Search PubMed⌕ Search

Biomedical subjects

H W Reid

Publications and source records attributed to H W Reid.

At least 55 records · Page 3Linked to original sources
PubMed1995

The virus causing encephalomyelitis in sheep in Spain: a new member of the tick-borne encephalitis group.

The nucleotide and deduced primary amino acid sequence of the envelope gene of two virus isolates from the brains of Spanish sheep with encephalomyelitis, were determined and compared with those of other flaviviruses. The amino acid alignments showed that the Spanish viruses shared 95 to 96 per cent homology with the envelope protein of louping ill virus and western European tick-borne encephalitis virus. In comparison, the maximum variation in amino acid identities among strains of louping ill virus from the British Isles is 1.8 per cent. The Spanish isolates were distinguishable from all other known flaviviruses by the presence of a unique tripeptide sequence (AQR) at amino acid positions 232 to 234 in the E protein, the position at which a genetic marker for distinct flavivirus species has been identified. Other genetic markers, viz DSGHD (amino acids 320 to 324) and EHLPTA (amino acids 207 to 212), which identify the tick-borne encephalitis group within the genus Flavivirus, were present in the amino acid sequences of the Spanish virus. It is concluded that the cause of sheep encephalomyelitis in Spain is a distinct species in the tick-borne encephalitis virus group.

Animals↗
PubMed1995

Identification of a region of the alcelaphine herpesvirus-1 genome associated with virulence for rabbits.

The gammaherpesvirus Alcelaphine Herpesvirus 1 (AHV-1) causes the fatal lymphoproliferative disease known as malignant catarrhal fever (MCF), in susceptible hosts. The virulent C500 isolate of AHV-1 became attenuated for the laboratory model, the rabbit, as a result of serial passage in cells of bovine origin. This work describes the identification of a region of the central unique sequence of the C500 genome, located close to the terminal repeat units of the molecule, which is altered on attenuation. The virulent C500 genome contains two copies of a sequence of approximately 2 kbp, contained within a 7 kbp region of the unique DNA located adjacent to the terminal repeats at the left end of the molecule. In the genome of the attenuated virus, there are also two copies of the 2 kbp sequence but they are located at the ends of the attenuated genome unique region, adjacent to the terminally repeated sequences. One open reading frame (ORF), designated putative polypeptide 5, was altered on attenuation such that the 3' sequence was lost. The location of this ORF, coupled with the loss of its 3' sequence, suggests that this ORF may encode a gene involved in the virulent mechanisms of this virus, in a manner similar to that of the transforming proteins of Herpesvirus saimiri (HSV).

Amino Acid Sequence↗
PubMed1995

Antigenic similarity of central European encephalitis and louping-ill viruses.

Twenty isolates of Central European encephalitis (CEE) virus were compared with 20 isolates of louping-ill (LI) virus in indirect immunofluorescence test (IIFT), using a panel of 17 monoclonal antibodies (MoAbs) prepared against the prototype LI virus. Three Asian members of the tick-borne encephalitis (TBE) complex were also included in the comparison: Turkish sheep encephalitis (TSE), Russian spring-summer encephalitis (RSSE) and Langat (LGT) viruses. Antigenic relationships of the viruses were evaluated by Dice similarity coefficient and cluster analysis. The results revealed antigenic heterogeneity of LI isolates, antigenic homogeneity of CEE isolates, and indicated that CEE and LI are related varieties of Eurasian TBE flavivirus that also includes TSE and RSSE strains.

Animals↗
PubMed1994

Detection of louping ill virus in formalin-fixed, paraffin wax-embedded tissues of mice, sheep and a pig by the avidin-biotin-complex immunoperoxidase technique.

An immunohistochemical method for the detection of louping ill virus antigen in formalin-fixed, paraffin wax-embedded tissues by an avidin-biotin-complex (ABC) immunoperoxidase technique was established. The tissues examined were from the brains of 10 mice, five sheep and one pig. The mice were experimentally infected with louping ill virus whereas the sheep and the pig were field cases of louping ill confirmed by clinical examination, and by histological and serological methods.

