Specific depletion of Ly6C(hi) inflammatory monocytes prevents immunopathology in experimental cerebral malaria

PLoS One. 2015 Apr 17;10(4):e0124080. doi: 10.1371/journal.pone.0124080. eCollection 2015.

Abstract

Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice leads to experimental cerebral malaria (ECM) that is commonly associated with serious T cell mediated damage. In other parasitic infection models, inflammatory monocytes have been shown to regulate Th1 responses but their role in ECM remains poorly defined, whereas neutrophils are reported to contribute to ECM immune pathology. Making use of the recent development of specific monoclonal antibodies (mAb), we depleted in vivo Ly6C(hi) inflammatory monocytes (by anti-CCR2), Ly6G+ neutrophils (by anti-Ly6G) or both cell types (by anti-Gr1) during infection with Ovalbumin-transgenic PbA parasites (PbTg). Notably, the application of anti-Gr1 or anti-CCR2 but not anti-Ly6G antibodies into PbTg-infected mice prevented ECM development. In addition, depletion of Ly6C(hi) inflammatory monocytes but not neutrophils led to decreased IFNγ levels and IFNγ+CD8+ T effector cells in the brain. Importantly, anti-CCR2 mAb injection did not prevent the generation of PbTg-specific T cell responses in the periphery, whereas anti-Gr1 mAb injection strongly diminished T cell frequencies and CTL responses. In conclusion, the specific depletion of Ly6C(hi) inflammatory monocytes attenuated brain inflammation and immune cell recruitment to the CNS, which prevented ECM following Plasmodium infection, pointing out a substantial role of Ly6C+ monocytes in ECM inflammatory processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / immunology*
  • Brain / pathology
  • Disease Models, Animal
  • Malaria, Cerebral / immunology*
  • Malaria, Cerebral / pathology
  • Mice
  • Mice, Inbred C57BL
  • Monocytes / immunology*
  • Monocytes / pathology
  • Plasmodium berghei*

Grants and funding

This study received financial support from the German Research Foundation Excellence Cluster Immunosensation (DFG, EXC 1023), through an award to BS to establish a research group (http://www.immunosensation.de). AH is a steering committee member of the EXC 1023 and also of the German Center for Infection Research, DZIF (www.dzif.de). BS and JMK are supported by the BONFOR intramural funding scheme of the Medical Faculty at Bonn University (grants 2012-1-22, 2013-1-29) (www.ukb.unibonn.de/bonfor/). IRD is supported by the German Research Foundation (DU1112/3-1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.