Taenia Ovis

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Marshall W. Lightowlers - One of the best experts on this subject based on the ideXlab platform.

  • combined use of two separate but protective vaccine antigens provides protection against Taenia Ovis infection in lambs in the presence of protective maternal antibody
    Vaccine, 2021
    Co-Authors: G.b.l. Harrison, Charles G Gauci, D D Heath, Marshall W. Lightowlers, R.p. Dempster, S B Lawrence, C M Robinson, M D Rickard
    Abstract:

    Three recombinant Taenia Ovis antigens (To45, To16, To18) each induce protective immunity in lambs or ewes against infection with T. Ovis metacestodes. The degree and duration of immunity were assessed in lambs born from vaccinated ewes. Treatment group sizes varied, typically not fewer than 5 animals per group. Ewes were immunised with one T. Ovis recombinant protein prior to lambing and the degree and duration of passive immunity in their lambs was assessed by challenge infection up to 18 weeks. Lambs were fully protected up to 6 weeks of age but immunity waned from 6 to 12 weeks and there was no protection when lambs were challenged at 15 weeks. Immunisation of lambs with the homologous recombinant antigen was not effective when vaccinations were given when maternal antibody was high. Lambs were effectively immunised in the presence of passively protective antibody when vaccinated with an antigen that was different to that given to ewes. Vaccination of lambs with a combination of two proteins, To16 and To18, was more effective than giving these single antigens and gave a significant reduction of cyst numbers when lambs were challenged 12 months after immunisation. These results indicate that the use of combinations of T. Ovis recombinant antigens could enable complete protection of lambs against infection, if a delivery system becomes available that will maintain antibody at protective levels for 12 months. Alternatively, a third injection given at 6 months may promote the anamnestic response to give long lasting protection.

  • oncospheral penetration glands and secretory blebs are the sources of Taenia Ovis vaccine antigens
    Infection and Immunity, 2010
    Co-Authors: Abdul Jabbar, Charles G Gauci, Simon Crawford, Anna Walduck, G A Anderson, Marshall W. Lightowlers
    Abstract:

    Taenia Ovis is a cestode parasite infecting primarily sheep as intermediate hosts and dogs as definitive hosts. The first highly effective, recombinant vaccine against a parasitic organism was developed against T. Ovis infection in sheep. Three separate host-protective antigens (To16, To18, and To45W) have been cloned from the oncosphere of the parasite. We localize these antigens in the oncosphere by using quantitative immunogold labeling and transmission electron microscopy. The three antigens were uniquely associated with penetration gland cells. The cytoplasm and secretory granules of both penetration gland type 1 and type 2 cells exhibited statistically significant levels of staining for each of the three antigens. The intensity of labeling of the penetration gland type 1 cell was approximately three to five times greater (P < 0.01) compared to the level of staining intensity seen in the penetration gland type 2 cell. In activated oncospheres, secretory blebs were found to contain granules with a structure similar to those observed in the penetration gland cells. The granules within the secretory blebs were shown to stain specifically for the presence of each of the three host-protective antigens. The absence of surface location of the T. Ovis antigens suggests that the parasite may not be susceptible to vaccine-induced antibody- and complement-mediated attack until some postoncospheral development has occurred after infection of the intermediate host.

  • Ultrastructural reconstruction of Taenia Ovis oncospheres from serial sections
    International journal for parasitology, 2010
    Co-Authors: Abdul Jabbar, Z. Swiderski, Daniel Młocicki, Ian Beveridge, Simon Crawford, David Bruce Conn, Malcolm K. Jones, Marshall W. Lightowlers
    Abstract:

    The cellular organisation of Taenia Ovis oncospheres is interpreted from ultrathin serial sections and transmission electron microscopy following high pressure freezing and freeze-substitution. The surface of a hatched, non-activated T. Ovis oncosphere is covered by an oncospheral membrane below which is the tegument bearing microvilli. The basal lamina of the tegument is underlain by broad bands of peripheral somatic musculature. Three pairs of hooks and associated muscles are present in the somatophoric third of the oncosphere. Approximately 19 cells of seven different types were identified which include: (i) a quadri-nucleated syncytium of penetration gland type 1 containing two lateral pairs of cell bodies interconnected by narrow cytoplasmic bridges (PG1); (ii) a quadri-nucleated syncytium of penetration gland type 2 (PG2); (iii) a single-nucleated median mesophoric gland cell; (iv) 10 somatic cells; (v) two germinative cells; (vi) two nerve cells; and (vii) a pair of median somatophoric cells. This study provides a clear understanding of the morphology of T. Ovis oncospheres and forms the basis for further investigations into the biology of taeniid oncospheres.