Animals↗
PubMed1994

Lack of cross-protection between vaccinia virus and orf virus in hysterectomy-procured, barrier-maintained lambs.

Hysterectomy-procured, barrier maintained lambs were immunised with either of virus or vaccinia virus and subsequently challenged with both viruses. Under these conditions lambs were protected from challenge with the homologous virus but no cross-protection was observed. The feeding of colostrum that contained antibodies to orf virus had no effect on the duration of viral lesions. Immunoblotting analysis and ELISA of serum samples taken during the course of the experiment indicated that the animals mounted antibody responses to both viruses. The cross recognition of 3 vaccinia virus antigens by the hyperimmune anti-orf virus serum was revealed by immunoblotting.

Animals↗
PubMed1994

Tick-borne flavivirus NS1 gene: identification of conserved peptides and antigenic analysis of recombinant louping ill virus NS1 protein.

The nucleotide sequence of the NS1 gene of louping ill (LI) virus has been determined. The sequence shows a high degree of homology with other members of the tick-borne serocomplex of flaviviruses and a lower homology with the mosquito-borne flaviviruses. Alignment of the deduced NS1 amino acid sequences with all tick-borne flavivirus NS1 sequences, identified four peptide regions which were conserved for all tick-borne flaviviruses, but were variable amongst mosquito-borne flaviviruses. A dendrogram, derived from the alignment of the NS1 protein sequences, indicated an evolutionary relationship that quite closely reflects the recognised serological classification. The LI virus NS1 protein expressed in Escherichia coli and baculoviruses showed similar antigenic reactivity to the authentic virus-coded protein when tested with NS1-specific monoclonal antibodies, but did not form high molecular weight complexes and was not secreted from cells.

Amino Acid Sequence↗
PubMed1994

PCR detection of ovine herpesvirus-2 DNA in Indonesian ruminants--normal sheep and clinical cases of malignant catarrhal fever.

Malignant catarrhal fever (MCF), a fatal viral disease of cattle and other large ruminants, has a worldwide distribution. There are two forms of the disease, one of which, is caused by Alcelaphine herpesvirus-1 (AHV-1) and is derived from wildebeest. The other form is associated with domestic sheep and is caused by ovine herpesvirus-2 (OHV-2). The disease in Indonesia is sheep-associated with the preferred livestock of this area, Balinese cattle (Bos javanicus) and water buffalo (Bubalus bubalis), both highly susceptible to SA-MCF. The incidence in these species is thought to be high but the prevalence and economic losses attributable to SA-MCF have been difficult to assess. a polymerase chain reaction (PCR) test, based on a cloned OHV-2 gene sequence, was successfully applied to the detection of OHV-2 DNA in normal sheep and animals affected with SA-MCF. OHV-2 DNA was detected in eleven confirmed cases of SA-MCF and in the peripheral blood leucocyte (PBL) fraction of six latently infected sheep. These findings have confirmed that the PCR can be of value in establishing a diagnosis of MCF and that the aetiological agent of MCF in Indonesia is OHV-2. The amplification of DNA from the PBL of goats suggests that they are infected with a similar or identical herpesvirus.

Animals↗
PubMed1994

Identification of naturally occurring monoclonal antibody escape variants of louping ill virus.

Louping ill virus isolates from Great Britain, Ireland and Norway were compared antigenically by indirect immunofluorescence, haemagglutination-inhibition and neutralization tests using a panel of five envelope-specific and five non-structural protein NS1-specific monoclonal antibodies raised against louping ill virus. The viruses were grouped according to their reactivities with the antibodies. Group 1, members of which were isolated between 1931 and 1987, consisted of 13 viruses that reacted with all antibodies, whereas group 2, members of which were isolated after 1980, consisted of five viruses that were positive with only eight of the 10 monoclonal antibodies. The two monoclonal antibodies that did not react with the group 2 viruses are known to be neutralizing antibodies and the amino acids that they recognize in the viral envelope protein have been identified. We therefore refer to the group 2 viruses as naturally occurring monoclonal antibody escape variants. When compared with group 1 viruses, the escape variants showed reduced virulence for mice in terms of the time taken to kill and/or the proportion that died, following intraperitoneal inoculation. The nucleotide and deduced amino acid sequences of the envelope gene of one escape variant were compared with those of several group 1 viruses. A single amino acid substitution at residue 308 was detected in the envelope protein of the escape variant which corresponds precisely to the position in experimentally selected attenuated monoclonal antibody escape mutants. The importance and potential implications of these naturally occurring variants in louping ill epizootiology and vaccine-based control are discussed.

