PubMed Health⌕ Search

Biomedical subjects

I E Anderson

Publications and source records attributed to I E Anderson.

At least 19 recordsLinked to original sources
PubMed2001

Detection of cellular cytokine mRNA expression during orf virus infection in sheep: differential interferon-gamma mRNA expression by cells in primary versus reinfection skin lesions.

In sheep infected with the parapoxvirus orf virus, primary infection orf skin lesions developed and resolved within 8 weeks. Reinfection lesions were smaller and resolved within 3 weeks. The host response in the skin was characterized by an accumulation of neutrophils, dendritic cells, CD4+ T cells, CD8+ T cells, B cells and T19+ gammadelta T cells. The magnitude of this accumulation paralleled orf virus replication in the skin. In situ hybridization was used to detect cells expressing interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and interleukin-4 (IL-4) mRNAs in orf skin. Cells expressing IL-4 mRNA were not detected at any time after infection. Cells expressing IFN-gamma mRNA were detected after reinfection but not after primary infection. Cells expressing TNF-alpha mRNA included epidermal cells, vascular endothelium and uncharacterized cells that increased more rapidly in the skin after reinfection compared to primary infection. The results are consistent with a prominent role for IFN-gamma in the host immune response controlling the severity of the disease.

Animals↗
PubMed1997

Cloning and expression of the 75 kDa DnaK-like protein of Chlamydia psittaci and the evaluation of the recombinant protein by immunoblotting and indirect ELISA.

The 75 kDa dnaK-like gene of Chlamydia psittaci ovine abortion strain S26/3 was isolated from an EMBL 3 chlamydial DNA library. A 7 kb DNA fragment containing the gene was subcloned into Bluescribe (M13+) plasmid and used to transform competent E. coli. These cells were found to express a cytoplasmic protein of 75 kDa. Monospecific antibodies against the protein prepared by antibody elution reacted with the native 75 kDa protein. Recombinant clones did not adhere to McCoy cell monolayers in cell adhesion studies. The 75 kDa protein purified by ion-exchange chromatography was used in immunoblotting and indirect enzyme-linked immunosorbant assay (ELISA) studies using sera previously screened for chlamydial antibodies by an indirect ELISA incorporating solubilised chlamydial elementary bodies and by microimmunofluorescence. Immunoblotting identified 6/11 sera from infected ewes that had either typical placental lesions or had been found positive on examination of stained placental smears and 1/11 sera from ewes that had no typical placental lesions. The ELISA gave positive reactions with 29 of 65 known positive sera and 15 of the 76 negative sera. It is concluded that the 75 kDa DnaK-like protein is unsuitable as an antigen for antibody detection but its potential as a component for a sub-unit vaccine against ovine enzootic abortion warrants further study.

Abortion, Veterinary↗
PubMed1996

Analyses of the genomes of chlamydial isolates from ruminants and pigs support the adoption of the new species Chlamydia pecorum.

Analysis of the genomic DNAs of chlamydial isolates from sheep, cattle, and pigs was performed by Southern blot hybridization and by restriction endonuclease (RE) profiling of DNA amplified by PCR. The hybridization probes were derived from whole genomic DNA, the major outer membrane protein (MOMP) gene, the 16S rRNA gene, and an avian Chlamydia psittaci isolate plasmid. The PCR analysis used targets in the MOMP gene, the 16S rRNA gene, and the 60-kDa cysteine-rich protein gene. Together, the results showed that although there was considerable heterogeneity in the DNA sequence in the MOMP gene region, all the isolates had the same underlying total genomic RE profiles and yielded identical RE profiles for the rRNA and 60-kDa-protein gene regions. Most of the isolates were found to hybridize with the plasmid probe. Comparison of the MOMP sequence of one of the isolates (P787) with that of a known Chlamydia pecorum strain together with the results of the RE analyses allowed the conclusion that the isolates should all be classified within this new species.

