenge with JEV. Recombinants which coexpressed the genes for the structural glycoproteins, prM and E, elicited high levels of neutralizing (NEUT) and hemagglutination inhibiting (HAI) antibodies in mice and protected mice from a lethal challenge by JEV. Recombinants expressing only the gene for the nonstructural glycoprotein, NS1, induced antibodies to NS1 but provided low levels of protection from a similar challenge dose of JEV. Antibodies to the NS3 protein in postchallenge sera, representing the degree of infection with challenge virus, were inversely correlated to NEUT and HAI titers and levels of protection. These results indicate that although vaccinia recombinants expressing NS1 can provide some protection from lethal JEV infection, recombinants expressing prM and E elicited higher levels of protective immunity.

Animals↗
PubMed1991

Detection of alphaviruses in a genus-specific antigen capture enzyme immunoassay using monoclonal antibodies.

A genus-specific antigen capture assay using similar combinations of monoclonal antibodies for capture and detection of 24 alphaviruses belonging to the seven serocomplexes was developed. The sensitivity of the test ranged from 10(3.4) 50% tissue culture infective doses/ml for o'nyong-nyong virus to 10(6.1) 50% tissue culture infective doses/ml for Middelburg virus. The antigen capture test uses a combination of cross-reacting monoclonal antibodies directed against the nucleocapsid protein and envelope glycoprotein E1 of Semliki Forest virus.

Aedes↗
PubMed1991

Flavivirus type-specific antigens produced from fusions of a portion of the E protein gene with the Escherichia coli trpE gene.

Based on previous data showing that JEV and DEN-1 fusion proteins can be used as antigens, we engineered analogous fusion proteins for the same regions of the E proteins of DEN-2, DEN-3, and DEN-4, using the polymerase chain reaction. The resulting fusion proteins were tested in a modified ELISA for their reactivity with mouse immune ascitic fluids (MIAF) generated against 10 different flaviviruses. The results showed that these recombinant antigens could be used as type-specific immunological reagents, and suggest that these antigens could serve as the basis for rapid, safe, and inexpensive flavivirus serosurveys.

Amino Acid Sequence↗
PubMed1991

The effect of chloroquine prophylaxis on yellow fever vaccine antibody response: comparison of plaque reduction neutralization test and enzyme-linked immunosorbent assay.

Weekly oral chloroquine prophylaxis for malaria has been associated with impaired antibody response to intradermal rabies vaccination. Experimental data indicate that chloroquine may inhibit yellow fever virus in vitro, yet there has been no clinical evidence to suggest that antibody response to yellow fever vaccine is impaired by concomitant oral administration of chloroquine. A prospective trial was undertaken to evaluate the antibody response to yellow fever 17D vaccine (Connaught Laboratories) of volunteers who were randomized to taking either chloroquine or no drug. Of fifty subjects, 28 were randomized to taking chloroquine, 22 were randomized to taking no drug. Yellow fever 17D vaccine was administered on day 0 and blood sampled on days 0, 14, 35 and 210. Chloroquine was administered weekly for four weeks. There was no significant difference in peak antibody titer by plaque reduction neutralization testing (PRNT) between the group that took chloroquine (mean log peak of reciprocal titer 1.43 +/- SD 0.60) with vaccine subcutaneously compared to vaccine-only group (mean log peak of reciprocal titer = 1.21 +/- 0.55). All fifty subjects seroconverted to yellow fever vaccine by day 210. ELISA testing was also performed on all subjects. The two tests showed good correlation (Spearman r = 0.675), although ELISA readings were positive by day 14 in significantly more subjects (p = .01). We conclude that routine anti-malarial doses of chloroquine do not affect antibody response to yellow fever 17D vaccine. ELISA testing, a less complex and less time-consuming test, correlates well with PRNT and is proposed for additional trials to measure yellow fever 17D vaccine response in flavivirus non-immune subjects.

Administration, Oral↗
PubMed1990

Evidence that Cache Valley virus induces congenital malformations in sheep.