Animals↗
PubMed1993

PCR detection of the sheep-associated agent of malignant catarrhal fever.

From a genomic library previously constructed from a lymphoblastoid cell line (LCL) propagated from a bovine case of sheep-associated malignant catarrhal fever (SA-MCF), caused by ovine herpesvirus-2 (OHV-2), several OHV-2 clones were identified and characterised by hybridisation using probes from the unique region of the Alcelaphine herpesvirus-1 (AVH-1) genome. Nucleotide sequence from one clone was generated and the predicted amino acid sequence was found to contain regions of homology with the 140 and 160 kDa tegument proteins of Epstein-Barr virus and herpesvirus saimiri respectively. Oligonucleotide primers were constructed and a polymerase chain reaction (PCR) test was developed for the detection of OHV-2 viral DNA. Amplified product was identified by restriction with RsaI and BmyI. The primers were highly specific for OHV-2 DNA with a limit of detection of 6.4 pg of genomic DNA derived from the parent LCL. This was estimated to correspond to one diploid bovine cell. The PCR was successfully applied to detect OHV-2 DNA in peripheral blood leucocytes (pbl) from clinical cases of SA-MCF and normal sheep.

Amino Acid Sequence↗
PubMed1993

Classification of a new member of the TBE flavivirus subgroup by its immunological, pathogenetic and molecular characteristics: identification of subgroup-specific pentapeptides.

The antigenic, pathogenic and molecular characteristics of Turkish sheep encephalitis (TSE) virus, strain TTE80, were compared with other members of the tick-borne encephalitis (TBE) virus complex. Monoclonal antibodies with defined specificity for the flavivirus envelope glycoprotein distinguished TSE virus from louping ill (LI), western or far eastern TBE, Langat and Powassan virus in indirect immunofluorescence, haemagglutination-inhibition and neutralization tests. On the other hand, TSE virus, which produces an LI-like disease in sheep, resembled LI virus in mouse neurovirulence tests. Molecular homology data of all the structural genes of TSE virus compared with other tick-borne flaviviruses demonstrated that TSE virus is a distinct member in the TBE virus subgroup. The data are consistent with the conclusion that TSE virus has evolved by a separate evolutionary pathway as compared with the close antigenic relatives, western European, far eastern TBE viruses and LI virus. By aligning the encoded amino acids in the viral envelope glycoprotein of mosquito- and tick-borne flaviviruses, we have also identified subgroup-specific pentapeptide motifs for the tick-borne encephalitis, Japanese encephalitis and dengue subgroup viruses of the genus Flavivirus. These pentapeptides have important implications for the evolution, classification and diagnosis of flaviviruses.

Amino Acid Sequence↗
PubMed1993

Sequencing and antigenic studies of a Norwegian virus isolated from encephalomyelitic sheep confirm the existence of louping ill virus outside Great Britain and Ireland.

We have carried out an antigenic analysis and nucleotide sequence comparison of the envelope glycoprotein of recognized louping ill virus strains isolated from Scotland with that of a Norwegian virus known to cause encephalomyelitis in sheep. Monoclonal antibodies with defined specificity for the louping ill virus envelope glycoprotein failed to distinguish between the Norwegian virus and prototype louping ill virus in indirect immunofluorescence, haemagglutination inhibition and neutralization tests. Nucleotide sequencing of the envelope glycoprotein and alignment of the deduced amino acid sequence with other known sequences revealed that the Norwegian virus closely resembles (> 95% identity for nucleotide and > 98% identity for amino acid sequences) louping ill virus. Maximum variation in identities among four strains of louping ill virus were 4.4% and 1.8% respectively for nucleotide and amino acid alignments. We conclude that sheep encephalomyelitis in Norway is caused by louping ill virus. These results imply that other viruses present in Europe and known to cause encephalitis/encephalomyelitis of sheep could be caused by louping ill virus.

