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Biomedical subjects

J R Crowther

Publications and source records attributed to J R Crowther.

At least 55 records · Page 3Linked to original sources
PubMed1983

Characterization of Vilyuisk virus as a picornavirus.

The V-1 strain of Vilyuisk virus, isolated from the cerebrospinal fluid of a chronic case of encephalomyelitis in Siberia and subsequently passaged 41 times in mice, was examined to determine its serological relationship to Theiler's murine encephalomyelitis virus (TMEV) and encephalomyocarditis (EMC) virus and some physicochemical characteristics of the virion. On the basis of virion size (28 nm), icosahedral symmetry, buoyant density (1.33 g/ml), sedimentation coefficient (150S), and capsid polypeptide profile, Vilyuisk virus appears to belong to the family Picornaviridae. Acute phase mouse antisera were used to study the antigenic relatedness of Vilyuisk, GDVII (the prototypic strain TMEV), and EMC viruses by enzyme-linked immunosorbent assay (ELISA). The results indicate that Vilyuisk and GDVII viruses are similar but distant subtypes, and that Vilyuisk and EMC viruses are unrelated.

Animals↗
PubMed1982

Differentiation of foot-and-mouth disease virus strains using a competition enzyme-linked immunosorbent assay.

Foot-and-mouth disease virus isolates were compared using solid-phase competition and indirect microenzyme-linked immunosorbent assays. Results were compared to those obtained from complement fixation tests. Similar relationships between the isolates were obtained using the indirect enzyme immunoassay and complement fixation tests. The competition assay was more discriminatory and the results did not always correlate with the other two assays.

Aphthovirus↗
PubMed1981

Detection and quantification of IgM, IgA, IgG1 and IgG2 antibodies against foot-and-mouth disease virus from bovine sera using an enzyme-linked immunosorbent assay.

A simple solid-phase enzyme immunoassay is described for the detection of antibody classes showing activity against foot-and-mouth disease (FMD) virus in bovine sera. The assay achieves a preliminary separation of the specific class of antibody from other serum proteins through immuno-adsorption to class-specific immunoglobulin-coated wells of micro-titre plates. The specific antibody is reacted with FMD virus, which is then detected by an enzyme-labelled anti virus IgG.

Animals↗
PubMed1980

Detection of antibodies against foot-and-mouth disease virus using purified Staphylococcus A protein conjugated with alkaline phosphatase.

Purified protein A (PA) from Staphylococcus aureus was conjugated with the enzyme alkaline phosphatase. This reagent reacted well with pig, rabbit and guinea pig IgG and less well with mouse and bovine IgG. Radioactive 125I-labelled PA showed a similar affinity for the IgGs examined. Antibodies against foot-and-mouth disease virus contained in guinea pig, rabbit and pig serum were detected, using the enzyme-conjugated PA in indirect tests, which were of similar sensitivity to those using enzyme-conjugated anti-species antibody as tracer.

Alkaline Phosphatase↗
PubMed1979

Solid-phase radioimmunoassay techniques for the detection of African swine fever antigen and antibody.

A solid phase radioimmunoassay (RIA) has been successfully developed to measure both African swine fever virus (ASFV) antigen and antibody. Studies show that the assay is reproducible and will detect limiting antigen concentrations equivalent to 50--500 HAD50/ml. Both direct and indirect antibody RIA have been developed and have proved to be approximately 100 times fore sensitive than the complement fixation test at present available and 1000 times more sensitive than the immuno-electro-osmophoresis test for the detection of ASFV antibody.

African Swine Fever Virus↗
PubMed1979

A solid-phase enzyme linked immunosorbent assay for the detection of African swine fever virus antigen and antibody.

A solid-phase enzyme-linked immunosorbent assay was developed to measure both African swine fever virus (ASFV) antigen and antibody. Experiments showed it to be reproducible and able to detect limiting antigen concentrations of 50--500 HAD50/ml. The assay was more sensitive than those used at present to detect ASFV antibody and it is suggested that it might be of great diagnostic use in countries where African swine fever has recently appeared.

African Swine Fever Virus↗
PubMed1979

Application of the enzyme linked immunosorbent assay to the detection and identification of foot-and-mouth disease viruses.

An indirect enzyme linked immunosorbent assay (ELISA) was applied to the detection and identification of foot-and-mouth disease (FMD) virus types. The test proved successful for the specific detection of virus from infected tissue culture, and from epithelial tissues from bovines suspected of having FMD. The ELISA compared favourably with the complement fixation (CF) test, being more sensitive and unaffected by anticomplementary factors.

Animals↗
PubMed1979

Detection and quantification of foot and mouth disease virus by enzyme labelled immunosorbent assay techniques.

Enzyme labelled immunosorbent assays (ELISA) have been developed to detect and quantify foot and mouth disease (FMD) virus using flexible plastic microtitre plates. The methods were successful for the specific detection of FMD virus and were 50 to 100 times more sensitive than the complement fixation test. The application of the ELISA techniques to FMD virus typing and subtyping, and to the assay of antigen concentration during manufacture of vaccines is discussed.

Aphthovirus↗
PubMed1979

Comparative biochemical and serological analysis of five isolates of a single serotype of foot-and-mouth disease virus.

