Papers by Margaret Collins
Vaccine, 2001
The effect of cytokine adjuvancy on a bovine viral diarrhoea virus (BVDV) DNA vaccine expressing ... more The effect of cytokine adjuvancy on a bovine viral diarrhoea virus (BVDV) DNA vaccine expressing the major glycoprotein E2 was investigated in mice. Murine interleukin-2 (IL-2) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were chosen for their potential ability to enhance the humoral and cellular immune responses involved in protection against BVDV. Both cytokines, co-administered as separate plasmid constructs, had a marked effect on ELISA and neutralising antibody titres, improving the spectrum of neutralisation induced by the E2 DNA vaccine, as demonstrated in heterologous neutralisation assays. The predominance of IgG2a isotypes, in sera from all DNA injected groups, indicated a Th1 biased immune response. Antigen specific proliferation of murine splenocytes from immunised mice was enhanced by cytokine co-administration, with the highest stimulation indexes observed in the group co-injected with the GM-CSF construct. These results obtained in the mouse (Balb/c; H2-k d ) animal model demonstrate the value of the two cytokines as adjuvants for the E2 DNA vaccine. The need for an adjuvant in this system was emphasised by the MHC restriction observed when C57BL/6 mice (H2-k b ) were immunised with the E2 DNA construct. Antibody levels were dramatically lower in this mouse strain.
Vaccine, 2003
The immune response induced by a DNA construct expressing the E2 envelope glycoprotein of bovine ... more The immune response induced by a DNA construct expressing the E2 envelope glycoprotein of bovine viral diarrhoea virus (BVDV) was studied in cattle. Four groups of five calves, were immunised by intradermal injection with a total of 1 mg of plasmid DNA on each of two occasions, with a 3-week dose interval. Group 1 received non-coding plasmid DNA only (control), group 2 received the E2 coding plasmid (0.5 mg) plus non-coding plasmid DNA (0.5 mg) and groups 3 and 4 received the E2 coding plasmid plus plasmid encoding either bovine interleukin 2 (IL-2) or granulocyte macrophage colony stimulating factor (GM-CSF) respectively. Two weeks after the final immunisation, all calves were challenged by intranasal inoculation with 5×10 6 TCID 50 of homologous virus. On the day of challenge, neutralising antibodies were detectable in 13 of 15 vaccinated calves (one animal in each of groups 3 and 4 remained seronegative at this point). Thereafter, a strong anamnestic serological response was evident in all vaccinated animals. Furthermore, T-cell proliferation following in vitro re-stimulation with BVDV antigen was significantly elevated in the cytokine adjuvanted groups. This enhancement of BVDV specific immune responses in vaccinated animals was reflected in the clinical responses observed post-challenge. In particular, reduced febrile responses provided evidence of a disease sparing effect of vaccination. Significantly, whilst a transient viraemia was detected in all control animals following challenge, no virus was isolated from the leucocytes from 8 out of the 15 vaccinated animals. In groups 2 and 4, three animals remained virus free, although virus was isolated from two animals in each group at a single time point, while in group 3, three out of five animals had detectable viraemia.
Virology, 1999
Analysis of viral genome sequences from two calves persistently infected with bovine viral diarrh... more Analysis of viral genome sequences from two calves persistently infected with bovine viral diarrhea virus revealed a quasispecies distribution. The sequences encoding the glycoprotein E2 were variable, translating to a number of changes in predicted amino acid sequences. The NS3 region was found to be highly conserved in both animals. The number of E2 clones showing variant amino acids increased with the age of the animal and comparison of the consensus sequences at the different time points confirmed differences in the predicted E2 sequences over time. The immune tolerance that allows the lifelong persistence of this viral infection is highly specific. It is likely that some of the variant viruses generated within these animals will differ antigenically from the persisting virus and be recognized by the immune system. Evidence of an immune response to persisting virus infection was gathered from a larger sample of cattle. Serum neutralizing antibodies were found in 4 of 21 persistently infected animals. Accumulations of viral RNA in the lymph nodes of all animals examined, particularly in the germinal center light zone, may represent antigenic variants held in the form of immune complexes on the processes of follicular dendritic cells.
