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Biomedical subjects

L Spence

Publications and source records attributed to L Spence.

At least 19 recordsLinked to original sources
PubMed1992

Monoclonal antibody characterization of Jamestown Canyon (California serogroup) virus topotypes isolated in Canada.

Jamestown Canyon (JC) virus of the California (CAL) serogroup has been isolated in 12 American states and 6 Canadian provinces. A study was undertaken to produce monoclonal antibodies (MAbs) to JC virus and to use these MAbs to assay for possible heterogeneity among naturally occurring JC topotypes in Canada. MAbs were produced to the prototype strain of JC virus using BALB/c mice. Twenty-seven secreting MAbs were obtained and three of these MAbs were propagated and studied. All three MAbs, M1 (IgG1), M2 (IgG2b), and M3 (IgG2a), were reactive by immunofluorescent antibody assay against JC-infected vero cells and by ELISA against JC antigen. MAb M2 reacted with all members of the Melao complex, MAb M1 reacted only with Keystone virus, while MAb M3 exhibited no reactivity with other CAL serogroup viruses. Only MAb M3 possessed neutralization and hemagglutination inhibition activities against JC virus. The MAbs were also tested by ELISA and for neutralizing activity against 13 JC topotypes isolated in 5 provinces from Newfoundland to Saskatchewan. ELISA confirmed closer identity of the Canadian topotypes to JC as opposed to the closely related South River virus. The MAbs verified all Canadian topotypes to be JC virus but revealed different patterns of reactivity between these topotypes and prototype JC virus.

Animals↗
PubMed1979

A prospective study of respiratory infection in adult asthmatics and their normal spouses.

A prospective study of respiratory infections was performed in nineteen married asthmatics and their normal spouses who were examined at monthly intervals during a 1-year period. The colds described were associated with nasal symptoms, sore throat and usually malaise, fever, cough and hoarseness. The asthamtics reported a larger number of these symptomatic episodes than the non-asthmatics but significantly fewer of the episodes in the asthmatics were objectively confirmed by viral isolation or rise in serum titre of viral antibody. The frequency of respiratory infections was not influenced by the long term use of inhaled beclomethasone dipropionate and oral corticosteroid drugs. Less than 10% of the exacerbations of asthma were associated with respiratory infection. The disability resulting from respiratory infections in the asthmatics did not significantly exceed that in the non-asthmatics.

Adult↗
PubMed1979

Quantitative determination of cytomegalovirus IgG antibody by enzyme-linked immunosorbent assay (ELISA).

Quantitative determination of cytomegalovirus (CMV) human IgG antibody by ELISA performed in polystyrene trays was carried out and compared with results obtained by the routine complement fixation (CF) test. The antibody titres of all the sera determined by ELISA were higher than those detected by the CF test. Of the 27 sera negative (less than 1:8) by the CF test, 22 of them were also negative (less than 1:50) by ELISA. The other five CF negative sera were found to have low levels of antibody by ELISA. ELISA is a sensitive and specific assay for CMV antibody. The CMV antigen adsorbed readily to the microtitre plates and the test was simple to perform. The results of ELISA could be obtained in 5 to 6h. A description of the test procedure is given including the method of CMV antigen attachment to the plates. The possibility of using paired sera at a single dilution in the ELISA test to detect seroconversion is discussed.

Antibodies, Viral↗
PubMed1979

Use of antisera against bovine (NCDV) and simian (SA11) rotaviruses in ELISA to detect different types of human rotavirus.

Two ELISA systems for the detection of human rotaviruses were developed. In the first system antibodies to Nebraska calf diarrhea virus (NCDV) were used for coating the solid matrix and for the preparation of the enzyme conjugate. In the second system antibodies to human rotavirus and antibodies to simian rotavirus (SA11) were used for coating the solid matrix and for the preparation of the enzyme conjugate respectively. The second ELISA system proved to have a broader spectrum for the detection of human rotaviruses. By using the two ELISA systems, the different types of human rotavirus could be distinguished. The ELISA tests developed were 8 to 64 times as sensitive as electron microscopy (EM) and (or) counterimmunoelectrophoresis (CIEP). The antigen detected by ELISA was shown to be different from that detected by the hemagglutination test.

Animals↗
PubMed1978

Immune adherence hemagglutination test applied to the study of herpes simplex and varicella-zoster virus infections.

The immune adherence hemagglutination (IAHA) test has been used successfully to detect antibody to herpes simplex (HS) virus and varicella-zoster (V-Z) virus. Comparative studies between the complement-fixation (CF) test and the IAHA test revealed that, in most cases, the IAHA test was more sensitive than the CF test. Furthermore, diagnosis on the basis of a fourfold change in antibody titer was made more rapidly by the IAHA test. The IAHA test was found to be a very simple and practical technique requiring only a few hours for completion compared with the conventional CF test which required up to 24 h. In addition, both sera and cerebrospinal fluids could be tested in very low dilutions in the IAHA test, so that very low levels of antibody could be detected. Also, the IAHA test detected antibody to V-Z virus more frequently than did the CF test in adults with a history of varicella occurring 9 to 30 years prior to sampling. The level of cross-reaction between HS and V-Z viruses was examined by both the CF test and the IAHA test, and no major differences between the two techniques were found.

