Mast cell/IL-4 control of Francisella tularensis replication and host cell death is associated with increased ATP production and phagosomal acidification.
Mucosal Immunol
; 4(2): 217-26, 2011 Mar.
Article
em En
| MEDLINE
| ID: mdl-20861832
ABSTRACT
Mast cells are now recognized as effective modulators of innate immunity. We recently reported that mast cells and secreted interleukin-4 (IL-4) effectively control intramacrophage replication of Francisella tularensis Live Vaccine Strain (LVS), and that mice deficient in mast cells or IL-4 receptor (IL-4R(-/-)) exhibit greater susceptibility to pulmonary challenge. In this study, we further evaluated the mechanism(s) by which mast cells/IL-4 control intramacrophage bacterial replication and host cell death, and found that IL-4R(-/-) mice exhibited significantly greater induction of active caspase-3 within lung macrophages than wild-type animals following intranasal challenge with either LVS or the human virulent type A strain SCHU S4. Treatment of LVS-infected bone-marrow-derived macrophages with a pancaspase inhibitor (zVAD) did not alter bacterial replication, but minimized active caspase-3 and other markers (Annexin V and propidium iodide) of cell death, whereas treatment with both rIL-4 and zVAD resulted in concomitant reduction of both parameters, suggesting that inhibition of bacterial replication by IL-4 was independent of caspase activation. Interestingly, IL-4-treated infected macrophages exhibited significantly increased ATP production and phagolysosomal acidification, as well as enhanced mannose receptor upregulation and increased internalization with acidification, which correlated with observations in mast cell-macrophage co-cultures, with resultant decreases in F. tularensis replication.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Tularemia
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Fagossomos
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Trifosfato de Adenosina
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Interleucina-4
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Interações Hospedeiro-Patógeno
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Francisella tularensis
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Mastócitos
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article