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Biomedical subjects

C G Bridges

Publications and source records attributed to C G Bridges.

10 recordsLinked to original sources
PubMed1992

Latent equid herpesviruses 1 and 4: detection and distinction using the polymerase chain reaction and co-cultivation from lymphoid tissues.

The polymerase chain reaction (PCR) and co-cultivation were used to identify the lymphoreticular system as the site of latency of equid herpesvirus I (EHV-1). Primers for PCR were designed from aligned nucleotide sequences of the glycoprotein gB genes to amplify the same region of both the EHV-1 and EHV-4 genomes. Subsequent restriction digests using specific enzymes distinguished the amplified fragments of the EHV-1 genome from those of the EHV-4 genome. Ten weeks following an experimental infection of five ponies with EHV-1, latent virus was detected by PCR and recovered by co-cultivation, predominantly from lymphoid tissues draining the respiratory tract. Significantly, latent EHV-1 also persisted in peripheral blood leukocytes (PBL). Latent EHV-4, presumably from a preceding natural infection, was also detected in some tissues, including PBL, from all animals. Of additional interest was the recovery of EHV-1 and -4 only in the presence of the ubiquitous EHV-2.

Acute Disease↗
PubMed1990

One way protection between equid herpesvirus 1 and 4 in vivo.

Two groups each of six sibling ponies were exposed to sequential infections with equid herpesvirus 1 or 4 (EHV-1 or EHV-4) at four or five month intervals. Two exposures to EHV-4 did not significantly reduce virus shedding or pyrexia when the ponies were subsequently exposed to EHV-1. However, two sequential infections with EHV-1 completely protected against challenge with EHV-4. Virus neutralising antibody in each group did not increase until 21 days after primary exposure and was subtype specific. However, complement fixing antibody rose within seven days after inoculation with EHV-1, and 14 days after inoculation with EHV-4, and while the latter was subtype specific the former was directed against both EHV-1 and EHV-4. Interpretation of these findings in relation to vaccination is discussed.

Animals↗
PubMed1990

Olga--oligonucleotide primer design program for the Atari ST.

A program to facilitate the design of oligonucleotide primers has been devised. Olga is written in draft ANSI standard 'C' and makes use of the implementation of Digital Research GEM (Graphics Environment Manager) on the Atari ST. Olga is specifically suited to the polymerase chain reaction (PCR) allowing simultaneous analysis of two primer sequences. The advantage of Olga is that it provides in one program analyses for direct repeats, secondary structures and primer dimerization as well as several useful 'finishing' tools for workers engaged in PCR optimization and oligonucleotide syntheses.

Drug Design↗
PubMed1989

Further investigations of equine interferons in vitro.

Following a published procedure, preparations of equine interferon (EqIFN) were prepared. Equine mononuclear leukocytes were induced with equine influenza virus to yield a preparation designated EqIFN-alpha, or with phytohemagglutinin to yield a preparation designated EqIFN-gamma. A preparation designated EqIFN-beta was obtained from equine embryo kidney cells treated with poly(rI):poly(rC) and DEAE Dextran. The pH and heat stability of these preparations were studied, and also their activity on various equine and ovine cells challenged with difference viruses. Unexpectedly, the EqIFN-gamma preparation was found to be stable at pH 2 and to heat at 60 degrees C for 2 h, whereas the EqIFN-beta preparation was labile under these conditions.

Animals↗
PubMed1989

Equine interferons following exposure to equid herpesvirus-1 or -4.

When 23 ponies were infected with equid herpesvirus-1 or -4 (EHV-1 or EHV-4), nasal shedding of interferon (IFN) correlated closely with the duration of viral excretion. Equine interferon (EqIFN) was detected in the serum only from animals infected with the EHV-1 virus, and here high levels correlated with clinical symptoms of locomotor disorder and indicated a poor prognosis. Low levels of IFN were detected in explanted mononuclear cells from ponies infected with either virus.

Animals↗
PubMed1988

The characterization of equine herpes virus-1-infected cell polypeptides recognized by equine lymphocytes.

