Activated Brain Endothelial Cells Cross-Present Malaria Antigen

PLoS Pathog. 2015 Jun 5;11(6):e1004963. doi: 10.1371/journal.ppat.1004963. eCollection 2015 Jun.

Abstract

In the murine model of cerebral malaria caused by P. berghei ANKA (PbA), parasite-specific CD8+ T cells directly induce pathology and have long been hypothesized to kill brain endothelial cells that have internalized PbA antigen. We previously reported that brain microvessel fragments from infected mice cross-present PbA epitopes, using reporter cells transduced with epitope-specific T cell receptors. Here, we confirm that endothelial cells are the population responsible for cross-presentation in vivo, not pericytes or microglia. PbA antigen cross-presentation by primary brain endothelial cells in vitro confers susceptibility to killing by CD8+ T cells from infected mice. IFNγ stimulation is required for brain endothelial cross-presentation in vivo and in vitro, which occurs by a proteasome- and TAP-dependent mechanism. Parasite strains that do not induce cerebral malaria were phagocytosed and cross-presented less efficiently than PbA in vitro. The main source of antigen appears to be free merozoites, which were avidly phagocytosed. A human brain endothelial cell line also phagocytosed P. falciparum merozoites. Besides being the first demonstration of cross-presentation by brain endothelial cells, our results suggest that interfering with merozoite phagocytosis or antigen processing may be effective strategies for cerebral malaria intervention.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen Presentation / immunology*
  • Antigens, Protozoan / immunology*
  • Brain / immunology*
  • Brain / parasitology
  • CD8-Positive T-Lymphocytes / immunology
  • Cell Line
  • Cross-Priming / immunology*
  • Disease Models, Animal
  • Endothelial Cells / immunology*
  • Fluorescent Antibody Technique
  • Humans
  • Malaria, Cerebral / immunology*
  • Mice
  • Mice, Inbred C57BL

Substances

  • Antigens, Protozoan

Grants and funding

This work was supported by an intramural grant from Singapore’s Agency for Science, Technology and Research. CMP is supported by a postgraduate scholarship from the Yong Loo Lin School of Medicine, National University of Singapore. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.