  • localisation of three host protective oncospheral antigens of Taenia Ovis
    International Journal for Parasitology, 2010
    Co-Authors: Abdul Jabbar, Charles G Gauci, Craig T Kyngdon, Ian Beveridge, Malcolm K. Jones, Anna Walduck, Christina Mccowan, Marshall W. Lightowlers
    Abstract:

    Immunohistochemistry, confocal immunofluorescence and immunogold labelling were used to determine the localisation of the host-protective antigens To16, To18 and To45W in Taenia Ovis oncospheres. During maturation of the adult tapeworm the antigens were initially seen as diffuse staining in the developing oncospheres but in mature oncospheres four distinct cells stained positively for the antigens. Confocal fluorescence microscopy using different fluorophores revealed that each of the antigens co-localises within the same cells in the oncosphere. No surface localisation was seen in non-activated or recently activated parasites. Immunogold labelling of non-activated oncosphere sections viewed in transmission electron microscopy revealed labelling of bilateral cells, however the identities of these cells was unclear due to deficiencies in the current level of understanding of oncosphere ultrastructure. Localisation of all the antigens changed dramatically after oncospheres were activated in vitro with each of the antigens being dispersed more generally throughout the parasite parenchyma. During development of the parasites in in vitro culture, surface localisation of the proteins was seen in parasites after 3 or more days in culture. All three antigens were found to be completely absent in parasites by 15 days of culture. The location of the host-protective antigens suggests that initially the invading oncospheres are not susceptible to vaccine-induced antibody and complement mediated attack, but that as the parasites mature, the host-protective antigens come to be associated with the parasite's surface, rendering them susceptible to immune attack.

  • Vaccination with recombinant oncosphere antigens reduces the susceptibility of sheep to infection with Taenia multiceps.
    International Journal for Parasitology, 2007
    Co-Authors: Charles G Gauci, Craig T Kyngdon, Antonio Varcasia, Gülay Vural, Taraneh Oncel, Veronica Damian, Philip S. Craig, Garry A. Anderson, Marshall W. Lightowlers
    Abstract:

    Taenia multiceps is a cestode parasite, the larval stage of which encysts in the brain of sheep, goats and cattle causing an often fatal condition. The parasite also causes zoonotic infections in humans. Homologues of the recombinant oncosphere vaccine antigens from Taenia Ovis and other Taenia species were identified in T. multiceps. Sequencing of the associated T. multiceps genes and cloning of the encoding mRNA has revealed conserved features in the genes and proteins. The T. multiceps oncosphere proteins, designated Tm16 and Tm18, contain a predicted secretory signal and fibronectin type III domain. The recombinant Tm16 and Tm18 proteins were successfully expressed in Escherichia coli as fusion proteins with GST. The antigens, formulated with Quil A adjuvant, were tested in a vaccine trial in sheep. The antigens stimulated immunity in sheep against challenge infection with T. multiceps eggs. Five of nine control sheep died due to a challenge infection with T. multiceps whereas none of 20 vaccinated animals died as a result of the parasite challenge (P = 0.001). In addition, vaccination with the Tm16 protein, or Tm16 plus Tm18, induced significant protection against the number of parasites encysting in the brain as a result of the challenge infection (P = 0.023, P = 0.015, respectively). No clear relationship was apparent between the level of specific serum antibody in vaccinated animals and either the presence or absence of parasites or the number of parasites that occurred in some of the vaccinated animals. We believe this study is the first description of recombinant vaccine-related investigations for T. multiceps. The recombinant oncosphere antigens identified may allow development of effective vaccination strategies against T. multiceps infection in sheep. They raise the potential for the development of a combined vaccine with the Echinococcus granulosus EG95 antigen for prevention of T. multiceps as well as preventing the transmission of cystic hydatid disease.

G.b.l. Harrison - One of the best experts on this subject based on the ideXlab platform.

  • combined use of two separate but protective vaccine antigens provides protection against Taenia Ovis infection in lambs in the presence of protective maternal antibody
    Vaccine, 2021
    Co-Authors: G.b.l. Harrison, Charles G Gauci, D D Heath, Marshall W. Lightowlers, R.p. Dempster, S B Lawrence, C M Robinson, M D Rickard
    Abstract:

    Three recombinant Taenia Ovis antigens (To45, To16, To18) each induce protective immunity in lambs or ewes against infection with T. Ovis metacestodes. The degree and duration of immunity were assessed in lambs born from vaccinated ewes. Treatment group sizes varied, typically not fewer than 5 animals per group. Ewes were immunised with one T. Ovis recombinant protein prior to lambing and the degree and duration of passive immunity in their lambs was assessed by challenge infection up to 18 weeks. Lambs were fully protected up to 6 weeks of age but immunity waned from 6 to 12 weeks and there was no protection when lambs were challenged at 15 weeks. Immunisation of lambs with the homologous recombinant antigen was not effective when vaccinations were given when maternal antibody was high. Lambs were effectively immunised in the presence of passively protective antibody when vaccinated with an antigen that was different to that given to ewes. Vaccination of lambs with a combination of two proteins, To16 and To18, was more effective than giving these single antigens and gave a significant reduction of cyst numbers when lambs were challenged 12 months after immunisation. These results indicate that the use of combinations of T. Ovis recombinant antigens could enable complete protection of lambs against infection, if a delivery system becomes available that will maintain antibody at protective levels for 12 months. Alternatively, a third injection given at 6 months may promote the anamnestic response to give long lasting protection.

  • duration of immunity efficacy and safety in sheep of a recombinant Taenia Ovis vaccine formulated with saponin or selected adjuvants
    Veterinary Immunology and Immunopathology, 1999
    Co-Authors: G.b.l. Harrison, D D Heath, Marshall W. Lightowlers, R.p. Dempster, S B Lawrence, C M Robinson, T R Shakes, M D Rickard
    Abstract:

    The efficacy and safety of a recombinant Taenia Ovis protein was tested in sheep using 13 different adjuvant formulations, including oil adjuvants, aluminium salts, saponin, Iscoms and DEAE-dextran. The oil adjuvants, saponin and DEAE-dextran gave the highest antibody responses and greatest degree of protection against challenge infection with T. Ovis eggs. Duration of immunity studies with a saponin based vaccine showed that highly significant protection (>90% reduction of cyst numbers) was achieved when sheep were challenge infected one month after immunisation. Significant protection (79%) was still present when sheep were challenged 6 months after immunisation. The optimum dose for this batch of saponin was 10 mg, which stimulated a peak antibody titre of 38,400, 4 weeks after immunisation and did not cause injection site reactions. Dialysed saponin was shown to retain its adjuvant properties and allowed an increase in dose to 30 mg without site reaction, resulting in a peak antibody titre of 51,200.

  • host protective fragments and antibody binding epitopes of the Taenia Ovis 45w recombinant antigen
    Parasite Immunology, 1996
    Co-Authors: Marshall W. Lightowlers, Charles G Gauci, J.s. Rothel, Jacqueline G. Waterkeyn, G.b.l. Harrison
    Abstract:

    The protective efficacy of a recombinant Taenia Ovis vaccine antigen, 45W, was compared in sheep vaccine trials with antigen expressed by the full length 45W cDNA and by incomplete copies of the cDNA. Vaccine, trials were also carried out using antigen expressed by a cDNA (45S) having a sequence similar, but not identical, to 45W. Stability of the 45W antigen expressed in Escherichia coli was found to be increased after deletion of cDNA sequence encoding 19 COOH-terminal amino acids. This truncated form of the antigen was designated 45WB/X. Vaccination of sheep with antigen expressed by 45W, 45WB/X, as well as full length 45W and 45S cDNAs, induced high levels of protection. Vaccination with antigen expressed by an incomplete copy of the 45S cDNA clone did not induce protection. Comparison of deduced amino acid sequences for these clones suggests that the host-protective epitope(s) of the 45W antigen occur on either or both of the 23 and 9 amino acid peptides at the amino and carboxyl termini of 45W, respectively. Antibody binding epitopes of 45W were investigated in ELISA using overlapping 9 amino acid peptides. Protection was found to correlate with the induction of antibody to two 9 amino acid peptides.

  • pilot field trial of a recombinant Taenia Ovis vaccine in lambs exposed to natural infection
    New Zealand Veterinary Journal, 1996
    Co-Authors: S B Lawrence, D D Heath, Marshall W. Lightowlers, G.b.l. Harrison, R.p. Dempster, T K Gatehouse, C M Robinson, M D Rickards
    Abstract:

    Abstract Previous trials of an experimental Tuenia Ovis vaccine using the recombinant antigen GST-45W(B/X) established that it was possible to achieve >90% protection against a single artificial challenge of T. Ovis eggs. This trial was undertaken to assess vaccine efficacy against artificial challenge and natural infection acquired by lambs grazing contaminated pasture. Two hundred Romney lambs were vaccinated at 6 and 12 weeks of age. One hundred control lambs were not vaccinated but were allowed to run with the vaccinated mob. At 15 weeks of age, 10 controls and 18 vaccinated lambs were artificially challenged with 2000 T. Ovis eggs. The remaining control and vaccinated lambs were allowed to graze contaminated pasture for 3 weeks and were then moved to clean pasture for 5 months. The artificially challenged lambs plus 24 of the field-infected lambs were slaughtered and the carcasses dissected to obtain cyst counts. The remaining field-infected lambs were slaughtered at a commercial processing plant and...