Animals↗
PubMed1992

The detection of Alcelaphine herpesvirus-1 DNA by in situ hybridization of tissues from rabbits affected with malignant catarrhal fever.

Tissue sections and cultured lymphocytes from rabbits clinically affected following experimental infection with Alcelaphine herpesvirus-1 (AHV-1) were assessed for the presence of viral DNA by in situ hybridization with the cloned major HindII repeat sequence of this virus. Small numbers of virus-infected cells were consistently detected only in submandibular lymph nodes, while other tissues showed no evidence of viral DNA. Virus titration in culture suggested that there were higher titres of virus in the lymph nodes, spleen and lung of infected animals than in the kidney or peripheral blood lymphocytes and confirmed the low level of virus in these animals. Substantially more viral DNA was detected by in situ hybridization in lymphocytes following at least 24 h of culture, suggesting that viral replication is normally repressed by the host.

Animals↗
PubMed1992

Nucleotide sequence of the envelope glycoprotein of Negishi virus shows very close homology to louping ill virus.

Negishi virus, a member of the family Flaviviridae, was originally isolated in Japan, during an outbreak of Japanese encephalitis. Antigenically, however, Negishi virus resembles the tick-borne rather than the mosquito-borne flaviviruses. Monoclonal antibodies that bind louping ill virus showed a close antigenic relationship between louping ill and Negishi virus. The genes encoding the envelope glycoprotein of Negishi virus (strain 3248/49/P10) and louping ill virus (strain SB526) were cloned and sequenced. They showed a very close homology at both the nucleotide and deduced amino acid levels. Comparison with the known sequence of another strain of louping ill virus (strain 369/T2) and with other tick-borne flaviviruses showed that Negishi virus was more closely related to louping ill virus than to the other tick-borne viruses. The significance of this observation for virus evolution, virus distribution in the environment, and the potential use of nucleotide sequencing for rapid and precise identification of flaviviruses are discussed.

Amino Acid Sequence↗
PubMed1992

Louping ill virus envelope protein expressed by recombinant baculovirus and vaccinia virus fails to stimulate protective immunity.

We have constructed recombinant baculoviruses and vaccinia viruses containing cloned DNA, encoding either the envelope protein alone or all of the structural proteins (core, membrane and envelope) of louping ill virus. Glycosylated viral envelope protein, presented both inside and on the surface of insect and mammalian cells, was expressed by all four recombinant viruses. Differences in antigenic presentation of the envelope protein were observed between the envelope protein and structural protein constructs as well as between the insect and mammalian cell expression systems. Despite the expression of epitopes known to elicit neutralizing and protective antibodies when present in authentic antigen, the recombinant envelope protein expressed by either vector failed to induce, in mice or rabbits, either neutralizing or protective antibodies against louping ill virus.

Amino Acid Sequence↗
PubMed1992

A cytotoxic rabbit T-cell line infected with a gamma-herpes virus which expresses CD8 and class II antigens.

A rabbit T-cell line, BJ-610, has been derived from a New Zealand White rabbit infected with Alcelaphine herpes virus-1, which has the characteristics of a lymphokine activated killer (LAK) cell. The surface phenotype of this cell line has been studied by flow cytometry, using a panel of monoclonal antibodies (mAb) to rabbit leucocyte surface markers, and compared with that of another rabbit T-cell line, RL-5, transformed with herpes virus ateles. The expression of a number of markers is common to the two lines; these include the rabbit analogues of CD11a/CD18, CD43, CD44 and CD45. Three antigens are expressed on BJ-610 but not RL-5. One of these is recognized by a mAb thought to recognize CD8, while a second is a class II R-DQ molecule. The third antigen is expressed on thymocytes, a subset of T cells, neutrophils and platelets but its molecular nature is unknown. These two cell lines should prove useful in preparing reagents which recognize subsets of rabbit T cells and for studying the mechanism of herpes virus-induced lymphoid cell deregulation.

Animals↗