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Biomedical subjects

J S Mackenzie

Publications and source records attributed to J S Mackenzie.

At least 109 records · Page 6Linked to original sources
PubMed1981

The detection of influenza A virus antigens in cultured cells by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was employed to investigate the expression of influenza A/Hong Kong/68 (H3N3) virus structural proteins on the surface of infected MDCK cells, and to detect viral antigens in culture media and cell extracts. Infected cells were fixed with 0.1 per cent glutaraldehyde before being examined for the presence of cell-surface antigens. Viral antigens were first observed on the surface of cells 4 hours after infection and reached a maximum 10-12 hours after infection, when measured by haemadsorption with chicken erythrocytes and by ELISA and immunofluorescence with hyperimmune antiserum to Hong Kong virus. A good correlation was found between the three assay systems. The presence of individual virion structural proteins on the cell surface was determined by ELISA using specific antibodies purified by differential affinity chromatography. Either or both or the internal matrix and nucleoprotein antigens were expressed from 2 to 6 hours after infection, with maximum expression after 2 hours, and the strain-specific and common antigenic determinants of haemagglutinin were observed on the cell surface from 4 hours after infection, and reached a maximum 8 to 10 hours after infection. Low levels of neuraminidase were detected between 4 and 8 hours after infection. Culture media and cell extracts were titrated by infectivity and haemagglutination assays, and by ELISA. Titres obtained from the culture media showed a close correlation between the three assay methods, with peak titres being attained 24 hours after infection. Viral antigens were first observed in cell extracts by ELISA 4 hours after infection, and infectious virions and haemagglutinin 2 hours later, but whereas maximum titres of infectious virus and haemagglutinin were found 10 hours after infection, the ELISA titre continued to rise until 24 hours after infection, which suggested that virus structural proteins were being accumulated in the cells after most of the progeny virions had been released. The results are discussed in terms of the potential use of ELISA in rapid virus diagnosis.

Animals↗
PubMed1981

Influence of H-2 and non-H-2 genes on resistance to murine cytomegalovirus infection.

The resistance of adult mice to acute lethal infection with murine cytomegalovirus is controlled by genes linked to the H-2 complex. The k haplotype is approximately 10 times more resistant than the b or d haplotypes. Susceptibility is inherited as a completely dominant trait. At least two genes within the H-2 complex are involved, one mapping to the K/IA subregion and the other to the D subregion. The data suggest that interactions may occur between these K- and D-end genes which further affect resistance to the virus. The precise mechanism of H-2 gene control of resistance to murine cytomegalovirus remains to be elucidated. Non-H-2 linked genes also affect resistance to the virus, particularly in the C57BL genetic background, which is associated with an increased resistance to murine cytomegalovirus. Newborn mice of all strains are equally susceptible: both the H-2- and the non-H-2-associated resistances develop in the first few weeks of life and are retained up to at least 18 months of age.

Aging↗
PubMed1980

The use of enzyme-linked immunosorbent assay to determine the appearance, specificity and immunoglobulin class of antibodies to the structural proteins of influenza A virus in mice.

The immune response of mice to sublethal infection with influenza A virus was investigated by enzyme-linked immunosorbent assay, haemagglutination-inhibition and neutralization tests. The specificity and immunoglobulin class of antibodies were determined by competition enzyme-linked immunosorbent assay. A rise in geometric mean antibody levels was observed between 4 and 16 days by haemagglutination-inhibition, and between 8 and 32 days by neutralization. A positive correlation was found between the geometric mean antibody responses measured by the three assay systems, but there was no consistent relationship between the titres of individual sera by each assay method. More antibodies to the strain-specific determinants of haemagglutinin were observed 8 days after infection than antibodies to the common determinants, but by day 16 there were equal amounts of antibody to strain-specific and common determinants of haemagglutinin and to neuraminidase. Antibodies to matrix and nucleoprotein antigens were not detected until 64 days after infection. The antibody response 8 days after infection was composed of IgM and IgA immunoglobulin classes, but IgG predominated from 16 days after infection.

Animals↗
PubMed1980

The serological response of chickens to an avian influenza A virus administered by various routes.

An avian influenza A virus (Hav7 Neq2) isolated from a feral duck in Western Australia was transmitted to groups of broiler chickens by cloaca, mouth, eye drop or spray. No disease or deaths occurred. Serum samples were examined by haemagglutination inhibition test and enzyme linked immunosorbent assays and the results gave reasonable correlation. Chickens infected by cloaca or spray gave the best overall seroconversions.

Animals↗
PubMed1979

The effect of long-term exposure to cigarette smoke on the height and specificity of the secondary immune response to influenza virus in a murine model system.

