Infect. Immun. doi:10.1128/IAI.01388-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
Neutrophils contribute to the development of a protective immune response during the onset of infection with Leishmania donovani
Emma McFarlane,
Cynthia Perez,
Mélanie Charmoy,
Cindy Allenbach,
K. Christine Carter,
James Alexander,
and
Fabienne Tacchini-Cottier*
From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom, and the WHO Immunology Research and Training Center, Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
* To whom correspondence should be addressed. Email:
Fabienne.Tacchini-Cottier{at}unil.ch.
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Abstract |
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Neutrophils are key components of the inflammatory response and as such contribute to the killing of microorganisms. In addition, recent evidence suggests their involvement in the development of the immune response. The role of neutrophils during the first weeks post infection with Leishmania donovani was investigated in this study. When L. donovani-infected mice were selectively depleted of neutrophils with the NIMP-R14 mAb, a significant increase of parasite numbers was observed in the spleen and bone marrow, and to a lesser extent in the liver. Increased susceptibility was associated with enhanced splenomegally, a delay in the maturation of hepatic granulomas and a decrease in iNOS expression within granulomas. In the spleen, neutrophil depletion was associated with a significant increase in IL-4 and IL-10 levels, and reduced IFN-
secretion by CD4+ and CD8+ T cells. Increased production of serum IL-4 and IL-10 and higher levels of Leishmania-specific IgG1versus IgG2a, revealed the preferential induction of a Th2 responses in neutrophil-depleted mice. Altogether, these data suggest a critical role for neutrophils in the early protective response against L. donovani, both as effector cells involved in the killing of the parasites, and as significant players influencing the development of a protective Th1 immune response.