Influence of sensitisation to environmental mycobacteria on subsequent vaccination against bovine tuberculosis

Buddle, Bryce M.; Wards, Barry J.; Aldwell, Frank E.; Collins, Desmond M.; Lisle, Geoffrey W. de

doi:10.1016/s0264-410x(01)00436-4

Cited by 136 publications

(102 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is possible that the stronger mycobactericidal activity observed for the bovine macrophages used in our study may have resulted from the cattle having been sensitized by natural exposure to environmental mycobacteria, although they had negative test results for tuberculin. This phenomenon has been suggested as a probable explanation for the highly variable efficacy of BCG vaccination in both humans (7) and cattle (10). In the bovine study, BCG vaccination was seen to be moderately effective in protecting cows against tuberculosis in two experimental trials but was ineffective in a third trial using cattle that were accredited as being tuberculosis-free.…”

Section: Discussionmentioning

confidence: 98%

RecombinantMycobacterium bovisBCG Expressing the Sm14 Antigen ofSchistosoma mansoniProtects Mice from Cercarial Challenge

et al. 2004

View full text Add to dashboard Cite

The Sm14 antigen of Schistosoma mansoni was cloned and expressed in Mycobacterium bovis BCG as a fusion with the Mycobacterium fortuitum ␤-lactamase protein under the control of its promoter, pBlaF*; the protein was localized in the bacterial cell wall. The rBCG-Sm14 strain was shown to be relatively stable in cultured murine and bovine monocytes in terms of infectivity, bacterial persistence, and plasmid stability. The immunization of mice with rBCG-Sm14 showed no induction of anti-Sm14 antibodies; however, splenocytes of immunized mice released increased levels of gamma interferon upon stimulation with recombinant Sm14 (rSm14), indicating an induction of a Th1-predominant cellular response against Sm14. Mice immunized with one or two doses of rBCG-Sm14 and challenged with live S. mansoni cercaria showed a 48% reduction in worm burden, which was comparable to that obtained by immunization with three doses of rSm14 purified from Escherichia coli. The data presented here further enhance the status of Sm14 as a promising candidate antigen for the control of schistosomiasis and indicate that a one-dose regimen of rBCG-Sm14 could be considered a convenient means to overcome many of the practical problems associated with the successful implementation of a multiple-dose vaccine schedule in developing countries.

show abstract

Section: Discussionmentioning

confidence: 98%

RecombinantMycobacterium bovisBCG Expressing the Sm14 Antigen ofSchistosoma mansoniProtects Mice from Cercarial Challenge

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Apart from being potentially infectious to cattle, either by ingestion or more likely by creation of an aerosol during olfactory investigation, there is a possibility that the presence of environmental M. bovis could compromise test-andslaughter programmes for bTB control and help explain bTB persistence. Sensitization of cattle to other species of environmental mycobacteria can compromise cattle immune responses to subsequent vaccination with BCG (Buddle et al 2002), and can cause cattle to remain skin-test negative even though they are potentially infectious (Hope et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Is Mycobacterium bovis in the environment important for the persistence of bovine tuberculosis?

et al. 2006

View full text Add to dashboard Cite

Mycobacterium bovis is the causative agent of bovine tuberculosis (bTB) in cattle and wildlife. Direct aerosol contact is thought to be the primary route of infection between conspecifics, whereas indirect transmission via an environmental reservoir of M. bovis is generally perceived not to be a significant source for infection. Here, we report on the application of molecular technology (PCR) to quantify the prevalence of M. bovis in the environment and to explore its epidemiological significance. We show that the detectability of viable M. bovis at badger setts and latrines is strongly linked to the frequency of M. bovis excretion by infected badgers, and that putative M. bovis in the environment is prevalent on a large proportion of endemic cattle farms in Britain. These results raise important questions about the role of an environmental reservoir in bTB persistence.

show abstract

“…In some recent vaccine models of tuberculosis in which animals were first exposed to environmental mycobacteria, BCG provided little or no protection against tuberculosis (Brandt et al, 2002 ;Buddle et al, 2002), although in the second of those studies chemical mutants of M. bovis gave significant protection. These differences in protection may result from differences in persistence between BCG and other avirulent strains or from stimulation of a qualitatively different immune response.…”

Section: Vaccination Studymentioning

confidence: 99%

Production of avirulent mutants of Mycobacterium bovis with vaccine properties by the use of illegitimate recombination and screening of stationary-phase cultures

et al. 2002

View full text Add to dashboard Cite

A better tuberculosis vaccine is urgently required to control the continuing epidemic. Molecular techniques are now available to produce a better live vaccine than BCG by producing avirulent strains of the Mycobacterium tuberculosis complex with known gene deletions. In this study, 1000 illegitimate recombinants of Mycobacterium bovis were produced by illegitimate recombination with fragments of mycobacterial DNA containing a kanamycin resistance gene. Eight recombinant strains were selected on the basis of their inability to grow when stationary-phase cultures were inoculated into minimal medium. Five of these recombinants were found to be avirulent when inoculated into guinea pigs. Two of the avirulent recombinants produced vaccine efficacy comparable to BCG against an aerosol challenge in guinea pigs with M. bovis. One of these recombinants had an inactivated glnA2 gene encoding a putative glutamine synthetase. Transcriptional analysis showed that inactivation of glnA2 did not affect expression of the downstream glnE gene. The other recombinant had a block of 12 genes deleted, including the sigma factor gene sigG. Two avirulent recombinants with an inactivated pckA gene, encoding phosphoenolpyruvate carboxykinase which catalyses the first step of gluconeogenesis, induced poor protection against tuberculosis. It is clear that live avirulent strains of the M. tuberculosis complex vary widely in their ability as vaccines to protect against tuberculosis. Improved models may be required to more clearly determine the difference in protective effect between BCG and potential new tuberculosis vaccines.

show abstract

Influence of sensitisation to environmental mycobacteria on subsequent vaccination against bovine tuberculosis

Cited by 136 publications

References 23 publications

RecombinantMycobacterium bovisBCG Expressing the Sm14 Antigen ofSchistosoma mansoniProtects Mice from Cercarial Challenge

RecombinantMycobacterium bovisBCG Expressing the Sm14 Antigen ofSchistosoma mansoniProtects Mice from Cercarial Challenge

Is Mycobacterium bovis in the environment important for the persistence of bovine tuberculosis?

Production of avirulent mutants of Mycobacterium bovis with vaccine properties by the use of illegitimate recombination and screening of stationary-phase cultures

Contact Info

Product

Resources

About