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Apoptosis of lymph node and peripheral blood cells in ovine Johne's disease

Kumudika de Silva1, Sally Browne, Douglas J Begg

  • 1Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden, NSW 2570, Australia.

Veterinary Immunology and Immunopathology
|September 24, 2013
PubMed

Insights

Ovine Johne's disease (OJD) involves lymphocyte apoptosis, a programmed cell death. This study tracked apoptosis in sheep experimentally infected with Mycobacterium avium subsp. paratuberculosis (MAP), revealing antigen-specific cell death in later stages.

Area of Science:

  • Immunology
  • Veterinary Medicine
  • Microbiology

Background:

  • Ovine Johne's disease (OJD) is a chronic wasting condition in ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP).
  • Disease progression is linked to immune dysfunction, with underlying immunological mechanisms, including apoptosis, remaining unclear.
  • Understanding lymphocyte apoptosis in OJD can aid early diagnosis, identification of resistant animals, and disease control strategies.

Purpose of the Study:

  • To investigate lymphocyte apoptosis in sheep experimentally infected with MAP.
  • To determine the kinetics and cell types involved in MAP antigen-specific apoptosis during OJD progression.

Main Methods:

  • Longitudinal study of lymphocyte apoptosis in peripheral blood mononuclear cells (PBMC) and lymph node cells from MAP-exposed and control sheep.
  • Measurement of ex vivo PBMC apoptosis and MAP antigen-specific apoptosis at various time points post-inoculation.
  • Identification of lymphocyte subsets (e.g., γδ and CD4(+) T cells) undergoing apoptosis.

Main Results:

  • A transient increase in ex vivo PBMC apoptosis was observed in MAP-exposed sheep at 4 months post-inoculation.
  • MAP antigen-specific lymphocyte apoptosis occurred later, at 12 months post-inoculation, primarily involving γδ and CD4(+) T cells.
  • Intestinal lymph node cells from infected sheep showed increased apoptosis in response to MAP antigen.

Conclusions:

  • Antigen-mediated lymphocyte apoptosis is a feature of Ovine Johne's disease progression in sheep.
  • This apoptosis, particularly in γδ and CD4(+) T cells, may contribute to the immune dysfunction observed in MAP-infected animals.
  • The findings provide insights into the immunological mechanisms of OJD and potential targets for intervention.
Keywords:
ApoptosisJohne's diseaseLymphocytesParatuberculosis

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