  • immune responses associated with protection in sheep vaccinated with a recombinant antigen from Taenia Ovis
    Parasite Immunology, 1996
    Co-Authors: J.s. Rothel, D D Heath, Marshall W. Lightowlers, Paul R. Wood, H F Seow, L J Rothel, G.b.l. Harrison
    Abstract:

    This paper describes the evaluation of the protective antibody response of sheep to vaccination against Taenia Ovis infection with a defined recombinant antigen (45W). Sera from 181 vaccinated sheep, collected prior to experimental challenge with T.Ovis, were assessed for 45W specific IgA, IgG, IgG1, IgG2 and IgM levels and these results correlated with protection data. There were significant relationships (P < 0.001) between IgG, IgG1 and IgG2 titres and protection. Serum IgA levels did not correlate with protection and there were no significant levels of 45W specific IgM detected. Killing of several other taeniid cestodes has been shown to be complement mediated and the findings in this study are consistent with the involvement of this immune mechanism in 45W vaccinated sheep. A comparison of the adjuvants used in this study (saponin and oil in water) demonstrated that whereas both adjuvants stimulated the production of similar levels of 45W specific IgG1, the IgG2 response was significantly higher in sheep vaccinated with oil adjuvant.

Charles G Gauci - One of the best experts on this subject based on the ideXlab platform.

  • combined use of two separate but protective vaccine antigens provides protection against Taenia Ovis infection in lambs in the presence of protective maternal antibody
    Vaccine, 2021
    Co-Authors: G.b.l. Harrison, Charles G Gauci, D D Heath, Marshall W. Lightowlers, R.p. Dempster, S B Lawrence, C M Robinson, M D Rickard
    Abstract:

    Three recombinant Taenia Ovis antigens (To45, To16, To18) each induce protective immunity in lambs or ewes against infection with T. Ovis metacestodes. The degree and duration of immunity were assessed in lambs born from vaccinated ewes. Treatment group sizes varied, typically not fewer than 5 animals per group. Ewes were immunised with one T. Ovis recombinant protein prior to lambing and the degree and duration of passive immunity in their lambs was assessed by challenge infection up to 18 weeks. Lambs were fully protected up to 6 weeks of age but immunity waned from 6 to 12 weeks and there was no protection when lambs were challenged at 15 weeks. Immunisation of lambs with the homologous recombinant antigen was not effective when vaccinations were given when maternal antibody was high. Lambs were effectively immunised in the presence of passively protective antibody when vaccinated with an antigen that was different to that given to ewes. Vaccination of lambs with a combination of two proteins, To16 and To18, was more effective than giving these single antigens and gave a significant reduction of cyst numbers when lambs were challenged 12 months after immunisation. These results indicate that the use of combinations of T. Ovis recombinant antigens could enable complete protection of lambs against infection, if a delivery system becomes available that will maintain antibody at protective levels for 12 months. Alternatively, a third injection given at 6 months may promote the anamnestic response to give long lasting protection.

  • oncospheral penetration glands and secretory blebs are the sources of Taenia Ovis vaccine antigens
    Infection and Immunity, 2010
    Co-Authors: Abdul Jabbar, Charles G Gauci, Simon Crawford, Anna Walduck, G A Anderson, Marshall W. Lightowlers
    Abstract:

    Taenia Ovis is a cestode parasite infecting primarily sheep as intermediate hosts and dogs as definitive hosts. The first highly effective, recombinant vaccine against a parasitic organism was developed against T. Ovis infection in sheep. Three separate host-protective antigens (To16, To18, and To45W) have been cloned from the oncosphere of the parasite. We localize these antigens in the oncosphere by using quantitative immunogold labeling and transmission electron microscopy. The three antigens were uniquely associated with penetration gland cells. The cytoplasm and secretory granules of both penetration gland type 1 and type 2 cells exhibited statistically significant levels of staining for each of the three antigens. The intensity of labeling of the penetration gland type 1 cell was approximately three to five times greater (P < 0.01) compared to the level of staining intensity seen in the penetration gland type 2 cell. In activated oncospheres, secretory blebs were found to contain granules with a structure similar to those observed in the penetration gland cells. The granules within the secretory blebs were shown to stain specifically for the presence of each of the three host-protective antigens. The absence of surface location of the T. Ovis antigens suggests that the parasite may not be susceptible to vaccine-induced antibody- and complement-mediated attack until some postoncospheral development has occurred after infection of the intermediate host.