Vaccine, 2001
The effect of cytokine adjuvancy on a bovine viral diarrhoea virus (BVDV) DNA vaccine expressing ... more The effect of cytokine adjuvancy on a bovine viral diarrhoea virus (BVDV) DNA vaccine expressing the major glycoprotein E2 was investigated in mice. Murine interleukin-2 (IL-2) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were chosen for their potential ability to enhance the humoral and cellular immune responses involved in protection against BVDV. Both cytokines, co-administered as separate plasmid constructs, had a marked effect on ELISA and neutralising antibody titres, improving the spectrum of neutralisation induced by the E2 DNA vaccine, as demonstrated in heterologous neutralisation assays. The predominance of IgG2a isotypes, in sera from all DNA injected groups, indicated a Th1 biased immune response. Antigen specific proliferation of murine splenocytes from immunised mice was enhanced by cytokine co-administration, with the highest stimulation indexes observed in the group co-injected with the GM-CSF construct. These results obtained in the mouse (Balb/c; H2-k d ) animal model demonstrate the value of the two cytokines as adjuvants for the E2 DNA vaccine. The need for an adjuvant in this system was emphasised by the MHC restriction observed when C57BL/6 mice (H2-k b ) were immunised with the E2 DNA construct. Antibody levels were dramatically lower in this mouse strain.
Vaccine, 2003
The immune response induced by a DNA construct expressing the E2 envelope glycoprotein of bovine ... more The immune response induced by a DNA construct expressing the E2 envelope glycoprotein of bovine viral diarrhoea virus (BVDV) was studied in cattle. Four groups of five calves, were immunised by intradermal injection with a total of 1 mg of plasmid DNA on each of two occasions, with a 3-week dose interval. Group 1 received non-coding plasmid DNA only (control), group 2 received the E2 coding plasmid (0.5 mg) plus non-coding plasmid DNA (0.5 mg) and groups 3 and 4 received the E2 coding plasmid plus plasmid encoding either bovine interleukin 2 (IL-2) or granulocyte macrophage colony stimulating factor (GM-CSF) respectively. Two weeks after the final immunisation, all calves were challenged by intranasal inoculation with 5×10 6 TCID 50 of homologous virus. On the day of challenge, neutralising antibodies were detectable in 13 of 15 vaccinated calves (one animal in each of groups 3 and 4 remained seronegative at this point). Thereafter, a strong anamnestic serological response was evident in all vaccinated animals. Furthermore, T-cell proliferation following in vitro re-stimulation with BVDV antigen was significantly elevated in the cytokine adjuvanted groups. This enhancement of BVDV specific immune responses in vaccinated animals was reflected in the clinical responses observed post-challenge. In particular, reduced febrile responses provided evidence of a disease sparing effect of vaccination. Significantly, whilst a transient viraemia was detected in all control animals following challenge, no virus was isolated from the leucocytes from 8 out of the 15 vaccinated animals. In groups 2 and 4, three animals remained virus free, although virus was isolated from two animals in each group at a single time point, while in group 3, three out of five animals had detectable viraemia.
Virology, 1999
Analysis of viral genome sequences from two calves persistently infected with bovine viral diarrh... more Analysis of viral genome sequences from two calves persistently infected with bovine viral diarrhea virus revealed a quasispecies distribution. The sequences encoding the glycoprotein E2 were variable, translating to a number of changes in predicted amino acid sequences. The NS3 region was found to be highly conserved in both animals. The number of E2 clones showing variant amino acids increased with the age of the animal and comparison of the consensus sequences at the different time points confirmed differences in the predicted E2 sequences over time. The immune tolerance that allows the lifelong persistence of this viral infection is highly specific. It is likely that some of the variant viruses generated within these animals will differ antigenically from the persisting virus and be recognized by the immune system. Evidence of an immune response to persisting virus infection was gathered from a larger sample of cattle. Serum neutralizing antibodies were found in 4 of 21 persistently infected animals. Accumulations of viral RNA in the lymph nodes of all animals examined, particularly in the germinal center light zone, may represent antigenic variants held in the form of immune complexes on the processes of follicular dendritic cells.
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Papers by Margaret Collins