An outbreak of congenital abnormalities occurred in sheep at San Angelo, Texas, between December 1986 and February 1987. Of 360 lambs born, 19.2% had arthrogryposis or other musculo-skeletal problems and hydranencephaly (AGH), and the total neonatal loss was 25.6%. In 1987, all ewes that were tested with AGH lambs had antibody to Cache Valley virus (CVV), whereas 62% of the ewes with normal lambs had CVV-specific antibody. Pre-colostral serum samples from AGH lambs had neutralizing antibody to CVV. An increase in prevalence of CVV-specific antibody, from 5% during the spring of 1986 to 63.4% during the winter of 1987, occurred during a time that included the gestation of these affected lambs, as well as a period of increased rainfall. The isolation of a CVV-related strain from a sentinel sheep in October 1987 confirmed the continued presence of this virus in the pasture where this outbreak occurred and provided a recent field strain for future studies.

Animals↗
PubMed1990

Antigen and antibody detection and update on the diagnosis of dengue.

The diagnosis of dengue is an imperfect science. By 1983 we had sensitive isolation systems including arthropods and arthropod cell cultures, specific-and group-reactive monoclonal antibodies, and a rapid and sensitive immunoassay for IgM and IgG. Progress in the past 7 years encompasses the use of monocyte lines for primary isolation, a more rapid plaque reduction neutralization test with BHK-21 cells, labeled RNA probes to detect dengue-specific nucleic acid, and improved ELISA technology with specific synthetic and engineered antigens.

Antibodies, Viral↗
PubMed1989

Electron microscopy and antigenic studies of uncharacterized viruses. I. Evidence suggesting the placement of viruses in families Arenaviridae, Paramyxoviridae, or Poxviridae.

During approximately 35 years, investigators in various laboratories studying arbovirus ecology and epidemiology accumulated many virus isolates, more than 60 of which were not characterized or placed in taxa. By a combination of electron microscopic and antigenic studies we collected information sufficient to provisionally classify 60 isolates. Electron microscopic observations suggest that 20 are members of the virus family Bunyaviridae, 20 Rhabdoviridae, 14 Reoviridae, one Togaviridae, one Paramyxoviridae (Mapuera virus, from a bat), and one Poxviridae (Yoka virus, from mosquitoes). Serologic studies provided evidence sufficient to place some of these viruses in recognized antigenic groups, within families and genera, and to establish new antigenic groups and taxa for others. Three viruses were found to have morphologic and morphogenetic characteristics consistent with those of members of the family Arenaviridae: Quaranfil virus, a human pathogen, Johnston Atoll virus, isolated from birds and ticks, and Araguari virus, isolated from an opossum. This, the first in a series of three papers, described methods used for these investigations and also presents descriptions of viruses provisionally placed in the families Arenaviridae, Paramyxoviridae, or Poxviridae. Descriptions of viruses provisionally placed in families Bunyaviridae and Reoviridae are published in the second and third papers, respectively. Viruses of the family Rhabdoviridae have been described separately.

Animals↗
PubMed1989

Electron microscopic and antigenic studies of uncharacterized viruses. II. Evidence suggesting the placement of viruses in the family Bunyaviridae.

This is the second of three papers describing the use of electron microscopy and antigenic analyses intended to characterize and place in taxa more than 60 previously unclassified viruses. The first paper of the series describes the viruses we classified as provisional members of the families Arenaviridae, Paramyxoviridae, or Poxviridae; another paper, published separately, discusses the Rhabdoviridae. In this paper we report that electron microscopy provided sufficient evidence to place 17 of these viruses (Belem, Erve, Estero Real, Mojui dos Campos, Nyando, Odrenisrou, Okola, Pacora, Para, Santarem, Tanga, Telok Forest, Termeil, Thiafora, Thottapalayam, Wanowrie, and Yacaaba) in the family Bunyaviridae and to support the observations of others that Yogue and Kasokero viruses are members of this virus family. Subsequent antigenic studies allowed us to place some of these viruses in recognized antigenic groups and to establish new antigenic groups for others.

Bunyaviridae↗