  • localisation of three host protective oncospheral antigens of Taenia Ovis
    International Journal for Parasitology, 2010
    Co-Authors: Abdul Jabbar, Charles G Gauci, Craig T Kyngdon, Ian Beveridge, Malcolm K. Jones, Anna Walduck, Christina Mccowan, Marshall W. Lightowlers
    Abstract:

    Immunohistochemistry, confocal immunofluorescence and immunogold labelling were used to determine the localisation of the host-protective antigens To16, To18 and To45W in Taenia Ovis oncospheres. During maturation of the adult tapeworm the antigens were initially seen as diffuse staining in the developing oncospheres but in mature oncospheres four distinct cells stained positively for the antigens. Confocal fluorescence microscopy using different fluorophores revealed that each of the antigens co-localises within the same cells in the oncosphere. No surface localisation was seen in non-activated or recently activated parasites. Immunogold labelling of non-activated oncosphere sections viewed in transmission electron microscopy revealed labelling of bilateral cells, however the identities of these cells was unclear due to deficiencies in the current level of understanding of oncosphere ultrastructure. Localisation of all the antigens changed dramatically after oncospheres were activated in vitro with each of the antigens being dispersed more generally throughout the parasite parenchyma. During development of the parasites in in vitro culture, surface localisation of the proteins was seen in parasites after 3 or more days in culture. All three antigens were found to be completely absent in parasites by 15 days of culture. The location of the host-protective antigens suggests that initially the invading oncospheres are not susceptible to vaccine-induced antibody and complement mediated attack, but that as the parasites mature, the host-protective antigens come to be associated with the parasite's surface, rendering them susceptible to immune attack.

  • Vaccination with recombinant oncosphere antigens reduces the susceptibility of sheep to infection with Taenia multiceps.
    International Journal for Parasitology, 2007
    Co-Authors: Charles G Gauci, Craig T Kyngdon, Antonio Varcasia, Gülay Vural, Taraneh Oncel, Veronica Damian, Philip S. Craig, Garry A. Anderson, Marshall W. Lightowlers
    Abstract:

    Taenia multiceps is a cestode parasite, the larval stage of which encysts in the brain of sheep, goats and cattle causing an often fatal condition. The parasite also causes zoonotic infections in humans. Homologues of the recombinant oncosphere vaccine antigens from Taenia Ovis and other Taenia species were identified in T. multiceps. Sequencing of the associated T. multiceps genes and cloning of the encoding mRNA has revealed conserved features in the genes and proteins. The T. multiceps oncosphere proteins, designated Tm16 and Tm18, contain a predicted secretory signal and fibronectin type III domain. The recombinant Tm16 and Tm18 proteins were successfully expressed in Escherichia coli as fusion proteins with GST. The antigens, formulated with Quil A adjuvant, were tested in a vaccine trial in sheep. The antigens stimulated immunity in sheep against challenge infection with T. multiceps eggs. Five of nine control sheep died due to a challenge infection with T. multiceps whereas none of 20 vaccinated animals died as a result of the parasite challenge (P = 0.001). In addition, vaccination with the Tm16 protein, or Tm16 plus Tm18, induced significant protection against the number of parasites encysting in the brain as a result of the challenge infection (P = 0.023, P = 0.015, respectively). No clear relationship was apparent between the level of specific serum antibody in vaccinated animals and either the presence or absence of parasites or the number of parasites that occurred in some of the vaccinated animals. We believe this study is the first description of recombinant vaccine-related investigations for T. multiceps. The recombinant oncosphere antigens identified may allow development of effective vaccination strategies against T. multiceps infection in sheep. They raise the potential for the development of a combined vaccine with the Echinococcus granulosus EG95 antigen for prevention of T. multiceps as well as preventing the transmission of cystic hydatid disease.

  • Taenia solium and Taenia Ovis stage specific expression of the vaccine antigen genes tsol18 tsol16 and homologues in oncospheres
    Experimental Parasitology, 2006
    Co-Authors: Charles G Gauci, Robert H. Gilman, Manuela Verastegui, Marshall W. Lightowlers
    Abstract:

    Recombinant antigens that have been cloned from Taenia solium and Taenia Ovis have been shown to be highly effective when used as vaccines against cysticercosis in the intermediate hosts. This study investigated the presence of mRNA encoding the TSOL18 and TSOL16 antigens in different life-cycle stages of T. solium, and their related homologues in T. Ovis. Reverse transcription-PCR and Southern blotting demonstrated that the antigens are stage-specifically expressed in the oncosphere. The apparent absence of expression of TSOL18 in the metacestode life-cycle stage suggests that the vaccine based on this antigen targets exclusively the early stages in the development of the parasite.

R.p. Dempster - One of the best experts on this subject based on the ideXlab platform.

