Regulation of the CD8+ T cell responses against Plasmodium liver stages in mice

Alexandre Morrot, Fidel Zavala

Research output: Contribution to journalArticle

Abstract

CD8+ T cells induced by immunization with Plasmodium sporozoites play a major role in protective immunity against parasite infection, inhibiting the development of liver stages. The activation of these T cells is initiated just a few hours after exposure to parasites and progresses rapidly through a tightly regulated program. Effector functions in CD8+ T are detectable as early as 24 h after immunization and this event is followed 24-48 h later by an accelerated expansion of the CD8+ T cell numbers which reaches a peak 4-5 days after priming. Concomitantly with the development of anti-parasite activity, CD8+ T cells acquire a self-regulatory role limiting the magnitude of the CD8+ T cell response. Once activated, CD8+ T cells strongly inhibit the priming of additional naive CD8+ T cells by competing for antigen presenting cells. On days 6-8 after immunization, a sudden contraction of this T cell response occurs due to programmed cell death of 70-80% of the activated cells. After this contraction phase, 15-20 days after priming, activated cells establish memory populations. The development and maintenance of these memory populations strictly depends on the presence of CD4+ T cells and IL-4, and probably also IL-7, IL-15 and IL-2. These cytokines, some of which are produced by CD4+ T cells, provide signals to prevents apoptosis and also induce the differentiation of memory sub-populations, most of which acquire definitive phenotypes 20-30 days after immunization.

Original languageEnglish (US)
Pages (from-to)1529-1534
Number of pages6
JournalInternational Journal for Parasitology
Volume34
Issue number13-14
DOIs
StatePublished - Dec 1 2004

Keywords

  • Cytokines
  • Immunity
  • Memory
  • Plasmodium yoelii
  • T-cells
  • Transgenic mice

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases

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