The effect of long-term exposure to cigarette smoke on the height and specificity of the secondary humoral immune response to influenza was investigated in a murine model system. It was shown that if mice were pre-immunized with a sub-lethal infection of influenza virus and then exposed to cigarette smoke daily for 36 weeks, they were able to mount a secondary immune response of normal height on subsequent challenge with the homologous virus strain. The response however, was less specific than that elicited in control mice, with high titres of cross-reacting antibody by haemagglutination-inhibition to the following strain in the same antigenic series. Recall of antibody to the previous strain in the antigenic series was not observed in either control or smoke-exposed animals. These results serve to correct an earlier discrepancy between the murine system and human studies in which the response to influenza infection in mice was depressed by prolonged exposure to cigarette smoke, whereas in man the response of smokers did not differ significantly from that of non-smokers. This apparent discrepancy had been caused by a lack of previous experience of influenza in the mice, which had therefore mounted a primary response, compared with the secondary response observed in the human studies.

Animals↗
PubMed1979

The effect of protein-deprivation on the susceptibility to influenza virus infection: a murine model system.

The effect of a 4% albumin diet initiated at weaning on the susceptibility to influenza virus infection was studied in C57Bl mice. Protein-deprivation was found to enhance markedly the susceptibility to a lethal infection with both mouse-virulent and avirulent strains of virus. Viraemia was observed more frequently in protein-deprived mice, and virus persisted longer in the lungs. The humoral immune response following intranasal infection was depressed, with normal levels of IgG antibody but reduced levels of IgM antibody. No difference was found in the seroconversion frequencies between well-nourished and protein-deprived mice. Pre-immunization did not affect the virus titres in the lungs of protein-deprived mice after challenge with the homologous virus, nor did it prevent the spread of virus to the thymus and brain. The results were discussed in terms of the immunocompetence of the malnourished host and of the potential risk of epidemic influenza in children suffering from severe forms of protein-energy malnutrition.

Animals↗
PubMed1979

Purification of antibodies to influenza A virus structural proteins by affinity chromatography, and their participation in haemagglutination-inhibition, neutralization and enzyme-linked immunosorbent assay.

Affinity chromatography was used to purify rabbit antibodies to common and strain-specific antigeneic determinants of haemagglutinin, to neuraminidase, and to a combination of the internal proteins of influenza A viruses. The purity of the antibodies was assessed by haemagglutination-inhibition, enzyme-linked immunosorbent assay (ELISA) and competition ELISA. The antibodies were examined for their participation in neutralization and haemagglutination-inhibition assays, and in ELISA. ELISA was found to be the most sensitive technique for detecting antibodies. Antibodies to the common and strain-specific determinants of haemagglutinin were shown to participate in neutralization assay and ELISA, but only those antibodies to the common determinants were detected by haemagglutination-inhibition.

Animals↗
PubMed1979

HLA antigens and the response to influenza A virus.

An attempt was made to confirm a previously reported association between HLA type B16 and resistance to infection with live attenuated influenza A virus vaccine. No differences were found either in the ability of influenza virus to attach to fractionated white blood cells from HLB B16 subjects compared to cells from subjects of other HLA types, nor in the incidence of antibodies to three consecutive epidemic strains of influenza in sera from B16 subjects and control subjects. The association between HLA B16 and resistance to influenza could not be confirmed in a retrospective analysis of a clinical trial of a live attenuated influenza vaccine.

Adsorption↗
PubMed1978

The effect of ABO blood groups on the incidence of epidemic influenza and on the response to live attenuated and detergent split influenza virus vaccines.

The effect of blood group status on the incidence of epidemic influenza A (H3N2) infections and on serological response to influenza vaccination with killed subunit and live attenuated vaccines have been investigated during comparative vaccine trials in Western Australia. A significantly higher incidence of epidemic influenza was observed in subjects of blood group B compared with those of other blood groups, regardless of whether they had serological evidence of previous exposure to H3N2 antigens or not. Volunteers of different blood groups exhibited similar seroconversion frequencies to both vaccines after the administration of two doses, but a significantly higher proportion of blood group A subjects seroconverted after receiving their first dose of live attenuated vaccine compared with those of other blood groups. Although this finding was inconsistent with the increased incidence of epidemic influenza in subjects of blood group B, it is discussed in terms of the methods employed to obtain attenuation. Higher geometric mean HI antibody titres were observed in blood group O subjects after the administration of killed subunit vaccine. The results described in this report supported the contention that genetic factors linked to ABO blood groups may play a role in susceptibility to infection with influenza A virus, but that any association must be indirect.

ABO Blood-Group System↗
PubMed1977

Influenza infections during pregnancy in the mouse.