A comparison has been made of some of the biochemical and serological characteristics of five isolates of foot-and-mouth disease virus (FMDV), serotype A. Three of the viruses have been assigned to the same subtype, A22; the other two belong to different subtypes, A5 and A24. RNA competition hybridization and two-dimensional electrophoresis of the oligonucleotides produced by ribonuclease T1 showed that the three A22 viruses formed a group which could be distinguished from the A5 and A24 viruses. However, the three A22 viruses showed some differences by both tests. Analysis of the virus polypeptides by polyacrylamide gel electrophoresis methods also distinguished the A22 viruses as a group distinct from the A5 and A24 viruses, but small differences within the A22 group were observed using electrofocusing techniques. Serological differences were observed between the viruses using complement fixation tests and by competition radioimmunoassay with antisera obtained from guinea pigs infected with these viruses. The greatest similarity occurred between the viruses previously subtyped as A22, with A5 and A24 being distinct from the A22 group and from each other. The relationship of the biochemical and serological data is discussed.

Animals↗
PubMed1979

Molecular approach to the epidemiology of swine vesicular disease: correlation of variation in the virus structural polypeptides with serological properties.

Variation has been observed in the structural polypeptides of swine vesicular disease viruses isolated from the United Kingdom and Hong Kong. Despite the limited number of isolates examined, several distinct polypeptide patterns were obtained when the virus structural proteins were examined by polyacrylamide gel electrophoresis. Isolates from outbreaks in the United Kingdom which were known to be connected gave the same polypeptide pattern, whereas viruses with different polypeptide patterns could not be traced to a common source. The different polypeptide patterns were obtained consistently and were not altered by passage of the virus in tissue culture. In general, isolates with identical polypeptide patterns could not be distinguished by neutralization or antibody blocking tests or by competition radioimmunoassays. However, isolates with different polypeptide patterns could be differentiated by antibody blocking tests or radioimmunoassay. The correlation between the serological tests and the polyacrylamide gel electrophoresis analyses illustrates the value of analyzing structural polypeptides in the epidemiological study of swine vesicular disease.

Animals↗
PubMed1978

Enzyme-labelled immunosorbent assay techniques in foot-and-mouth disease virus research.

The indirect ELISA technique has been developed successfully to measure antibodies to foot-and-mouth disease virus (FMDV) in cattle sera. Preliminary studies using a standard serum assay show that reproducible results are obtained. The method should prove useful for the examination of antibody titres in sera from large numbers of cattle or other animals.

Animals↗
PubMed1976

Examination of differences between foot-and-mouth disease virus strains using a radioimmunoassay techinque.

A radioimmunoassay (RIA) technique was used to compare different samples of type SAT 2 foot-and-mouth disease (FMD) viruses. The reaction involved the measurement of the competition of heterologous virus with homologous virus for previously titrated homologous antiserum. The results showed that differences occurred between the viruses examined. Viruses could be grouped according to their ability to compete with the homologous virus, and statistically significant differences between virus 'groups' were observed. A comparison of the relationships between the viruses using RIA and complement fixation tests was made. The results did not always correlate. Certain homologous antigen/antibody combinations were more discriminating. The method might prove useful in the examination of a large number of field strain viruses using a well-characterized vaccine virus homologous system, particularly if the method is adapted to use antisera specific for the neutralizing antigen of the homologous test virus.

Antigen-Antibody Reactions↗
PubMedDate not supplied

The detection of antibodies against foot-and-mouth disease virus (FMDV) in filter paper eluates from pig sera or whole blood by ELISA.

The use of pig blood samples dried on paper discs for the detection of antibodies against FMDV by the liquid phase blocking ELISA has been evaluated. The average volume of whole heparinised blood required to fully saturate 6.0 mm discs was 7.65 microliters (range 7.2 to 8.1; variation = 0.24, P = 0.05). When 200 clinically healthy animals were assessed by virus neutralisation (VN) titres up to 1/22 were recorded against types O, A and C, 97% being 1/11 or less. Using ELISA, results were more skewed. Overall, 91% showed titres of 1/32 or less, and there were occasional high non-specific reactors with types O and A. Using small groups of sera from experimental animals, a VN titre of 1/16 was found to be equivalent to an ELISA titre of approximately 1/100 (log10 2.0 +/- 0.2) with type O and 1/56 (log10 1.75 +/- 0.1) for type A. Although some loss in sensitivity from disc dried sera was found in selected negatives on testing at a single dilution of 1/32, sera from vaccinated animals with VN titres of 1/16 to 1/708 all gave strong positive results. A monoclonal antibody (Mab) assay was successfully developed to detect different swine anti-FMDV antibody isotypes.

Animals↗
PubMedDate not supplied

A serogroup specific enzyme-linked immunosorbent assay for the detection and identification of African horse sickness viruses.

A serogroup specific, indirect, sandwich ELISA was developed for the rapid detection of African horse sickness virus and viral antigens in field samples or in infected tissue cultures. The assay was shown to be highly sensitive and capable of providing confirmation of clinical diagnosis within one day. The results demonstrated that this ELISA will be useful for epidemiological surveillance of insect and mammalian host populations.

African Horse Sickness↗