  • combined use of two separate but protective vaccine antigens provides protection against Taenia Ovis infection in lambs in the presence of protective maternal antibody
    Vaccine, 2021
    Co-Authors: G.b.l. Harrison, Charles G Gauci, D D Heath, Marshall W. Lightowlers, R.p. Dempster, S B Lawrence, C M Robinson, M D Rickard
    Abstract:

    Three recombinant Taenia Ovis antigens (To45, To16, To18) each induce protective immunity in lambs or ewes against infection with T. Ovis metacestodes. The degree and duration of immunity were assessed in lambs born from vaccinated ewes. Treatment group sizes varied, typically not fewer than 5 animals per group. Ewes were immunised with one T. Ovis recombinant protein prior to lambing and the degree and duration of passive immunity in their lambs was assessed by challenge infection up to 18 weeks. Lambs were fully protected up to 6 weeks of age but immunity waned from 6 to 12 weeks and there was no protection when lambs were challenged at 15 weeks. Immunisation of lambs with the homologous recombinant antigen was not effective when vaccinations were given when maternal antibody was high. Lambs were effectively immunised in the presence of passively protective antibody when vaccinated with an antigen that was different to that given to ewes. Vaccination of lambs with a combination of two proteins, To16 and To18, was more effective than giving these single antigens and gave a significant reduction of cyst numbers when lambs were challenged 12 months after immunisation. These results indicate that the use of combinations of T. Ovis recombinant antigens could enable complete protection of lambs against infection, if a delivery system becomes available that will maintain antibody at protective levels for 12 months. Alternatively, a third injection given at 6 months may promote the anamnestic response to give long lasting protection.

  • duration of immunity efficacy and safety in sheep of a recombinant Taenia Ovis vaccine formulated with saponin or selected adjuvants
    Veterinary Immunology and Immunopathology, 1999
    Co-Authors: G.b.l. Harrison, D D Heath, Marshall W. Lightowlers, R.p. Dempster, S B Lawrence, C M Robinson, T R Shakes, M D Rickard
    Abstract:

    The efficacy and safety of a recombinant Taenia Ovis protein was tested in sheep using 13 different adjuvant formulations, including oil adjuvants, aluminium salts, saponin, Iscoms and DEAE-dextran. The oil adjuvants, saponin and DEAE-dextran gave the highest antibody responses and greatest degree of protection against challenge infection with T. Ovis eggs. Duration of immunity studies with a saponin based vaccine showed that highly significant protection (>90% reduction of cyst numbers) was achieved when sheep were challenge infected one month after immunisation. Significant protection (79%) was still present when sheep were challenged 6 months after immunisation. The optimum dose for this batch of saponin was 10 mg, which stimulated a peak antibody titre of 38,400, 4 weeks after immunisation and did not cause injection site reactions. Dialysed saponin was shown to retain its adjuvant properties and allowed an increase in dose to 30 mg without site reaction, resulting in a peak antibody titre of 51,200.

  • pilot field trial of a recombinant Taenia Ovis vaccine in lambs exposed to natural infection
    New Zealand Veterinary Journal, 1996
    Co-Authors: S B Lawrence, D D Heath, Marshall W. Lightowlers, G.b.l. Harrison, R.p. Dempster, T K Gatehouse, C M Robinson, M D Rickards
    Abstract:

    Abstract Previous trials of an experimental Tuenia Ovis vaccine using the recombinant antigen GST-45W(B/X) established that it was possible to achieve >90% protection against a single artificial challenge of T. Ovis eggs. This trial was undertaken to assess vaccine efficacy against artificial challenge and natural infection acquired by lambs grazing contaminated pasture. Two hundred Romney lambs were vaccinated at 6 and 12 weeks of age. One hundred control lambs were not vaccinated but were allowed to run with the vaccinated mob. At 15 weeks of age, 10 controls and 18 vaccinated lambs were artificially challenged with 2000 T. Ovis eggs. The remaining control and vaccinated lambs were allowed to graze contaminated pasture for 3 weeks and were then moved to clean pasture for 5 months. The artificially challenged lambs plus 24 of the field-infected lambs were slaughtered and the carcasses dissected to obtain cyst counts. The remaining field-infected lambs were slaughtered at a commercial processing plant and...

  • parasite vaccine development large scale recovery of immunogenic Taenia Ovis fusion protein gst 45w b x from escherichia coli inclusion bodies
    Parasitology Research, 1996
    Co-Authors: R.p. Dempster, C M Robinson, G.b.l. Harrison
    Abstract:

    Genetically modified Escherichia coli expressing the Taenia Ovis fusion protein GST-45W(B/X) as inclusion bodies were grown in volumes ranging up to 1000 l. Bacteria were inactivated by heat or chemical treatment without affecting immunogenicity. The fusion protein was recovered in a highly immunogenic form from washed inclusion bodies and from urea-solubilised inclusion bodies. The fusion protein was found to be stable in solution after storage at 4°C for up to 2 years. Vaccines formulated with fusion protein from urea-soluble inclusion bodies gave consistently high protection (89–100%) against challenge infection. The methods described enabled the production of sufficient vaccine for large field trials. These trials generated the data required for product registration and manufacture of a vaccine to prevent T. Ovis infection in sheep.