The effect of a sublethal dose (0-5 LD50) of influenza A/WSN (H0N1) administered intranasally in the 1st and 3rd weeks of pregnancy was studied in C3H inbred mice. Maternal and neonatal mortality rates were significantly increased by infections in the 3rd week of pregnancy, but not in the 1st week. Infections during the last part of the 1st week significantly depressed the growth rate of neonates. No evidence of viraemia, transplacental transmission or congenital malformations were observed from infections during either week. The results are discussed in terms of a possible model for human influenza infections during pregnancy to determine the potential risks to the mother, fetus and neonate.

Animals↗
PubMed1977

Resistance to murine cytomegalovirus linked to the major histocompatibility complex of the mouse.

Studies of the resistance patterns to infection with a murine cytomegalovirus in inbred strains of mice revealed the existence of resistant and susceptible strains. Resistance was found to be associated with possession of the H-2k allele at the major histocompatibility locus of the mouse. The F1 hybrid between a resistant strain (C3H/HeJ) and a susceptible strain (BALB/c) was found to have a resistance intermediate between that of both parents, indicating that the gene(s) controlling resistance is partly dominant. Susceptible BALB/c mice could be made resistant to lethal infection by pre-treatment with thioglycollate broth but not by pre-treatment with endotoxin or BCG. Resistant C3H/HeJ mice could be made susceptible to lethal infection by pre-treatment with cyclophosphamide.

Alleles↗
PubMed1977

The potential advantages and requirements of live attenuated influenza virus vaccines.

Live attenuated influenza A virus vaccines are potentially the most efficient and effective method of immunization against epidemic influenza, and offer the only feasible means of mass vaccination at a socially acceptable cost. The advantage of live virus vaccines are described and compared with killed virus vaccines in terms of immune responses, protection and commercial production. The most frequently considered methods of attenuation and their individual drawbacks are discussed with speculation on the future development and rationale of master vaccine strains. Recommended minimal requirements of master vaccine strains and candidate live vaccines are presented as a basis for their eventual evaluation by licensing authorities.

Antibodies, Viral↗
PubMed1976

Cell-mediated immune response to influenza virus infections in mice.

The local and systemic cell-mediated immune (CMI) responses to influenza virus infection in mice were examined by leukocyte migration inhibition and lymphocyte-mediated cytotoxicity tests. Mice were inoculated intranasally with 5 50% lethal doses of the A/WSN (H0N1) strain of influenza virus. Cells from the lymph nodes draining the upper and lower respiratory tract were used to measure the local response, and the spleen was the source of cells used for systemic determinations. The local response by pulmonary lymph node cells was greater and appeared earlier than was observed systemically in the spleen. The specificity of the CMI response was investigated by using a heterologous virus strain, A/Jap (H2N2), and recombinants A/Jap-NWS (H2N1) and A/NWS-Jap (H0N1), obtained from a cross between A/Jap (H2N2) and a virus, A/NWS (H0N1), with surface antigenic specificity similar to that of the inoculated virus. From the results of both tests used as correlates of CMI, it appeared that the response was specific against the hemagglutinin component of the inoculated virus. No reactivity was observed against the heterologous virus A/Jap (H2N2) nor against the recombinant A/Jap-NWS (H2N1) bearing the same neuradminidase as that of the inoculated virus.

Animals↗
PubMed1975

Comparative trials of live attenuated and detergent split influenza virus vaccines.

Comparative clinical trials of live attenuated and detergent-split subunit influenza virus vaccines were undertaken with 1048 volunteers in Western Australia. Volunteers were divided into three main groups, each of which received either live virus vaccine or a saline control administered intranasally, or subunit vaccine injected subcutaneously. No differences were recorded between the three groups in their post-vaccination symptoms. Serum samples were collected at various times up to 50 weeks after vaccination, and antibody titres were measured by haemagglutination-inhibition (HI) tests and, for 231 volunteers, by virus neutralization tests. The two vaccines were almost equivalent in inducing seroconversion in vaccinees with pre-trial HI titres of 96 or less, but the subunit vaccine stimulated a higher geometric mean HI antibody titre. The longevity of the HI antibody response was greater for the live virus vaccine. The height of the response and the longevity of neutralizing antibody were the same for both vaccines. Both vaccines provided a high degree of protection against epidemic A/England/42/72 influenza, and some protection against A/Port Chalmers/1/73 influenza.

Adolescent↗
PubMed1975

Evidence for recombination between two different immunological types of foot-and-mouth disease virus.

Recombination was observed between temperature-sensitive (ts) mutants of two immunological types of foot-and-mouth disease virus which were distinguishable by two marker characteristics in addition to their antigenic type. Putative ts+ recombinants were isolated and the segregation patterns of their marker characteristics examined. The results are discussed in terms of the origin of new sub-type strains.

Antigens, Viral↗