Ponies, without evidence of previous exposure to Equine herpes virus-1 (EHV-1), were experimentally infected with EHV-1 subtype 2 and investigated for lymphocyte transformation to virus-infected cell polypeptides, as shown by separation with gel electrophoresis. Animals made significant responses to Western blot fractions that corresponded to molecular weights of approximately 30,000, 40,000-45,000, 60,000-65,000, 80,000-95,000 and 100,000-140,000 MW. These molecular weight ranges correlated with the positions of major EHV-1 subtype 2 glycoproteins that were found at migration distances approximating to 137,000, 111,000, 90,000, 65,000 and 47,000 MW. Responses were also made to a subset of similar points on the subtype 1 profile. Hyperimmune equine serum precipitated numerous infected-cell proteins of both subtypes; in particular the recognition of polypeptides with MW of 142,000, 132,000, 114,000, and 46,000 was in agreement with the mitogenic responses. Labelling with 125I indicated that immunoprecipitated greater than 250,000, 182,000, 142,000, 132,000, 75,000, 46,000 and 32,000/34,000 MW products were exposed on the surface of infected cells.

Animals↗
PubMed1987

Rapid diagnosis and characterization of equid herpesvirus 1 using monoclonal antibodies.

Twelve monoclonal antibodies (Mabs) were produced against the attenuated RACH subtype 1 strain of Equid herpesvirus 1. Nine were subtype specific by immunofluorescence or immunoperoxidase, while the other three were against epitopes common to both subtypes. Use of these Mabs allowed isolates to be rapidly and easily subtyped. Immunoblotting indicated that the subtype common Mabs were against viral proteins of MW 140 K and 90 K (VP 9 and 14), while the subtype-specific Mabs were against the glycosylated VP 2 (MW greater than 240 K), and also against VP 12 (MW 110 K) and VP 15 (MW 88 K). Membrane, cytoplasmic, or particulate nuclear patterns of fluorescence were characteristic for each of these proteins. None of the Mabs had neutralising activity but those directed against VP 2 restricted plaque size.

Animals↗
PubMed1987

Genetic restriction of cytolysis during equid herpesvirus 1 subtype 2 infection.

Six Welsh Mountain pony foals were experimentally infected with a subtype 2 isolate of Equid Herpesvirus 1 (EHV-1) and subsequently examined for T cell mediated cytotoxicity against both subtypes. Cytotoxicity was not observed at 3 or 7 days after primary exposure but virus-specific, and genetically restricted, cytotoxicity of EHV-1-labelled autologous skin fibroblasts could be demonstrated 7 and 21 days after the animals were given a second exposure to live virus. Killing of subtype 2 antigen-labelled targets was more efficient than subtype 1 coated cells. This finding was paralleled by the observation that virus-neutralizing and complement-fixing antibody levels were subtype specific after the primary infection but after secondary exposure were directed against both subtypes. During primary infection the lymphocyte proliferative response to EHV-1 subtype 2 was not evident at 7 days post infection (dpi) but by 18 dpi was present in all animals. The second exposure produced an earlier (3 dpi) and larger proliferative response which was specific to the infecting isolate. The non-specific proliferative response to Concanavalin A mitogen indicated that virus infection induced a state of activation in circulating lymphocytes.

Animals↗
PubMed1986

Innate immunity during Equid herpesvirus 1 (EHV-1) infection.

Intrinsic phagocytosis and killing of C. albicans by equine monocytes and polymorphonuclear leucocytes (PMN) was examined during Equid Herpesvirus 1 (EHV-1) (subtypes 1 or 2) and Adenovirus infections. Monocyte function increased during EHV-1 subtype 2 and Adenovirus infection. Conversely, there was an impairment of monocyte ingestion during EHV-1 subtype 1 infection which was ascribed to virus replication in peripheral blood mononuclear cells. PMN phagocytosis was not decreased in any of the infections studied. The raised levels of haemolytic complement in animals which subsequently developed EHV-1 subtype 1 induced paresis suggested an abnormality of complement turnover. Increased levels of interferon were evident in the nasal secretions of both subtype 1 and subtype 2 infected animals but only subtype 1 virus induced measurable levels of serum interferon. No intrinsic abnormality of interferon production by monocytes or lymphocytes was found.

Adenoviridae Infections↗