Amino Acid Sequence↗
PubMed1995

Efficacy trials with tissue-culture grown, inactivated vaccines against chlamydial abortion in sheep.

Vaccines containing inactivated, semi-purified antigen of ovine abortifacient Chlamydia psittaci were prepared from tissue-culture grown harvests of two strains. These were evaluated for efficacy against experimentally reproduced enzootic abortion of ewes (EAE), the protection index (PI) of each vaccine being calculated from three variables. Trial 1 tested the adjuvants Marcol 52/Arlacel A, ISCOM matrix, Novasomes and Alhydrogel, each administered with a total antigen dose of 4 micrograms chlamydial protein (cp), against challenge with the two homologous vaccine strains. The first three formulations yielded PIs of 39-42%, while that of Alhydrogel was 23%. Marked granuloma and/or abscess formation occurred in the Marcol 52/Arlacel A group but in none of the others, and only this group seroconverted following vaccination. In Trial 2, ISCOM matrix containing 16 micrograms cp per dose was administered once or twice. Two challenges were used, one involving the two vaccine strains and the other these two strains plus five others, but no significant differences were seen between them. The double dose schedule, which was better than the single dose and also several Novasomes formulations tested concurrently, gave PIs of 64 and 77% against the two challenges (combined value 71.5%). Trial 3 studied duration of immunity over two lambing seasons using three different administration schedules of 16 micrograms cp in ISCOM matrix, namely single dose in year 1, single dose in year 2 (Group 1), double dose then booster (Group 2), and double dose without booster (Group 3). PIs against the homologous bivalent challenge were 79-80% for Groups 1 and 3 and 91% for Group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗
PubMed1995

Development and evaluation of an indirect ELISA to detect antibodies to abortion strains of Chlamydia psittaci in sheep sera.

A novel indirect enzyme-linked immunosorbent assay (ELISA) for antibodies against abortion strains of Chlamydia psittaci (C. psittaci) has been developed. The antigen used was chlamydial elementary bodies treated sequentially with N-lauroyl sarcosine and n-octyl-beta-D-glucopyranoside and finally solubilized with N-lauroyl sarcosine and dithiothreitol. Treating the antigen with sodium periodate after coating of the plates increased the specificity for antibodies to abortion strains. The test was evaluated initially with sera from experimentally infected sheep and an uninfected control group. These sheep were monitored for lambing performance and infection status. When used in conjunction with the indirect micro-immunofluorescence test (MIF), the ELISA was able to identify as negative all twenty-five sera from ewes that had no typical placental lesions and identified as positive twenty of twenty-one sera from infected ewes that had either typical placental lesions or had been found positive by isolation of chlamydia in cell culture. The combination of ELISA and MIF was also able to discriminate correctly groups of sera from six flocks with a history of infection from four known uninfected flocks.

Abortion, Veterinary↗
PubMed1991

Immune responses of the ovine lymph node to Chlamydia psittaci. A cellular study of popliteal efferent lymph.

The popliteal efferent lymphatics were cannulated in sheep of two categories, seronegative or immune to Chlamydia psittaci. Following subcutaneous injection of live C. psittaci or control material into the draining area of the popliteal node, sequential samples of efferent lymph were collected and analysed. Both categories of sheep responded to C. psittaci with increased outputs of lymphocytes and blast cells. Numbers of blast cells rose both absolutely and as a proportion of the total. Plasmablasts increased in number only in seronegative sheep. Outputs of total T cells (CD5+), helper T cells (CD4+), cytotoxic/suppressor T cells (CD8+) and non-helper, non-suppressor T cells (T19) were maximal 4 and 7 days after challenge in immune and seronegative sheep, respectively. Proportionally, CD4+ T cells declined, CD8+ T cells increased and T19 cells were unaltered with time after infection. Chlamydial antigens could not be demonstrated in the cells of efferent lymph by an immunoperoxidase method. The results of this preliminary study show that both T and B cell responses are involved in immunity to C. psittaci.

