Mice lacking Programmed cell death-1 show a role for CD8(+) T cells in long-term immunity against blood-stage malaria

Sci Rep. 2016 May 24:6:26210. doi: 10.1038/srep26210.

Abstract

Even after years of experiencing malaria, caused by infection with Plasmodium species, individuals still have incomplete immunity and develop low-density parasitemia on re-infection. Previous studies using the P. chabaudi (Pch) mouse model to understand the reason for chronic malaria, found that mice with a deletion of programmed cell death-1 (PD-1KO) generate sterile immunity unlike wild type (WT) mice. Here we investigated if the mechanism underlying this defect during acute immunity also impacts on long-term immunity. We infected WT and PD-1KO mice with Pch-malaria and measured protection as well as immune responses against re-infections, 15 or 20 weeks after the original infection had cleared. WT mice showed approximately 1% parasitemia compared to sterile immunity in PD-1KO mice on re-infection. An examination of the mechanisms of immunity behind this long-term protection in PD-1KO mice showed a key role for parasite-specific CD8(+) T cells even when CD4(+) T cells and B cells responded to re-infection. These studies indicate that long-term CD8(+) T cell-meditated protection requires consideration for future malaria vaccine design, as part of a multi-cell type response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD8-Positive T-Lymphocytes / immunology*
  • Disease Models, Animal
  • Malaria / immunology*
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Plasmodium chabaudi / immunology*
  • Programmed Cell Death 1 Receptor / deficiency
  • Programmed Cell Death 1 Receptor / metabolism*

Substances

  • Pdcd1 protein, mouse
  • Programmed Cell Death 1 Receptor