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Biomedical subjects

R C Wardley

Publications and source records attributed to R C Wardley.

At least 55 records · Page 3Linked to original sources
PubMed1982

Generation of cross-reactive cytotoxic T lymphocytes following immunization of mice with various bluetongue virus types.

Mice immunized with a single bluetongue (BT) virus type were shown to produce cytotoxic T lymphocytes (CTL's) which cross-reactive with a number of BT virus types. These cross-reactive CTL's could be induced by both primary in vivo and secondary in vitro stimulation. A varying degree of cross-reactivity occurred with the six BT types examined. Aspects of the character of this cross-reactivity were examined and its role in protection from disease and vaccination strategy is discussed.

Animals↗
PubMed1982

Production of murine cytotoxic T lymphocytes by bluetongue virus following various immunisation procedures.

The induction of bluetongue virus specific cytotoxic T lymphocytes (CTLs) in C3H mice by various live and inactivated bluetongue virus preparations was studied. Live virus preparations were shown to induce good levels of CTLs; however, inactivation of virus preparations either by beta propriolactone or glutaraldehyde induced only a low level response. The use of Freund's adjuvants and double immunisation procedures failed to improve the response of the inactivated preparations. These findings are discussed in relationship to protection from bluetongue disease with various bluetongue virus vaccines.

Animals↗
PubMed1982

Complement-mediated lysis of African swine fever virus-infected cells.

Using an homologous pig system, th lysis of African swine fever virus-infected cells by antibody and complement was investigated. The optimal conditions necessary for lysis are described, and it was found that the system was unique amongst reported virus infections in that infected cells were lysed by the classical complement pathway and not the alternative pathway. Development of antibody capable of initiating complement-mediated lysis was relatively late in the infected pig, although functional in vitro assays suggested that it might act as a significant effector mechanism. Investigations of sera taken from pigs infected with varying African swine fever isolates indicate that the assay may provide a means of discriminating between strains.

African Swine Fever↗
PubMed1980

A microtechnique for the titration for African swine fever virus.

African swine fever virus isolates were titrated in swine monocyte cultures established in microtitre trays. Although technically simpler and less laborious than conventional tube assays the microtitration assay was less sensitive, but for routine and comparative titrations offers distinct advantages.

African Swine Fever Virus↗
PubMed1980

The establishment of continuous macrophage cell lines from peripheal blood monocytes.

Peripheral blood monocytes were established in cultured from ten different animal species. Using a method of repeated medium changes, monolayers of cells developed from seven of these species. These cells had the following characteristics: they were glass and plastic adherent, phagocytic, possessed many vacuoles and pseudopodia, esterase-positive, exhibited complement and Fc receptors and could partake in antigen-specific immune induction of T cells. These characteristics classify the cells as macrophages. The monolayers could be serially passaged and used for virological and immunological assays.

Animals↗
PubMed1980

Lymphocyte responses to African swine fever virus infection.

The immunological response of pigs infected with African swine fever virus was related to both quantitative and qualitative changes in the lymphocyte population. The cytolytic effect of the virus on lymphocytes caused a proportionally greater drop in B cell than in T cell numbers. A blastogenic test was developed to measure the appearance of specifically sensitised lymphocytes in the circulation. These appeared about 10 days after infection in animals infected with attenuated virus; pigs infected with virulent strains died before the appearance of this response.

African Swine Fever↗
PubMed1979

The replication of virulent and attenuated strains of African swine fever virus in porcine macrophages.

The replication of virulent and attenuated strains of African swine fever virus (ASFV) was studied in pure cultures of swine macrophages. To ensure complete destruction of the macrophage monolayers about 50--100 times more virulent ASFV was needed than attenuated virus although both isolates could be used to establish persistently infected cultures. Interferon did not appear to influence virus yields from such cultures. Fluorescent and electron microscopy studies of infected macrophages suggested that the cycle of infection of the two isolates was different.

African Swine Fever Virus↗
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

A blastogenic test for foot-and-mouth disease.

A blastogenic test to detect peripheral blood leukocytes specifically sensitized to foot-and-mouth disease virus antigen is described. The test is carried out in microtitre plates and optimum conditions were found by titration. These employed 7.5 x 10(5) cells/well and 20 complement fixing units of antigen. Peak [3H]thymidine incorporation was found to take place at 2-3 days.

Animals↗
PubMed1978

The growth of virulent African swine fever virus in pig monocytes and macrophages.

The replication of virulent African swine fever virus (ASFV) in cultures of monocytes and macrophages derived from pig bone marrow (PBM) and pig leukocyte (PL) cells was investigated by light microscopy, immunofluorescence, haemadsorption and infective virus release. Monocytes showed a high rate of infection and complete destruction within 2 to 3 days, whereas macrophages had only a very low level of infection and survived to form persistently infected cultures. These observations may explain the decrease in sensitivity of PBM and PL cells for ASFV assay after extended periods of incubation and suggest that the macrophage may be one of the cell types concerned with virus persistence in the pig.

African Swine Fever Virus↗
PubMed1977

The association of African swine fever virus with blood components of infected pigs.

The distribution of African swine fever virus (ASFV) in whole blood, plasma, red blood cells (RBC) and white blood cell (WbC) sub-populations was determined in pigs infected with virulent virus. Changes in the RBC and WBC populations were also examined. Total WBC counts decreased and RBC numbers remained unchanged during the course of the disease. The number of circulating lymphocytes decreased whilst neutrophil numbers increased owing to the replacement of mature forms by juveniles. Virus was present in all major blood fractions and was associated with equivalent numbers of both RBC and WBC. However, 90 per cent of the virus in whole blood was associated with RBC. Of the WBC subpopulations, virus was definitely associated with lymphocytes and possibly neutrophils.

African Swine Fever↗
PubMed1977

African swine fever virus replication in porcine lymphocytes.

Purified preparation of porcine lymphocytes were infected with three isolates of virulent African swine fever virus (ASFV). Electron microscopy showed the presence of small numbers of mature virus particles in degenerating cells. The titres of infective virus released were low and reached a maximum by 24 h after infection.

African Swine Fever Virus↗
PubMed1977

The role of neutrophils in antiviral defense--in vitro studies on the mechanism of antiviral inhibition.

Highly enriched populations of bovine neutrophils were added, in the presence of antiviral antibody, to herpesvirus-infected bovine cell cultures. A cell dose-dependent reduction in virus-induced cytopathology was observed. The mechanism of inhibition was presumed to be mediated by a subcellular neutrophil product and not the result of either direct cytotoxicity or antibody-dependent cell-mediated cytotoxicity (ADCC). Thus, inhibition of comparable magnitude was observed when neutrophils and virus-infected cells were separated by cell impermeable membranes. In addition, plaque reduction occurred when antiviral immunoglobulins or fragments unable to mediate ADCC were used in the assays. Killed neutrophils and sonicates were unable to mediate plaque inhibition. Speculations were made as to the origin of the virus-inhibitory substances and the role that neutrophils might assume in mediating recovery from virus infection.

Animals↗
PubMed1977

The pathology and sites of persistence associated with three different strains of feline calicivirus.

The pathology and sites of multiplication associated with three different strains of feline caliciviruses are described. The main pathological lesions were found in the tongue, soft palate and lungs and like the clinical signs were of mild nature. Virus multiplication was associated mainly with the tissues of the mouth and tonsils and in asymptomatic carrier animals the tonsil appeared to be preferred organ of viral persistence.

Animals↗