  • parasite vaccine development large scale recovery of immunogenic Taenia Ovis fusion protein gst 45w b x from escherichia coli inclusion bodies
    Parasitology Research, 1996
    Co-Authors: R.p. Dempster, C M Robinson, G.b.l. Harrison
    Abstract:

    Genetically modified Escherichia coli expressing the Taenia Ovis fusion protein GST-45W(B/X) as inclusion bodies were grown in volumes ranging up to 1000 l. Bacteria were inactivated by heat or chemical treatment without affecting immunogenicity. The fusion protein was recovered in a highly immunogenic form from washed inclusion bodies and from urea-solubilised inclusion bodies. The fusion protein was found to be stable in solution after storage at 4 degrees C for up to 2 years. Vaccines formulated with fusion protein from urea-soluble inclusion bodies gave consistently high protection (89-100%) against challenge infection. The methods described enabled the production of sufficient vaccine for large field trials. These trials generated the data required for product registration and manufacture of a vaccine to prevent T. Ovis infection in sheep.

Richard A Strugnell - One of the best experts on this subject based on the ideXlab platform.

  • in vitro oncosphere killing assays to determine immunity to the larvae of Taenia pisiformis Taenia Ovis Taenia saginata and Taenia solium
    Journal of Parasitology, 2006
    Co-Authors: Craig T Kyngdon, Charles G Gauci, Rick A Rolfe, Jeanette Velasquez C Guzman, Marilu Farfan J Salazar, Manuela Verastegui R Pimentel, Armando E. Gonzalez, Robert H. Gilman, Hector H Garcia, Richard A Strugnell
    Abstract:

    Taeniid cestodes infect humans and livestock, causing considerable morbidity and mortality, as well as economic loss. Substantial progress has been made toward the production of recombinant vaccines against cysticercosis in livestock animals. Further development of these vaccines would be aided if a reliable in vitro test were available to measure host-protective immune responses in vaccinated animals. Here, we describe in vitro oncosphere-killing assays for the quantification of host-protective serum antibodies against Taenia pisiformis, Taenia Ovis, Taenia saginata, and Taenia solium in rabbits, sheep, cattle, and pigs, respectively. Activated oncospheres of T. pisiformis, T. Ovis, T. saginata, and T. solium were incubated in vitro in culture medium, test serum, and a source of complement, and oncosphere killing was assessed after 10 days of culture. In vitro oncosphere killing reflected the presence of specific antibody, and the oncosphere-killing assay typically indicated immunity to the homologous pa...

  • IN VITRO ONCOSPHERE-KILLING ASSAYS TO DETERMINE IMMUNITY TO THE LARVAE OF Taenia PISIFORMIS, Taenia Ovis, Taenia SAGINATA, AND Taenia SOLIUM
    The Journal of parasitology, 2006
    Co-Authors: Craig T Kyngdon, Charles G Gauci, Rick A Rolfe, Armando E. Gonzalez, Robert H. Gilman, Hector H Garcia, Marilu J. Farttn Salazar, Jeanette C. Velásquez Guzmán, Manuela R. Verástegui Pimentel, Richard A Strugnell
    Abstract:

    Taeniid cestodes infect humans and livestock, causing considerable morbidity and mortality, as well as economic loss. Substantial progress has been made toward the production of recombinant vaccines against cysticercosis in livestock animals. Further development of these vaccines would be aided if a reliable in vitro test were available to measure host-protective immune responses in vaccinated animals. Here, we describe in vitro oncosphere-killing assays for the quantification of host-protective serum antibodies against Taenia pisiformis, Taenia Ovis, Taenia saginata, and Taenia solium in rabbits, sheep, cattle, and pigs, respectively. Activated oncospheres of T. pisiformis, T. Ovis, T. saginata, and T. solium were incubated in vitro in culture medium, test serum, and a source of complement, and oncosphere killing was assessed after 10 days of culture. In vitro oncosphere killing reflected the presence of specific antibody, and the oncosphere-killing assay typically indicated immunity to the homologous parasite that had been determined in vivo. This study describes the first reliable oncosphere-killing assays for T. pisiformis, T. Ovis, T. saginata, and T. solium. These assays will be used for further research into the optimization of recombinant vaccines against cysticercosis.