Abortion, Veterinary↗
PubMed1990

Antibody response of the ovine lymph node to experimental infection with an ovine abortion strain of Chlamydia psittaci.

After primary infection with Chlamydia psittaci in the draining area of the popliteal lymph node, viable organisms could be isolated from the efferent lymph only before the primary immune response developed. The lymph antibody response, as assayed by the complement fixation and immunofluorescence (IF) antibody tests, showed a rise in titre that peaked approximately 2 weeks after infection. Immunoblotting revealed that antibodies produced during this period were predominantly directed against the major outer membrane protein (MOMP). In secondary infection of convalescent sheep, an elevated IF antibody titre, already present in the lymph and blood, could not be boosted. Viable organisms could not be isolated from these sheep. Antibodies produced reacted to 12-14 bands in the immunoblot profile including the MOMP band. These potentially immunoprotective antigens, particularly MOMP, should be considered as useful candidates for an improved vaccine against ovine enzootic abortion, in further investigations.

Abortion, Veterinary↗
PubMed1990

Efficacy against ovine enzootic abortion of an experimental vaccine containing purified elementary bodies of Chlamydia psittaci.

A vaccine prepared from purified, inactivated elementary bodies of Chlamydia psittaci protected sheep against abortion after subcutaneous challenge with live chlamydiae. Immunoblot analysis of serum samples revealed a consistently dominant antibody response against the chlamydial major outer membrane protein in all vaccinated sheep. Reactions to other chlamydial antigens were also detected but were less pronounced or inconsistent. Serological responses detected by complement fixation were variable and did not correlate with immunity.

Abortion, Veterinary↗
PubMed1990

The ovine immune response to Chlamydia psittaci; histopathology of the lymph node.

The histopathological response of the ovine popliteal lymph node to infection by an ovine abortion strain of Chlamydia psittaci was studied. After infection of 10 seronegative sheep by the subcutaneous route, the draining popliteal lymph nodes enlarged considerably. By day 6, expansion was more marked in the medulla than in the cortex but, by day 18, cortical follicles were prominent. Immunoglobulin-containing cells increased in number both in the medulla and cortex between days 6 and 18. C. psittaci was re-isolated from three nodes on day 6 and one on day 12, but at no stage was it demonstrated in tissue sections by an immunoperoxidase method. Thus it was shown that while C. psittaci could apparently become "latent" in lymphoid tissue, it could also stimulate a profound response at the same site.

Animals↗
PubMed1990

Protection of sheep against Chlamydia psittaci infection with a subcellular vaccine containing the major outer membrane protein.

An outer membrane (OM) preparation from elementary bodies (EBs) of Chlamydia psittaci (ovine abortion strain) was used to vaccinate pregnant ewes in a single subcutaneous dose and was found to achieve protection after subcutaneous challenge with infectious organisms. Inactivated purified EBs used as a single-dose vaccine also gave protection. The ratio of live to dead lambs was significantly higher in the vaccinated groups (16:1 and 15:1, respectively) than in the placebo group (8:9). Polyacrylamide gel electrophoresis and immunoblotting showed that a 40-kilodalton protein was the main protein constituent of the OM preparation, and this was positively identified as the major outer membrane protein by protein microsequencing. Electron microscopy revealed that fine particulate structures on the outermost surface of the EB were also present in the OM preparation. The findings suggest that the major outer membrane protein is an important immunoprotective determinant in ovine abortion vaccines.

Amino Acid Sequence↗
PubMed1990

Observations on the pathogenesis of Chlamydia psittaci infection of pregnant sheep.

