Interaction of Rhodococcus equi with phagocytic cells from R. equi-exposed and non-exposed foals

S. K. Hietala, Alex Ardans

Research output: Contribution to journalArticle

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Abstract

The interaction of Rhodococcus equi with alveolar macrophages from adult horses, foals experimentally exposed to R. equi (sensitized foals) and non-exposed foals was studied using in vitro bactericidal assays, cytochemical staining and transmission electron microscopy. It was demonstrated that R. equi is a facultative intracellular parasite, able to survive and multiply within the alveolar macrophages of the host by interfering with phagosome-lysosome fusion. Opsonization of R. equi with antibody against capsular components was associated with increased phagosome-lysosome fusion and significantly enhanced (P<0.05) killing of the organism by alveolar macrophages from non-exposed foals. Macrophages from non-exposed foals were able to ingest the non-opsonized organism, but unable to kill > 65% of the infective dose by 6 h post-exposure. Alveolar macrophages from sensitized foals behaved as adult macrophages, able to kill > 95% of the infective dose by 6 h. Lymphocyte factors, derived by in vitro incubation of sensitized peripheral blood lymphocytes with R. equi surface antigens, enhanced macrophage bactericidal activity. Macrophages from non-exposed foals incubated in the presence of the lymphocyte factors had a 50% increase in killing of R. equi, while sensitized macrophages incubated with lymphocyte factors had a > 100% increase in killing capacity.

Original languageEnglish (US)
Pages (from-to)307-320
Number of pages14
JournalVeterinary Microbiology
Volume14
Issue number3
DOIs
StatePublished - Jan 1 1987

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Rhodococcus equi
phagocytes
Phagocytes
foals
macrophages
Alveolar Macrophages
Macrophages
Lymphocytes
lymphocytes
Phagosomes
phagosomes
Lysosomes
lysosomes
Surface Antigens
Transmission Electron Microscopy
surface antigens
Horses
dosage
Parasites
transmission electron microscopy

ASJC Scopus subject areas

  • Microbiology
  • veterinary(all)

Cite this

Interaction of Rhodococcus equi with phagocytic cells from R. equi-exposed and non-exposed foals. / Hietala, S. K.; Ardans, Alex.

In: Veterinary Microbiology, Vol. 14, No. 3, 01.01.1987, p. 307-320.

Research output: Contribution to journalArticle

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abstract = "The interaction of Rhodococcus equi with alveolar macrophages from adult horses, foals experimentally exposed to R. equi (sensitized foals) and non-exposed foals was studied using in vitro bactericidal assays, cytochemical staining and transmission electron microscopy. It was demonstrated that R. equi is a facultative intracellular parasite, able to survive and multiply within the alveolar macrophages of the host by interfering with phagosome-lysosome fusion. Opsonization of R. equi with antibody against capsular components was associated with increased phagosome-lysosome fusion and significantly enhanced (P<0.05) killing of the organism by alveolar macrophages from non-exposed foals. Macrophages from non-exposed foals were able to ingest the non-opsonized organism, but unable to kill > 65{\%} of the infective dose by 6 h post-exposure. Alveolar macrophages from sensitized foals behaved as adult macrophages, able to kill > 95{\%} of the infective dose by 6 h. Lymphocyte factors, derived by in vitro incubation of sensitized peripheral blood lymphocytes with R. equi surface antigens, enhanced macrophage bactericidal activity. Macrophages from non-exposed foals incubated in the presence of the lymphocyte factors had a 50{\%} increase in killing of R. equi, while sensitized macrophages incubated with lymphocyte factors had a > 100{\%} increase in killing capacity.",
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