  • a comparison of dna vaccines expressing the 45w 18k and 16k host protective antigens of Taenia Ovis in mice and sheep
    Veterinary Immunology and Immunopathology, 2000
    Co-Authors: Damien R Drew, Marshall W. Lightowlers, Richard A Strugnell
    Abstract:

    The immunogenicity of DNA vaccines encoding three different Taenia Ovis host-protective antigens was compared in mice and sheep. DNA vaccines encoding the 45W, 18k and 16k antigens of T. Ovis were constructed. The ability of DNA vaccines encoding the 45W and 18k genes to express antigen was confirmed by Western blotting of transfected Cos-7 cells. BALB/c mice were vaccinated intramuscularly with 45W, 18k or 16k DNA vaccines and the humoral immune response analysed by ELISA. DNA vaccines expressing 45W, 18k or 16k antigen were immunogenic in mice and generated significant titres of antigen-specific antibody. Intramuscular vaccination of outbred sheep with the T. Ovis DNA vaccines generated significantly lower titres of 45W-specific antibody and failed to generate 18k or 16k-specific antibody. The findings of this study show that each of the three T. Ovis host-protective antigens are amenable to delivery via DNA vaccines, and that the parameters governing the efficacy of DNA vaccines in sheep require further investigation.

  • humoral immune responses to dna vaccines expressing secreted membrane bound and non secreted forms of the Taenia Ovis 45w antigen
    Vaccine, 2000
    Co-Authors: Damien R Drew, Marshall W. Lightowlers, Richard A Strugnell
    Abstract:

    The antibody response to DNA vaccines expressing secreted, membrane bound and non-secreted forms of the same antigen was investigated. The antigen gene selected for these studies was the full length 45W antigen gene from Taenia Ovis. This gene encodes a host protective membrane bound antigen with a native secretion signal at the amino terminus and a hydrophobic anchor domain at the carboxyl terminus. Full length and rationally truncated forms of the 45W antigen gene were generated and used to construct DNA vaccines encoding membrane bound, secreted and non-secreted forms of the 45W antigen. The cellular localisation of these antigen forms was confirmed by Western blot studies. BALB/c mice were immunised intramuscularly with plasmid DNA and serum antibody responses measured by enzyme linked immunosorbant assay (ELISA). The cellular localisation of DNA vaccine antigen had a significant effect on the magnitude but not the subclass of antibody responses. Immunisation with DNA expressing secreted 45W generated three-fold higher antibody titres than immunisation with DNA expressing membrane bound 45W, and 18-fold higher antibody titres than DNA expressing non-secreted 45W. All mice generated a predominantly IgG1 antibody response indicative of a TH-2 type immune response. These results indicate that the optimal induction of humoral immune responses to intramuscular genetic immunisation with the 45W antigen, requires the active secretion of antigen. This observation may be of value during the design of DNA vaccines in the future.

  • nucleic acid vaccination of sheep use in combination with a conventional adjuvanted vaccine against Taenia Ovis
    Immunology and Cell Biology, 1997
    Co-Authors: J.s. Rothel, Richard A Strugnell, Jacqueline G. Waterkeyn, Paul R. Wood, H F Seow, Jim Vadolas, Marshall W. Lightowlers
    Abstract:

    This report describes the use of a nucleic acid vaccine in a large outbred animal species both alone and in combination with a conventionally adjuvanted vaccine. The gene encoding a host-protective antigen (45W) from the sheep parasite Taenia Ovis was cloned into the expression vector pcDNA3 and the resultant plasmid termed pcDNA3-45W. Eleven of 15 sheep injected either intramuscularly or intradermally with pcDNA3-45W mounted a serum antibody response to 45W which for both routes of injection was predominantly IgG1. However, the level of antibody elicited by the nucleic acid vaccine was low and repeated vaccinations did not boost the response. Injection of pcDNA3-45W into animals in which an immune response had previously been generated by vaccination with recombinant 45W using Quil A as adjuvant (rec45W vaccine), did not result in enhanced antibody levels. Initial vaccination with pcDNA3-45W and subsequently with the rec45W vaccine resulted in antibody levels significantly higher (P < 0.05) than those obtained in sheep which had only received the rec45W vaccine. This enhanced antibody response was predominantly of the IgG1 subclass (IgG1 : IgG2, 5 : 1) in animals injected with the nucleic acid vaccine by the i.m. route. Surprisingly, a second rec45W vaccination of these animals led to little or no increase in IgG1 levels and a 10-fold increase in IgG2 resulting in a predominance of 45W-specific IgG2 (IgG1 : IgG2, 0.25 1). These studies revealed that nucleic acid vaccination has efficacy, albeit limited, in the sheep and supports previous investigations which showed that antibody responses elicited by immunization are determined by both the route and mode of antigen delivery.

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