Susceptible pregnant sheep were infected with Chlamydia psittaci at different stages of early and mid-gestation. Placentas and foetuses were examined by microbiological, serological, histopathological and immunochemical methods at various intervals thereafter. While ewes were susceptible to infection from early gestation onwards and infections of placentas and foetuses occurred from about 60 days gestation (dg), pathological changes were not detected until after 90 dg. These changes consisted of initial rapid replication of C. psittaci in the trophoblast at the limbus of the placentomal hilus, leading to local necrosis and contiguous spread of infection to involve the cotyledonary and intercotyledonary placenta and apposing endometrium. Foetal pathology consisted of focal necrosis in liver and other organs suggestive of embolic dissemination of infection from the placenta. An early foetal immune response was detected including the demonstration of IgM and IgG antibody to C. psittaci and quantitative evidence of a B cell response to infection. Pathogenetic mechanisms are discussed.

Animals↗
PubMed1989

The effect of chlamydial infection on the initiation of premature labour: serial measurements of intrauterine prostaglandin E2 in amniotic fluid, allantoic fluid and utero-ovarian vein, using catheterised sheep experimentally infected with an ovine abortion strain of Chlamydia psittaci.

The initiation of premature labour by an ovine abortion strain of Chlamydia psittaci was studied in relation to Prostaglandin E2 (PGE2), which plays a major role in parturition. The local intrauterine concentration of PGE2 was monitored after experimental infection with C. psittaci, during late gestation, using a catheterised sheep model. Indwelling catheters were implanted into the amniotic and allantoic cavities of six control sheep, and into six sheep infected with an ovine abortion of C. psittaci. The release of PGE2 into the utero-ovarian vein of these sheep was also monitored. Infection with C. psittaci was associated with a premature rise in PGE2 in the amniotic fluid between days 122 and 135 of gestation (P less than 0.01). A premature increase in PGE2 was defected between days 127 and 136 of gestation (P less than 0.05) in the allantoic fluid of sheep infected with C. psittaci, but not in the control uninfected sheep. Chlamydial infection significantly decreased the secretion of PGE2 into the utero-ovarian vein. The mean concentration of PGE2 in the utero-ovarian vein of infected sheep was 68.8 +/- 5.2% of the PGE2 concentration of control sheep between days 122 to 141 of gestation (P less than 0.01). The release of PGE2 into the utero-ovarian vein increased between days 126 to 136 of gestation in infected and control sheep (P less than 0.01). The results from the catheterised sheep model indicated that C. psittaci infection is associated with a local intrauterine release of PGE2. The magnitude of this release was similar to the PGE2 release in control sheep prior to parturition.(ABSTRACT TRUNCATED AT 250 WORDS)

Allantoin↗
PubMed1988

Chlamydia psittaci: is tonsillar tissue the portal of entry in ovine enzootic abortion?

Ewes at 70 days of gestation were exposed by various routes to a culture of Chlamydia psittaci. Chlamydial infection of fetal tissues, generally accompanied by abortion, was observed only in four of six ewes inoculated via the tonsillar crypts and in five of seven ewes injected subcutaneously; most of these also developed antibodies to C psittaci. Seroconversion after normal lambing was also observed in most ewes inoculated orally or by stomach tube, despite failure to detect chlamydia in them.

Abortion, Veterinary↗
PubMed1987

Comparison of some ovine Chlamydia psittaci isolates by indirect immunofluorescence.

Four ovine abortion isolates, including the A22 vaccine isolate, and an isolate from a case of lamb arthritis, were compared by indirect immunofluorescence using antisera raised in chickens and mice. Cross titrations with homologous and heterologous antisera showed a one-way reaction between the single chlamydial isolate from a lamb with arthritis and the four isolates from cases of ovine enzootic abortion. The abortion isolates could not be distinguished.

Abortion, Veterinary↗
PubMed1986

Comparison of the virulence in mice of some ovine isolates of Chlamydia psittaci.

Virulence associated with five ovine isolates of Chlamydia psittaci was compared using a mouse model. Comparable doses of each isolate were inoculated via the footpad into separate groups of 6-week-old mice. Four isolates from abortion were judged more virulent than an isolate from arthritis because of their ability to migrate from the site of infection to the spleen. Similar results were obtained using three different mouse strains. Re-isolation of C. psittaci indicated variation in susceptibility to infection between different mouse strains.

Animals↗