Antibodies, Viral↗
PubMed1978

Comparison of rotavirus strains by hemagglutination inhibition.

Rotaviruses have been shown to be of importance as aetiologic agents of gastroenteritis in infants and in domestic animals of several species. Hemagglutinins were prepared from two Canadian isolates of bovine rotavirus and from one isolate of a simian rotavirus. A United Kingdon isolate of bovine rotavirus was shown not to possess hemagglutinating activity, indicating a strain difference between a Canadian and United Kingdom bovine rotavirus. In hemagglutination-inhibition (HAI) tests a rabbit hyperimmune (two injections) serum, prepared to one of the bovine rotaviruses, was not helpful in distinguishing the two bovine viruses because of cross-reactions between the viruses. However, it was possible to distinguish the bovine viruses from the simian virus with this serum. When guinea pig immune sera were prepared to the four rotavirus strains and tested with the three hemagglutinins in the HAI test, antigenic differences between the four strains of rotavirus were demonstrated. Hyperimmune guinea pig serum prepared to a strain of human rotavirus did not inhibit any of three hemagglutinins indicating that the human strain is different from the three rotavirus strains which gave hemagglutinins.

Animals↗
PubMed1978

California encephalitis virus activity in mosquitoes and horses in southern Ontario, 1975.

A study was undertaken in 1975 to determine California encephalitis virus activity in southern Ontario. Three thousand and sixty-one mosquitoes, primarily Aedes species, were divided into 104 pools and inoculated into suckling mice. Isolates of snowshoe hare virus were obtained from one pool each of Aedes fitchii and A. triseriatus mosquitoes collected in the Guelph area. Serological testing of horse sera revealed extensive virus activity in southern Ontario and indicated that horses may serve as excellent monitors for California encephalitis virus.

Aedes↗
PubMed1978

Hemagglutination and hemagglutination-inhibition studies with a strain of Nebraska calf diarrhea virus (bovine rotavirus).

A hemagglutinin has been prepared from Nebraska calf diarrhea virus (NCDV) propagated in BS-C-1 cell line. After cesium chloride centrifugation, the hemagglutinin of the bovine rotavirus was found to be associated with intact virions (density 1.355 g/ml) but not with virions lacking an outer capsid layer (density 1.375 g/ml). In hemagglutination-inhibition (HAI) tests, the hemagglutinin reacted specifically with NCDV serum, and HAI seroconversions were detected in some sera tested. Cross-reactions were observed in complement fixation tests between the human and bovine rotaviruses but were not demonstrated by HAI, suggesting that the hemagglutinin detects a specific rather than a group antibody response.

Animals↗
PubMed1977

St. Louis encephalitis in southern Ontario: laboratory studies for arboviruses.

The first reported outbreak of St. Louis encephalitis in Canada occurred in the summer of 1975 in southern Ontario -- in the Windsor-Sarnia-Chatham area, the Niagara region and the city of Toronto. Hemmagglutination inhibition and complement fixation testing of serum samples collected during the outbreak confirmed that St. Louis encephalitis virus was the etiologic agent. Furthermore, this virus was isolated from brain tissue of a patient who died. This outbreak was probably an extension of the outbreak that occurred in the United States that summer. It was the first outbreak of arbovirus encephalitis in the province of Ontario.

Antibodies, Viral↗
PubMed1977

Rotavirus isolation and cultivation in the presence of trypsin.

Rotaviruses are generally difficult to isolate and culture in vitro; therefore, virus isolation has not been used as a method of diagnosing this group of agents. The present report describes a simple procedure for isolating bovine rotaviruses directly from feces after pretreatment of fecal samples with trypsin. This procedure resulted in virus isolation from five of five samples that contained virus particles, as demonstrated by electron microscopy, and four of seven samples where virus particles could not be observed but were considered positive by the presence of immunofluorescent-staining cells in feces. Virus could not be isolated from "normal" feces. If the virus was not passaged in the presence of trypsin, the infectivity was gradually lost, but infectivity could be restored again if trypsin was added, resulting in increased virus spread and concomitant increase in virus yield. The application of this technique as a diagnostic tool for bovine and other rotaviruses is briefly discussed.

Cell Line↗
PubMed1977

Immune electron microscopy of arboviruses.

Representative members of four arbovirus taxons were studied by immune electron microscopy (IEM) in an attempt to determine whether the technique can be applied to the specific identification of arboviruses. Alphavirus, flavivirus, bunyavirus, and rhabdovirus antigens were prepared by propagation in tissue culture. The viruses were used to titrate homologous antibody and test heterologous antibody in the IEM test. Specific clumping together with visualization of antibody attachment was observed for all homologous systems studied. For the alphaviruses, titers of antibody, as determined by IEM, were comparable with the titers obtained by hemagglutination inhibition. Alphavirus cross-reactions were observed at low antibody dilutions by IEM. However, further dilution of antibody resulted in specific clumping only of homologous virus, allowing specific identification of alphavirus unknowns. For all viruses studied, positive IEM reactions were obtained with homologous grouping ascitic fluids but not with heterologous grouping fluids.

Antibodies, Viral↗